Handbook of Systemic Autoimmune Diseases, Volume 9

Endocrine Manifestations of Systemic Autoimmune Diseases

Sara E. Walker and Luis J. Jara, editors

CHAPTER 16

Pregnancy, Hormones, and Autoimmune Rheumatic Diseases

Luis J. Jaraa,�, Gabriela Medinab, Carmen Navarroc, Miguel A. Saavedrad,Francisco Blanco-Favelae, Luis R. Espinozaf

aDirection of Education and Research, Hospital de Especialidades, Centro Medico La Raza,

IMSS, Universidad Nacional Autonoma de Mexico, Mexico City, MexicobClinical and Epidemiology Research Unit, Hospital de Especialidades, Centro Medico La Raza,

IMSS, Mexico City, MexicocInstituto Nacional de Enfermedades Respiratorias, SSA, Mexico

dDepartment of Rheumatology, Hospital de Especialidades, Centro Medico La Raza, IMSS,

Mexico City, MexicoeHospital de Pediatria, Centro Medico Nacional Siglo XXI, IMSS, Mexico City,

MexicofRheumatology Section, School of Medicine, Louisiana State University, New Orleans, Louisiana, USA

1. Introduction

Pregnancy is a physiological condition character-ized by complex molecular interactions betweenthe mother and the embryo. Following implanta-tion, the maintenance of pregnancy depends on aconstellation of endocrinological and immunolo-gical events that will eventually lead to thesuccessful growth and development of the fetus.Immune and endocrine alterations could poten-tially lead to recurrent pregnancy loss. Inadequateprogesterone secretion, luteal phase deficiency,hyperprolactinemia, thyroid disease, hypopara-thyroidism, uncontrolled diabetes, decreased ovar-ian reserve, and polycystic ovarian syndrome aresome examples of conditions that affect theoutcome of pregnancy. Cytokines make impor-tant contributions to successful pregnancy. Both

Th1 and Th2 cytokines play roles at diffe-rent stages of pregnancy. Changes in patterns oflocal cytokines during pregnancy correspond toneuroendocrine changes in which hormones actas powerful regulators of cytokine expression(Arredondo and Noble, 2006; Rai and Regan,2006).

During pregnancy, experimental animals andpatients with autoimmune diseases develop abnor-mal immune–neuroendocrine responses. In rheu-matic diseases with a predominance of Th1 immuneresponse, a shift to the Th2 response during pre-gnancy is regarded as beneficial. Pregnant patientswith rheumatoid arthritis (RA) and systemic lupuserythematosus (SLE) have shown significant diffe-rences in a few cytokines, related to the activity ofthe underlying disease (Ostensen et al., 2006).Estrogens (E), progesterone (P), androgens (A),and prolactin (PRL) have the potential to predis-pose to either successful or pathologic pregnancies(Jara et al., 2006). The aim of this chapter is toanalyze the influence of the immune–neuroendo-crine system on autoimmune disease during preg-nancy.E-mail address: luis_jara_quezada@hotmail.com

�Corresponding author.

Tel.: +5255-57245900-23117; Fax: +5255-57245900-23117

r 2008 Published by Elsevier B.V.

DOI: 10.1016/S1571-5078(07)00216-4

2. Hormones, the immune system,

and pregnancy

2.1. The first days of pregnancy

Implantation of the blastocyst into the endome-trium involves a series of steps leading to effective‘‘crosstalk’’ between invasive trophoblast cells andthe maternal endometrium. This dynamic processinvolves the coordinated effects of endocrine,paracrine, and autocrine factors. Therefore, suc-cessful implantation depends on development ofthe embryo to the blastocyst stage, followed byits invasion into the decidualized endometrialstroma. In humans, decidualization is initiated inthe luteal phase of the menstrual cycle. Thedisruption of certain pathways results in fertilitydefects. Uterine differentiation to support blasto-cyst implantation is coordinate by P and E. Theseovarian hormones produce molecular and mor-phological changes of the endometrium anddevelopment of large ectoplasmic projectionscalled pinopodes (markers of endometrial recep-tivity) during a limited period of time (window ofimplantation). In humans the receptive window isdays 20–23 of a typical 28-day menstrual cycle(Makrigiannakis et al., 2006). The window ofuterine receptivity remains open for an extendedperiod at lower E levels, but closes rapidly athigher levels (Ma et al., 2003). Increases anddecreases of P levels and P receptor B were closelyassociated with the formation and regression ofpinopodes respectively (Stavreus-Evers et al., 2001).Corticotrophin-releasing hormone (CRH) is pro-duced in several organs of the female reproduc-tive system, including the endometrial glands,decidualized stroma, and the trophoblast. Thegene encoding the CRH receptor type 1 (CRHR1)is expressed in human endometrial and myometrialcells, due to a local effect of uterine CRH. In thisregard, a new role in implantation has beendescribed for CRH, which has been shown toinhibit the invasion of extravillous trophoblasts.This action of CRH was controlled through thetype 1 CRH receptor (CRHR1) by means ofinhibition of carcinoembryonic antigen-related celladhesion molecules by extravillous trophoblasts.Interestingly, maternal plasma concentrations of

CRH are elevated and there is a concomitantreduction in CRHR1 expression in pregnanciescomplicated by pre-eclampsia. Therefore, it hasbeen suggested that a defective CRH/CRHR1system is involved in the pathophysiology ofplacental ischemia in pre-eclampsia (Bambergeret al., 2006).

Different isoforms of PRL receptors may bepresent in various stages of development of themouse preimplantation embryo and may play animportant role in controlling its growth anddevelopment (Kiapekou et al., 2005). Other factorsand genes are involved in implantation, includingchorionic gonadotropin, leukemia inhibitor factor,cytokines and growth factors, matrix metallopro-teinases (MMPs), adhesion molecules. Numerousgene networks participate in the endometrialresponses to ovarian stimuli, and further analysisis required to understand the molecular pathwaysleading to successful implantation (Makrigiannakiset al., 2006).

2.2. HLA, endocrine–immune response,and pregnancy

In order for gestation to be maintained, it isimportant to have immunological recognitionbetween the mother and the fetus, by fetal antigenpresentation and by recognition and reaction tothese antigens by the maternal immune system. Avariety of hormonal and immunologic eventsoccurring during pregnancy could modulate mater-nal immunity against fetal antigens. Therefore, morethan one mechanism appears to induce toleranceand immunological privilege. These mechanismsoccur not because the uterus is the site of thepregnancy, but because of the combined functions oftrophoblast cells at the materno–fetal interface andmaternal immunoregulatory processes that controlresponses to fetal alloantigens (Simpson, 2006).

