Interaction effects between MHC and non-MHC genes have also been reported in several autoimmune diseases, such as interaction with cytotoxic T lymphocyte antigen 4 (CTLA4) [85], several killer immunoglobulin receptor (KIR) genes [86, 87], and ERAP1 and 2 [88, 89]. The gene discussed is HLA-C; the disease is autoimmune disease.