EBV genome loads in tonsillar B-cell subsets isolated by CD38/IgD/CD27 sorting. EBV genome loads in naive (N), isotype-switched memory (SM), nonswitched memory (NSM), CD38⁺ and CD38^hi B-cell subsets were determined by quantitative PCR and the results expressed as EBV genomes per 10⁶ cells. Median values for each group (shown by the horizontal bars) are 2.1 × 10², 9.1 × 10³, 3.1 × 10³, 4.9 × 10², and 4.5 × 10², respectively, for chronic carrier tonsils, and 2.9 × 10⁴, 5.2 × 10⁵, not determined, 2.5 × 10⁶ and 1.8 × 10⁶, respectively, for IM tonsils.