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

BACKGROUND: 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.

METHODS: AVR (Banff score: v >0) was diagnosed in 31 renal allograft biopsy specimens (BS) obtained from 31 renal transplant patients receiving follow-up care at the Department of Urology, Tokyo Women's Medical University, between January 2010 and April 2016.

RESULTS: AVR was diagnosed at a median of 124.6 days after transplantation. Among the 31 BS showing evidence of AVR, AVR was mild (v1 in Banff's classification) in 25 cases, moderate (v2) in 6, and severe (v3) in none. We classified the 31 BS with evidence of AVR by their overall histopathological features as follows: isolated v lesions were observed in 6 BS, acute antibody-mediated rejection (AAMR) in 7, acute T-cell-mediated rejection (ATCMR) in 12, and both ATCR and AAMR in 6. Loss of the renal allograft occurred during the observation period in 3 patients, and, of the remaining cases with functioning grafts, deterioration of renal allograft function after biopsy occurred in only 2 patients.

CONCLUSIONS: The results of our study suggest that ATCMR contributes to AVR in 40% to 60% of cases, AAMR in 20% to 40% of cases, and isolated v lesions in 20% of cases. The prognosis of the patient with the graft that had AVR was relatively good under the present immunosuppression protocol and current anti-rejection therapies.