CLINICAL-SIGNIFICANCE OF IMMUNOGLOBULIN-A ANTIPHOSPHOLIPID ANTIBODIES- POSSIBLE ASSOCIATION WITH SKIN MANIFESTATIONS AND SMALL VESSEL VASCULITIS

Objective. To clarify whether immunoglobulin A (IgA) antiphospholipid antibodies (aPL) are an independent risk factor for specific manifesta tions of collagen vascular diseases. Methods. We determined IgG, IgM, and IgA anticardiolipin antibodies (aCL) and lupus anticoagulant (LAC) in 77 patients with various collagen diseases. Fifty-four patients wh o had positive results for either or both antibody classes were compar ed to 23 patients with systemic lupus erythematosus who had none of th ese antibodies. The association between the antibodies and clinical ma nifestations (thrombosis, fetal loss, thrombocytopenia. biological fal se positive test for syphilis, cutaneous manifestations, central nervo us system involvement, and renal involvement) was analyzed. Results. O f 54 patients with aPL, 33 showed significantly high levels of IgA aCL , Among them, IgA aCL coexisted with other aCL isotypes or LAC in 24 p atients. The 9 patients with IgA aCL alone frequently had vasculitis a ssociated manifestations, although thrombotic events and recurrent fet al loss were rare. Multivariate linear regression analysis showed that IgA aCL were independently associated with thrombocytopenia, skin ulc ers, chilblain lupus, and vasculitis. There was also an association be tween IgM aCL and skin ulcers or chilblain lupus, Conclusion. Clinical manifestations of patients with IgA aCL differ from those of patients with IgG aCL. Determination of all 3 aCL isotypes and LAC is importan t to assess the risk of specific clinical manifestations in patients w ith aPL.