Among PyVs and hepatitis viruses tested, BKPyV and HBV DNA positivities among HIV/AIDS patients with CD4 + counts < 200 cells/mm3 were significantly higher than those with CD4 + counts > 500 cells/mm3 (P = 0.045 for HBV; P = 0.002 for BKPyV). The gene discussed is CD4; the disease is AIDS.