Relationship Between Serum Interleukin-6 Levels, Systemic Immune-Inflammation Index, and Other Biomarkers Across Different Rheumatoid Arthritis Severity Levels.

Background Rheumatoid arthritis (RA) is a chronic autoimmune disorder characterized by joint inflammation, pain, and progressive disability. Identifying biomarkers that accurately reflect disease severity is crucial for effective management. Interleukin-6 (IL-6) is a pro-inflammatory cytokine involved in the pathogenesis of RA, and the systemic immune-inflammation index (SII) is emerging as a useful marker of systemic inflammation.