Study of T-regulatory cells in patients with acute, idiopathic thrombocytopenic purpura

Introduction Idiopathic thrombocytopenic purpura (ITP) is an autoimmune bleeding disorder that occurs because of enhanced peripheral platelet destruction. Antibodies and T cells are involved in the pathogenesis of the disease and, like other autoimmune diseases, patients with ITP have a peripheral deficiency in regulatory T cells (Treg) numbers and function that may be responsible for loss of tolerance. Our aim was to measure Tregs (CD4 + CD25 +high FoxP + 3) and levels of interleukins (IL-10 and IL-12) in peripheral blood mononuclear cell (PBMC) cultures from patients with ITP and analyze their relationship with the clinical features and outcome of treatment of ITP. Participants and methods Forty-five participants were included in this study, divided into two groups. Group I included 15 healthy children as a control group. Group II included 30 pediatric patients with ITP. According to treatment, group II was divided into three subgroups: group IIa (no treatment) included two (6.7%) patients, group IIb (steroid treatment) included 10 (33.3%) patients, and group IIc (steroid+intravenous immunoglobulin treatment) included 18 (60%) patients. ITP is diagnosed by platelet count less than 100 Χ 103/μl. Tregs were analyzed by flow cytometry. IL-10 and IL-12 in the supernatants of basal and lipopolysaccharide-stimulated PBMC cultures were estimated using an enzyme-linked immunosorbent assay. Results A significantly lower percentage of Tregs was found in patients than in controls (1.46 ± 0.97 vs. 7.09 ± 1.5%) and the lowest percentage of Tregs was recorded in group IIc. A positive correlation was observed between Tregs% and platelet count in the patient group. PBMCs from patients had significantly higher basal levels of IL-10 and IL-12, with a marked reduction in responsiveness to lipopolysaccharide in vitro compared with the controls. Conclusion Children with ITP had reduced Tregs% and IL-10/IL-12 imbalance. Thus, Tregs may play a role in modifying immune responses in these patients, resulting in new strategies of treatment and monitoring of disease activity.