Plasma sLOX-1 is a potent biomarker of clinical remission and disease activity in patients with seropositive RA

OBJECTIVES: Soluble lectin-like oxidized low-density lipoprotein receptor 1 (sLOX-1) is present in the circulation and synovial fluid in patients with rheumatoid arthritis (RA). The aim of this study was to assess whether sLOX-1 level is associated with clinical remission and disease activity in patients with RA. METHODS: Clinical and laboratory data were analyzed for 282 patients with RA. Plasma sLOX-1 level was measured by enzyme-linked immunosorbent assay (ELISA). The remission status and sLOX-1 levels were compared between four groups of patients based on the positivity of rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPAs). Relationships between sLOX-1 level and the 28-joint Disease Activity Score with erythrocyte sedimentation rate (DAS28-ESR) were analyzed by multivariate logistic regression. RESULTS: The patients in the RF + ACPA + group tended to exhibit higher sLOX-1 levels when compared to the other three groups. In the RF + ACPA + group, the sLOX-1 level was significantly higher in the non-remission group than in the remission group, irrespective of treatment. Multivariate logistic regression showed significant correlations between sLOX-1 level and DAS28-ESR. CONCLUSIONS: sLOX-1 level might be a useful biomarker for assessing clinical remission and disease activity in double-positive RA patients.