Changes in T-lymphocytes and response to high-dose gamma-globulin therapy in idiopathic thrombocytopenic purpura.

Peripheral blood lymphocytes were studied using OKT3, OKT4 and OKT8 monoclonal antibodies in patients with idiopathic thrombocytopenic purpura ITP) before and after high dose gammaglobulin therapy. Total lymphocyte counts increased in 8 of 10 patients studied within 16 weeks of presentation (acute ITP) but decreased in all 6 with chronic (6 months-14 years) thrombocytopenia (P = 0.003). A relative increase in the proportion of inducer-helper (OKT4) cells was seen in 5 of 6 patients with sustained responses whereas there was no clear cut change or a relative increase in suppressor-cytotoxic (OKT8) cells in 7 or 9 with transient responses. The data suggest that short term gammaglobulin therapy may induce sustained responses by immunoregulation of T-lymphocyte subsets.