Natural killer cell dynamics and its association with response to imatinib-treated patients with chronic myeloid leukemia

Objective This study aims to assess the effect of natural killer (NK) cells and natural killer T (NKT) cells on response to imatinib (IM) therapy in patients with chronic myeloid leukemia (CML). Background NK cells and NKT cells play a vital role in innate immunity against tumors. NKT cells recognize tumor cells by receptor-ligand interaction. After contact with the ligand, NKT cells activate NK cells through inflammatory cytokines [interferon-gamma (IFN-γ) and interleukin 2]. Patients and methods A total of 48 newly diagnosed patients with CML (chronic phase) were included. They were followed up for 1 year after the start of IM therapy and were categorized into IM-responder patients with CML (n = 23) and IM-resistant patients with CML (n = 25). Flow cytometry was used to measure NK and NKT cells. Serum levels of IFN-γ were determined by enzyme-linked immunoassay. Results We found that NK cell% and NKT cell% were increased in the IM-responder group after 1 month of IM therapy. IFN-γ was increased at both presentation and 1 month after the start of IM therapy. Major molecular response was achieved earlier in the IM-responder group, with increased NK cell%, absolute count of NK cell, and IFN-γ. Conclusion We conclude that NK cells have a critical role in the response of patients with CML to IM therapy and are a predictor of major molecular response in patients with CML.