Icteric acute hepatitis E with no response of immunoglobulin M class anti-hepatitis E virus antibody

A 68-year-old Japanese man developed icteric acute hepatitis during periodic care after undergoing gastrectomy due to early gastric cancer. The routine serological markers for hepatitis A, B and C viruses were all negative. Although the liver enzymes spontaneously recovered without any specific therapy, cholestasis was relatively prolonged and successfully treated with prednisolone. Determination of serum hepatitis E virus (HEV) RNA revealed the transient infection of HEV, and both immunoglobulin (Ig)A and IgG class anti-HEV antibodies were detected after the disease onset, whereas those were negative when measured 3 weeks prior to the onset. In addition, the titer of serum IgA class antibody was associated with the clinical signs of hepatitis. In contrast, no IgM class antibody was detected throughout the course. This case suggests that screening only with IgM class antibody is not sufficient to detect acute HEV infection.