CD40LG and infection: Although no direct evidence of transfusion transmission of HEV, HEV antigen or HEV nucleic acid was found in blood donors in this study, 1.13% of blood donors were anti-HEV IgM positive, and 1.84% of blood donors were anti-HEV IgA positive, which represented a recent infection and may create the risk of transfusion-transmitted HEV infection [19–22].