Association between intestinal permeability, systemic inflammation, and response to anti-TNF therapy in patients with rheumatoid arthritis: a prospective controlled study

Objectives: To evaluate the association between biomarkers related to intestinal epithelial barrier integrity, systemic inflammation, and clinical response to anti-TNF therapy in patients with rheumatoid arthritis (RA). Methods: A prospective controlled 24-week study of patients with active RA receiving anti-TNF therapy was performed. Findings were compared with those of age- and sex-matched healthy controls. Values of tight junction proteins (occludin, claudin-1), zonulin, lipopolysaccharide (LPS), and LPS-binding protein (LBP) were determined in serum and feces at baseline and at 6 months. The associations with clinical, inflammatory, and remission parameters (DAS28-CRP ≤2.6) were analyzed. Multivariate models explored links between intestinal, inflammatory, and treatment response biomarkers. Results: The study population comprised 70 patients with RA and 70 controls. Baseline serum levels of occludin and claudin-1 were lower in patients than in controls (p