Clinicopathologic Analyses of Chronic Vascular Rejection After Kidney Transplantation.

Aim: We discuss the clinicopathologic analyses of cases of biopsy specimens (BS) after renal transplantation and clarify the mechanisms underlying the development and prognostic significance of chronic vascular rejection (CVR).

Patients: CVR was diagnosed in 30 renal allograft BS obtained from 23 renal transplant patients being followed up at the Department of Urology and Transplant Surgery, Toda Chuo General Hospital, between January 2010 and August 2017.

Results: CVR was diagnosed at a median of 33.1 months post-transplantation. Among the 23 patients, 14 had a history of rejection. Among the 30 BS showing evidence of CVR, the CVR was mild (cv1 on Banff's classification) in 19, moderate (cv2) in 6, and severe (cv3) in 5. We then classified the 30 BS showing evidence of CVR by their overall histopathologic features as follows: cv alone was seen in 9 (30%), cv + antibody-mediated rejection (AMR) in 11 (37%), and cv + T-cell-mediated rejection (TCMR) in 8 (27%). Loss of the renal allograft occurred during the observation period in 2 patients (9%). Of the remaining patients with functioning grafts, deterioration of the renal allograft function after the biopsies occurred in 6 (26%).

Conclusions: Our study results suggest that AMR contributes to CVR in 30% to 40% of cases, TCMR in 20% to 30% of cases, isolated v lesions in 10% of cases, and cv lesions alone in 30%. The prognosis of the graft exhibiting CVR was not too poor even under the present immunosuppressive protocol.