Background Chronic myeloid leukemia (CML) is a clonal
disease, characterized by a reciprocal t(9, 22) that
results in a chimeric BCR/ABL fusion gene. Regulatory T
cells (Tregs) constitute the main cell population that
enables cancer cells to evade immune surveillance.
Objective The purpose of our study was to investigate the
level of Tregs in newly diagnosed CML patients and to
correlate it with the patients’ clinical, laboratory and
molecular data. We also aimed to assess the effect of
treatment using tyrosine kinase inhibitor (TKI) on Treg
levels.
Methods Tregs were characterized and quantified by flow
cytometry in 63 newly diagnosed CML patients and 40
healthy controls. TKI was used in 45 patients with chronic
phase CML, and the response to therapy was correlated
with baseline Treg levels.
Results The percentages of Tregs were significantly
increased in CML patients compared to the controls. Treg
numbers were significantly lower in patients with chronic
phase CML versus the accelerated and blast phases, and
were significantly lower in patients with complete molecular
remission (CMR) compared to those patients without
CMR.
Conclusion Tregs may play a role in the maintenance of
CML. Moreover, the decrease of their levels in patients
with CMR suggests that Tregs might have a clinical value
in evaluating the effects of therapy.