Type-III interferons and rheumatoid arthritis: Correlation between interferon lambda 1 (interleukin 29) and antimutated citrullinated vimentin antibody levels

Aim: To assess serum type III or lambda (λ) interferons (IFN) levels and its clinical and laboratory associations in rheumatoid arthritis (RA). Methods: A cross-sectional study including 43 patients with RA (86% females; age 45.3?±?10.3 years) and 43 healthy individuals was performed. Clinical data including disease activity, acute-phase reactants, rheumatoid factor and anticyclic citrullinated peptide (anti-CCP) antibodies were collected. Serum IFNλ1, IFNλ2, IFNλ3, CXCL8 and anti-mutated citrullinated vimentin (anti-MCV) antibody levels were measured. Results: Patients with RA had higher IFNλ1 (113.5?±?118.6?pg/mL versus 55.9?±?122.3?pg/mL; p?<?0.0001) and IFNλ2 (245.4?±?327.7?pg/mL versus 5.1?±?11.0?pg/mL; p?=?0.009) levels than controls, but not IFNλ3 levels. Notably, IFNλ1 levels were found to be higher in both patients with active disease (124.9?±?135.9?pg/mL; p?<?0.001) and quiescent disease (99.0?±?93.7?pg/mL; p?<?0.01), while IFNλ2 levels were higher only in patients with active disease (264.0?±?356.1?pg/mL; p?=?0.02). A noteworthy association between serum IFNλ1 levels and anti-MCV antibody titers (Spearman's rho coefficient 0.36, 95% CI 0.36 to 0.61; p?=?0.02) was observed. Conclusion: Serum IFNλ1 and IFNλ2 levels are abnormally elevated in patients with RA and the former are linearly associated with circulating anti-MCV antibody levels. These results may place type-III IFN as an attractive new therapeutic target in RA.