MO206: HLA Frequency in A Spanish Transplant Patients Cohort With ANCA-Associated Vasculitis

Abstract

BACKGROUND AND AIMS ANCA-associated vasculitis (AAV) is an autoimmune disease that causes end-stage renal disease in ∼20%–25% of patients who develop kidney failure with progression to end-stage kidney disease with requirement of renal replacement therapy. Previous studies have found a genetic association between some major histocompatibility complex (MHC) loci, like the locus DPB1*0401, and AAV. We conducted a retrospective observational unicentric study with the objective to identify other possible loci related to AAV. METHOD As MHC determination is not usually done in patients with AAV, we looked for patients with AAV included in the kidney transplant list with a complete classic HLA allele determination registered (A, B, C, DR, and DQ). Only 14 patients with diagnosis of AAV included in the kidney transplant list from August 1993 to December 2020 in our hospital centre fulfilled this inclusion criterion. To the statistical analysis, we compared the observed proportion to the theoretical one using a normal test, since the groups in our sample included at least five subjects. We also use a continuity correction factor to approach to a binomial test. RESULTS The highest allele frequency in our cohort were the HLA B*51and the haplotype HLA DRB1*04-DQB1*03:02. We identified a B*51 frequency of 42.8% (6/14 patients) in our AAV register, while its population frequency in Spain is 15%, difference = 27.86% [Confidence interval (CI) 1.93%–53.78%] P = .01. We detected a DRB1*04 frequency of 57.1% (8/14 patients) in our cohort, while the population frequency of DRB1*04 and its associated loci DQB1*03:02 is 22%, difference = 35.14% (CI 9.22%–61.07%) P < .05. CONCLUSION HLA B*51 and the haplotype DRB1*04-DQB1*03:02 are alleles more frequent in patients with AAV than general population. This could translate a genetic predisposition of people with these alleles to develop AAV.