title: Autoantibodies to platelet glycoproteins in patients with disease-related immune thrombocytopenia.
abstract: Although increased platelet destruction and elevated platelet-associated IgG have been shown in patients with lymphomas and various autoimmune diseases, such as systemic lupus erythematosus (SLE), there have been few studies evaluating autoantibodies against platelet-specific antigens. We evaluated 24 patients retrospectively with disease-related thrombocytopenia (12 with lymphoproliferative diseases and 12 with various autoimmune disorders) using a recently reported antigen-specific assay. Autoantibodies against platelet GPIIb/IIIa or GPIb/IX were noted in 15 of the 24 patients (10 of 12 with autoimmune disease and five of 12 with lymphoproliferative disorders). Platelet-associated autoantibodies were present in 60% and plasma autoantibodies in 33%. Anti-GPIIb/IIIa autoantibodies were much more common than those against GPIb/IX. In one patient each with thrombocytopenia and either SLE or myasthenia gravis, absorption of plasma with platelets completely removed the anti-GPIIb/IIIa autoantibodies, but did not affect the level of anti-cochlear autoantibody involved with immune-mediated hearing loss in the SLE patient or the anti-acetylcholine receptor autoantibody in the myasthenic patient. These findings show that, in some cases of disease-related immune thrombocytopenia, autoantibodies against GPIIb/IIIa or GPIb/IX can be detected similar to those seen in chronic ITP. As shown in two patients with multiple autoimmune manifestations, the various autoantibodies have diverse specificities and do not crossreact.
authors.affiliation: Department of Molecular and Experimental Medicine, Research Institute of Scripps Clinic, La Jolla, California.
authors.forename: P
authors.initials: P
authors.lastname: Berchtold
authors.forename: J P
authors.initials: JP
authors.lastname: Harris
authors.forename: P
authors.initials: P
authors.lastname: Tani
authors.forename: L
authors.initials: L
authors.lastname: Piro
authors.forename: R
authors.initials: R
authors.lastname: McMillan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000032:analysis*; D001327:Autoimmune Diseases / Q000276:immunology; D006801:Humans; D008232:Lymphoproliferative Disorders / Q000276:immunology; D008875:Middle Aged; D010976:Platelet Count; D010980:Platelet Membrane Glycoproteins / Q000276:immunology*; D012189:Retrospective Studies; D013921:Thrombocytopenia / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D010980:Platelet Membrane Glycoproteins