Abstract
Genetic associations within the human leukocyte antigen (HLA) gene complex and linked genes in TB-IRIS outcomes remains population specific and not well understood. Here, we conducted a study including well characterised HIV-TB coinfected patients with (n = 86) and without (n = 124) TB-IRIS from the randomized, double-blind, prophylactic prednisone trial (PredART study) with HLA, ERAP and KIR genotyping data. We confirmed the association of TB-IRIS with lower CD4 counts pre-ART initiation. We identified nine classical class I and II HLA alleles protective against TB-IRIS, while four alleles were linked to increased risk. Associations ranged from strongly protective (HLA-DQB1*05:01, OR: 0.07, 95%CI: 0.02-0.28, Pc < 0.001) to strongly risk associated (notably DRB1*01:02, OR: 5.92, 95%CI: 1.36-26.7, Pc = 0.028), with conflicting signals at the HLA-DRB1 locus. Conditional regression analysis revealed that residue E71 at the polymorphic position 71 within the HLA-DRB1 peptide-binding groove was critical, and grouping of HLA-DRB1 alleles by the residue at position 71 corresponded with differential TB-IRIS association. In conclusion, this study identifies population-specific genetic factors influencing TB-IRIS susceptibility and highlights a potential mechanistic role for specific HLA-DRB1 residues in modulating immune responses during ART.