The placenta plays a key role in the maintenanceof local tolerance and allows the mother to acceptthe embryo until completion of pregnancy. Regu-lation of the expression of HLA antigens, such asHLA-G, HLA-C, and HLA-E by the trophoblast,and the virtual absence of HLA class I proteins,

L.J. Jara et al.186

favors the induction of maternal tolerance. HLA-Gclass Ib is expressed in extravillous cytotropho-blast and also in endothelial cells of fetal vessels inthe chorionic villi, amnion cells, and amnioticfluid. Progesterone regulates HLA-G expressionthrough P receptor activation, followed by bindingto a novel P response element in the HLA-Gpromoter region. HLA-G presents antigens forgamma/delta T cells and at the same time defendsthe trophoblast from cytotoxic effector mecha-nisms. Previous studies indicate that solubleisoforms of HLA-G have immunosuppressiveproperties (Yie et al., 2006). Normal human preg-nancy is characterized by low peripheral natural killer(NK) cell activity, whereas increased NK activityseems to play a role in spontaneous abortions.Uterine NK (uNK) cells are under hormonal control,and increased uNK have been found in sites wherefetal trophoblasts infiltrate the decidua, suggestingthat one of the functions of these cells is control ofplacentation. Another protective mechanism opera-ting in favor of pregnancy is progesterone-dependentimmunomodulation. Due to stimulation by fetal-derived antigens, pregnancy lymphocytes develop Preceptors and in the presence of P produce amediator that alters the cytokine balance, inhibitsNK activity, and exerts an effect that suppressesabortion in mice (Szekeres-Bartho, 2002).

Global crosstalk between the trophoblast anddecidua was detected in an in vitro study, using afunctional genomics approach. Products secretedby the trophoblast induced pro-inflammatorycytokines and chemokines, as well as angiogenic/static factors, in decidualized endometrial stromalcells. The data suggest that the trophoblast altersthe local immune environment of the decidua tofacilitate the process of implantation and ensure anenriched cytokine/chemokine environment. At thesame time, trophoblast limits the mitotic activityof stromal cells during the invasive phase ofimplantation (Hess et al., 2007).

2.3. Hormones, innate immunity,and pregnancy

During normal pregnancy, cellular immunity andTh1 cytokines—which are potentially harmful to

the fetus—are inhibited, whereas humoral immu-nity, autoantibody production, and Th2 cytokinesare enhanced (Ostensen et al., 2006). Although theexact mechanism is unclear, high levels of E, P,and PRL may be responsible for these immuneprofile changes. The changes of local and systemiccytokine patterns during pregnancy correspond toneuroendocrine changes, with hormones as power-ful modulators of cytokine expression. During thethird trimester of gestation, high levels of cortisol(C), E, P, and 1,25-dihydroxyvitamin D3 suppressTh1-mediated immune responses and stimulateTh2-mediated responses. Ex vivo monocytic IL-12production was about threefold and tumor necro-sis factor (TNF) production was approximately40% lower than postpartum values. At the sametime, urinary C and norepinephrine excretion andserum levels of 1,25-dihydroxyvitamin D3 weretwo- to threefold higher compared to postpartumvalues. These hormones can directly suppressIL-12 and TNF production by monocytes/macro-phages in vitro, and P and E up-regulate theproduction of IL-4 and IL-10 by Th2 cells in vitro.These findings suggested that C, norepinephrine,and 1,25-dihydroxyvitamin D3 induced inhibition.Subsequent postpartum rebound of IL-12 andTNF production may represent a major mecha-nism by which pregnancy and postpartum altereither susceptibility to autoimmune diseases or thecourse of these disorders (Kanik and Wilder, 2000;Elenkov et al., 2001).

Moreover, cytokines such as IL-10 and IL-6 riseduring pregnancy, but IL-15 and IL-18 also have arole in different stages of gestation. IL-15 has beenimplicated in differentiation and proliferation ofuNK cells, while IL-18 enhanced innate immunityand both Th1- and Th2-driven immune responsesdepending on the cytokine milieu (Laskarin et al.,2005). On the other hand, the trophoblastexpresses Fas ligand, thereby conferring immuneprivilege: maternal immune cells expressing Faswill undergo apoptosis at the placenta/deciduainterface. The cytolytic mediators, perforin andFas/Fas ligand (FasL), are found at the maternal–fetal interface, where they may affect the immu-nological interrelations between maternal tissuesand trophoblast cells (Bogovic Crncic et al., 2005).In support of these findings, decidual lymphocytes

Pregnancy, Hormones, and Autoimmune Rheumatic Diseases 187

have the characteristics of lymphokine-activatedkiller (LAK) cells and are able to use both theperforin and the FasL cytolytic pathways effec-tively (Crncic et al., 2007).

Experimental models and clinical studies showthat the innate immune system is enhanced and theadaptive immune response is suppressed duringpregnancy. Maternal plasma concentrations ofcomplement proteins (an important componentof innate immune response) are increased, andalterations of total complement hemolytic acti-vity (CH50), and C3a, C4a, and C5a have beendemonstrated (Richani et al., 2005). In addition,active complement proteins are also present inthe placenta. Eight complement proteins (factor B,C3, C1r, C1s, C1 inhibitor, factor H, C4, C2) weredetected in chorionic tissue, and complementsynthesis was regulated by IL-1 beta, TNF-a, andIL-6. On the other hand, interferon (IFN)-gammaincreased the synthesis of C1s, C1r, C1 inhibitor,C4, and factor H in chorion-derived cells. Thefact that the latter two complement proteinshave opposing effects on immune activation ofthe complement cascade demonstrates the complexbalance required to protect both the fetus and themother against infectious and other toxic agentswhile, at the same time, the immune response issuppressed to enable tolerance of the allograftfetus (Goldberg et al., 2007). Protection againstthe undesired effects of complement activationproducts is achieved by the surface expression ofcomplement regulators acting at different steps ofthe complement sequence, such as decay accelera-ting factor (DAF), membrane cofactor protein(MCF), and CD59. However, excessive comple-ment activation could potentially harm the deve-loping fetus (Girardi et al., 2006). Recent evidencein murine models suggests that Crry (a proteinthat belongs to a family of molecules and regu-lates complement activation, protecting tissuesfrom complement-mediated damage) deficiency,a C3 convertase inhibitor, and C3 products areimplicated in the mechanisms of pregnancy loss(Molina, 2005; Richani et al., 2005). Therefore, ithas been proposed that inhibition of the comple-ment system is an absolute requirement for normalpregnancy. As fetal tissues are semi-allogeneic andalloantibodies commonly develop in the mother,

the placenta is potentially subject to complement-mediated immune attack at the fetal–maternalinterface with the risk of fetal loss. However, thetotal inhibition of complement activation maylimit defense mechanisms against infection.

The regulation of complement proteins bysteroid hormones and the role of complement inhost defense in the uterus are not clearly defined. Arecent study demonstrated that the estrogen, 17beta-estradiol (E2), and the glucocorticoid, dexa-methasone, had major and opposing effects on theamount and latent activity of complement effec-tors in the uterus. E2 increased the amount andlatent activity of complement proteins in the ratuterus, and simultaneous dosing with dexametha-sone completely blocked this increase (Rhen andCidlowski, 2006).

In conclusion, a complex interaction is estab-lished during pregnancy between the maternalendocrine system and immune system and fetalcells to allow survival and normal growth of thefetus. Clinical observations are needed to provide abetter understanding of the fetal–maternal inter-action in normal and pathologic conditions ofpregnancy (Fig. 1).

