EOSINOPHIL RECRUITMENT IS ASSOCIATED WITH IL-5, BUT NOT WITH RANTES, 24 HOURS AFTER ALLERGEN CHALLENGE

Several lines of evidence suggest that the chemokine RANTES may play a role in eosinophilia observed during allergic inflammation. To rest t his hypothesis six patients with allergic asthma were studied. After p erforming bronchoalveolar lavage in a lung segment (baseline), segment al bronchoprovocation was performed with saline solution in another se gment and with ragweed in a third segment. Bronchoalveolar lavage was performed 24 hours Inter in the saline-challenged (sham) and ragweed-c hallenged lung segments. The bronchoalveolar lavage fluids from the ba seline, sham, and ragweed segments were analyzed for cell counts and f or the levels of IL-5, RANTES, and eosinophil-derived neurotoxin. IL-5 levels were elevated in the ragweed (984 +/- 588 pg/ml) compared with sham segments (2.8 +/- 0.2 pg/ml, p = 0.02). Likewise, RANTES levels were elevated in the ragweed (12.93 +/- 3.4 pg/ml) compared with the s ham segments (3.05 +/- 1.19 pg/ml, p = 0.006). The IL-5 levels correla ted with both eosinophil numbers (r = 0.90, p < 0.02) and eosinophil-d erived neurotoxin levels (r = 0.89, p < 0.02). In contrast, RANTES lev els did not correlate with either eosinophil numbers or eosinophil-der ived neurotoxin levels. These results indicate that although both IL-5 and RANTES are elevated 24 hours after allergen challenge only IL-5 c orrelates with eosinophil recruitment and degranulation.