β 2-Glycoprotein I IgA antibodies and ischaemic stroke: reply

Abstract Objectives aCL and anti-β2 glycoprotein I antibody (aβ2GPI) are autoantibodies associated with thromboembolic diseases. Here we investigated whether they are correlated with ischaemic cardiovascular disease in a Chinese population. Methods Serum total aCL and aβ2GPI isotypes (IgA, IgG or IgM, separately) were measured in 11 015 Chinese adults. Differences of antibody level between disease and non-disease groups were examined by t-test. The correlation between antibody and ischaemic cardiovascular disease was determined by logistic regression analysis. Performance of risk prediction models employed aCL or aβ2GPI isotypes was evaluated by C statistic, net reclassification improvement index and integrated discrimination improvement. Results Total aCL and aβ2GPI isotypes maintained low levels and increased with increasing age except total aCL and aβ2GPI IgG in participants older than 70 years. When distinguishing ischaemic cardiovascular disease by coronary heart disease (CHD) and ischaemic stroke, the stroke group had higher levels of aCL and aβ2GPI isotypes than the non-stroke group, while the CHD group only had a slightly higher aβ2GPI IgG than non-CHD groups. aCL and aβ2GPI were positively correlated with stroke but not with CHD, and improved the performance of conventional risk factors for stroke risk prediction, with C statistic from 0.769 (95% CI 0.744, 0.793) to 0.777 (95% CI 0.754, 0.800) (aβ2GPI IgG, P = 0.0091), and 0.778 (95% CI 0.754, 0.801) (aβ2GPI IgA, P = 0.0793). Stroke risk could be better reclassified by aCL and aβ2GPI, in association with both net reclassification improvement and integrated discrimination improvement statistics (P < 0.05). Conclusion aCL and aβ2GPI are associated with ischaemic stroke and have added value for stroke risk prediction.

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Is There an Additional Value in Detecting Anticardiolipin and Anti-β2 glycoprotein I IgA Antibodies in the Antiphospholipid Syndrome?

Thrombosis and Haemostasis ◽

10.1055/s-0040-1714653 ◽

2020 ◽

Vol 120 (11) ◽

pp. 1557-1568

Author(s):

Walid Chayoua ◽

Dong-mei Yin ◽

Hilde Kelchtermans ◽

Gary W. Moore ◽

Jean-Christophe Gris ◽

...

Keyword(s):

Antiphospholipid Syndrome ◽

Immunoglobulin A ◽

Clinical Manifestations ◽

Pregnancy Morbidity ◽

Medical Centers ◽

Glycoprotein I ◽

Iga Antibodies ◽

Obstetric Aps ◽

Current Criterion ◽

Additional Value

Abstract Background Anticardiolipin (aCL) and anti-β2 glycoprotein I (aβ2GPI) immunoglobulin A (IgA) antiphospholipid antibodies (aPL) have shown to associate with thrombosis and pregnancy morbidity. However, inclusion of IgA aPL in the classification criteria of the antiphospholipid syndrome (APS) has been debated. We investigated the value of aCL and aβ2GPI IgA aPL in the detection of thrombosis and pregnancy morbidity in addition to the current aPL panel for APS. Methods We included 1,068 patients from eight European medical centers: 259 thrombotic APS patients, 122 obstetric APS patients, 204 non-APS thrombosis patients, 33 non-APS obstetric patients, 60 APS patients with unspecified clinical manifestations, 196 patients with autoimmune diseases, and 194 controls. aCL and aβ2GPI IgG/M/A were detected with four commercial assays and lupus anticoagulant was determined by the local center. Results Positivity for IgA aPL was found in 17 to 26% of the patients with clinical manifestations of APS and in 6 to 13% of the control population. Both aCL and aβ2GPI IgA were significantly associated with thrombosis and pregnancy morbidity. Isolated IgA positivity was rare in patients with clinical manifestations of APS (0.3–5%) and not associated with thrombosis and/or pregnancy morbidity. Addition of IgA to the current criterion panel did not increase odds ratios for thrombosis nor pregnancy morbidity. Conclusion aCL and aβ2GPI IgA are associated with clinical manifestations of APS. However, isolated IgA positivity was rare and not associated with thrombosis or pregnancy morbidity. These data do not support testing for aCL and aβ2GPI IgA subsequent to conventional aPL assays in identifying patients with thrombosis or pregnancy morbidity.

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