Background Triggering receptor expressed on myeloid cells 1 (TREM-1) is an immunoglobulin-like cell surface receptor mainly expressed on neurtophils, monocytes and macrophages. TREM-1 serves as a critical amplifier of inflammatory signaling, and its expression is increased in the synovium of rheumatoid arthritis (RA) patients. It can exist as a soluble form. However, the association between plasma sTREM-1 levels and disease activity in RA patients remains unclear.
Objectives In this study, we investigated whether plasma soluble TREM-1 (sTREM-1) levels are elevated in patients with RA and whether its levels are correlated with disease activity and other parameters.
Methods This cross-sectional study included 71 patients with RA and 50 age- and sex- matched healthy controls. Plasma samples were obtained from patients with RA during active and inactive disease status and from controls. We assessed clinical characteristics and laboratory parameters including the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and disease activity score 28 (DAS28). Their plasma levels of sTREM-1 and tumor necrosis factor (TNF)-α were quantitatively measured by enzyme-linked immunosorbent assay (ELISA).
Results Patients with RA had significantly higher plasma sTREM-1 levels than healthy controls (170.10±84.71 pg/mL vs 97.41±40.64 pg/mL, p<0.001). In RA patients plasma sTREM-1 levels were found to be correlated with DAS28, ESR, CRP, white blood cell counts, neutrophil counts, and plasma TNF-α levels (r =0.329, p =0.005;r =0.241, p =0.043; r =0.314, p <0.001; r =0.261, p =0.028; r =0.278, p =0.019; r =0.313, p =0.009, respectively). Plasma sTREM-1 levels in patients with a active disease status (DAS28 >3.2) were significantly higher than in those with a low disease status (DAS28 ≤3.2) (208.89±100.14 pg/mL vs 150.29±68.70 pg/mL, p=0.005).
Conclusions RA patients had higher plasma sTREM-1 levels than healthy controls, and plasma sTREM-1 levels were correlated with disease activity parameters, suggesting that plasma sTREM-1 could play a role in the inflammatory process associated with TNF-α, and that it may be a useful disease activity marker in RA.
Collins CE, La DT, Yang HT, Massin F, Gibot S, Faure G, et al. Elevated synovial expression of triggering receptor expressed on myeloid cells 1 in patients with septic arthritis or rheumatoid arthritis. Ann Rheum Dis 2009;68;1768-74.
Kuai J, Gregory B, Hill A, Pittman DD, Feldman JL, Brown T, et al. TREM-1 expression is increased in the synovium of rheumatoid arthritis patients and induces the expression of pro-inflammatory cytokines. Rheumatology 2009:1352-8.
Disclosure of Interest None Declared
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