Significance of Th17 and Treg in Treatment Efficacy and Outcome in Pediatric Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia represents a malignant proliferation of lymphoid cells blocked at an early stage of cell differentiation. It is the most common cancer occurring in children. Despite favorable prognosis, the survival rate of patients with poor treatment response or relapse remains dismal. The interaction between leukemic cells and the tumor immune microenvironment is pivotal in mediating tumor progression. In this study we evaluated associations between Treg and Th17 lymphocytes and the clinical presentation of ALL pediatric patients to validate their value in monitoring treatment outcome. The peripheral blood and bone marrow aspirates from 35 pediatric patients with ALL and 48 healthy control subjects were selected for the experiment. We demonstrated the numbers of Th17 lymphocytes and Tregs were increased in the bone marrow of ALL patients at the moment of diagnosis compared to the healthy control group, with the latter significantly decreasing during the course of ALL treatment. Patients with lower Th17 were found to demonstrate higher risk of blasts prevalence in bone marrow at day 33. ALL patients with lower WBC demonstrated higher frequency of Tregs. In summary, we identified a significant role of Th17 and Treg lymphocytes in ALL of pediatric patients and their contribution to disease-related parameters.