Elevated IL-38 Serum Levels in Newly Diagnosed Multiple Sclerosis and Systemic Sclerosis Patients

Objective: Interleukin (IL)-38 is a newly discovered member of the IL-1 cytokine family with a proposed anti-inflammatory profile. We studied the probable role of this cytokine in the pathogenesis of two autoimmune diseases: multiple sclerosis (MS) and systemic sclerosis (SSc). Subjects and Methods: A total of 87 MS patients and 86 SSc patients (40 new and recently untreated cases and 46 treated cases) were selected for this study. Eighty-seven and 80 age- and sex-matched healthy subjects were included as controls for MS and SSc, respectively. Clinical and paraclinical features of the patients were recorded at the time of sampling. Serum IL-38 was measured by ELISA. Results: Levels of serum IL-38 did not significantly differ between the total MS or SSc patients compared to controls. However, levels of IL-38 were significantly higher in newly diagnosed patients of MS (206.43 +/- 38.97 pg/mL, p < 0.0001) than in those previously treated (158.04 +/- 39.45 pg/mL). Similarly, new/recently untreated cases of SSc patients showed increased IL-38 levels (185.19 +/- 36.27 pg/mL, p = 0.001) compared to treated patients (166.82 +/- 33.08 pg/mL). IL-38 levels in newly diagnosed MS patients (p = 0.007) and new/recently untreated SSc patients (p = 0.032) were significantly higher than those in healthy controls. Conclusion: The higher serum levels of IL-38 in new or recently untreated cases of MS and SSc patients than in treated patients and healthy controls suggest the possible role of this cytokine in the development of these diseases or as part of a feedback loop to attenuate the inflammatory conditions in early stages of these diseases.