Natural Course in Childhood Chronic Immune Thrombocytopenic Purpura (ITP) and Their Relation to CD4⁺CD25⁺FoxP3⁺ Regulatory T Cells.

The proposal of the present study was to determine the frequency of CD4⁺CD25⁺FoxP3⁺ regulatory T cells (Treg) in the peripheral blood and to assess the serum levels of IL-2, IL-10 and TGF-β1 in childhood chronic ITP with thrombocytopenia and spontaneous remission. In anticipation of the findings would elucidate the possible role in order to predict spontaneous recovery and pathogenesis of childhood chronic ITP.

Eleven children with chronic ITP (7 thrombocytopenic and 4 recovered cases, mean age 8.8 years; range, 1.7∼14.9 years) were enrolled. Five healthy children and eight healthy adults were included in this study as controls. The frequency of Treg was evaluated in peripheral blood by flow cytometry. The serum levels of IL-2, IL-10 and TGF-β1 were measured by ELISA technique.

During this study, it was observed that four patients (36%) achieved spontaneous remission within 2.8 years (mean year; range, 1.0∼4.4 years). The frequency of Treg was significantly decreased in the patients with thrombocytopenia as compared to spontaneously recovered patients and controls. A significant positive correlation was found between the frequency of Treg and the platelet count in children. The serum level of IL-10 was higher in the patients recovered spontaneously comparing to the patients with thrombocytopenia, but the difference was not significant statistically. The serum level of IL-2 was not able to detect as too low to be analyzed. TGF-β1 showed no significant differences in this study.

These data suggest that the decreased frequency of Treg would contribute to breakdown of self-tolerance as well as form a base for future specific immunomodulatory therapies and have prognostic significances toward the natural course and long-term outcome of childhood chronic ITP.

No relevant conflicts of interest to declare.