ASSOCIATION OF ANTICARDIOLIPIN ANTIBODIES AND AUTOIMMUNE THROMBOCYTOPENIC PURPURA IN CHILDREN

Purpose: High levels of anticardiolipin antibodies (ACAs) have been de monstrated in the serum of patients with autoimmune thrombocytopenic p urpura (AITP). However, their clinical and pathogenic significance is still unknown. To determine the role of ACAs in the occurrence and evo lution of thrombocytopenia, we devised a prospective study in children with acute and chronic AITP. Patients and Methods: ACA IgG levels wer e assessed in each new patient admitted for AITP and in a control popu lation. Antinuclear antibodies, lupus anticoagulant, and ACA levels we re assessed monthly for at least 6 months in the case of positivity. T he rate and interval of resolution of thrombocytemia were compared acc ording to initial ACA levels and their evolution with time. Results: A mong 39 thrombocytopenic children (32 with acute AITP and 7 with chron ic AITP), 16 were ACA-positive (41%) while only 4 of 38 (10.5%) contro l patients displayed ACAs. Evolution of thrombocytopenia was not diffe rent in ACA-positive or negative patients, but the resolution of the t hrombocytopenia was highly correlated with ACA disappearance. Platelet count normalization usually occurred before ACA disappearance. Conclu sion: This frequent association of ACA and AITP suggests that ACAs pla y no role in the etiology of idiopathic thrombocytopenic purpura, but rather it results from the increase of platelet destruction that occur s during acute and chronic AITP.