Clinical and Pathological Analysis of Transplant Glomerulopathy Cases

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Transplant glomerulopathy (TG) is involved in the criteria of chronic active antibody-mediated rejection (c-AMR) in Banff 09 classification. In this report, we discuss the clinical and pathological analysis of TG cases after renal transplantation. Patients: TG was diagnosed in 58 renal allograft biopsy specimens (BS) from 37 renal transplant patients followed in our institute between January 2006 and December 2010. We retrospectively reviewed these 58 BS and 37 cases. Results: Among 37 cases, 29 (78%) had a history of acute rejection (AR). Of them, 25 (86%) cases had the history of acute antibody-mediated rejection (a-AMR). Among 58 BS of TG, 27 BS were mild (cg1 in Banff classification), 16 were moderate (cg2) and 15 were severe (cg3). Peritubular capillaritis was present in 49 (84%), transplant glomerulitis was seen in 47 BS (81%), interstitial fibrosis and tubular atrophy (IF/TA) in 47 (81%) and the thickening of the peritubular capillary (PTC) basement membrane in 44 (76%) and interstitial inflammation was present in 26 BS (45%). C4d deposition in PTC was presented in 32 BS (55%) and 26 of 32 had diffuse C4d deposits in PTC (C4d3) and the remainder 6 had focal deposits (C4d2). Diffuse C4d deposition in glomerular capillaries (GC) was seen in 42 BS (72%), and focal C4d deposition in CG in 9 (16%). By assaying with plastic beads coated with HLA antigen performed in 50 times at the biopsy, the circulating ant-HLA alloantibody was detected in 38 times (76%), of which 27/38 (54%) were donor-specific antibodies (DSA). In our cases, there was 15 BS (41%) which fully met criteria for c-AMR in Banff '09 classification, which including TG, C4d deposition in PTC and existence of DSA, but 19 BS were diagnosed as suspicious for c-AMR. Deterioration of renal allografts' function after biopsies was seen in 12 patients (32%) with 6 of them lost their graft. Conclusions: We suggest that histopathological changes of TG accompanying by transplant glomerulitis, peritubular capillaritis, the thickening of the peritubular capillaries basement membrane and circulating anti-HLA antibodies might indicate c-AMR, even if C4d deposition in PTC is negative. Many of TG cases had the history of AR. Anti-HLA antibody Class II, particularly when the antibody was DSA Class II, might be associated with TG. The prognosis of the graft exhibiting TG was relatively good under the present immunosuppression protocol in short time.