Analysis of EBV genome load in B-cell subsets isolated from XLP blood. Results of quantitative PCR analysis to determine the EBV load in purified CD20+ CD10+ CD27− (transitional; □), CD20+ CD10− CD27− (naïve; ) and CD20+ CD10− CD27+ (memory; ■) B cells. Data (mean and SD of 3 replicates) are reported as EBV genome copies per 106 cells.