Effects of Exercise Training on the Bone Marrow Immune Microenvironment and Minimal Residual Disease in Multiple Myeloma Patients Following First‐Line Treatment

The purpose of the study was to investigate the effects of exercise training on the bone marrow immune microenvironment and on minimal residual disease of multiple myeloma patients who completed first‐line induction treatment. Eight multiple myeloma patients underwent 5 months of exercise training along with standard medical treatment. Eight age‐ and sex‐matched patients who received medical treatment only, served as controls. Before and after the intervention, white blood cells, red blood cells, and platelets, as well as the percentages of neutrophils, lymphocytes, monocytes, eosinophils, and basophils, were measured in the peripheral blood. Abnormal plasma cells, normal plasma cells, B cells, T cells, NK/NKT cells, monocytes, neutrophils, eosinophils, basophils, mast cells, myeloid progenitors, erythroid progenitors, and erythroblasts were assessed in the bone marrow. Exercise training increased the percentage of blood monocytes (mean difference 3.5% ± 2.6%; p = 0.006), while no change was detected in the control group. In the bone marrow, the CD27+ T cell subset increased (mean difference 18.2% ± 21.9%; p = 0.043) and the ratio of CD27−/CD27+ T lymphocytes decreased (pre: 1.06 ± 0.59; post: 0.76 ± 0.47; p = 0.049) in the exercise group, but remained unaltered in the control group. In conclusion, the study provides evidence that 5 months of exercise training can induce an increase in the percentage of activated T lymphocytes, as shown by the higher expression of the costimulatory CD27 marker. It also suggests that exercise‐induced changes in the bone marrow microenvironment may be beneficial in the control of clonal cell proliferation.