medwireNews: Individuals with COVID-19 have a high prevalence of lupus antigen (LA) positivity upon hospital admission, but this is not associated with an increased risk for venous thromboembolism (VTE) or in-hospital mortality, French researchers report.
The prospective, observational study, by David Smadja (Georges Pompidou European Hospital, Paris) and colleagues, included 249 people who were hospitalized with suspected COVID-19 between March 14 and April 20, 2020.
Of these, 61.8% had confirmed COVID-19 and the remainder were ultimately diagnosed with other illnesses.
Smadja and team found that the LA positivity rate at admission was significantly higher among the patients with versus without COVID-19, at 60.9% versus 23.7%.
They also report that the prevalence of conventional and non-conventional antiphospholipid antibodies (APA) was low (≤10.5%) in both groups, with few significant differences between them.
For example, anti-cardiolipin immunoglobulin (Ig)G, IgM, and IgA antibodies were detected in 5.8%, 1.3%, and 1.9% of people with COVID-19, respectively, and in a corresponding 3.2%, 7.4%, and 2.1% of those without COVID-19. The difference for IgM, but not IgG or IgA, was statistically significant. Other antibodies measured included anti-beta-2-GP1 and anti-prothrombin.
Among the inflammatory markers measured, levels of fibrinogen (6.0 vs 5.3 g/L) and C-reactive protein (CRP, 115.5 vs 91.8 mg/L) were significantly higher in the COVID-19 patients who were positive versus negative for LA. Conversely, interleukin-6 and ferritin levels did not differ significantly between the two groups.
Smadja and co-authors note in Arthritis and Rheumatology that the “[d]iscrepancy between different inflammatory markers and LA positivity association suggested that those inflammation markers do not [each] have the same relevance in COVID-19.”
They add: “Further studies need to decipher the exact involvement of inflammatory proteins and COVID-19 severity and/or their involvement in COVID-19 associated coagulopathy.”
In terms of outcomes, there were no significant differences between LA-positive and LA-negative COVID-19 cases in the rates of intensive care referrals (61.4 vs 55.6%), VTE (27.1 vs 26.8%), or in-hospital mortality (24.3 vs 15.6%).
And both univariate and multivariate analyses showed no significant associations between LA positivity and VTE or in-hospital mortality risk.
The investigators “acknowledge that in the present study, APA [tests] were performed during the acute phase,” which they say “is discouraged in the guidelines because of potential interference and guidelines recommend retesting after 3 months to avoid overdiagnosis by classification of transient positivity of APA.”
They therefore conclude: “LA and APA testing is not recommended and must be discouraged during the acute phase of COVID-19 as for other viral infections.”
medwireNews is an independent medical news service provided by Springer Healthcare Ltd. © 2021 Springer Healthcare Ltd, part of the Springer Nature Group
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