title: In vivo and in vitro blocking of human lymphocyte Fc gamma-receptors by intravenous gammaglobulin.
abstract: Lymphocyte subpopulations were measured in patients with idiopathic thrombocytopenic purpura before and immediately after high dose intravenous gammaglobulin (IV-IgG) therapy. A significant relative and absolute reduction in the Fc gamma-receptor bearing lymphocyte subpopulation was observed in 5 out of 7 patients tested. In vivo modulation of lymphocyte Fc gamma-receptors therefore probably occurs: an effect which may be attributable to the Fc gamma R-blocking anti-lymphocytic antibodies found in IV-IgG preparations. In vitro studies showed that IV-IgG preparations also contain antibodies with the capacity to block Fc gamma-receptors on human monocytes and polymorphs and that these antibodies can inhibit the T cell response to phytohaemagglutinin. These anti-lymphocyte antibodies may be important in the mode of action of high dose IV-IgG therapy.
mesh_terms: D000368:Aged; D000911:Antibodies, Monoclonal; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000494:pharmacology*; D007275:Injections, Intravenous; D007958:Leukocyte Count; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000145:classification* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology; D009504:Neutrophils / Q000276:immunology; D010835:Phytohemagglutinins / Q000494:pharmacology; D011696:Purpura, Thrombocytopenic / Q000628:therapy*; D011961:Receptors, Fc / Q000276:immunology*; D012397:Rosette Formation; D006377:T-Lymphocytes, Helper-Inducer / Q000166:cytology; D050378:T-Lymphocytes, Regulatory / Q000166:cytology
chemical_list: D000911:Antibodies, Monoclonal; D007074:Immunoglobulin G; D010835:Phytohemagglutinins; D011961:Receptors, Fc