3. Systemic lupus erythematosus

3.1. Obstetrical systemic lupuserythematosus (O-SLE)

SLE is an autoimmune disease that affects pre-dominantly women during their reproductiveyears and its course is altered by menses, meno-pause, the use of oral contraceptives, and especiallypregnancy. These observations suggest a role forendogenous sex hormones in disease predisposition.Here, we will explore the relationship between SLE,hormones, the immune system, and pregnancy.

Despite previous controversial reports, thepresent consensus is that pregnancy could exacer-bate lupus activity, perhaps by hormonal shiftsrequired to maintain pregnancy. Rates of preg-nancy or postpartum flares of SLE are in therange of 15–63%. Other frequent maternal com-plications in pregnant patients with SLE include

L.J. Jara et al.188

pre-eclampsia and hypertension, especially inpatients with active renal disease. Fetal adverseoutcome in O-SLE frequently includes fetal loss(spontaneous abortion and intrauterine fetaldeath), intrauterine growth restriction (IUGR),premature birth, premature rupture of mem-branes, neonatal lupus, and perinatal mortality.Fortunately, the majority of pregnancies in womenwith SLE are successful. However, the interactionbetween pregnancy and SLE activity can lead tomaternal–fetal complications (Warren and Silver,2004; Clowse, 2007).

3.2. Human studies

Hormones such as P, E, C, and PRL play animportant role in the immune response, andhormonal–immune system interactions are crucial

during SLE pregnancy (Szyper-Kravitz et al.,2005). An early report showed high levels of PRLand low levels of E and T in pregnant SLE patientsin comparison to healthy pregnant women andwomen with RA (Jara-Quezada et al., 1991). Thesechanges may be related to fetal wastage and diseaseactivity. Doria et al. (2002) confirmed the variationof steroid hormone levels during pregnancy inpatients with SLE. Serum levels of E, dehydro-epiandrosterone sulfate (DHEAS) and P weredecreased throughout pregnancy, especially in thelast trimester of gestation, probably as a resultof placental insufficiency. These findings couldexplain why some studies showed a low percentageof lupus flares in the third trimester of gestation.A prospective study was performed to analyzeimmune and neuroendocrine changes in pregnantwomen with RA or SLE. Serum levels of P andE were increased during pregnancy and diminished

HORMONES, IMMUNE SYSTEM AND PREGNANCY

Cortisol,

Estrogen,

Testosterone

Progesterone

Ovary

HLA-G

HLA class I

T cell

Amniotic fluid

TH1 TH2

ACTH

IL10

IL-4

PRL

Progesterone

Trophoblast cells

LH γ/δ

Figure 1. From the first days of pregnancy, hypothalamic-pituitary-adrenal and gonadal axis, and PRL secretion interact locally with

HLA, T cells, trophoblast cells, innate, and adaptive immune response, producing the Th1/Th2 shift, in order to maintain tolerance and

to assure fetal survival.

Pregnancy, Hormones, and Autoimmune Rheumatic Diseases 189

in the postpartum period. In pregnant lupuspatients, C was decreased significantly comparedto healthy pregnant women, and production ofIL-10 was increased, possibly as a result oftreatment with prednisone (Munoz-Valle et al.,2003).

PRL is a peptide hormone that acts as acytokine and is critical for maintaining pregnancyand lactation. It is produced by the anteriorpituitary gland and in various extra-pituitary sites,such as neurons, prostate, decidua, mammaryepithelium, skin, and immune cells. PRL productionin lymphocytes and the expression of PRLreceptors in immune cells suggest that PRL affectsthe immune system (Szyper-Kravitz et al., 2005).Hyperprolactinemia (HPRL) has been describedin about 25% of patients with SLE, and highPRL levels during pregnancy in SLE patientscorrelate with disease activity (Jara et al.,2001).

Recent data suggests that PRL complexed withIgG has a biological role in O-SLE. In this regard,a woman with SLE and increased circulating150-kDa PRL (big big PRL) and remission ofdisease during pregnancy was studied before,during, and after pregnancy. The circulating formof PRL (IgG-23 kDa bioactive complex) andremission of SLE persisted during pregnancy,a finding suggesting that these autoantibodiescontributed to morbidity (Leanos-Miranda et al.,2001). A controlled study in 99 consecutive SLEpregnant women confirmed this interesting obser-vation. In fact, an adverse outcome of pregnancywas more frequent in SLE women without anti-PRL autoantibodies than those who had anti-PRLautoantibodies. The frequency of anti-PRL auto-antibodies in lupus pregnancy was 13.1% (Leanos-Miranda et al., 2007).

Of interest, bromocriptine (BRC), an ergotderivative that inhibits secretion of PRL, showedefficacy in preventing postpartum flares in lupuspatients (Yang et al., 2003). More recently, BRCwas used during SLE pregnancy in a pilot clinicaltrial. Our results suggested that BRC plays a rolein the prevention of maternal–fetal complica-tions such as premature rupture of membranes,preterm birth, and active disease (Jara et al.,2007a).

3.3. Experimental models

There are few reports of the effects of pregnancy inSLE animal models. McMurray et al. (1993) showedthat female autoimmune B/W mice, which areexcellent models of hormonally influenced SLE, weresubject to sustained HPRL in the pseudopregnantstate and had significant acceleration of multiplevariables of autoimmune disease activity such as anti-DNA antibodies, antibodies against the viral proteingp70, and hypergammaglobulinemia. Another studyanalyzed the effects of treating pregnant dams witheither T or the androgen blocker, flutamide, toexamine the effects on autoimmune B/W fetuses andnon-autoimmune C57BL/6 fetuses. The alterationsof the hormonal environment in late gestationproduced significant depression of serum E in maleB/W fetuses, and these fetuses had reduced placentaltestosterone content. It was concluded that placentalandrogen control was regulated differently inthe autoimmune vs. non-autoimmune maternal-placental-fetal unit (Keisler et al., 1995).

4. Rheumatoid arthritis

4.1. Obstetrical rheumatoid arthritis(O-RA)

RA is an inflammatory and autoimmune disorderthat is more common in women than men. Asignificant body of evidence implicates gender-specific factors in facilitating the development ofRA. E-containing oral contraceptives can modifythe disease course or onset of RA, a finding thatsupports a role for this hormone in diseasepathogenesis. Pregnancy has an ameliorating effecton disease activity, while the disease tends to flarein the postpartum period. Breast feeding appearsto increase the risk of RA, possibly through theactions of PRL (Jara et al., 2006).

4.2. Experimental models

Pregnancy influences the course of experimentalRA, such as type II collagen-induced arthritis in

L.J. Jara et al.190

DBA/1 mice. A characteristic feature is remissionduring gestation and exacerbation during thepostpartum period, with the postpartum flarepossibly due to decreased steroid hormone levelsand HPRL. In this regard, treatment with Eactually protected against postpartum flares(Mattsson et al., 1991). Postpartum exacerbationsof arthritis were found within 30 days of parturi-tion in 68% of MRL-lpr mice, a model ofaccelerated autoimmunity with features of RAand SLE. Microscopic examination of synovialtissue showed a significant increase of subsynovialinflammation and synovial hyperplasia, withoutchanges in the level of cartilage and bone erosion.Injection of physiological levels of E postpartumdelayed and reduced the flare to 23% of theanimals (Ratkay et al., 1994).

