Psoriasis patients are more likely to harbor alleles such as HLA-B*57, HLA-B*27, HLA-C*06 (in high LD with the HLA-C 3′UTR deletion polymorphism), and KIR3DS1+Bw4-80I, theoretically resulting in vigorous cytotoxic T cell and NK cell responses upon infection with HIV-1 virus. This evidence concerns the gene HLA-C and infection.