title: Antibodies against platelet glycoproteins and antiphospholipid antibodies in autoimmune thrombocytopenia.
abstract: Autoantibodies against platelet glycoproteins (anti-GP) are found in the majority of patients with autoimmune thrombocytopenia (AITP) as well as in thrombocytopenia associated with systemic lupus erythematosus (SLE). Some of these patients may have anti-phospholipid antibodies (anti-PL). To evaluate the pathogenetic significance of anti-PL and anti-GP antibodies in AITP and SLE patients, we investigated anti-cardiolipin (anti-CL), anti-phosphatidylserine (anti-PS) and anti-GP antibodies (anti-GPIIb-IIIa and anti-GPIb-IX) in 71 patients with AITP and 3 thrombocytopenic patients with SLE. Anti-GP antibodies were detected in 52 (70%) patients. Fifty-six (73%) patients showed anti-PL antibodies. Seven patients (6 AITP, 1 SLE) with both anti-GPIIb-IIIa and IgG anti-PL antibodies were followed during treatment with corticosteroids. Antibodies were measured before treatment and at the time of platelet-peak. Anti-GPIIb-IIIa antibodies decreased in all or became undetectable in five. In contrast, IgG anti-PS and IgG anti-CL antibodies decreased only moderately or remained positive. Adsorption experiments, using gelfiltered platelets, erythrocyte (Ec)-inside-out-vesicles and purified GPIIb-IIIa, showed that anti-GP and anti-PL antibodies have distinct specificities and do not crossreact. We conclude that anti-PL and anti-GP antibodies may be present simultaneously in some patients with immune mediated thrombocytopenia. Although anti-PS as well as anti-CL antibodies may be responsible for thrombocytopenia, we speculate that anti-GPIIb-IIIa antibodies are more related to the severity of thrombocytopenia.
authors.affiliation: Department of Medicine, University Hospital, Bern, Switzerland.
authors.forename: E
authors.initials: E
authors.lastname: Lipp
authors.forename: A
authors.initials: A
authors.lastname: von Felten
authors.forename: H
authors.initials: H
authors.lastname: Sax
authors.forename: D
authors.initials: D
authors.lastname: Müller
authors.forename: P
authors.initials: P
authors.lastname: Berchtold
mesh_terms: D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000327:Adsorption; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017153:Antibodies, Anticardiolipin / Q000097:blood; D017152:Antibodies, Antiphospholipid / Q000097:blood*; D001323:Autoantibodies / Q000097:blood*; D001327:Autoimmune Diseases / Q000276:immunology*; D001792:Blood Platelets / Q000276:immunology; D002850:Chromatography, Gel; D004910:Erythrocyte Membrane; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010718:Phosphatidylserines / Q000276:immunology; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000276:immunology; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000276:immunology; D010980:Platelet Membrane Glycoproteins / Q000276:immunology*; D013921:Thrombocytopenia / Q000276:immunology*
chemical_list: D000305:Adrenal Cortex Hormones; D017153:Antibodies, Anticardiolipin; D017152:Antibodies, Antiphospholipid; D001323:Autoantibodies; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D010718:Phosphatidylserines; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D019038:Platelet Glycoprotein GPIb-IX Complex; D010980:Platelet Membrane Glycoproteins