In another experimental study, the prolactinsuppressor BRC suppressed the postpartumexacerbations of collagen-induced arthritis in mice.Approximately 50% reduction in severity ofdisease was achieved with BRC. The effect wasdue to suppression of the maternal PRL releasethat normally occurs following parturition (Whyteand Williams, 1988). The successful use of E andBRC supports the protective role of E supplemen-tation and PRL suppression in suppression ofdisease following pregnancy in RA.

4.3. Human studies

Hormonal changes during pregnancy and thepostpartum period have profound effects on RAincidence and activity. The effect of pregnancy onRA activity is actually greater than the effect ofsome of the newer therapeutic agents. The strikingincrease in C, E, and P during pregnancy maysuppress RA onset or activity through the regula-tion of production or action of cytokines such asTNF-a, IL-1, IL-6, IL-12, and IL-10 (Kanik andWilder, 2000; Munoz-Valle et al., 2003).

Pregnancy is a period of transient relativehypercortisolism. Activation of the hypothalamic-pituitary-adrenal axis during pregnancy has beenproposed to function as a biological clock. Theplacenta is perceived as a stress-sensitive organ andplacental CRH as a timing starter that determines

preterm, term, or post-term labor. In pregnancyand the immediate postpartum period, maternalhypothalamic CRH secretion is suppressed becauseof circulating levels of C. This transient postpartummaternal hypothalamic CRH suppression, lasting12 weeks, together with the steroid withdrawal thatfollows parturition, might be causally related to thevulnerability to RA often observed during thepostpartum period (Mastorakos and Ilias, 2000).In fact, the ameliorating effect of pregnancy on RAhas been well known since 1938 and confirmed for75% of RA pregnancies. Improvement of symp-toms usually occurs in the first trimester andincreases as pregnancy progresses. A flare of RAis observed within 6 months after delivery in mostpatients. However, some studies did not find acorrelation between C levels and disease activity inpregnancy and the timing of gestational improve-ment and postpartum flares does not coincide withthe rise and fall of C. New research has disclosedneuroendocrine disturbances in RA, including arelative glucocorticoid deficiency. Therefore, preg-nancy may modify the neuroendocrine defects inRA patients (Ostensen, 2000).

5. Future directions

The risk of complications and adverse fetaloutcome in pregnant women with O-SLE is high.Complications of pregnancy, particularly pre-eclampsia, can be difficult to distinguish fromsymptoms of lupus making diagnosis and treat-ment challenging. Elevation of total serum inhibinA and activin A (placental hormones) has beeninterpreted as evidence of placental dysfunction inwomen who develop pre-eclampsia. The possiblerole of inhibin A and activin A in SLE pregnancyhas not been studied (Hamar et al., 2006).

Relaxin is a 6-kDa polypeptide hormone ofpregnancy that has been implicated in decreasedimmune responsiveness. Elevated serum relaxinlevels have been reported in pregnant women withtype I diabetes, but the significance of this changehas not been explained (Whittaker et al., 2003).Relaxin and estradiol valerate therapy ameliorateadjuvant-induced arthritis. The roles of relaxin in

Pregnancy, Hormones, and Autoimmune Rheumatic Diseases 191

human O-SLE and O-RA are worthy of furtherstudy (Santora et al., 2005).

A recent study of Th1/Th2 cytokine balanceduring and after pregnancy in patients with RA,juvenile idiopathic arthritis (JIA), and ankylosingspondylitis (AS) yielded results that were inconflict with earlier reports. Concentrations ofIL-10 were low, and IFN-gamma and IL-1betawere not detected. Increases of IL-1Ra andsTNFR from the second to the third trimestercorrelated with improvement of disease activity inboth RA and AS, and it was proposed that theseanti-inflammatory mediators affected diseaseactivity (Østensen et al., 2005). The hormonal andcytokine environments have not been studied inpregnant women with other autoimmune diseases,such as systemic sclerosis, Sjogren’s syndrome, andadult-onset Still’s disease.

6. Antiphospholipid antibody syndrome

6.1. Obstetrical antiphospholipid syndrome

Obstetrical antiphospholipid syndrome (O-APL),described initially in the 1950s, included recurrentpre-embryonic and embryonic miscarriage, fetalloss, pre-eclampsia, IUGR, and possibly placentalabruption in association with lupus anticoagulant.At present, live birth rates of approximately70–80% are reported when O-APL is treated withlow-dose acetylsalicylic acid and heparin. Despitethese encouraging results, the incidence of severematernal and fetal complications remains high(Wu and Stephenson, 2006).

The mechanism by which antiphospholipidantibodies (APA) lead to pregnancy loss is unclear,and studies have been performed in animal modelsand humans to resolve this question. Traditionally,pregnancy loss associated with APA was ascribedto thrombosis and infarction of the uteroplacentalvasculature (Rai and Regan, 2006). However, thesefindings are neither universal nor specific to APSand other mechanisms are believed to be involved.This discussion will focus on the important roles ofendocrine and immunologic factors in experimentaland human O-APS.

6.2. Experimental obstetricalantiphospholipid syndrome

Evidence from animal models strongly suggeststhat APA have direct effects on fecundity and theoutcome of pregnancy (Blank et al., 1991), andhormonal interactions with APA may play a rolein maintaining pregnancy. An analysis of placentalexplants showed that mouse monoclonal antibo-dies to cardiolipin (ACL) increased the pulsatilityof beta human chorionic gonadotropin (bhCG). Incontrast, human polyclonal ACL were inhibitory.These results showed that ACL antibodies mayhave an effect on placental hormone secretion andthus could affect the outcome of pregnancy(Shurtz-Swirski et al., 1993). The increase in bhCGproduction was inhibited under phospholipase A2and phospholipase C stimulation. These observa-tions suggested that aPL antibodies exerted theiradverse effect on reproductive processes throughthe interception of signal transduction processes(Gleicher et al., 1992). In fact, b2GPI binds totrophoblast in vitro through its fifth domain andcan be recognized by anti-beta 2GPI antibodies.The antibody binding down regulates trophoblasthCG synthesis and secretion. This mechanismmight explain defective placentation in womenwith APS (Di Simone et al., 2000; Di Simone et al.,2005). There is evidence that aPL antibodiesstimulate premature onset of cytotrophoblastproliferation and syncytial fusion, leading to loss oftrophoblast function and increased risk of pregnancyfailure (Bose et al., 2006). A study performed usinghuman placental explants showed that aPL anti-bodies could damage the placenta directly in patientswith APS by inhibiting bhCG secretion withoutaffecting E or P secretion. Therefore, circulatingbhCG levels are a predictive marker for placentaldamage and pregnancy loss in women with APS(Schwartz et al., 2007).

