CD19 and Epstein-Barr virus infection: To determine the localization of EBV infection in the lymphocyte subpopulations of patient 1, CD4+ T cells, CD8+ T cells, CD19+ B cells and CD56+ NK cells were sorted using the immunomagnetic bead method and the presence of EBV was evaluated in each lymphocyte subpopulation by EBER-1 ISH (Figure 1A).