HLA-A and immune system disorder: KEGG analysis revealed that HLA class I histocompatibility antigen A (HLA-A) and HLA class II histocompatibility antigen DRB1 (HLA-DRB1) participated in immune-related biological processes such as antigen processing and presentation, graft-versus-host disease, allograft rejection, and autoimmune thyroid disease, which may play an important role in the pathways of immune diseases.