2013

Ultrastructural Pathology, 2013; 37(6): 449–451! Informa Healthcare USA, Inc.

ISSN: 0191-3123 print / 1521-0758 online

DOI: 10.3109/01913123.2013.829147

LETTER TO THE EDITOR

Value of a Simple Method to Assess Chronic Rejectionin Renal Allograft on Electron Microscopy

Miguel A. Martınez, MD, PhD, and Yolanda Rodrıguez Gil, MD

Servicio de Anatomıa Patologica. Hospital 12 de Octubre, Madrid, Spain

ABSTRACT

Electron microscopy is a powerful tool for the assessment of complex lesions in nontumor renal pathology,however it is a time-consuming procedure. We evaluated a simple method to assess morphological signs ofchronic rejection in renal allograft that seems to have prognostic significance.

Keywords: Chronic rejection, electron microscopy, kidney

To the editor,

From the pioneering reports of Monga et al. [1–3]most authors agree that basement membrane multi-layering of intertubular capillaries in renal allograftsis a significant clue to chronic alloimmune injury [4].Although some lamination of the interstitial capillarybasement membrane has been reported in diversenative kidney injuries, such as leptospirosis [5],cyclosporin toxicity, membranoproliferative glomeru-lonephritis, lupus nephritis, cryoglobulinemic nephri-tis and thrombotic microangiopathy [6], large serieshave shown that six or more lamina densa layerssurrounding the lumen of peritubular capillaries is,practically, pathognomonic of chronic alloimmuneinjury [4,6]. However, electron microscopy is a time-consuming procedure and some experts havereported that more than 3 layers of basementmembrane in peritubular capillaries are very uncom-mon in settings other than chronic rejection [4,6,7]. Asmultilayering of the basement membrane reflects areparative response to repeated endothelial injuries[8–10] and there are several reports relating submicro-scopic capillary abnormalities with c4d deposition[9,11], it appears a reasonable assumption to considerthat, in the absence of other causes of endothelialstress, this lesion could be accepted as sign of currentor previous alloimmune reaction in the setting ofkidney transplantation. Thus, we hypothesized thatsearching for three or more layers of basement

membrane in at least two of three capillaries in theperiglomerular interstice could be an easy andreasonable routine practice with diagnostic andprognostic implications. Since hepatitis C virus(HCV) has been related to kidney allograft chronicrejection [12], we also evaluated the relationshipbetween intertubular capillary abnormatities andHCV infection.

We reviewed 49 unselected samples correspondingto 49 kidney-transplanted patients who underwent abiopsy because of proteinuria or renal functionderangement. In all cases, we examined one to threeglomeruli with at least three mesangial areas andthree intertubular capillaries in the adjacent inter-stitium. We divided our samples in two groups: (A)those that showed three or more layers of laminadensa covering at least the 50% of the contour of atleast two of three peritubular capillaries (Figure 1)and (B) those that did not meet this criterion. Thefollowing parameters were analyzed in both groups:time after transplantation, association with transplantglomerulopathy, relationship with C4d deposition inperitubular capillaries and HCV infection, and graftoutcome. Differences in time after transplantationbetween both groups were analyzed by Mann-Whitney U test, relationship of capillary lesions withtransplant glomerulopathy, c4d deposition and HCVinfection were studied using Fisher’s exact test, andthe outcome of the graft was evaluated by log-ranktest on Kaplan Meyer survival curves.

Correspondence: Miguel A. Martınez, Servicio de Anatomıa Patologica. Hospital 12 de Octubre, Avda de Cordoba, s/n.28041 Madrid, Spain.E-mail: miguelangel.martinez.gonzalez@salud.madrid.org

Received 5 May 2013; Revised 29 June 2013; Accepted 23 July 2013; Published online 15 October 2013

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Table 1 summarizes our results. Group A included16 patients and group B had 33 patients. In 6 cases(1 of group A and 5 of group B) glomerularsubmicroscopic structures could not be assessedbecause of global sclerosis. In group A the lapsebetween transplant and biopsy ranged from 5 to 167months (mean 73 months), 5 of 15 patients showedtransplant glomerulopathy, 5 of 11 presented c4ddeposition in peritubular capillaries, 5 of 12 wereinfected with HCV, and 4 of the 16 patients returned

to the dialysis program 0, 2, 15, and 16 months afterthe diagnosis of the lesion (follow-up: range, 0–74months; mean, 13 months). In group B time fromtransplant to biopsy ranged from 0 to 198 months(mean, 38 months), none of 28 the samples in whichglomeruli were suitable for examination showedtransplant glomerulopathy, 6 of 27 samples exhibitedc4d deposition in peritubular capillaries, 4 of 29patients were infected with HCV, and at the endpoint of our study 1 patient had returned to dialysis57 months after the biopsy (follow-up: range, 0–66months; mean, 20 months).

