Comparison of cytotoxic activity of the bcr-abl–specific clone P218 against peripheral blood MNC from patients with CML expressing transcripts for b3a2 and T-cell PHA blasts from each patient. Cytotoxicity of CML cells and each patient's control cells before and after incubation with interferon are shown. HLA types for each patient are listed in Table 1. Data shown represent the mean ± SD percent specific lysis in chromium release assays performed in triplicate at an E:T ratio of 10:1.