Antileukemia T-cell responses develop in remission after imatinib. (A) IFN-γ ELISPOT data (triplicate) depicted from P12: leukemic cells alone (first row), remission sample alone (second row), and leukemic and remission samples (last row). (B) Detection of antileukemia immune responses in 9 of 14 patients via IFN-γ ELISPOT. Leukemic cells alone (□), remission sample alone (■), and leukemic and remission samples (). The following stimulated remission samples from the patients are shown and depicted as median and range: P1, 5 months; P2, 12 months; P3, 6 months; P4, 18 months; P6, 14 months; P8, 15 months; P11, 4 months; P12, 5 months; P13, 12 months. All responses were statistically significant (P < .05) compared with leukemic or remission samples alone. (C) TNF-α and IFN-γ production (CFC) by CD4⁺ T and CD8⁺ T cells in stimulated remission samples (■) from 6 patients. Leukemic cells alone (□) and remission samples alone (). The same remission samples shown in panel B were analyzed (*P < .05, statistically significant responses over background).