Serum interleukin 9 levels are increased in patients with systemic sclerosis: association with lower frequency and severity of pulmonary fibrosis

J Rheumatol. 2011 Oct;38(10):2193-7. doi: 10.3899/jrheum.110268. Epub 2011 Aug 1.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Female
  • Humans
  • Interleukin-9 / blood*
  • Male
  • Middle Aged
  • Pulmonary Fibrosis / diagnosis
  • Pulmonary Fibrosis / epidemiology
  • Pulmonary Fibrosis / immunology*
  • Scleroderma, Systemic / complications
  • Scleroderma, Systemic / immunology*
  • Severity of Illness Index

Substances

  • Interleukin-9