PRL has emerged as a factor that interacts withAPA and is involved in recurrent miscarriage. ACLinhibited the expression of decidual markers suchas PRL and insulin-like growth factor-bindingprotein 1 (IGFBP-1) in endometrial cultures (Pierroet al., 1999). Anti-b2GPI antibodies have the sameeffect, inhibiting the expression of PRL, signal

L.J. Jara et al.192

transducers, and activators of transcription 5(Stat5) (Mak et al., 2002). Expression of theendometrial PRL gene, Stat5, and complementregulatory proteins was significantly lower insamples obtained from aPL (+) patients withrecurrent pregnancy loss in comparison withwomen who were negative for APL before concep-tion (Francis et al., 2006). The molecular relation-ship between PRL and APL at the level ofendometrial stromal cells is an area that requiresfurther exploration.

6.3. Human studies

Lockshin et al. (1985) were the first investigators tosuggest an interaction between APL and hCGduring pregnancy in SLE/APS patients. Theyfound that hCG levels were abnormal for the stageof gestation when there were alterations in fetalheart rate. These hormonal changes could be dueto placental insufficiency. Another clinical observa-tion in women with lupus anticoagulant showed anassociation between disproportionately elevatedmaternal serum hCG and severe IUGR, withoutDown’s syndrome. Elevated hCG on prenatalscreening should prompt consideration of maternaltesting for lupus anticoagulant (Clark et al., 1995).In this regard, a recent study suggested that highPRL levels were associated with LA, active SLE,and poor outcome of pregnancy in SLE/APSpatients (Jara et al., 2007b). Therefore, dispropor-tionately high levels of PRL seem to be a new riskfactor for poor pregnancy outcome in SLE/APS.

During human pregnancy, the placenta producesa variety of proteins for the establishment of thefetoplacental unit, including inhibins and activins.Inhibins suppress and activins increase gonado-tropin-releasing hormone (GnRH)-induced hCGrelease with stimulation of P release (Petragliaet al., 1989; Mylonas et al., 2006). Prakash et al.(2006) did not find any alteration in bhCG, inhibinA or activin A in APS women from the time ofconception to 11 weeks compared with a controlgroup. Another study found low, normal, andhigh levels of hCG in patients with anti-b2GPIduring the first and second trimester of pregnancy,

with a negative correlation between anti-b2GPIantibodies and a1-fetoprotein. High levels ofa1-fetoprotein suggested an immunosuppressiveeffect on anti-b2GPI biosynthesis (Fialova et al.,2002).

6.4. Treatment

The conventional therapy for pregnant womenwith APS focuses on anticoagulation. Heparin hasanti-complementary effects at various points inthe classical, alternative, and terminal pathways(Girardi et al., 2006) and prevents obstetricalcomplications by blocking activation of comple-ment induced by APL targeted to decidual tissues(Girardi et al., 2004). On the other hand, low-doseaspirin improves pregnancy outcome in womenwith aPL by irreversibly blocking the action ofcyclooxygenase in platelets, inhibiting plateletthromboxane synthesis, acting as a potent stimu-lator of interleukin-3 (IL-3), raising leukotrieneproduction and preventing thrombosis of theplacental vasculature (Fishman et al., 1995).Combination of heparin and low-dose aspirin issuperior to aspirin alone in achieving successfulpregnancies in women with recurrent pregnancylosses and non-thrombotic APS (Rai and Regan,2006). Evidence of inflammatory-mediated tissuedamage in placentas of APS patients suggests thattherapy should also include prevention of inflam-mation (Salmon et al., 2007). Recent studies havesuggested that heparin may exert direct effects onplacental trophoblast, independently of its anti-coagulant activity. Heparin abrogates apoptosisof primary first trimester villous trophoblast inresponse to treatment with the pro-inflammatorycytokines IFN-gamma and TNF-a (Hills et al.,2006). Heparin treatment did not produce asignificant change in activin and inhibin levels,suggesting that the beneficial effect of heparintreatment was unlikely associated with significantalteration of these hormones in early APS preg-nancy (Prakash et al., 2006). Di Simone et al.(1997) observed in trophoblast cells that apharmacological dose of low molecular weightheparin significantly reduced APL and restored

Pregnancy, Hormones, and Autoimmune Rheumatic Diseases 193

GnRH-induced hCG secretion. Low aspirin dosesalso restored, at least partially, GnRH-inducedhormone secretion. These findings provide anotherexplanation of beneficial effects of both treatmentsin women with recurrent miscarriage and APS.

7. Future directions

Even when interventions toward inhibition ofcomplement activation prevent thrombosis andmiscarriage, conclusive data on the mechanisms ofaction in humans are lacking. It is possible thatwomen with recurrent miscarriage, fetal losses orthrombosis belong to different APS subsets, makingit necessary to develop new targeted therapies toaddress different forms of APS (Ruiz-Irastoza andKhamashta, 2005). Understanding the molecularpathways in endocrine–immune interactions in thehuman endometrium is crucial to understandingevents such as blastocyst implantation and deve-loping new therapies that can be used duringpregnancy (Kayisli et al., 2004). In this context,compounds that promote endometrial differentia-tion such as P, hCG, and phosphodiesteraseinhibitors may be useful in the management ofrecurrent pregnancy loss associated with APS,especially if conventional anticoagulation therapyhas been ineffective (Francis et al., 2006). Ofinterest, combination treatment with prednisone,aspirin, folate, and P was associated with a higherlive birth rate compared with no treatment inwomen with idiopathic recurrent miscarriages.There were no cases of IUGR or Cushing’ssyndrome (Tempfer et al., 2006). The combinedtherapy of P, folate, aspirin, and low weight heparinhas not been tried in APS. Nowadays, prednisoneuse in APS patients is more harmful than beneficialin preventing pregnancy loss.

At the level of the decidua, P, E, and PRL havepotential roles on proliferation, promotion, differ-entiation, and maturation of uNK cells. Disruptionof any of these mechanisms may result in pregnancyloss (Dosiou and Giudice, 2005). Restoration ofhormonal balance may improve pregnancy outcomein APS patients. In a murine model, pregnancyfailure resulted from impaired P synthesis by thecorpus luteum of the ovary associated with ovarianresistance to PRL effects with participation of TNF-a. Such links between innate immune activation(activated uNK cells, T-cells, aPL antibodies,complement, systemic immune activation by CD40ligation, TNF-a) and reproductive endocrine dys-function involving the hypothalamic-pituitary-gona-dal axis with ovarian insufficiency may be relevant topregnancy failure without inflammatory injury indecidual tissues. New therapies directed at innateimmune and hormonal mediators are needed(Erlebacher et al., 2004; Salmon, 2004).

8. Conclusion

1. Experimental studies and clinical observationsstrongly suggest an abnormal immune–neu-roendocrine interaction in rheumatic autoim-mune diseases: SLE, RA, and APS.

2. The most important immunological modifica-tion during normal pregnancy, SLE and RA,are the Th1/Th2 shift. Th1, Th2 cytokines,and hormones have not been studied in APS.

3. Th1-mediated diseases such as RA improveand Th2-mediated diseases, like SLE, worsenduring pregnancy due to Th1/Th2 shift.Decreased gonadal hormones and increasedPRL have roles in activation of autoimmunediseases (Table 1).

