Lipopolysaccharide-binding protein is a sensitive disease activity biomarker for rheumatoid arthritis.

This study was performed to evaluate the performance and clinical significance of lipopolysaccharide-binding protein (LBP) as a disease activity biomarker in rheumatoid arthritis (RA).LBP levels were measured by enzyme-linked immunosorbent assay (ELISA). The associations between LBP and the clinical and serological features of RA and its clinical significance as a RA disease activity biomarker were analysed.The serum level of LBP in RA was significantly elevated compared to those in OA, SLE, pSS and HC. The level of LBP in RA synovial fluid (SF) was higher than that in OA SF. LBP was significantly correlated with RA disease activity parameters such as ESR, CRP, tender joint counts, swelling joint counts and DAS28. Furthermore, LBP positive RA patients were more likely to show higher disease activity (DAS28>5.1), positive APF, interstitial lung disease and metabolic disorders. The predictive value of LBP on high disease activity was comparable with those of CRP and ESR. In 52.5% of the patients with active disease but negative in CRP /ESR, LBP was still positive and correlated with swelling joint counts.LBP is a sensitive serum biomarker to evaluate RA disease activity, and it could be a promising laboratory marker to assist RA disease activity assessment in active RA patients with negative ESR or CRP.