The prevalence of hepatitis virus infections among 110 consecutive patients (16-48 years) with acute hepatitis in Mongolia, HAV (IgM-positive) was diagnosed in 18 patients (16.4%), had detectable HAV ribonucleic acid (RNA).1 In the current study (2012-2014), results show that acute hepatitis A was diagnosed in 47.9%.2, 3. This evidence concerns the gene CD40LG and hepatitis A virus infection.