Table 1

Immune–neuroendocrine alterations in pregnancy SLE, APS, and RA

Disease Innate immune Adaptive immune Th1 Th2 C E T P PRL hCG

Normal pregnancy m k k m m m m m m mSLE-pregnancy ? ? k m k k k k m kAPS-pregnancy ? ? ? ? ? ? ? ? ? kRA-pregnancy ? ? k m m m m m m ?

L.J. Jara et al.194

Key points

� During normal pregnancy, high levels ofestrogen, progesterone, and prolactinparticipate in Th1 cytokines inhibitionand Th2 cytokines enhancement.� Abnormal immunoneuroendocrine inter-

actions in pregnancy and SLE, APS, or RAmay lead to adverse maternal–fetal out-come.� New therapies directed toward immune

response and hormonal mediators areneeded in SLE, APS, and RA pregnancy.

References

Arredondo, F., Noble, L.S. 2006. Endocrinology of recurrent

pregnancy loss. Semin. Reprod. Med. 24, 33–39.

Bamberger, A.M., Minas, V., Kalantaridou, S.N., Radde, J.,

Sadeghian, H., Loning, T., Charalampopoulos, I., Brummer, J.,

Wagener, C., Bamberger, C.M., Schulte, H.M., Chrousos,

G.P., Makrigiannakis, A. 2006. Corticotropin-releasing hor-

mone modulates human trophoblast invasion through carci-

noembryonic antigen-related cell adhesion molecule-1

regulation. Am. J. Pathol. 168, 141–150.

Blank, M., Cohen, J., Toder, V., Shoenfeld, Y. 1991. Induction

of anti-phospholipid syndrome in naıve mice with mouse

lupus monoclonal and human polyclonal anti cardiolipin

antibodies. Proc. Natl. Acad. Sci. USA 88, 3069–3073.

Bogovic Crncic, T., Laskarin, G., Juretic, K., Strbo, N., Dupor,

J., Srsen, S., Randic, L., Le Bouteiller, P., Tabiasco, J.,

Rukavina, D. 2005. Perforin and Fas/FasL cytolytic path-

ways at the maternal–fetal interface. Am. J. Reprod.

Immunol. 54, 241–248.

Bose, P., Kadyrov, M., Goldin, R., Hahn, S., Backos, M.,

Regan, L., Huppertz, B. 2006. Aberrations of early

trophoblast differentiation predispose to pregnancy failure:

lessons from the anti-phospholipid syndrome. Placenta 27,

869–875.

Clark, F., Dickinson, J.E., Walters, B.N., Marshall, L.R.,

O’Leary, P.C. 1995. Elevated mid-trimester hCG and

maternal lupus anticoagulant. Prenat. Diagn. 15, 1035–1039.

Clowse, M.E. 2007. Lupus activity in pregnancy. Rheum. Dis.

Clin. North Am. 33, 237–252.

Crncic, T.B., Laskarin, G., Frankovic, K.J., Tokmadzic, V.S.,

Strbo, N., Bedenicki, I., Le Bouteiller, P., Tabiasco, J.,

Rukavina, D. 2007. Early pregnancy decidual lymphocytes

beside perforin use Fas ligand (FasL) mediated cytotoxicity.

J. Reprod. Immunol. 73, 108–117.

Di Simone, N., Ferrazzani, S., Castellani, R., De Carolis, S.,

Mancuso, S., Caruso, A. 1997. Heparin and low-dose

aspirin restore placental human chorionic gonadotrophin

secretion abolished by antiphospholipid antibody-contain-

ing sera. Hum. Reprod. 12, 2061–2065.

Di Simone, N., Meroni, P.L., de Papa, N., Raschi, E.,

Caliandro, D., De Carolis, C.S. 2000. Antiphospholipid

antibodies affect trophoblast gonadotropin secretion and

invasiveness by binding directly and through adhered beta2-

glycoprotein I. Arthritis Rheum. 43, 140–150.

Di Simone, N., Raschi, E., Testoni, C., Castellani, R., D’Asta,

M., Shi, T., Krilis, S.A., Caruso, A., Meroni, P.L. 2005.

Pathogenic role of anti-beta 2-glycoprotein I antibodies in

antiphospholipid associated fetal loss: characterization of

beta 2-glycoprotein I binding to trophoblast cells and

functional effects of anti-beta 2-glycoprotein I antibodies

in vitro. Ann. Rheum. Dis. 64, 462–467.

Doria, A., Cutolo, M., Ghirardello, A. 2002. Steroid hormones

and disease activity during pregnancy in systemic lupus

erythematosus. Arthritis Rheum. 47, 202–209.

Dosiou, C., Giudice, L.C. 2005. Natural killer cells in

pregnancy and recurrent pregnancy loss: endocrine and

immunologic perspectives. Endocr. Rev. 26, 44–62.

Elenkov, I.J., Wilder, R.L., Bakalov, V.K., Link, A.A.,

Dimitrov, M.A., Fisher, S., Crane, M., Kanik, K.S.,

Chrousos, G.P. 2001. IL-12, TNF-alpha, and hormonal

changes during late pregnancy and early postpartum:

implications for autoimmune disease activity during these

times. J. Clin. Endocrinol. Metab. 86, 4933–4938.

Erlebacher, A., Zhang, D., Parlow, A.F., Glimcher, L.H. 2004.

Ovarian insufficiency and early pregnancy loss induced by

activation of the innate immune system. J. Clin. Invest. 114,

39–48.

Fialova, L., Malhoban, I., Mikulikova, L., Benesova, O.,

Zwinger, A. 2002. Antibodies against beta 2-glycoprotein I

(beta 2-GP I) and their relationship to fetoplacental

antigens. Physiol. Res. 51, 449–455.

Fishman, P., Falach-Vaknin, E., Sredni, B., Meroni, P.L.,

Rudniki, C., Shoenfeld, Y. 1995. Aspirin modulates

interleukin-3 production: additional explanation for the

preventive effects of aspirin in antiphospholipid antibody

syndrome. J. Rheumatol. 22, 1086–1090.

Francis, J., Rai, R., Sebire, N.J., El-Gaddal, S., Fernandes, M.S.,

Jindal, P., Lokugamage, A., Regan, L., Brosens, J.J. 2006.

Impaired expression of endometrial differentiation markers

and complement regulatory proteins in patients with

recurrent pregnancy loss associated with antiphospholipid

syndrome. Mol. Hum. Reprod. 12, 435–442.

Girardi, G., Bulla, R., Salmon, J.E., Tedesco, F. 2006. The

complement system in the pathophysiology of pregnancy.

Mol. Immunol. 43, 68–77.

Girardi, G., Redecha, P., Salmon, J.E. 2004. Heparin prevents

antiphospholipid antibody-induced fetal loss by inhibiting

complement activation. Nat. Med. 10, 1222–1227.

Gleicher, N., Harlow, L., Zilberstein, M. 1992. Regulatory

effect of antiphospholipid antibodies on signal trans-

duction: a possible model for autoantibody-induced

reproductive failure. Am. J. Obstet. Gynecol. 167,

637–642.

Pregnancy, Hormones, and Autoimmune Rheumatic Diseases 195

Goldberg, M., Luknar-Gabor, N., Keidar, R., Katz, Y. 2007.

