Association of HLA Alleles with IgA Nephropathy and Its Recurrence After Kidney Transplantation

BACKGROUND The recurrence of IgA nephropathy (IgAN) after kidney transplantation (KT) varies between 9% and 51%. Our analysis aimed to identify risk and protective HLA alleles for the development of IgAN and its recurrence after KT. MATERIAL AND METHODS This retrospective single-center analysis included all patients after KT. Patients underwent HLA typing prior to being listed on the waiting list for KT. Comparisons were performed with a cohort of 10 000 healthy donors from the Eurotransplant registry. RESULTS A total of 470 patients were included. Biopsy-proven IgAN, as the underlying cause of renal failure, was found in 7.2% (n=48), of whom 77% were male (n=37). The DRB1*11 allele was present in 47.92% and was identified as a significant risk factor for IgAN (OR 2.09, P=0.0048). The DRB1*03 allele was detected in 4.17%, and we identified it as potentially protective (OR 0.2, P=0.5472). Recurrence of IgAN was detected in 20.8%, 100% of whom were male. The mean time to confirm recurrence was 56.1 months. We identified the DRB1*11 risk allele in 77.8% of patients with confirmed recurrence but did not identify it as an independent risk factor (HR 2.3967; P=0.3956). We found a significant correlation of IgAN recurrence with the development of DSA after KT (r 0.3980, P=0.0218). CONCLUSIONS Our study identified a 20.8% incidence of IgAN recurrence after KT; 77.8% of these patients had the HLA-DRB1*11 allele, which we also identified as a risk allele for the development of IgAN in native kidneys. De novo DSA after KT was correlated with IgAN recurrence.