title: Serum IL-15 in patients with early systemic sclerosis: a potential novel marker of lung disease.
abstract: The pathogenesis of systemic sclerosis (SSc) is characterized by autoimmunity, vasculopathy and fibrosis. IL-15 is a pleiotropic cytokine that has impact on immune, vascular and connective tissue cells. We therefore investigated IL-15 in the circulation of patients with early SSc and explored possible associations of serum IL-15 with vasculopathy and fibrosis. Serum levels of IL-15 were analysed in 63 consecutive patients with SSc of disease duration less than 4 years and without disease-modifying treatment. Thirty-three age-matched healthy control individuals were enrolled. Serum IL-15 levels were increased in the sera of SSc patients compared with that of healthy control individuals (P < 0.01). Serum IL-15 levels correlated with impaired lung function, assessed both by the vital capacity (P < 0.05) and by the carbon monoxide diffusion capacity (P < 0.05). The association between IL-15 and the vital capacity remained after multiple linear regression analysis. Patients with intermediate serum IL-15 levels had a higher prevalence of increased systolic pulmonary pressure compared with patients with either low or high serum IL-15 levels (P < 0.05). Moreover, increased serum IL-15 levels were associated with a reduced nailfold capillary density in multivariable logistic regression analysis (P < 0.01). Serum IL-15 levels also correlated inversely with the systolic blood pressure (P < 0.01). We conclude that IL-15 is associated with fibrotic as well as vascular lung disease and vasculopathy in early SSc. IL-15 may contribute to the pathogenesis of SSc. IL-15 could also be a candidate biomarker for pulmonary involvement and a target for therapy in SSc.
authors.affiliation: Department of Rheumatology, Lund University Hospital, S-221 85 Lund, Sweden. dirk.wuttge@med.lu.se
authors.forename: Dirk M
authors.initials: DM
authors.lastname: Wuttge
authors.forename: Marie
authors.initials: M
authors.lastname: Wildt
authors.forename: Pierre
authors.initials: P
authors.lastname: Geborek
authors.forename: Frank A
authors.initials: FA
authors.lastname: Wollheim
authors.forename: Agneta
authors.initials: A
authors.lastname: Scheja
authors.forename: Anita
authors.initials: A
authors.lastname: Akesson
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D019409:Interleukin-15 / Q000097:blood*; D008171:Lung Diseases / Q000097:blood* / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D012595:Scleroderma, Systemic / Q000097:blood* / Q000175:diagnosis; D013997:Time Factors