HLA-C and psoriasis: The HLA-Cw6 allele, mapped in the major histocompatibility complex (MHC) at the 6p21 chromosome region, has been thoroughly validated in numerous studies as a susceptibility psoriasis locus, participating in the self-antigen presentation in T cells, including the nucleic acid/LL-37 complex and the melanocyte-secreted ADAMTS5 protein (Tsoi LC et al., 2017; Capon F, 2017).