Isolated IgA Anti-β2 Glycoprotein I Antibodies in Patients with Clinical Criteria for Antiphospholipid Syndrome

Abstract

Seronegative antiphospholipid syndrome (SNAPS) is an autoimmune disease present in patients with clinical manifestations highly suggestive of Antiphospholipid Syndrome (APS) but with persistently negative consensus antiphospholipid antibodies (a-PL). IgA anti-β2 Glycoprotein I (aB2-GPI) antibodies are associated with APS. However, they are not currently considered to be laboratory criteria due to the heterogeneity of published works and the use of poor standardized diagnostic systems. We have aimed to assess aPL antibodies in a group of patients with clinical manifestations of APS (C-APS) to evaluate the importance of the presence of IgA aB2GPI antibodies in APS and its relation with other aPL antibodies. Only 14% of patients with C-APS were positive for any consensus antibody, whereas the presence of isolated IgA aB2GPI antibodies was found in 22% of C-APS patients. In patients with arterial thrombosis IgA aB2GPI, antibodies were the only aPL antibodies present. Serologic profile in primary APS (PAPS) is different from systemic autoimmune disorders associated APS (SAD-APS). IgA aB2GPI antibodies are more prevalent in PAPS and IgG aB2GPI antibodies are predominant in SAD-APS. The analysis of IgA aB2GPI antibodies in patients with clinical manifestations of PAPS might avoid underdiagnosed patients and provide a better diagnosis in patients with SAD-APS. Laboratory consensus criteria might consider including analysis of IgA aB2GPI for APS diagnosis.

Update on the pathogenesis and treatment of the antiphospholipid syndrome

“…Anti-b2GPI IgA might even provide a marker of seronegative APS, since this test has been shown to identify patients with manifestations highly suggestive of APS, but no consensus aPLs [40][41][42].…”

Anti-phospholipid Antibodies and Smoking: An Overview

“…In a large multi-center, multi-ethnic cohort (LUMINA), Murthy et al reported that isolated IgA anti-β2GPI was associated with thrombosis [125]. Ruiz-García et al reported that IgA anti-β2GPI was associated with primary APS [126], and similar findings were reported by Mattia et al [127]. None of these studies reported whether there was an association between smoking and the IgA antibodies in their patient population.…”

Association of Early Kidney Allograft Failure with Preformed IgA Antibodies to β 2-Glycoprotein I

“…The manufacturer's cutoff was perfectly comparable with that observed in the Spanish population. 19 Crossmatching between recipient (serum) and donor (lymphocyte suspension) was performed by cytolysis mediated by a specific antibody in the presence of complement. 56 Patients were transplanted only if the crossmatch was negative.…”

“…Only 14% of patients with C-APS were positive for any consensus antibody, whereas the presence of isolated IgA aB2GPI antibodies was found in 22% of patients with C-APS. 19 Although most of the works highlighted the value of IgA aB2GPI antibodies in the diagnosis of APS, the meaning of the presence of aB2GPI IgA antibodies is still under debate in the literature, because the available diagnostic tools have not been sufficiently standardized and the diagnostic assays used in some works with negative results were not optimal. 20 aPL antibodies of isotypes IgG and IgM are more frequent in patients with CKD than the general population.…”