The occurrence of CRTH2⁺ and CCR5⁺ cells in human Th-cell–polarizing cultures. (A) Naive CD4⁺ T cells from 18 donors were polarized as detailed in Figure 1. Seven-day cultures were analyzed by FACS using PE-conjugated Abs for human CRTH2 or CCR5 (see “Materials and methods”). Each dot represents an individual donor (P < .001; paired t test). (B) Polarized Th cells from 14 donors were restimulated with PMA and ionomycin in the presence of monensin and then permeabilized and stained for expression of IL-4 or IFN-γ. Shown is the correlation (Spearman) of the frequencies of IL-4– or IFN-γ–producing cells with baseline expression of CRTH2 in parallel samples of Th2 cultures.