Changes of proportions of circulating lymphocyte subsets in cancer patients after chemotherapy

It remains unknown how chemotherapy affects circulating lymphocyte subsets and whether the pattern of change is related to prognosis in cancer patients.

Cancer patients who received chemotherapy between 2018/03/01 and 2019/12/31 were enrolled from the Hefei Cancer Hospital, Chinese Academy of Sciences. Peripheral blood samples were collected before and 3 weeks after the start of chemotherapy, and the proportions of T cells (CD3+), helper T cells (CD3+CD4+), cytotoxic T cells (CD3+CD8+), B cells (CD19+), and Natural killer (NK) cells (CD3-CD56+) were examined by flow cytometry. Multivariable logistic regression analysis was employed to explore risk factors associated with overall survival within 12 months after the start of chemotherapy.

A total of 167 patients with cancer were included in the analysis, including 14 cases of cervical cancer, 18 cases of breast cancer, 33 cases of gastric cancer, 48 cases of lung cancer, 21 cases of colorectal cancer, and 33 cases of esophageal cancer. The proportion of T cells (72.58%±10.44% vs. 80.67%±11.63%, P<0.001) and cytotoxic T cells (25.38%±8.87% vs. 39.20%±12.26%, P<0.001) significantly increased, while the proportion of helper T cells (45.58%±10.19% vs. 41.98%±10.47%, P<0.001), B cells (15.10%±5.23% vs. 11.29%±5.60%, P<0.001), and NK cells (19.33%±7.54% vs. 18.28%±7.62%, P<0.001) significantly decreased at 3 weeks after chemotherapy when compared to baseline levels. The overall mortality rate was 14.97% (25/167) within 1 year after the start of chemotherapy. Patients who survived showed a significantly less increase in cytotoxic T cells (13.38%±8.28% vs. 17.28%±7.97%, P=0.030) and less decrease in B cells (-3.58%±2.81% vs. -5.29%±3.03%, P=0.006) when compared to non-survivors. Greater decreases in helper T cells (OR 0.81, 95% CI, 0.68-0.96) and B cells (OR 0.72, 95% CI, 0.59-0.87), and a greater increase in cytotoxic T cells (OR 1.09, 95% CI, 1.03-1.16) were risk factors for poor overall survival.

Circulating lymphocyte subsets of cancer patients presented characteristic changes after chemotherapy. Patients with a greater decrease in helper T cells and B cells, or greater increase in cytotoxic T cells, may have worse survival.