Regulation of CD4+CD25+FOXP3+ cells in Pediatric Acute Lymphoblastic Leukemia (ALL): Implication of cytokines and miRNAs.

Regulatory T cells (Tregs) is one of the immunosuppressive subsets of CD4+ T cells characterized by transcription factor forkhead box protein P3 (FOXP3) expression which are involved in tumor development and progression. Identification of the factors that influence Treg cell function is extremely important. Our current study aimed to evaluate the frequency of Treg cells, cytokine secretion and the expression of microRNAs (miRNAs) in pediatric acute lymphoblastic leukemia (ALL) patients. The frequency of CD3+, CD4+ and CD4+CD25+FOXP3+ Treg was assessed by flow cytometry in 43 ALL patients versus 42 controls. Plasma levels of IL-10, transcription factor β (TGF-β), IL-6, IL-17, IL-23 and tumor necrosis factor (TNF-α) were measured by Enzyme-linked immunosorbent assay (ELISA). miR-21, miR-24, miR-26a, miR133b, miR-148a and miR-155 expression were analyzed using quantitative real-time polymerase chain reaction (qRT-PCR). A slight insignificant increase in Treg cells in ALL patients compared to controls was observed. There was a significant elevation in IL-10 (p < 0.05), IL-6 (p < 0.01), IL-23 (p < 0.05) and TNF-α (p < 0.01) in ALL patients compared with controls. Meanwhile, a significant reduction in TGF-β (p < 0.001) was recorded. A slight insignificant decrease in IL-17 in ALL patients was observed.ALL patients showed a significant increase in miR-21 (p < 0.05), miR-148a (p < 0.01), miR-24 (p < 0.05) and a significant reduction in miR-155 (p < 0.01). In conclusion, the slight change in Treg cells frequency and alteration in related cytokines could possibly involve in the pathogenesis of ALL. Dysregulated miRNAs, as a regulatory mechanism of epigenetics, might contribute to these observed results. Further researches are required to confirm our interesting findings.