Chemotherapy-induced Changes and Immunosenescence of CD8+ T-Cells in Patients with Breast Cancer

BACKGROUND: Changes in sub-populations of cytotoxic (CD8(+)) T-cells, which are observed in aging and in conditions of chronic immune stimulation, are not well-documented in cancer.

MATERIALS AND METHODS: Using flow cytometry, CD8(+) T-cell subsets were analyzed in patients with breast cancer undergoing DNA-damaging chemotherapy and in an older female control group during a six-month longitudinal study, to explore shifts in CD8(+) T-cells and the effect of DNA-damaging chemotherapy on different T-cell sub-populations.

RESULTS: As expected, there was a consistent decrease in absolute numbers of leukocytes, lymphocytes, T-cells and CD8(+) T-cells during chemotherapy in patients with cancer. Among the T-cells, there was a lower CD8(-)/CD8(+) ratio, persisting over the six months, in patients with cancer compared to controls. The proportion of CD28(-)CD57(+) cells also remained higher among patients with cancer throughout the sampling duration. The number of CD28(+)CD57(-) and CD28(-)CD5(-) cells decreased faster during DNA-damaging chemotherapy than CD28(+)CD57(+) and CD28(-)CD57(+) cells, while only CD28(-)CD57(-) cells showed a significant reconstitutive capacity after six months.

CONCLUSION: Immunosenescence appeared to be pronounced in patients with breast cancer, with senescent CD8(+) T-cells playing a role. The normal condition was not restored after six months of chemotherapy.