Elevated IgG Anticardiolipin Rate Linked with Increased Risk of Thrombotic Events in SLE Patients

By | July 12, 2016

Patients with systemic lupus erythematous had higher rates of thromboses when they had elevated rates of immunoglobulin G anticardiolipin and lupus anticoagulant, according to this study.

Vinicius Domingues, MD, from the Department of Rheumatology at New York University School of Medicine in New York, and colleagues analyzed 1,390 patients in the Hopkins Lupus Cohort with systemic lupus erythematous (SLE) who were tested multiple times for lupus anticoagulant and anticardiolipin antibodies, according to the abstract. The researchers categorized patients into immunoglobulin G (IgG), immunoglobulin M (IgM) and immunoglobulin A (IgA) anticardiolipin and lupus anticoagulant groups based on the geometric mean titres in dilute Russell’s viper venom time (RVVT) seconds, by which they compared the number of thrombotic events since patients’ SLE diagnosis.

Domingues and colleagues found a rate of 1.7 events per 100-person years from a total of 284 thrombotic events across 17,025 person-years since diagnosis, with patients who had a geometric mean titer of IgG anticardiolipin greater than 20 showing a higher rate of thromboses compared to other groups (rate ratio [RR] of 1.8), according to the abstract.

“Surprisingly, adding different anticardiolipin isotypes seems to decrease the isolated IgG anticardiolipin risk for thrombosis,” Domingues and colleagues wrote in their study. “Thus, additive scores do not appear to be valid in SLE.”

However, they found no association between elevated IgM geometric mean and thromboses (RR of 1.2) and there was insufficient evidence to determine an increased association between patients with elevated IgA geometric mean and thromboses (RR of 1.7).

“We are not implicitly recommending that the geometric mean titres should be used in clinical practice,” Domingues and colleagues wrote in their study. “We do recognize that [antiphospholipid syndrome] APS Classification Criteria recommend looking at repeat titres.” – by Jeff Craven

Source: Healio Rheumatology

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