On the other hand, HLA-G variation sites and/or expression levels are associated with pathological conditions such as viral infections (15–20), cancer (21–27), recurrent miscarriage (28–37), pregnancy outcome and pregnancy complications (37–45), autoimmune diseases (46–54), transplantation outcome (55–57), and inflammatory diseases (58–61), indicating that HLA-G encodes a critical molecule for the immune system. The gene discussed is HLA-G; the disease is viral infectious disease.