From our series we deduce that moderate basementmembrane multilayering shows a tendency to beassociated with c4d deposits and HCV infection.On the other hand, intertubular capillary abnormal-ities show close relationship with transplant glomer-ulopathy and are a sign of relative poor graft outcome.Thus, three or more layers of lamina densa inintertubular capillaries of the periglomerular inter-stice seem to be a predictive lesion in kidney allograftsand this lesion appears to be more sensitive to detectchronic rejection than glomerular abnormalities.

DECLARATION OF INTEREST

The authors report no conflicts of interest. The authorsalone are responsible for the content and writing ofthe paper.

FIGURE 1. (A) Periglomerular capillary showing 3–4 layers of lamina densa in the basement membrane (EM original 10000x).(B) Same sample of A. Detail of a glomerulus with no relevant abnormalities (EM, original 1500x).

TABLE 1. Summary of the results.

Group A(n = 16)

Group B(n = 33)

Statisticalsignificance p

Age (years)Range 30–67 27–81Mean 51.5 52.3

Time postTx (months)Range 5–167 0–198 0.003Mean 73 38

Follow-up (months)Range 0–74 0–66Mean 13 20

Tx glomerulopathy 5/15a 0/28 0.003C4d deposition 5/11 6/27 0.035HCV infection 5/12 4/29 0.097Graft loss 4/16 1/33 0.011

Time postTx, time from transplant to biopsy; Tx glomerulo-pathy, transplant glomerulopathy; HCV, hepatitis C virus.aAll fractions (n/m) indicate number of positive cases/totalnumber of cases evaluated.

450 M. A. Martınez and Y. Rodrıguez

Ultrastructural Pathology

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REFERENCES

1. Monga G, Mazzuco G, Novara R, Reale L. Intertubularcapillary changes in kidney allografts: an ultrastructuralstudy in patients with transplant glomerulopathy.Ultrastruct Pathol 1990;14: 201–8.

2. Monga G, Mazucco G, Messina M, et al. Intertubularcapillary changes in kidney allografts: a morphologicinvestigation on 61 renal specimens. Mod Pathol 1992;5:125–30.

3. Mazzuco G, Motta M, Segoloni G, Monga G. Intertubularcapillary changes in the cortex and medulla of trans-planted kidney and their relationship with transplantglomerulopathy: an ultrastructural study of 12 transplan-tectomies. Ultrastruct Pathol 1994;18: 533–7.

4. Ivanyi B, Fahmy H, Brown H, et al. Peritubular capillariesin chronic renal allograft rejection: a quantitative ultra-structural study. Hum Pathol 2000;31: 1129–38.

5. Zollinger HU, Colombi A, Schiltknecht J. New clinicaland ultrastructural aspects in leptospirosis icterohaemor-rhagica (Weil’s disease): a clinical, light- and electronmicroscopic study. Virchows Arch A Pathol Anat 1971;354:336–48.

6. Drachenberg CB, Steinberger E, Hoehn-Saric E, et al.Specificity of intertubular capillary changes: comparative

ultrastructural studies in renal allografts and native kid-neys. Ultrastruct Pathol 1997;21: 227–33.

7. Chicano SL, Cornell LD, Selig MK, et al. Distinctiveultrastructural features of chronic allograft glomerulopa-thy: new formation of circumferential glomerular base-ment membrane. Lab Invest 2006;86: 260A–1A.

8. Lajoie G. Antibody-mediated rejection of human renalallografts: an electron microscopic study of peritubularcapillaries. Ultrastruct Pathol 1997;21: 235–42.

9. Solez K, Colvin RB, Racusen LC, et al. Banff ‘05 meetingreport: differential diagnosis of chronic allograft injury andelimination of chronic allograft nephropathy (‘CAN’). Am JTransplant 2007;7: 518–26.

10. Colvin RB, Nickeleit V. Renal transplant pathology. In:Jennette JC, Olson JL, Schwartz MM, Silva FG, eds.Heptinstall’s Pathology of the Kidney, 6th ed. Philadelphia:Lippincott Williams & Wilkins, 2007:1347–490.

11. Regele H, Bohmig GA, Habicht A, et al. Capillary depos-ition of complement split product C4d in renal allograft isassociated with basement membrane injury in peritubularcapillaries: a contribution of humoral immunity to chronicallograft rejection. J Am Soc Nephrol 2002;13: 2371–80.

12. Morales JM, Bloom R, Roth D. Kidney transplantation inthe patient with hepatitis C virus infection. Contrib Nephrol2012;176: 77–86.

Assessing Chronic Rejection in Renal Allograft 451

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