Neutrophils defensins: their possible role in allergic asthma

Background: Neutrophil defensins, originally identified as broad-spectrum antimicrobial peptides, have been implicated in the regulation of inflammatory and immunological processes. Objectives: To investigate whether the in vitro challenge of neutrophils from patients with bronchial asthma with allergens stimulated the release of alpha-defensins and whether levels released were dependent on lung infections. Method: The neutrophils were cultivated with different agonists and the concentration of alpha-defensin in cell-free supernatant was measured with enzyme-linked immunosorbent assay (ELISA). Results: Neutrophils from allergic patients released alpha-defensins via an allergen-dependent mechanism. Our results indicate that the in vitro activation of neutrophils is highly allergen-specific. In this context, allergens other than those which produced clinical symptoms did not elicit alpha-defensin release, and allergens had no effect on neutrophils from healthy donors. However, neutrophils from both allergic patients and healthy controls were able to release alpha-defensins upon treatment with PMA. In the allergen-stimulated neutrophils, cells from asthmatic patients stimulated with a sensitizing allergen showed a significantly higher production of alpha-defensin under respiratory tract infection than cells from the same patients without such an infection Conclusion: Neutrophils from allergic patients release alpha-defensins via an allergen-dependent mechanism.