Lymphocyte subsets in patients with idiopathic thrombocytopenic purpura during high-dose gamma globulin therapy.

Peripheral lymphocyte subsets (OKT3+, OKT4+, OKT8+) were studied by monoclonal antibodies in 10 patients with chronic idiopathic thrombocytopenic purpura (ITP), before and after high-dose intravenous gamma globulin therapy at a daily dose of 0.4 g/kg/body weight for 5 consecutive days followed by several boosters every 10-15 days. A stable increase of platelet count was obtained in 5 patients, whereas the other 5 showed a transient improvement of platelet count but then became refractory to the treatment. Phenotypic analysis of T cell subsets showed a decrease of the OKT4+/OKT8+ ratio following therapy, with non change in the percentage of OKT3+ cells. A significant decrease of lymphocyte count and platelet associated IgG was shown in 80% of our patients. These data suggest the possible long term efficacy of repeated iv IgG inchronic ITP patients through a mechanism of specific enhancement of suppressor T cell function.