Synthesis of complement proteins in the human chorion is

differentially regulated by cytokines. Mol. Immunol. 44,

1737–1742.

Hamar, B.D., Buhimschi, I.A., Sfakianaki, A.K., Pettker,

C.M., Magloire, L.K., Funai, E.F., Copel, J.A., Buhimschi,

C.S. 2006. Serum and urine inhibin A but not free activin A

are endocrine biomarkers of severe pre-eclampsia. Am. J.

Obstet. Gynecol. 195, 1636–1645.

Hess, A.P., Hamilton, A.E., Talbi, S., Dosiou, C., Nyegaard,

M., Nayak, N., Genbecev-Krtolica, O., Mavrogianis, P.,

Ferrer, K., Kruessel, J., Fazleabas, A.T., Fisher, S.J.,

Giudice, L.C. 2007. Decidual stromal cell response

to paracrine signals from the trophoblast: amplification

of immune and angiogenic modulators. Biol. Reprod. 76,

102–117.

Hills, F.A., Abrahams, V.M., Gonzalez-Timon, B., Francis, J.,

Cloke, B., Hinkson, L., Rai, R., Mor, G., Regan, L.,

Sullivan, M., Lam, E.W., Brosens, J.J. 2006. Heparin

prevents programmed cell death in human trophoblast.

Mol. Hum. Reprod. 12, 237–243.

Jara, L.J., Cruz-Cruz, P., Saavedra, M.A., Medina, G., Garcıa-

Flores, A., Angeles, U., Miranda-Limon, J.M. 2007a.

Bromocriptine during pregnancy in systemic lupus erythe-

matosus: a pilot clinical trial. Ann. N.Y. Acad. Sci. 1110,

297–304.

Jara, L.J., Navarro, C., Medina, G., Vera-Lastra, O., Blanco,

F. 2006. Immune–neuroendocrine interactions and auto-

immune diseases. Clin. Dev. Immunol. 13, 109–123.

Jara, L.J., Pacheco-Reyes, H., Medina, G., Angeles, U., Cruz-

Cruz, P., Saavedra, M.A. 2007b. Prolactin levels are

associated with lupus activity, lupus anticoagulant

and poor outcome in pregnancy. Ann. N.Y. Acad. Sci.

1108, 218–226.

Jara, L.J., Vera-Lastra, O., Miranda, J.M., Alcala, M., Alvarez-

Nemegyei, J. 2001. Prolactin in human systemic lupus

erythematosus. Lupus 10, 748–756.

Jara-Quezada, L., Graef, A., Lavalle, C. 1991. Prolactin in

gonadal hormones during pregnancy in systemic lupus

erythematosus. J. Rheumatol. 18, 349–353.

Kanik, K.S., Wilder, R.L. 2000. Hormonal alterations in

rheumatoid arthritis, including the effects of pregnancy.

Rheum. Dis. Clin. North Am. 26, 805–823.

Kayisli, U.A., Guzeloglu-Kayisli, O., Arici, A. 2004. Endo-

crine–immune interactions in human endometrium. Ann.

NY Acad. Sci. 1034, 50–63.

Keisler, L.W., vom Saal, F.S., Keisler, D.H., Rudeen, P.K.,

Walker, S.E. 1995. Aberrant hormone balance in fetal

autoimmune NZB/W mice following prenatal exposure to

testosterone excess or the androgen blocker flutamide. Biol.

Reprod. 53, 1190–1197.

Kiapekou, E., Loutradis, D., Patsoula, E., Koussidis, G.A.,

Minas, V., Bletsa, R., Antsaklis, A., Michalas, S.,

Makrigiannakis, A. 2005. Prolactin receptor mRNA expres-

sion in oocytes and preimplantation mouse embryos.

Reprod. Biomed. Online 10, 339–346.

Laskarin, G., Strbo, N., Bogovic Crncic, T., Juretic, K., Ledee

Bataille, N., Chaouat, G., Rukavina, D. 2005. Physiological

role of IL-15 and IL-18 at the maternal–fetal interface.

Chem. Immunol. Allergy 89, 10–25.

Leanos-Miranda, A., Cardenas-Mondragon, G., Ulloa-

Aguirre, A., Isordia-Salas, I., Parra, A., Ramırez-Peredo,

J. 2007. Anti-prolactin autoantibodies in pregnant women

with systemic lupus erythematosus: maternal and fetal

outcome. Lupus 16, 342–349.

Leanos-Miranda, A., Pascoe-Lira, D., Chavez-Rueda, K.A.,

Blanco-Favela, F. 2001. Persistence of macroprolactinemia

due to antiprolactin autoantibody before, during, and after

pregnancy in a woman with systemic lupus erythematosus.

J. Clin. Endocrinol. Metab. 86, 2619–2624.

Lockshin, M.D., Druzin, M.L., Goel, S., Qamar, T., Magid,

M.S., Jovanovic, L. 1985. Antibody to cardiolipin as

a predictor of fetal distress or death in pregnant patients

with systemic lupus erythematosus. N. Engl. J. Med. 313,

152–156.

Ma, W.G., Song, H., Das, S.K., Paria, B.C., Dey, S.K. 2003.

Estrogen is a critical determinant that specifies the duration

of the window of uterine receptivity for implantation. Proc.

Natl. Acad. Sci. USA 100, 2963–2968.

Mak, I.Y., Brosens, J.J., Christian, M., Hills, F.A., Chamley,

L., Regan, L., White, J.O. 2002. Regulated expression of

signal transducer and activator of transcription, Stat5, and

its enhancement of PRL expression in human endometrial

stromal cells in vitro. J. Clin. Endocrinol. Metab. 87,

2581–2588.

Makrigiannakis, A., Minas, V., Kalantaridou, S.N., Nikas, G.,

Chrousos, G.P. 2006. Hormonal and cytokine regulation of

early implantation. Trends Endocrinol. Metab. 17, 178–185.

Mastorakos, G., Ilias, I. 2000. Maternal hypothalamic-pitui-

tary-adrenal axis in pregnancy and the postpartum period.

Postpartum-related disorders. Ann. NY Acad. Sci. 900,

95–106.

Mattsson, R., Mattsson, A., Holmdahl, R., Whyte, A., Rook,

G.A. 1991. Maintained pregnancy levels of oestrogen afford

complete protection from post-partum exacerbation of

collagen-induced arthritis. Clin. Exp. Immunol. 85, 41–47.

McMurray, R.W., Keisler, D., Izui, S., Walker, S.E. 1993.

Effects of parturition, suckling and pseudopregnancy on

variables of disease activity in the B/W mouse model of

systemic lupus erythematosus. J. Rheumatol. 20, 1143–1151.

Molina, H. 2005. Complement regulation during pregnancy.

Immunol. Res. 32, 187–192.

Munoz-Valle, J.F., Vazquez-Del Mercado, M., Garcıa-Iglesias,

T. 2003. T(H)1/T(H)2 cytokine profile, metalloprotease-9

activity and hormonal status in pregnant rheumatoid

arthritis and systemic lupus erythematosus. Clin. Exp.

Immunol. 131, 377–384.

