CD40LG and infection: The anti-HAV assay used in this study measures total anti-HAV (IgG or IgM) in human serum or plasma, indicating past or present infection with HAV or vaccination against HAV.26 Interestingly, the incidence rate of reported Hepatitis A cases in the United States (one case per 100,000 population) was significantly lower than the seropositive rate of anti-HAV in the study population (68.74% in adolescents and 41.06% in adults).