Reduction in proportion of senescent CD8+ T lymphocytes during chemotherapy of children with acute lymphoblastic leukemia

Abstract

Aim: To evaluate quantitative changes in B, NK and T lymphocyte subsets in peripheral blood of children with acute lymphoblastic leukemia (ALL) undergoing chemotherapy. Patients and Methods: Children with ALL were treated according to NOPHO ALL 2008 protocol. Levels of B lymphocytes (CD19+), NK cells (CD3-CD56+) and subsets of T lymphocytes (CD3+CD4+, CD4+CD25+Foxp3+, CD3+CD8+, CD3+CD8+CD57+, CD3+CD8+CD57-) in peripheral blood were analyzed by flow cytometry prior and during treatment with cytotoxic drugs. Results: Immunological analyses were performed in 25 children with ALL. Levels of B and NK lymphocytes decreased continuously during chemotherapy. In contrast, levels of most T lymphocyte subsets decreased only transiently and returned to pretreatment levels by days 78 to 85. The only T lymphocyte subset that did not return to the pretreatment level contained senescent CD3+CD8+CD57+ lymphocytes. Conclusion: Immunomodulating action of chemotherapy in children with ALL results in reduction of proportion of senescent CD8+ T lymphocytes.