Interleukin-6 and Serum/Fecal Calprotectin as Useful Specific Markers for Monitoring Rheumatic Diseases: A Pilot Study

Abstract Objective Some conventional laboratory tests are routinely used for the prediction of systemic autoimmune disease activity, such as the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP); however, they can give false-negative results, pointing out the need to identify more specific markers. Methods We evaluated biomarkers in 21 Italian patients naïve to treatment with a diagnosis of autoimmune rheumatic disease according to the 2010 American College of Rheumatology/European League Against Rheumatism Classification Criteria for Rheumatoid Arthritis during 6 months of therapeutic treatments. Results We found a significant difference in interleukin-6 (IL-6), CRP, ESR, platelet count, and fecal calprotectin in diagnosed patients compared with healthy participants and a significant decrease in these values during follow-up, except for IL-6 and platelet count. Conclusion We found that CRP, ESR, and fecal calprotectin seemed to be related to autoimmune rheumatic disorders and to be associated with therapy, whereas serum calprotectin and IL-6 did not seem to be associated with disease improvement after the start of treatment, along with leukocyte count and platelet count.