Association and exploratory clinical significance of peripheral blood mononuclear cell microRNA-155 with T-Cell subset imbalance in newly diagnosed paediatric immune thrombocytopenia

To investigate the association of peripheral blood mononuclear cell micro RNA-155 miR-155 expression with T-cell subset imbalance and disease severity in newly diagnosed paediatric immune thrombocytopenia (ITP). Eighty-seven children with newly diagnosed ITP (43 severe, 44 non-severe) and 40 healthy controls were enrolled. Peripheral blood mononuclear cell miR-155 expression was measured via quantitative reverse transcription polymerase chain reaction; Th1, Th2, Th17 and regulatory T (Treg) cell proportions were detected using whole-blood flow cytometry and expressed as percentages of gated CD3 + CD4+ T cells. Associations and exploratory predictive performance were analysed using Pearson correlation and receiver operating characteristic curves. Peripheral blood mononuclear cell miR-155 expression was significantly higher in patients with ITP than in controls and higher in severe than in non-severe ITP ( P < 0.05); Th1 and Th17 cells, as well as Th1/Th2 and Th17/Treg ratios, were increased, whereas Th2 and Treg cells were decreased in ITP ( P < 0.05); miR-155 expression was positively associated with Th1, Th17, Th1/Th2 and Th17/Treg and negatively associated with Th2, Treg and platelet count ( P < 0.05). The exploratory combined model of miR-155, Th1/Th2 and Th17/Treg yielded an area under the curve of 0.928 (95%CI: 0.865–0.973) for severe ITP, with 79.10% sensitivity and 95.50% specificity. Peripheral blood mononuclear cell miR-155 expression is associated with T-cell subset imbalance and disease severity in newly diagnosed paediatric ITP. The combined immune–cellular indicator may support severe-risk stratification, but prospective validation and functional studies are required.