Interferons and systemic sclerosis: correlation between interferon gamma and interferon-lambda 1 (IL-29)

Background: Interferon (IFN)-1 is a newly described cytokine, member of type III interferons family, which is known for its antiviral, anti-proliferative and antitumor activity. Recent studies indicated that this cytokine has also immune-regulatory function, but its role in the pathogenesis of autoimmune diseases is not established yet. We evaluated serum levels of IFN-1 in systemic sclerosis (SSc) patients and healthy controls and its association with IFN- and clinical manifestations. Methods: IFN-1 and IFN- serum levels were measured by ELISA from 52 patients with SSc and 53 healthy controls. Association of cytokines serum levels was sought with clinical parameters. Results: IFN-1 and IFN- levels in SSc patients were significantly higher than those in healthy individuals (24.82 +/- 8.78 and 11.04 +/- 3.04pg/ml, p<0.0001; 34.11 +/- 8.11 and 10.73 +/- 2.77pg/ml, p<0.0001, respectively). We found a positive correlation between IFN-1 and IFN- levels in SSc patients (p=0.0103, r=0.3526). IFN- levels were associated with muscle involvement (p=0.0483). Conclusion: We first showed raised IFN-1 levels in SSc patients. Furthermore, we found a correlation between IFN-1 and IFN- levels and an association between IFN- and myositis. Additional in vitro and in vivo studies are needed to understand IFN-1 role in SSc.