Interlobular hyaline arteriopathy reflects severe arteriolopathy in renal allografts

The present study was performed to examine the clinicopathological significance of hyaline deposits in the smooth muscle of the interlobular artery (interlobular hyaline arteriopathy [IHA]) in renal allografts.Tissue specimens that included the interlobular artery from biopsies performed from January 2012 to December 2015, as well as specimens from biopsies performed ≥1 year after living kidney transplantation were analyzed. Biopsies of recipients with new-onset diabetes mellitus after transplantation were excluded, as well as those of recipients who had undergone transplantation because of diabetic nephropathy. Arteriolopathy was evaluated using the aah score determined by the Banff 2007 classification.In total, 51 specimens with IHA lesions were identified among 381 biopsies obtained from 243 recipients performed ≥1 year after kidney transplantation. Among these 51 biopsies, 18 specimens had a score of aah3, 29 had a score of aah2, and four had a score of aah1. The incidence of IHA lesions was 3.6% at ≥1 to4 years, 18.5% at ≥4 to8 years, and 54.1% at ≥8 years. Older kidney grafts exhibited more IHA lesions. Among the biopsy specimens obtained ≥8 years after transplantation, no significant differences in the recipient or donor age, duration after transplantation, or prevalence of hypertension were observed between the IHA and non-IHA groups. The aah scores were significantly higher in the IHA group ≥8 years after transplantation as determined by the mean score test (P0.01).IHA in renal allografts is associated with severe arteriolopathy.