The clonal Th2 cells are sensitive to Fas-mediated apoptosis.

Purified CD3⁺CD4⁺CD45RO⁺ cells from healthy individuals (♦) and CD3⁻CD4⁺ cells from hypereosinophilic patient 1 (▴) and patient 2 (▪) were cultured in the presence of graded concentrations of sFasL. Apoptotic cells were detected by flow cytometry according to FSC/SSC parameters. Results are the means ± SEM of percent apoptotic cells of 3 experiments. *P < .05 as compared with CD3⁺CD4⁺CD45RO⁺ cells from healthy individuals (ANOVA test).