Relationship of microparticles withβ 2-glycoprotein I and P-selectin positivity to anticardiolipin antibodies in immune thrombocytopenic purpura

1432-0584

Immune thrombocytopenic purpura Microparticle ; Anticardiolipin antibody P-selectin ; β 2-glycoprotein I

Springer Online Journal Archives 1860-2000

Medicine

Abstract We investigated the association ofβ 2-glycoprotein I and P-selectin with platelet-derived microparticles in 48 patients with immune thrombocytopenic purpura and 20 normal controls using two-color flow cytometric analysis. In addition, anticardiolipin antibodies were detected by an enzyme-linked immunosorbent assay. Platelet microparticles from the patients showed a higher positivity forβ 2-glycoprotein I than those from the normal controls (23.1±15.4% vs. 5.3±3.1%, p〈0.01), but this positivity was not related to the presence of platelet-associated IgG or to the severity of thrombocytopenia. In the 18 patients with more than 20% P-selectin-positive microparticles,β 2-glycoprotein I positivity was significantly higher than in the 30 patients with less than 20% P-selectin-positive microparticles (37.1±20.5% vs. 21.5±17.3%, p〈0.01). In addition, anticardiolipin antibodies were detected in eight patients, and they had a significantly higher level ofβ 2-glycoprotein I-positive microparticles than the patients without such antibodies (42.0±22.9% vs. 22.6±18.9%, p〈0.05). Our results suggest that anticardiolipin antibodies activate platelets in immune throm bocytopenic purpura and cause the generation of microparticles rich inβ 2-glycoprotein I and P-selectin. These microparticles may then act to regulate coagulation abnormalities in patients with anticardiolipin antibodies.

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