Lymphocyte depletion and in vitro apoptosis during chemotherapy.

(A) Kinetics of lymphocyte depletion in patients undergoing chemotherapy. Absolute lymphocyte counts were calculated daily from peripheral blood differentials and leukocyte counts of 7 patients. Mean, 2-sd (standard deviation), and extreme values are depicted in the graph. (B) Analysis of T-cell subset depletion. Absolute CD4 and CD8 T-cell numbers were calculated daily from the peripheral blood differentials and immunophenotyping. Mean and 1-sd values for CD4 cells (open diamonds) and CD8 cells (open circles) are depicted in the graph. (C) Increase of spontaneous in vitro cell death of CD4 T cells during in vivo chemotherapy. PBLs from 7 patients (open circles) were isolated before the start of chemotherapy (0 hour) and during treatment (24 hours, 48 hours). Lymphocytes were cultured for 24 hours in complete medium. CD3⁺/CD4⁺ T lymphocytes were analyzed for annexin V binding by flow cytometry. Percentages represent the proportion of annexin V–positive cells of CD4⁺ T lymphocytes. Mean and 1-sd values of 7 healthy controls are given for the same culture conditions.