Role of cellular immunity in the pathogenesis of immune thrombocytopenic purpura in children

Objective This study aimed to determine CD4+, CD8+ T cells, CD4/CD8, CD4+ 25+ cells, and regulatory T cells (CD4+ CD25+ Fox P3+) in children with immune thrombocytopenic purpura (ITP). Background ITP is an immune-mediated hemorrhagic condition characterized by the production of autoantibodies against platelet antigens. Primary immune thrombocytopenia is characterized by isolated thrombocytopenia with normal bone marrow or increased bone marrow megakaryocytes; if this condition persists for more than 12 months, it is known as chronic immune thrombocytopenia. Regulatory T cells play a major role in controlling immune homeostasis and preventing autoimmunity. Immune thrombocytopenic patients show decreased numbers of CD4+ CD25+ FoxP3+ regulatory T cells. Patients and methods The study included 45 children: 15 children with acute ITP, 15 children with chronic ITP, and 15 controls. Three microliters of venous blood samples were obtained. A complete blood count was performed first. Flow cytometric analysis of lymphocytes was carried out to detect CD3+, CD8+, CD4+, CD4+ 25+ cells, and regulatory T cells (CD4+ CD25+ FoxP3+). Results No significant difference was recorded between the three groups in CD4+, CD8+, CD4+ 25+ cells, or the CD4/CD8 ratio. A significantly lower percentage of regulatory T cells was found in chronic patients in comparison with the controls (P = 0.00) and a significantly lower percentage of regulatory T cells was found in chronic patients in comparison with acute patients (P = 0.00), but no significant difference was recorded between acute patients and control (P > 0.05) in regulatory T cells. Conclusion The present study showed that regulatory T cells are significantly lower in chronic immune thrombocytopenic patients, indicating its role in the pathogenesis of ITP.