Background: Immune thrombocytopenia (ITP) is an acquired autoimmune disease. This study's objective was to estimate the variations in the population of CD4+CD25+High FoxP3+ cells (CD4+ regulatory T-lymphocytes; Tregs) in previously untreated children with chronic ITP managed in Assiut University Hospitals, as well as to evaluate the efficacy of high-dose dexamethasone (HD-DXM) in these patients.

Methods: In this study, we investigated the frequencies of T-lymphocyte subsets in 27 untreated children with chronic ITP.

Results: Prior to treatment, the percentages of CD4+CD25High cells and Tregs were significantly lower in the chronic ITP group compared to the control group (p = 0.018 and p < 0.0001, respectively). After treatment with HD-DXM, Tregs and platelets were significantly increased in these patients (p < 0.0001 for both).

Conclusions: Our results suggest that Tregs are deficient in children with chronic ITP and that HD-DXM immunosuppressive therapy can restore the levels of these cells. Impact: CD4+CD25High cells and Tregs were significantly lower in children chronic ITP compared to healthy control. HD-DXM treatment led to significantly increased Tregs and platelets in these patients. Our results suggest that Tregs are deficient in children with chronic ITP and that HD-DXM immunosuppressive therapy can restore the levels of these cells.