ALLERGEN CHALLENGE IN ASTHMA - ASSOCIATION OF EOSINOPHILS AND LYMPHOCYTES WITH INTERLEUKIN-5

To test whether eosinophil recruitment after pulmonary allergen challe nge is associated with interleukin (IL)-5 in patients with asthma, we performed segmental bronchoprovocation (SBP) with saline, and with low and high dosages of ragweed extract in six patients with allergic ast hma. Bronchoalveolar lavage (BAL) of the challenged segments was perfo rmed 5 min after challenge (immediate BAL fluid) and repeated 24 h lat er (late BAL fluid). Allergen challenge resulted in recruitment of eos inophils, and increased levels of eosinophil-active cytokines. A bioas say showed the predominant eosinophil-active cytokine in the late BAL fluids to be IL-5. Analysis of the late BAL fluids revealed that IL-5 levels correlated with the numbers of eosinophils and lymphocytes. Thi s study provides evidence that IL-5 is a critical cytokine associated with eosinophil and lymphocyte recruitment into the airways of patient s with asthma following exposure to allergen.