IL-8 AND THE ACTIVATION OF EOSINOPHILS AND NEUTROPHILS FOLLOWING NASAL ALLERGEN CHALLENGE

Background: A growing body of evidence suggests that proinflammatory c ytokines play a role in allergic inflammation by attracting and activa ting inflammatory cells. In this study, we have investigated the relat ionship between interleukin-8 (IL-8) in nasal lavage fluid and the loc al activation of eosinophils and neutrophils following nasal allergen challenge of allergic patients. Methods: Nasal challenges were perform ed with grass pollen extract in 14 allergic patients and 5 nonallergic controls. Nasal lavage fluid was collected repeatedly for 10 h, and t he levels of eosinophil cationic protein (ECP) and myeloperoxidase (MP O) were used as markers of eosinophil and neutrophil activation, respe ctively. The levels of these molecules were compared with that of IL-g in nasal lavage fluid. Results: Allergen challenge of allergic patien ts produced a significant late-phase increase in the levels of ECP and MPO. Furthermore, the level of MPO showed a highly significant correl ation with the level of IL-8 in lavage fluid (r = 0.8, p < 0.0001), wh ereas there was no significant relationship between the levels of ECP and IL-8. Conclusion: Interestingly, our findings suggest that both eo sinophils and neutrophils are activated following nasal allergen chall enge. In addition, our results are consistent with the hypothesis that IL-8 acts as a chemoattractant/activator of neutrophils during the la te phase of the allergic inflammation. In contrast, we were not able t o demonstrate any significant relationship between the level of IL-8 i n lavage fluid and the activation of eosinophils.