IgG Anti-β2 Glycoprotein I Antibodies in Malaysian Patients with Antiphospholipid Syndrome and Systemic Lupus Erythematosus: Prevalence and Clinical Correlations

Abstract

The aim of this study was to investigate the incidence of IgG anticardiolipin antibody (ACL) and IgG anti-beta(2) glycoprotein I antibody (anti-beta2GPI) positivity in patients with primary or secondary antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE), to assess the association between IgG ACL and anti-beta2GPI, and the relationship between the presence of ACL and anti-beta2GPI with the clinical manifestations of APS. IgG ACL and IgG anti-beta2GPI levels were measured in 51 SLE patients, 20 patients with SLE and APS (secondary APS) and 11 primary APS patients using commercially available ELISA kits. Relationships between laboratory data and clinical manifestations of the patients were examined. The incidence of IgG ACL positivity was significantly higher in primary (36.4%) and secondary (40%) APS than in SLE (13.7%) patients (P = 0.02). The incidence of IgG anti-beta2GPI positivity was significantly higher in primary (54.5%) and secondary (35%) APS than in SLE (7.8%) patients (P = 0.0006). Mean levels of IgG ACL and anti-beta2GPI were significantly higher in the primary and secondary APS than in the SLE patients (P = 0.002 for both). A significant relationship was found between IgG ACL and IgG anti-beta2GPI (P = 0.01, R(2) = 0.56). There was a significant correlation between the presence of IgG ACL and a history of thrombosis in the combined primary and secondary APS group, but not in SLE patients. In conclusion, in this study IgG ACL and IgG anti-beta2GPI are closely related and mean levels of IgG ACL and IgG anti-beta2GPI are higher in patients with either primary or secondary APS than in SLE patients.

Antiphospholipid syndrome in Asians: clinical manifestations, serological markers and outcome of the National University of Singapore/National University Hospital antiphospholipid cohort

“…While most of the Asian studies have focused on aCL, there have been five studies, including our study, looking at the role of aβ2‐GPI 16,18,39,44 . A significant relationship was found between aβ2‐GPI and aCL and their titres were closely correlated 16,44 .…”

Diagnosis of the antiphospholipid syndrome: How far to go?

“…High-titer IgG aCL have been associated with an increased thrombotic tendency [12,13], however this is not confirmed in all studies [14]. Ethnicity and assay techniques may contribute to the variability in outcomes reported in what are mainly retrospective population studies [13].…”

“…It has also been reported as high as 34.9% in a population of lupus patients without thrombotic history [14], although in some series it has been found in as few as 7.8% of SLE patients [12]. A significant relationship has been described between IgG aCL and IgG anti-␤ 2 GPI [12] although this is dependent on testing methodology. Antibodies to ␤ 2 GPI have been associated with thrombotic risk in some but not all studies [11,21,22].…”

“…The incidence of IgG anti-beta 2 glycoprotein I (␤ 2 GPI) may be high in primary APS (54.5%) and in APS secondary to SLE (35%) [12]. It has also been reported as high as 34.9% in a population of lupus patients without thrombotic history [14], although in some series it has been found in as few as 7.8% of SLE patients [12]. A significant relationship has been described between IgG aCL and IgG anti-␤ 2 GPI [12] although this is dependent on testing methodology.…”

“…Widely Available, Well-accepted Tests for Antiphospholipid Antibodies Immunoglobluin (Ig) G anticardiolipin antibodies (aCL) are the best established as a relatively sensitive and inexpensive test for the presence of antiphospholipid-related autoimmunity [12]. High-titer IgG aCL have been associated with an increased thrombotic tendency [12,13], however this is not confirmed in all studies [14].…”