S122 Abstracts

developed severe leg pain and was diagnosed with deep veinthrombosis (DVT). The tamoxifen was stopped, and he wasstarted on anticoagulant therapy. His IgG level had been lowprior to starting tamoxifen and dropped down to 244 mg/dL.His IgA and IgM were also low, but B and T cell subsets werenormal. He was diagnosed with common variable immuno-deficiency (CVID). He was then started on intravenousgammaglobulin, which he tolerated well and has had nosignificant infections. He has developed more DVT's and acutaneous vasculitis (treated with oral steroids and hydro-xychloroquine) but no more signs of RPF or pulmonaryfibrosis. Conclusion: This patient has developed CVID whilerecovering from RPF. There are no previous reports of CVIDassociated with RPF.

doi:10.1016/j.clim.2010.03.365

S.44. MCAM/CD146 Defines and Regulates theFunction of a Population of Human Effector MemoryTh17 Lymphocytes Subset Involved inNeuroinflammationCatherine Larochelle1, Romain Cayrol1, Hania Kebir1, IgalIfergan1, Jorge Alvarez1, Emilie Viel1, Lyne Bourbonnière1,Arsalan Haqqani2, Danica Stanimirovic2, Nathalie Arbour1,Alexandre Prat1. 1CHUM-Université de Montréal, Montréal,QC, Canada; 2National Research Council of Canada, Ottawa,ON, Canada

Interaction between adhesion molecules on blood-brainbarrier endothelial cells (BBB-ECs) and their cognate ligandon lymphocytes promotes transmigration to the CNS. Ourdata demonstrate that Melanoma Cell Adhesion Molecule(MCAM/CD146) is expressed by a subset of effector memoryCD4+ T lymphocytes, co-expressing CD95, CD147, CD11a,CD49d and CCR6. In vitro polyclonal activation inducedMCAM expression on as much as 60% of CD4+CD45RO+ lym-phocytes. MCAM+ lymphocytes also expressed more RORγand IL-17 than MCAMneg cells, but comparable levels of IFNγ,IL-2 and GM-CSF both ex vivo and after polyclonal activation.The proportion of MCAM+ lymphocytes was found to behigher in the blood of MS patients than in healthy controls,and was enriched in the CSF of MS patients. When comparedto MCAM+ cells obtained from healthy control donors, MCAM+lymphocytes from MS patients consistently produced moreIL-17, in percentage and intensity. During IL-23-driven invitro polarization of lymphocytes, functional inactivation ofMCAM significantly reduced both lymphocyte proliferationand IL-17 production. We further found that MCAM isexpressed on the surface of human BBB-ECs in vitro and insitu in MS lesions and that MCAM blockers decreased therecruitment of MCAM+ lymphocytes across BBB-ECs. Our dataindicate that MCAM is expressed by both BBB-ECs and asubset of IL-17-expressing effector memory CD4 lymphocytesand that MCAM engagement promotes both IL-17 expressionin lymphocytes, as well as the recruitment of these cellsacross BBB-ECs.

doi:10.1016/j.clim.2010.03.366

S.45. Autoantigen T Cell Immune ResponsesObserved in the DR0401/DR0404 MHC-generated TCell Repertoire that are Absent in the HomozygousDR0401 or DR0404 Restricted T Cell RepertoireJohn Gebe, Betty Yue, Mary Rieck, Anton Preisinger, EddieJames, Crystal Rawlings, Brad Stone, Jane Buckner, GeraldNepom. Benaroya Research Institute, Seattle, WA

