Association of HLA-DRB1 and-DQB1 Alleles with Susceptibility to IgA Nephropathy in Korean Patients

Background: Associations between IgA nephropathy (IgAN) and HLA-DRB1 and -DQB1 alleles have been reported in several ethnic groups. We investigated the association of HLA-DRB1 and -DQB1 alleles with the predisposition for IgAN and disease progression to end-stage kidney disease (ESKD) in Korean patients. Methods: We analyzed HLA-DRB1 and -DQB1 genotypes in 399 IgAN patients between January 2000 and January 2019 using a LIFECODES sequence-specific oligonucleotide (SSO) typing kit (Immucor, Stamford, CT, USA) or a LABType SSO Typing Test (One Lambda, Canoga Park, CA, USA). Alleles with a significant difference in two-digit resolution were further analyzed using in-house sequence-based typing and sequence-specific primer PCR. As controls, 613 healthy hematopoietic stem cell donors were included. Kidney survival was analyzed in 281 IgAN patients with available clinical and laboratory data using Cox regression analysis. Where needed, P-values were adjusted using Bonferroni correction. Results: The allele frequencies of HLA-DRB1*04:05 (corrected P [Pc]<0.001), -DQB1 *04:01 (Pc=0.048), and -DQB1*03:02 (Pc=0.021) were significantly higher in IgAN patients than in controls, whereas those of HLA-DRB1*07:01, -DR B1*15:01, -DQB1*02:02, and -DQB1*06:02 (Pc<0.001 for all) were significantly lower in IgAN patients than in controls. The allele frequency of H LA-DQB 1*05:03 (Pc =0.016) was significantly lower in the ESKD group than in the non-ESKD group; however, there was no significant difference for ESKD progression between these groups. Conclusions: We report novel associations of H LA-DR B1*15:01, DQB1*02:02, -DQB1*03:02, and -DQB1*04:01 with IgAN. Further studies of HLA alleles associated with IgAN progression in a larger cohort and in various ethnic groups are needed.

Automated summary

This study investigated the association of HLA-DRB1 and -DQB1 alleles with the susceptibility to IgA nephropathy (IgAN) and its progression to end-stage kidney disease (ESKD) in Korean patients. The findings revealed novel associations between certain HLA alleles and IgAN, as well as a significant difference in the frequency of an HLA allele between ESKD and non-ESKD groups.