Effects of Tyrosine Kinase Inhibitors on the Th1 and Treg Cells of CML Patients

OBJECTIVE: To compare the immunomodulatory effects of the 2nd generation of tyrosine kinase inhibitors (TKIs)-dasatinib and nilotinib as well as the 1st generation of TKI-imatinib on chronic myeloid leukemia (CML) patients. METHOD: To evaluate the T cell subtypes by flow cytometry on the CML patients of our center who received the treatment with dasatinib (n=10), nilotinib (n=26) or imatinib (n=44) for more than 3 months, and to analyze and correlate these data with the clinical remission situations and prognosis. RESULTS: 80.0% of the patients in dasatinib group, 16.6% of the patients in nilotinib group and 27.5% of the patients in imatinib group respectively had a Th1 proportion in the peripheral blood (Th1/CD4+ T) above the upper limit of normal. More specifically, the Th1 proportion in dasatinib group (30.86%±9.75%) was significantly higher than that in nilotinib group(17.37%±9.35%) (P<0.001) and that in imatinib group (20.79%±9.01%) (P<0.001). Among the 3 groups, both the CD8+ T cell proportion (CD8+ T/Lymphocyte) and the Th2 proportion (Th2/CD4+ T) in the peripheral blood did not show a statistically significant difference. The Treg proportion (Treg/CD4+ T) in dasatinib group (1.31%±0.10%) was significantly lower than that in nilotinib group (2.65%±0.97%) (P<0.001) and that in imatinib group(2.99%±1.40%) (P<0.001).Among all the CML patients analyzed, for CML patients who had a Th1 proportion above the upper limit of normal(25.8%) (n=28), 84.62% of these patients obtained CCyR (complete cytogenetic response), 71.43% of these patients obtained MMR (major molecular response), 71.43% of these patients obtained MR4.5; for CML patients who had the Th1 proportion in the normal range(11.8%-25.8%) (n=45), 90.7% of these patients obtained CCyR, 75.56% of these patients obtained MMR, and 75.56% of these patients obtained MR4.5; for CML patients who had the Th1 proportion below the lower limit of normal (11.8%) (n=21), 57.14% of these patients obtained CCyR, 47.62% of these patients obtained MMR, and 47.62% of these patients obtained MR4.5. The above-mentioned data shows that the patients in high Th1 group and the normal Th1 group obtained the higher remission rate as well as the deeper remission level. CONCLUSION: This study shows that during the CML treatment with TKIs, the increased or normal Th1 proportion indicates a bigger chance for CCyR, MMR, and MR4.5. Dasatinib may significantly increase the level of Th1 while decrease the level of Treg in the patients, as compared with nilotinib and imatinib.