PT - JOURNAL ARTICLE AU - E L J van Rensen AU - R G Stirling AU - J Scheerens AU - K Staples AU - P J Sterk AU - P J Barnes AU - K F Chung TI - Evidence for systemic rather than pulmonary effects of interleukin-5 administration in asthma AID - 10.1136/thorax.56.12.935 DP - 2001 Dec 01 TA - Thorax PG - 935--940 VI - 56 IP - 12 4099 - http://thorax.bmj.com/content/56/12/935.short 4100 - http://thorax.bmj.com/content/56/12/935.full SO - Thorax2001 Dec 01; 56 AB - BACKGROUND Interleukin 5 (IL-5) has an important role in mobilisation of eosinophils from the bone marrow and in their subsequent terminal differentiation. A study was undertaken to determine whether inhaled and intravenous IL-5 could induce pulmonary eosinophilia and bronchial hyperresponsiveness (BHR) independently of these effects.METHODS Nine mild asthmatics received inhaled (15 μg) or intravenous (2 μg) IL-5 or placebo in random order in a double blind, crossover study. Blood samples were taken before and at 0.5, 1, 2, 3, 4, 5, 24, and 72 hours following IL-5 or placebo, and bronchial responsiveness (PC20 methacholine) and eosinophil counts in induced sputum were determined.RESULTS Serum IL-5 levels were markedly increased 30 minutes after intravenous IL-5 (p=0.002), and sputum IL-5 levels increased 4 and 24 hours after inhaled IL-5 (p<0.05). Serum eotaxin was raised 24 hours after intravenous IL-5 but not after inhaled IL-5 or placebo. Blood eosinophils were markedly reduced 0.5–2 hours after intravenous IL-5 (p<0.05), followed by an increase at 3, 4, 5, and 72 hours (p<0.05). Sputum eosinophils rose significantly in all three groups at 24 hours but there were no differences between the groups. Bronchial responsiveness was not affected by IL-5.CONCLUSION The effects of IL-5 appear to be mainly in the circulation, inducing peripheral mobilisation of eosinophils to the circulation without any effect on eosinophil mobilisation in the lungs or on bronchial responsiveness.