%0 Journal Article %A KOICHI YANABA %A AYUMI YOSHIZAKI %A YOSHIHIDE ASANO %A TAKAFUMI KADONO %A SHINICHI SATO %T Serum Interleukin 9 Levels Are Increased in Patients with Systemic Sclerosis: Association with Lower Frequency and Severity of Pulmonary Fibrosis %D 2011 %R 10.3899/jrheum.110268 %J The Journal of Rheumatology %P 2193-2197 %V 38 %N 10 %X Objective. To determine serum interleukin 9 (IL-9) levels and their clinical associations in patients with systemic sclerosis (SSc). Methods. Serum IL-9 levels were examined by ELISA in 71 patients with SSc, 15 with systemic lupus erythematosus (SLE), 15 with dermatomyositis (DM), 39 with atopic dermatitis, and 28 healthy individuals. Results. Serum IL-9 levels were significantly elevated in SSc patients (84.6 ± 76.0 pg/ml) compared with healthy individuals (40.4 ± 41.7 pg/ml; p < 0.001), and patients with SLE (50.7 ± 52.0 pg/ml; p < 0.05) or DM (50.6 ± 55.8 pg/ml; p < 0.05) or atopic dermatitis (41.8 ± 38.8 pg/ml; p < 0.001). Among SSc patients, there were no differences in serum IL-9 levels between those with limited cutaneous SSc and those with diffuse cutaneous SSc. Patients with SSc and raised IL-9 levels less often had pulmonary fibrosis and decreased percentage vital capacity than those with normal IL-9 levels. IL-9 levels were positively correlated with percentage vital capacity in patients with SSc. Conclusion. Serum IL-9 level was increased in patients with SSc, and was associated with lower frequency and severity of pulmonary fibrosis in SSc. IL-9 could be a protective factor against the development of pulmonary fibrosis in this disease, and as such would be a possible therapeutic target. %U https://www.jrheum.org/content/jrheum/38/10/2193.full.pdf