Human MHC DRA1*0101/B1*0401 (DR0401) and DRA1*0101/DRB1*0404 (DR0404) class II genes are both associatedwith autoimmune rheumatoid arthritis (RA). In individualscarrying both MHC genes the severity and incidence of RA isincreased in a synergistic fashion. Because the gene productsof DR0401 and DR0404 differ by only two amino acids, wehypothesized that the T cell functional repertoire generatedin an environment containing both DR0401 and DR0404 con-tains T cell recognition elements that are uniquely molded bythe heterozygous environment, and not present in eitherDR0401 or DR0404 homozygous immune systems. Method:DR0401, DR0404, and DR0401/DR0404 HLA transgenic micewere immunized with a citrullinated vimentin peptideGVYATcitSSAVcitLcitSSVPGVR (P2) encompassing two DR4-binding epitopes, GYATcitSSAVcit (P4) and SAVcitLcit-SSVPGVR (P6). CD4+ T cell immune responses generated inDR0401/DR0404 mice immunized with P2 were assayed in thecontext of DR0401 and DR0404 antigen presenting cells (APC)and compared with immune responses in homozygous DR0401and DR0404 mice. Results: While DR0401 binds both P4 andP6 epitopes, immune responses in P2 immunized DR0401mice results in a T cell response to P4, but not P6. In contrastP2 immunized DR0404 mice do not respond to P4 but do toP6. When DR0401/DR0404 mice are immunized with P2 apurified CD4+ T cell immune response restricted to DR0401APC is observed to P4 and surprisingly also to P6. CD4+ T cellresponses restricted to DR0404 APC are also seen to both P4and P6. The unmasking of new T cell immune responses tothese HLA-dependent cryptic epitopes in DR0401/DR0404generated T cell repertoires could be a contributing factor tothe enhanced severity of RA in DR0401/DR0404 individuals.

doi:10.1016/j.clim.2010.03.367

S.46. Gottron's Papules Exhibit Accumulation ofCD44 Variant 7 (CD44v7) and its Binding PartnerOsteopontin: A Unique Molecular SignatureJessica Kim1, Victoria Werth2. 1NYU Medical Center,New York, NY; 2Philadelphia VA Hospital, Philadelphia, PA

Wepreviously reported anabundance of chondroitin sulfate(CS) in dermis from dermatomyositis (DM) lesions. Because theCD44v7 variant has CS side-chains and can mediate autoim-munity in the gut (J Immunol 1998;161:1069), we examined itsdistribution in CS-rich regions of DM skin. Surprisingly, CD44v7was abundant in Gottron's papules, a hallmark lesion of DMoverlying interphalangeal (IP) joints, but not in lesional or non-lesional dermis in other regions. CD44v7 staining density inGottron's dermis was double that of healthy IP dermis(p=0.0045). Moreover, healthy IP dermis showed moreCD44v7 than did healthy non-IP dermis from the same vol-unteer, indicating location-specific induction, independent of

S123Abstracts

DM. We hypothesized a role for mechanical stretching as itinduces CD44v7/v8 in non-dermal cells (IOVS 2007;48:1164).We found that confluent dermal fibroblasts stretched onmembranes for 6 hours showed a 62%±3% increase in CD44v7mRNA levels relative to unstretched cells (pb0.0001). Interac-tion of CD44v7 with the cytokine-like molecule osteopontin isimplicated in chronic inflammation (JCI 2001;107:1055). Wefound 2.8-fold increased density of osteopontin staining in thedermal matrix of all DM skin compared to healthy controls(p=0.0055), with no difference between Gottron's vs. non-Gottron's skin. IFN-γ stimulates osteopontin expression bymonocytoid cells, and IFN-γ polymorphisms associate withmyositis. IFN-γ treatment of dermal fibroblasts for 6 hoursprovoked a ∼10-fold increase in OPN mRNA (pb0.0001).Overall, we propose that stretch-induced expression ofCD44v7 over joints, in concert with IFNγ-induction ofosteopontin, provides a unique molecular signature of Got-tron's papules in DM and may contribute to their pathogenesis.

doi:10.1016/j.clim.2010.03.368

S.47. A Dual Role for Interleukin-9 in the Regulationof Immune Responses under Control of ATF3Wassim Elyaman1, Elizabeth Bradshaw1, Ribal Bassil1,Youmna Lahoud1, Bing Zhu1, Hideo Yagita2, Samia Khoury1.1Harvard Medical School, Boston, MA; 2Juntendo School ofMedicine, Tokyo, Japan

