Cell numbers in IL-7- and IL-15-supplemented PBMC cultures. Mean results from 8 post-IM patients and 6 healthy EBV carriers in experiments where PBMCs were seeded in culture at 1 × 106/mL in the presence of (A) IL-7 or (B) IL-15 at 1 ng/mL, with or without anti-CD3/CD28-coated beads as a costimulus. Cell counts were performed on days 3, 5, 7, and 10, and viable cell numbers are expressed relative to the initial seeding.