Acute hepatitis B; no history of hepatitis B; negative for the presence of five serological markers of hepatitis B for nearly 2 months; acute onset; HBV surface antigen (HBsAg) and hepatitis B core antibody (HBcAb) IgM positive; and symptoms such as jaundice and pain over the liver area, but no signs of chronic liver disease and cirrhosis, portal hypertension, hypersplenism, and ascites. This evidence concerns the gene CD40LG and portal hypertension.