CD4 and Epstein-Barr virus infection: EBV-associated laboratory findings revealed: serum EBV DNA persistently positive (6.7 × 103 copies/ml), bone marrow EBV DNA 6.5 × 103 copies/ml, lymphocyte subset test for EBV infection showed: CD4+T cells: 3.4 × 104 per million cells, CD8+ T cells: 3.3 × 105 per million cells, B cells: 1.25 × 104 per million cells, NK/NKT cells: 2.3 × 104 per million cells.