APOA1 and viral infectious disease: A number of studies had shown that viral infections could cause the disorder of lipoprotein metabolism in vivo, such as ApoA1, ApoB, HDL-C, low density lipoprotein cholesterol (LDL-C), total triglyceride (TG) and other apolipoproteins, and lipoprotein levels in serum were reduced after heptatitis C virus (HCV) infection [12–14].