Clinical and Pathological Analyses of Cases of Acute Vascular Rejection After Kidney Transplantation

Abstract

Aim We performed a clinical and pathological analysis of cases of acute vascular rejection (AVR), characterized by intimal arteritis and transmural arteritis (Banff ‘v’ score) after kidney transplantation, in an attempt to clarify the mechanisms underlying the development and prognostic significance of AVR. Patients AVR (Banff score: v > 0) was diagnosed in 34 renal allograft biopsy specimens (BS) obtained from 27 renal transplant patients receiving follow-up care at the Toda Chuo General Hospital, between March 2007 and March 2017. Results AVR was diagnosed at a median of 493.1 (6-3845) days post-transplantation. Among the 34 BS showing evidence of AVR, AVR was mild (v1 in Banff’s classification) in 25 BS, moderate (v2) in seven, and severe (v3) in two. We classified the 34 BS with evidence of AVR by their overall histopathological features as follows: isolated-v lesions (IVL) were observed in seven BS, acute antibody-mediated rejection (AMR) in nine, acute T-cell-mediated rejection (TCMR) in 11, both ATCR and AAMR in two, and chronic active AMR in five BS. Loss of the renal allograft occurred during the observation period in six patients, and of the remaining cases with functioning grafts, deterioration of renal allograft function after biopsy occurred in only two patients. Conclusions The results of our study suggest that AMR contributes to AVR in 40–50% of cases, TCMR in 30–40% of cases, and IVL in 20% of cases. The prognosis of the patient with the graft that exhibited AVR was relatively good under the present immunosuppression protocol and current anti-rejection therapies.