Combined influence of adjuvant therapy and interval after surgery on peripheral CD4(+) T lymphocytes in patients with esophageal squamous cell carcinoma.

The aim of this study was to investigate possible differences in cellular immunity between chemo- and/or radiotherapy groups during a long interval after surgery in esophageal squamous cell carcinoma (ESCC) patients. Cellular immunity was assessed as peripheral lymphocyte subsets in response to chemotherapy (CT), radiotherapy (RT) and CT+RT by flow cytometric analysis. There were 139 blood samples obtained at different time points relative to surgery from 73 patients with ESCC. The changes in the absolute and relative proportions of lymphocyte phenotypes were significant among the adjuvant therapy groups. There were significant differences in the absolute counts of CD4(+) and CD8(+) T cells among the interval groups, and a lower CD4/CD8 ratio was found in patients following a prolonged interval. RT alone had a profound effect on the absolute counts of CD3(+), CD4(+) and CD8(+) T cells compared with the other groups. CD4(+) T cells exhibited a decreasing trend during a long interval, leading to a prolonged T-cell imbalance after surgery. Univariate analysis revealed that the interaction of the type of adjuvant therapy and the interval after surgery was correlated only with the percentage of CD4(+) T cells. The percentage of CD4(+) T cells can be used as an indicator of the cellular immunity after surgery in ESCC patients. However, natural killer cells consistently remained suppressed in ESCC patients following adjuvant therapy after surgery. These findings confirm an interaction between adjuvant therapy and the interval after surgery on peripheral CD4(+) T cells, and implies that adjuvant therapy may have selective influence on the cellular immunity of ESCC patients after surgery.