The presence of HLA-DRB1*15 or DRB1*16 alleles showed strongly significant association with disseminated opportunistic infection with anti- IFN- γ antibody (OR 10.5, 95% CI 3.42–32.33, and OR 33.48, 95% CI 8.74–128.21, respectively) (Tables 4 and 5). This evidence concerns the gene HLA-DRB1 and Opportunistic infection.