Mylonas, I., Schiessl, B., Jeschke, U., Vogl, J., Makrigiannakis, A.,

Kuhn, C., Schulze, S., Kainer, F., Friese, K. 2006. Expression

of inhibin/activin subunits alpha (-alpha), betaA (-betaA), and

betaB (-betaB) in placental tissue of normal, preeclamptic, and

HELLP pregnancies. Endocr. Pathol. 17, 19–33.

L.J. Jara et al.196

Ostensen, M. 2000. Glucocorticosteroids in pregnant patients

with rheumatoid arthritis. Z. Rheumatol. 59 (Suppl. 2: II),

70–74.

Østensen, M., Forger, F., Nelson, J.L., Schuhmacher, A.,

Hebisch, G., Villiger, P.M. 2005. Pregnancy in patients with

rheumatic disease: anti-inflammatory cytokines increase in

pregnancy and decrease post partum. Ann. Rheum. Dis. 64,

839–844.

Ostensen, M., Forger, F., Villiger, P.M. 2006. Cytokines and

pregnancy in rheumatic disease. Ann. NY Acad. Sci. 1069,

353–363.

Petraglia, F., Vaughan, J., Vale, W. 1989. Inhibin and activin

modulate the release of gonadotropin-releasing hormone,

human chorionic gonadotropin, and progesterone from

cultured human placental cells. Proc. Natl. Acad. Sci. USA

86, 5114–5117.

Pierro, E., Andreani, C.L., Lazzarin, N., Minici, F., Apa, R.,

Miceli, F., Ayala, G., Mancuso, S., Lanzone, A. 1999. Effect

of anticardiolipin antibodies on prolactin and insulin-like

growth factor binding protein-1 production by human

decidual cells. Am. J. Reprod. Immunol. 41, 209–216.

Prakash, A., Laird, S., Li, T.C., Ledger, W.L. 2006. Preliminary

prospective study of the endocrinology of conception cycles

and early pregnancy in women with antiphospholipid

syndrome treated with low molecular weight heparin. Fertil.

Steril. 85, 165–170.

Rai, R., Regan, L. 2006. Recurrent miscarriage. Lancet 368,

601–611.

Ratkay, L.G., Zhang, D., Tonzetich, J., Levy, J.G., Waterfield,

J.D. 1994. Evaluation of a model for post-partum arthritis

and the role of oestrogen in prevention of MRL-lpr associated

rheumatic conditions. Clin. Exp. Immunol. 98, 52–59.

Rhen, T., Cidlowski, J.A. 2006. Estrogens and glucocorticoids

have opposing effects on the amount and latent activity of

complement proteins in the rat uterus. Biol. Reprod. 74,

265–274.

Richani, K., Soto, E., Romero, R., Espinoza, J., Chaiwor-

apongsa, T., Nien, J.K., Edwin, S., Kim, Y.M., Hong, J.S.,

Mazor, M. 2005. Normal pregnancy is characterized by

systemic activation of the complement system. J. Matern.

Fetal Neonatal Med. 17, 239–245.

Ruiz-Irastoza, G., Khamashta, M.A. 2005. Management of

thrombosis in antiphospholipid syndrome and systemic

lupus erythematosus in pregnancy. Ann. NY Acad. Sci.

1051, 606–612.

Salmon, J.E. 2004. A noninflammatory pathway for pregnancy

loss: innate immune activation? J. Clin. Invest. 114, 15–17.

Salmon, J.E., Girardi, G., Lockshin, M.D. 2007. The antipho-

spholipid syndrome as a disorder initiated by inflammation:

implications for the therapy of pregnant patients. Nat. Clin.

Pract. Rheumatol. 3, 140–147.

Santora, K., Rasa, C., Visco, D., Steinetz, B., Bagnell, C. 2005.

Effects of relaxin in a model of rat adjuvant-induced

arthritis. Ann. NY Acad. Sci. 1041, 481–485.

Schwartz, N., Shoenfeld, Y., Barzilai, O., Cervera, R., Font, J.,

Blank, M., Yacobi, S., Patlas, N., Cohen, A., Mevorach, D.,

Ornoy, A. 2007. Reduced placental growth and hCG

secretion in vitro induced by antiphospholipid antibodies

but not by anti-Ro or anti-La: studies on sera from women

with SLE/PAPS. Lupus 16, 110–120.

Shurtz-Swirski, R., Inbar, O., Blank, M., Cohen, J., Bakimer,

R., Shoenfeld, Y. 1993. In vitro effect of anticardiolipin

autoantibodies upon total and pulsatile placental hCG

secretion during early pregnancy. Am. J. Reprod. Immunol.

29, 206–210.

Simpson, E. 2006. A historical perspective on immunological

privilege. Immunol. Rev. 213, 12–22.

Stavreus-Evers, A., Nikas, G., Sahlin, L., Eriksson, H., Landgren,

B.M. 2001. Formation of pinopodes in human endometrium

is associated with the concentrations of progesterone and

progesterone receptors. Fertil. Steril. 76, 782–791.

Szekeres-Bartho, J. 2002. Immunological relationship between

the mother and the fetus. Int. Rev. Immunol. 21, 471–495.

Szyper-Kravitz, M., Zandman-Goddard, G., Lahita, R.G.,

Shoenfeld, Y. 2005. The neuroendocrine-immune interac-

tions in systemic lupus erythematosus: a basis for under-

standing disease pathogenesis and complexity. Rheum Dis.

Clin. North Am. 31, 161–175.

Tempfer, C.B., Kurz, C., Bentz, E.K., Unfried, G., Walch, K.,

Czizek, U., Huber, J.C. 2006. A combination treatment of

prednisone, aspirin, folate, and progesterone in women with

idiopathic recurrent miscarriage: a matched-pair study.

Fertil. Steril. 86, 145–148.

Warren, J.B., Silver, R.M. 2004. Autoimmune disease in

pregnancy: systemic lupus erythematosus and antiphospholi-

pid syndrome. Obstet. Gynecol. Clin. North Am. 31, 345–372.

Whittaker, P.G., Edwards, J.R.G., Randolph, C., Bullesbach,

E., Schawabe, C., Steinetz, B.C. 2003. Abnormal relaxin

secretion during pregnancy in women with type I diabetes.

Exp. Biol. Med. 228, 33–40.

Whyte, A., Williams, R.O. 1988. Bromocriptine suppresses

postpartum exacerbation of collagen-induced arthritis.

Arthritis Rheum. 31, 927–928.

Wu, S., Stephenson, M.D. 2006. Obstetrical antiphospholipid

syndrome. Semin. Reprod. Med. 24, 40–53.

Yang, X.Y., Liang, L.Q., Xu, H.S. 2003. Efficacy of oral

bromocriptine in protecting the postpartum systemic lupus

erythematosus patients from disease relapse. Zhonghua Nei

Ke Za Zhi 42, 621–624.

Yie, S.M., Xiao, R., Librach, C.L. 2006. Progesterone regulates

HLA-G gene expression through a novel progesterone

response element. Hum. Reprod. 21, 2538–2544.

Pregnancy, Hormones, and Autoimmune Rheumatic Diseases 197