Antiphosphatidylinositol antibody in deep venous thrombosis patients

Antiphospholipid antibodies are a heterogeneous group of immunoglobulins with specificity for a number of phospholipids, phospholipid-binding proteins and phospholipid-protein complexes. The association between antiphospholipid antibodies and a variety of pathologic disorders, such as arterial and venous thrombosis and recurrent pregnancy loss is recognized as Antiphospholipid Syndrome. The immunoassay currently used to detect antiphospholipid antibodies is the anticardiolipin test. Anticardiolipin antibodies are believed to be polyspecific antibodies that cross-react with all the anionic phospholipids. Therefore, testing only for anticardiolipin antibodies does not always permit detection of all antiphospholipid antibodies, specially when only IgG are evaluated. In a selected population of 74 idiopathic and secondary deep venous thrombosis patients, IgG anticardiolipin, antiphosphatidylinositol and antiphosphatidylserine antibodies were detected by solid-phase immunoassays. Our results show that by testing for each antiphospholipid family, many patients, not evidenced by the standard anticardiolipin assay, were found to be antiphospholipid-positive. The anticardiolipin positive patients have always low, moderate or high levels of antiphospholipid antibodies, suggesting that the antiphospholipid positivity is predictive of anticardiolipin positivity. It should be noted that the patients with only antiphosphatidylinositol positive antibody have a story of nervous system pathology. The meaning of these results is at present under discussion.