Regulatory T cell subpopulations in chronic myeloid leukemiaand relationship with disease progression

Chronic myeloid leukemia is a chronic myeloproliferative neoplasm characterized by the presence of the oncogenic BCR-ABL1 fusion gene resulting from a reciprocal translocation of the long arms of chromosomes 9 and 22. During tumor formation, cancer cells develop complex strategies to evade immune surveillance. In chronic myeloid leukemia, leukemic cells have been shown to use similar mechanisms to evade the immune system. Based on the immunosuppressive role of Tregs in the cancer microenvironment, we aimed to study Tregs and their subtypes in CML patients with different clinical features and to reveal the relationship between Treg cell subsets and the course of CML. The study included 37 CML patients (14 women, 23 man) and 10 healthy subjects (5 women, 5 man). 4 ml of blood was collected to EDTA containing tubes from participants. Blood samples are analyzed in 12 hours after collection in hematology laboratory with 8 colour flow cytometry by using DuraClone IM Treg tube. Laboratory and clinical parameters are recorded. Statistical analysis was done with SPPS 24,0 for Windows programme. A p value <0.05 was treated as significant. CD3, CD3/CD4, CD4/Hellos, CD4/Foxp3, CD4/45Ra, CD4/Hellos/Foxp3 and lymphocyte percentage were similar between patients and healthy subjects. CD4/CD25 positive cell population including Treg cells, CD4 positive cells including CD39 positive effector Treg population were significantly higher in CML patients compared to controls. This point demonstrates increased number and activation of Treg cells in CML, similar to observations in various solid tumors.