Correlations among age, cytokines, lymphocyte subtypes, and platelet counts in autoimmune thrombocytopenic purpura

While autoimmune thrombocytopenic purpura is mediated by autoantibodies, accumulating evidence suggests that T helper cells and the cytokines they produce also play a key role. We determined correlations among age, serum cytokine concentrations, circulating lymphocyte, and platelet counts in adult (n=19) and children (n=29) with autoimmune thrombocytopenic purpura. Correlations between age and cytokine levels were also assessed in healthy controls (n=50). Significant positive correlations between age and serum levels of interferon-gamma, age and CD4+ lymphocytes, age and natural killer cell count were observed in these patients. Absolute lymphocyte and CD8+ cell count was significantly inversely correlated with age. In adult patients, a significant inverse correlation between platelet and absolute lymphocyte count was observed. In pediatric patients, an inverse correlation of platelet count with serum concentration of interleukin-3 was recorded. In 50 healthy volunteers there were significant positive correlations between age and interleukin-3, -4, -6, and interferon-gamma, and significantly negative correlations with interleukin-2, tumor necrosis factor-alpha, and interferon-alpha. Additional evaluations are necessary to identify the impact of age-related changes in immune function on the clinical course of autoimmune thrombocytopenic purpura.