The Increase on Th1 and CD8+T Levels While a Decrease on Treg Level after Dasatinib Treatment Indicate a Better Therapeutic Response to Dasatinib and Deeper Clinical Remission in Chronic Myelogenous Leukemia Patients

Objective: to investigate the differences on Th1, CD8+T and Treg levels before and after dasatinib treatment in chronic myelogenous leukemia patients, and to investigate their relevance with clinical remission. Methods: The Th1, CD8+T and Treg levels (Th1/CD4+T, CD8+T/Lymphocyte, Treg/CD4+T) before and after dasatinib treatment were detected by flow cytometry in chronic myelogenous leukemia patients (n=9), and all the patients received continuously dasatinib treatment for at least 3 months. The clinical remission status at the time of blood test were evaluated for these patients. Then the changes of the T-cell subtypes mentioned above were analyzed with paired t-test for the correlation with therapeutic response to dasatinib and clinical remission.

Results: 6 cases of the 9 patients achieved better clinical remission after dasatinib treatment compared with the remission status before treatment while the other 3 cases of the 9 patients didn't show improved clinical remission after treatment compared with the remission status before treatment. When analyzing with all the 9 patients, the Th1 and Treg levels after dasatinib treatment both didn't show statistically significant differences compared with the levels before treatment (P=0.148; P=0.240), whereas the level of CD8+T after dasatinib treatment showed a statistically significant increase compared with the level before treatment (P=0.042). Interestingly, when we analyzed only the 6 cases of the 9 patients who obtained the better clinical remission after dasatinib treatment, we found that they all showed an increase on both Th1 and CD8+ T levels (P=0.014; P=0.014) while simultaneously an decrease on Treg level (P=0.067) after dasatinib treatment. In the contrast, when we analyzed the other 3 cases of the 9 patients who didn't show an improved clinical remission after dasatinib treatment, we found that these 3 patients all showed a decrease on both Th1 and CD8+ T levels while simultaneously an increase on Treg level after dasatinib treatment.

Conclusion: Our data shows that an increase on both Th1 and CD8+T levels while simultaneously a decrease on Treg level after dasatinib treatment indicate a good therapeutic response to dasatinib and a better clinical remission. In contrast, a decrease on both Th1 and CD8+T levels while simultaneously an increase on Treg level indicate an unsatisfied therapeutic response to dasatinib and an un-improved clinical remission. As easily-acquirable immune markers (by flow cytometry) with relatively low cost, the levels of Th1, CD8+T as well as Treg can be valuable markers to be monitored for evaluating the therapeutic response to dasatinib and predicting the clinical remission. We would like to early share our above data with other hematologists, and in the future we will do further investigation with enlarged patients number and longer follow-up.