(a) Immunological monitoring of p190BCR–ABL-specific memory T-cell responses in the BM of five Ph+ ALL patients on TKIs therapy, and correlation with the disease course. Longitudinal data tracking MRD kinetics (right, y axis; continuous line with black squares) and IFNγ-producing p190BCR–ABL-specific T-cell responses as detected by the enzyme-linked immunospot assay (left, y axis, dotted line with white squares) are summarized in a single time-course graph (months, x axis) for each patient (patient (pt.) 1–5). Imatinib=dark gray bar; dasatinib=white bar; nilotinib=light gray bar. AlloSCT=allogeneic stem cell transplantation; BMMCs=bone marrow mononuclear cells; CHT=consolidation chemotherapy; IFNγ=interferon γ RT=central nervous system radiotherapeutic prophylaxis; SFC=spot forming cells. (b) Median frequencies of p190BCR–ABL-specific T cells upon treatment with the different TKIs. Dashed lines represent the median values. The upper and lower hinges of the boxes represent the 75th percentile and the 25th percentile values, respectively. Dots represent outside values. Statistically significant differences are indicated. (c, d) Analysis of cytokine profile and cytolytic activity of p190BCR–ABL-specific BM T cells from the Ph+ ALL patients. (c) The frequencies of p190BCR–ABL specific BM T cells producing IFNγ, tumor necrosis factor (TNF)-α or interleukin-2, either as effector memory (CCR7−) (EM, gray) or central memory (CCR7+) (CM, white), from all the five patients, are shown in columns as median percentage of positive cells, and expressed as percentages of CD8+ or CD4+ T cells. Single values of specific cytokine-producing T cells are represented on each column, either as EM (○) or CM (□). (d) Cytotoxicity profile of cultured BMMCs obtained from pt.1 under treatment with different TKIs. The figure reports percentage of specific lysis against autologous PHA blasts pulsed with p190BCR–ABL peptides of BMMC cultured for 13 days in the presence of p190BCR–ABL-derived peptides and obtained during imatinib (continuous black line with black squares), dasatinib (segmented black line with black triangles) and nilotinib treatment (dotted black line with black dots). The mean percentage of lysis of duplicate wells for six different effector to target (E:T) ratios is shown.