Galectin-1: A Potential Biomarker Differentiating between Early Rheumatoid Arthritis and Spondyloarthritis

Background: Galectin 1 (Gal1) is a lectin highly expressed in immune cells that plays a key immunoregulatory role in autoimmunity and resolution of chronic inflammation. Immune-mediated inflammatory diseases (IMIDs) are a broad group of disorders that share pathogenic mechanisms involving components of acquired and innate immunity. Although IMIDs can develop at onset similar features such as peripheral arthritis, they show differences in their evolution and response to treatments. Therefore, additional diagnostic biomarkers are needed in order to get a better classification of patients with early arthritis, especially those not fulfilling specific classification criteria. In this regard, we have recently described that Gal1 serum levels are increased in rheumatoid arthritis (RA) patients compared to healthy donors (HD). Thus, the objective of this work was to evaluate Gal1 levels in serum and synovial fluid from spondyloarthritis (SpA) patients in comparison with RA patients in order to determine their value as a diagnostic biomarker.Methods: We studied Gal1 levels in serum samples from SpA (n=55) and RA patients (n=52). In addition, 49 HD were studied. We also measured Gal1 synovial fluid levels in RA (n=26), osteoarthritis (OA) (n=26) and peripheral SpA (n=26). In SpA patients, clinical parameters were also collected in order to evaluate their association with Gal1 serum levels. Results: We found that SpA patients showed significantly lower Gal1 serum levels than RA patients and similar levels to the general population. In SpA patients, Gal1 synovial fluid levels were similar to those of OA patients and significantly lower than in RA patients. In addition, we did not find any correlation between Gal1 serum levels and clinical parameters of severity in SpA patients.Conclusions: Our results suggest that Gal1 might be a potential diagnostic biomarker of RA that could allow distinguishing between SpA and RA patients.