Correlation of T Regulatory Cells, Cytotoxic T-lymphocyte-associated Antigen 4, and Transforming Growth Factor-β1 with Treatment Response in Patients with Chronic Myeloid Leukemia Receiving Dasatinib Therapy.

Background: Tyrosine kinase inhibitors improve chronic myeloid leukemia (CML) outcomes. Dasatinib inhibits breakpoint cluster region-Abelson 1 proto-oncogene tyrosine kinase better than imatinib in CML. T-regulatory cells prevent autoimmune diseases and aberrant immune responses by reducing oncoprotein antigen reactivity. They also reduce self-antigen-induced immune responses to maintain peripheral tolerance. In this study, T-regulatory cells in peripheral blood of chronic myeloid leukemia-chronic phase patients were measured, together with serum levels of cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and transforming growth factor (TGF)-β1 at diagnosis and 3 months postdasatinib therapy.

Materials and methods: The Pathology and Clinical Haematology Departments at King George's Medical University, Lucknow, India, conducted this prospective analytical study. Forty CML-chronic patients and 10 healthy controls were analyzed. Flow cytometry was used to determine T-regulatory cell percentage in peripheral blood mononuclear cells of newly diagnosed CML patients before and after 3 months of dasatinib treatment; ELISA was used to measure serum levels of CTLA-4 and TGF-β1.

Results: T-regulatory cells, CTLA-4, and TGF-β1 significantly decreased in CML-chronic phase patients after 3 months of dasatinib therapy compared to the initial diagnosis. No significant change in T-regulatory cell, CTLA-4, or TGF-β1 percentages were seen between responders and poor responders. However, responders had a lower percentage of T-regulatory cells than suboptimal responders.

Conclusions: The study concluded that dasatinib treatment improved response in CML patients with decreased Treg cells. Dasatinib reduces Treg-mediated immunological suppression, reducing CTLA-4 and TGF-β1 levels.