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.
BackgroundLaboratory tests of blood and sometimes urine are used to diagnose and to monitor disease activity (DA) in SLE. Clinical practice would be simplified if non-invasive urine and salivary tests could be introduced as alternatives to blood samples. We therefore explored the levels of innate immunity-related biomarkers in matched serum, urine and saliva samples from patients with SLE.MethodsA total of 84 patients with SLE selected to represent high and low general DA, and 21 controls were included. All participants underwent a thorough clinical examination. General DA and renal DA were measured. The levels of colony-stimulating factor (CSF)-1, interleukin (IL)-34, tumour necrosis factor (TNF)-α, interferon-γ-induced protein (IP)-10, monocyte chemoattractant protein (MCP)-1, calprotectin, macrophage inflammatory protein (MIP)-1α and MIP-1β were analysed by immunoassays and related to DA.ResultsCSF-1, TNF-α, IP-10 and MCP-1 in saliva, serum and urine, as well as calprotectin in saliva and urine were increased in patients with SLE as compared with controls (p<0.05). TNF-α, IP-10 and MCP-1 in saliva, serum and urine, and CSF-1 in saliva and serum distinguished patients with SLE from controls (area under the curve >0.659; p<0.05 for all). CSF-1 in serum and urine, and calprotectin in saliva and urine, as well as TNF- α, IP-10 and MCP-1 in urine correlated positively with measures of general DA (p<0.05). Patients with SLE with active renal disease presented elevated levels of TNF-α, IP-10 and MCP-1 in urine and CSF-1 and IP-10 in serum as compared with patients with SLE with non-active renal disease.ConclusionsOur investigation demonstrates that saliva is a novel alternative body fluid, with potential for surveillance of general DA in patients with SLE, but urine is more informative in patients with SLE with predominantly renal DA.
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