Detection and characterization of autoreactive memory stem T-cells in children with acute immune thrombocytopenia

Primary immune thrombocytopenia (ITP) is an acquired autoimmune disorder characterized by an isolated decrease in platelets below 100 × 10⁹/l after the exclusion of other conditions associated with thrombocytopenia. We investigated the role of different memory T-cell subsets, including T stem cell memory (T_SCM), in children diagnosed with primary ITP and its association with therapeutic duration. This case-control study included 39 pediatric patients with acute ITP admitted to the Children's Hospital at Assiut University. Using a FACSCanto flow cytometer, CD8 + and CD4 + T-lymphocytes were gated. Five different subsets were characterized in each of these cells according to CD45RO and CD45RA expression. Afterward, gating was performed based on CCR7, CD95, and CD27. Examination of the CD8 + T cells subpopulation showed that Central memory T (T_CM) and CD8⁺ Naïve T (T_N) cells were significantly lower in ITP patients than in healthy children (p < 0.0001) and (p = 0.01), respectively. In addition, CD8 + T_EMRA was significantly higher in ITP children than in controls (p = 0.001). CD4 + T_CM cells were significantly lower in the ITP patient group (p = 0.04). However, CD4 + T_EM was significantly higher in patients than controls (p = 0.04). Our research found that ITP patients had an imbalance in the ratio of CD4⁺ to CD8⁺ T cells in the peripheral blood and that T_CM cells may be involved in the pathogenetic mechanism of ITP. T_CMs could help in prediction of patients with higher risk of developing ITP.