title: Antiplatelet antibodies detected by the MAIPA assay in newly diagnosed immune thrombocytopenia are associated with chronic outcome and higher risk of bleeding.
abstract: Immune thrombocytopenia (ITP) results in part from the presence of platelet antibodies, which can be demonstrated by the Monoclonal Antibody-Specific Immobilization of Platelet Antigens (MAIPA) assay. The aim of our study was to correlate the presence of antiplatelet autoantibodies and the natural history of ITP. We performed a retrospective, single-center study of 108 adults with newly diagnosed ITP who had indirect MAIPA assay performed at disease onset. Chronic ITP was defined by the presence of thrombocytopenia after 1 year. Bleeding diathesis was evaluated with a bleeding score. At baseline, patients with a positive indirect MAIPA have a greater bleeding score than patients with negative MAIPA assay [median (interquartile) = 8 (6-12) vs 2 (0-6), p = 0.002]. Patients with a positive indirect MAIPA also had a higher rate of chronic ITP (92.9 vs 68.7 %, p = 0.06). In multivariate analysis, a positive indirect MAIPA result and a platelet count at onset ≥10 × 10(9)/L remained independently associated with chronic ITP [adjusted OR (aOR) = 8.01; 95 % confidence interval (CI), 0.98-66.6; p = 0.05 and aOR = 3.09; 95 % CI, 1.18-8.10; p = 0.02, respectively]. Furthermore, when we analyzed together the results of direct (n = 41) and indirect MAIPA, the same results were observed. Thus, indirect MAIPA positivity at disease onset is associated with more severe hemorrhage and predicts a chronic course in adult ITP patients. MAIPA assay could be useful in the management of ITP patients when it is performed at diagnosis.
authors.affiliation: Service de Médecine interne, Centre de référence des cytopénies auto-immunes, hôpital Henri Mondor, AP-HP, Université Paris Est, Créteil, 94010, France.
authors.forename: David
authors.initials: D
authors.lastname: Grimaldi
authors.forename: Florence
authors.initials: F
authors.lastname: Canouï-Poitrine
authors.forename: Laure
authors.initials: L
authors.lastname: Croisille
authors.forename: Ketty
authors.initials: K
authors.lastname: Lee
authors.forename: Françoise
authors.initials: F
authors.lastname: Roudot-Thoraval
authors.forename: Laetitia
authors.initials: L
authors.lastname: Languille
authors.forename: Medhi
authors.initials: M
authors.lastname: Khellaf
authors.forename: Marc
authors.initials: M
authors.lastname: Michel
authors.forename: Bertrand
authors.initials: B
authors.lastname: Godeau
authors.forename: Philippe
authors.initials: P
authors.lastname: Bierling
mesh_terms: D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D001792:Blood Platelets; D002908:Chronic Disease; D005260:Female; D006470:Hemorrhage / Q000097:blood / Q000175:diagnosis / Q000209:etiology; D056945:Hep G2 Cells; D006801:Humans; D007163:Immunosorbent Techniques; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000097:blood / Q000150:complications / Q000175:diagnosis; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D001323:Autoantibodies