Clinical Significance of Isolated V1 Arteritis in Renal Transplantation

Background. The presence of intimal arteritis (v) in renal allograft biopsy specimens establishes the presence of acute T-cell mediated rejection (TCMR), Grade IIa-III, according to the Banff classification of rejection. The clinical significance of isolated v1 lesions (v1), characterized by arteritis alone, compared with lesions of arteritis with tubulointerstitial inflammation (i-t-v) has been controversial. Methods. We performed a retrospective review of 280 patients undergoing renal transplantation between 2005 and 2015 who received a for cause transplant biopsy using the Banff 2013 classification. Patients with TCMR grade IIa (n = 83) were subdivided into groups with isolated v1 arteritis and i-t-v. Pre- and postoperative renal function, graft survival, and overall survival were evaluated in all patients. Results. Donor and recipient demographics were similar between groups. One month following treatment of rejection, patients with v1 disease had superior recovery of glomerular filtration rate vs patients with i-t-v (P < .002). At a median follow-up of 41 months from transplant, death-censored graft survival was 92% vs 79% (P = .04), and overall survival was 98% vs 79% (P < .004) in the isolated v1 and i-t-v groups, respectively. Conclusion. Despite having identical Banff classification of TCMR IIa, our results indicate that graft survival in patients with isolated v1 rejection is superior to those with i-t-v. Following corroboration with data from other centers, modification of the Banff classification scheme should be considered.