Exercise and lymphocyte activation following chemotherapy for breast cancer

To determine whether exercise training would increase lymphocyte activation in patients with breast cancer following chemotherapy. Activation was determined by the presence of CD4(+)CD69(+) T-helper lymphocytes, mitogen-induced proliferation, and levels of cytokines produced by mitogen-stimulated lymphocytes and in the patients' plasma.

Patients with breast cancer (N = 28) who participated in a 6-month exercise program were compared with patients (N = 21) who did not exercise. Following chemotherapy, and 3 and 6 months later, patients underwent fitness evaluations and had blood drawn. The exercise program consisted of resistance training and aerobic activity at 60-75% functional capacity three times a week with a personal trainer. Immunochemistry and flow cytometry were used to measure the number of CD4(+)CD69(+) blood lymphocytes. Whole blood was stimulated with concanavalin A (ConA), phytohemagglutin (PHA), or pokeweed mitogen (PWM) to determine proliferation potential. Enzyme-linked immunosorbent assays (ELISA) were used to determine the concentration of interferon-gamma (IFN-gamma) and interleukin-6 (IL-6) in the culture medium of mitogen-stimulated lymphocytes as well as the plasma concentrations of IL-6, soluble IL-6 receptor, soluble gp130, and IFN-gamma. Analysis of groups across time was done using the Wilcoxon signed rank test, and comparisons of groups were done using the Mann-Whitney U test.

The exercising patients showed increases in maximal oxygen uptake and upper body strength. This group also showed a greater percentage of CD4(+)CD69(+) cells and a greater level of tritiated thymidine incorporation (DNA synthesis) when stimulated with ConA, PHA, and PWM at the end of the intervention. Plasma and mitogen-stimulated IL-6 and IFN-gamma production were similar in both groups.

Exercise may improve immune function by increasing lymphocyte activation in patients with breast cancer following treatment.