Relation of Immunoglobulin A Isotype of Anti -β2 Glycoprotein I to Clinical and Laboratory Features of Antiphospholipid Syndrome and Systemic Lupus Erythematosus

Introduction: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the production of autoantibodies to components of the cell nucleus. Antiphospholipid syndrome (APS) is the most common type of acquired thrombophilias. The diagnosis of APS should be made on the presence of the characteristic clinical manifestations of thrombosis/pregnancy morbidity and the presence persistently positive antiphospholipid antibodies [aPL] (anticardiolipin [aCL] IgM/IgG or anti-β2 glycoprotein I [anti-β2GPI] IgM/IgG), lupus anticoagulant [LA] or both. Aim of the Work: Clarifying the significance of anti-β2GPI of IgA isotype among Egyptian lupus patients with and without APS regarding clinical and laboratory features of both diseases. Patients and Methods: The study included 54 SLE patients. Twenty seven (50%) of those patients had no APS while the other half had secondary APS. Patients with other known causes of thrombophilia were excluded. Twenty seven apparently normal age and sex-matched Egyptian control persons were included. Patients were subjected to clinical assessment and routine laboratory tests. Both patients and controls were evaluated for the presence of lupus anticoagulant, anti-β2GPI of IgM, IgG and IgA isotype as well as aCL of IgM, IgG and IgA isotypes. Results: Dural sinus thrombosis and autoimmune thrombocytopenia were significantly more common in patients with positive anti -β2GPI IgA (p-value: 0.025 and 0.03 respectively). Conclusion: Anti -β2GPI of IgA isotype seems to contribute to the pathogenesis of thrombotic and non thrombotic manifestations of SLE and APS i.e. dural sinus thrombosis and autoimmune thrombocytopenia.