RT Journal Article SR Electronic T1 Serum Interleukin 9 Levels Are Increased in Patients with Systemic Sclerosis: Association with Lower Frequency and Severity of Pulmonary Fibrosis JF The Journal of Rheumatology JO J Rheumatol FD The Journal of Rheumatology SP 2193 OP 2197 DO 10.3899/jrheum.110268 VO 38 IS 10 A1 KOICHI YANABA A1 AYUMI YOSHIZAKI A1 YOSHIHIDE ASANO A1 TAKAFUMI KADONO A1 SHINICHI SATO YR 2011 UL http://www.jrheum.org/content/38/10/2193.abstract AB 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.