[Antiphospholipid antibodies in children with idiopathic thrombocytopenic purpura]

Three antiphospholipid antibodies (aPLs), namely, antiphosphatidylinositol antibody (antiinositol antibody), antiphosphatidylserine antibody (antiserine antibody), and anticardiolipin. beta 2-glycoprotein I complex antibody (antiCL. beta 2-GPI antibody), were determined in 49 children with idiopathic thrombocytopenic purpura (ITP) consisting of 14 newly-diagnosed cases and 35 chronic cases. Determination of aPL was performed twice in the newly-diagnosed patients, once each during the acute and convalescent phases, and once in the chronic patients. The positive rates in the acute and convalescent phases of the newly-diagnosed group and in the chronic group were, respectively, 14.3%, 28.6%, and 18.8% for the antiinositol antibody, 14.3%, 14.3%, and 15.6% for the antiserine antibody, and 21.4%, 28.6%, and 25.0% for either of these 2 antibodies. Thus, antiinositol and antiserine aPLs were present at high incidences; however, all patients were negative for the antiCL. beta 2-GPI antibody. No correlation was noted between either the antiinositol or the antiserine antibody and peripheral platelet count, anti-GP IIb/IIIa antibody or PAIgG. Thus, although some aPLs are present in both acute and chronic pediatric ITP, the aPLs seems to be of an infectious disease type. No results that suggest possible involvement of aPLs in ITP pathology were obtained.