Abstract
Objective. An often-neglected subset of patients with systemic lupus erythematosus (SLE) is those with secondary Sjögren syndrome (SLE-sSS). Further, primary SS overlaps and can be difficult to delineate from SLE. To shed light on the SLE-sSS subset, we investigated a large and well-characterized SLE cohort, comparing patients with SLE-sSS and SLE patients without SS (SLE-nonsSS) and controls.
Methods. We included 504 consecutive patients with SLE, fulfilling the 1982 revised American College of Rheumatology criteria, and 319 controls from the general population, matched for age and sex to the first 319 patients. SLE-sSS was defined according to the American-European Consensus Criteria (AECC). A thorough clinical examination, including subjective and objective quantifications of sicca symptoms, was performed in all participants. Autoantibodies and 20 selected cytokines were measured by luminex and multiplex analysis, respectively.
Results. SLE-sSS, as defined by AECC, occurred in 23% of the patients with SLE. In comparison to SLE-nonsSS, the SLE-sSS group was older and more frequently female. Leukopenia and peripheral neuropathy were more frequent and nephritis less frequent. Circulating levels of 6/20 investigated proinflammatory cytokines [tumor necrosis factor-α, interleukin (IL) 6, monocyte chemoattractant protein 4, macrophage inflammatory protein 1β, IL-12/IL-23p40, and interferon γ–induced protein 10], total IgG, anti-SSA/Ro52, anti-SSA/Ro60, anti-SSB/La antibodies, and rheumatoid factor (IgM and IgA) were higher in the SLE-sSS group (p < 0.05 for all comparisons).
Conclusion. The frequency of SLE-sSS increased with age and affected roughly one-quarter of all patients with SLE. Despite less internal organ involvement, a systemic inflammatory state with high levels of proinflammatory cytokines is present in the SLE-sSS subgroup. This is a novel observation that may affect future understanding and treatment of the SLE-sSS subset.
- SYSTEMIC LUPUS ERYTHEMATOSUS
- SJÖGREN SYNDROME
- SICCA SYMPTOMS
- SJÖGREN SYNDROME ANTIGEN A
- SJÖGREN SYNDROME ANTIGEN B
- CYTOKINES
Footnotes
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Supported by The Swedish Research Council (grant no. 2014-33867), Swedish Heart-Lung Foundation (grant nos. 20130430, 20130552,20170257), Stockholm County Council (ALF, grant nos. 2014016, 20170038), The King Gustaf V 80th Birthday Fund (grant no. FAI-2017-0390), The Swedish Rheumatism Association (grant no. R-739631), Karolinska Institutet’s Foundations, The Swedish Society of Medicine, Ingegerd Johansson’s foundation (SLS-713911), The Swedish Dental Society, and clinical research grants from Sörmland county (no: DLL-614351, DLL-648991). S. Eketjäll is an employee at AstraZeneca. AstraZeneca provided reagents for the cytokine analyses, but AstraZeneca had no influence on the analyses or on the presentations in this manuscript.
- Accepted for publication August 23, 2019.
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