Immunologic evaluation of patients treated in the multiple-doses protocol. Four patients received multiple doses of 5 × 107/m2 EBV-CTLs. Panel A shows the frequency of EBV-specific T cells in the peripheral blood as measured by the number of IFN-γ–secreting PBMCs upon stimulation with irradiated autologous LCLs before and after CTL infusion. Bars represent the mean of triplicate wells ± SD. ELISPOT assay shows an increase in the frequency of circulating EBV-specific T cells after CTL infusion, persisting for longer than 2 months after infusion. Panel B shows the immunologic response of 2 patients with informative tetramers in the EBV-CTLs infused. The right panels show the frequency of tetramer-positive T cells on PBMCs collected before infusion. Left panels show that the frequency of the tetramer-positive T cells increased after CTL infusion.
