Serum sTREM-1 in adult-onset Still's disease: a novel biomarker of disease activity and a potential predictor of the chronic course.

Objectives: Triggering receptor expressed on myeloid cells-1 (TREM-1) is an amplifier of inflammatory signals. Recently, a soluble form of TREM-1 (sTREM-1) was described. This study aimed to investigate the role of serum sTREM-1 in patients with adult-onset Still's disease (AOSD).
Methods: Serum sTREM-1 levels were detected in 108 AOSD patients, 88 RA patients and 112 healthy controls (HC). The correlations of sTREM-1 with disease activity, clinical characteristics and laboratory parameters in AOSD patients were analysed by the Spearman correlation test. Risk factors for the chronic course of AOSD were evaluated by multivariate logistic regression analysis.
Results: AOSD patients had significantly higher serum sTREM-1 levels than RA patients and HC, and serum sTREM-1 levels were correlated with the systemic score, ferritin, leucocyte count, CRP, IL-1β and IL-6. The elevation in the initial sTREM-1 level by itself could discriminate patients developing the chronic course from patients developing the nonchronic course. Moreover, an elevated sTREM-1 level (> 526.4475 pg/ml) was an independent risk factor for the chronic course in active AOSD patients. Furthermore, interfering with TREM-1 engagement led to reductions in the secretion of pro-inflammatory cytokines, such as IL-1β, IL-6 and TNF-α, in neutrophils and monocytes from active AOSD patients.
Conclusion: Serum sTREM-1 levels are correlated with disease activity, and an elevation in the initial serum sTREM-1 level is a potential predictor of the chronic course in AOSD patients, which currently provides the best predictive model for identifying patients prone to developing the chronic course of AOSD.
(© The Author(s) 2020. Published by Oxford University Press on behalf of the British Society for Rheumatology.)