Autologous T cells of 6 different patients were challenged with CD40-CLL cells at an E:T ratio of 5:1. Supernatants were collected 48 hours later and IL-4 and IFNγ were measured by ELISA (detection limit of the IL-4 assay is <5 pg/mL; detection limit of the IFNγ assay is <5 pg/mL).