IL-9 has an established role in allergy, and clinical trialswith anti-IL-9 monoclonal antibody for asthma have beeninitiated. In addition, IL-9-producing T cells have beenimplicated in TH17 responses, but whether IL-9 regulates orsustains inflammation has been controversial. Here, we showthat ligation of Notch1 and 2 receptors enhances IL-9production, while Notch1/2KO T cells have reduced IL-9.Notch activation through Jagged2 induces IL-9 production,and negatively regulates activating transcription factor 3(ATF3), which in turn inhibits IL-9 production. In vivo,Jagged2 ligation suppresses EAE when administered beforeimmunization by expanding regulatory T cells, but worseneddisease when administered concurrent with immunizationthrough induction of TH17 cells. These effects of Jagged2were reversed by anti-IL-9 blocking antibody. We proposethat IL-9 plays a dual role in the regulation of immuneresponses depending on the timing and the inflammatorymilieu and could be a therapeutic target in immunity.

doi:10.1016/j.clim.2010.03.369

S.48. Different Role of IL-6 and TNF-α in theImmune-Pathogenesis of RA, an AutoimmuneDiseaseKazuyuki Yoshizaki. Osaka University, Center for AdvancingScience Inovation, Suita, Japan

Autoimmune disease can be divided into an initial immuno-logical phase and a late chronic inflammatory phase. Both IL-6and TNF-α contribute to the development of autoimmunedisease in both phases. However, less is knownabout the preciserole of IL-6 and TNF-α on the immune-pathogenesis. Recently,

we use Biologic-therapeutics as an ideal tool for the analysis ofautoimmune disease in vivo and in vitro by using specific singlecytokine inhibitors, such as IL-6 and TNF-α blockades. Ourresults that IL-6 blockade improve the T cell dependentautoimmune mice, such as CIA and EAE with the reduction ofTh17 cells and the inactivation of auto-reactive T cells, indicateIL-6 may contribute the initial phase with the activation of Tcells (Th1 and TH17) and inhibition of Treg development. On theother hand, TNF-α blockades may contribute the macrophageactivated autoimmune model, such as EIV (endotoxin induceduveitis. In chronic inflammatory status, both blockades im-proved the clinical symptoms and laboratory findings. However,efficiency was somewhat different. IL-6 blockade induced thereduction and the normalization of acute phase proteins (CRP,SAA) and hemoglobin, on the other hand, TNF-α blockde hardlyinduced the normalization. Furthermore, we analyzed thesedifferent phenomenon in vitro using hepatoma derived cells,and proved that the difference is existed and explainable invitro based on analysis of CRP, SAA and hepcidin at the level ofintra-cellular signal transduction. These data indicate thedifferent role of IL-6 and TNF-α in the immune-pathogenesisof RA, and autoimmune diseases with inflammation.

doi:10.1016/j.clim.2010.03.370

S.49. Proliferation and Lack of Suppressor Capacityof CD4+CD25+FoxP3+ T Regulatory Cells Under theInfluence of Interleukin-7Anne Heninger, Anke Theil, Nicole Buechner, CarmenWilheim, Ezio Bonifacio, Paolo Monti. Center forRegenerative Therapies Dresden, Dresden, Germany

Interleukin 7 (IL-7) has been shown to promote expansion ofautoreactive T cells and therefore promote autoimmunedisease development. How T cells exposed to IL-7 can escaperegulation by peripheral tolerance mechanisms is currentlyunknown.Herewe showthat in the presenceof IL-7, CD4+CD25+CD127lowFoxP3+ T regulatory cells (Treg cells) fail tosuppress conventional T cell proliferation and undergoexpansion. Human Treg cells exposed to increasing doses ofIL-7 displayed STAT5 phosphorylation which was reduced ascompared to that in conventional T cells, consistent with alower expression of the IL-7 receptor alpha. Conventional Tcells but not Treg cells alone proliferated when exposed to IL-7.Moreover, the addition of IL-7 to FACS-sorted conventional Tcells and T reg cells (purityN98%) in a suppression assayresulted in no suppression of conventional T cell proliferation.Instead, we observed proliferation of both conventional T cellsand Treg cells. Further analysis revealed that in the presenceof IL-7 only CD45RA+ naïve Treg cells proliferated in thesuppression assay and acquired a CD45RO+ memory pheno-type. Sorted proliferating Treg cells maintained classical Tregcharacteristics including FOXP3+ phenotype and suppressivecapacity. In conclusion, our data suggest that in the presenceof IL-7, Treg cells lose their capacity to suppress T cellproliferation and support the hypothesis that IL-7 promote Teffector immune responses, including autoreactivity.

doi:10.1016/j.clim.2010.03.371