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J Allergy Clin Immunol. 2001 Feb;107(2):265-71.

IL-4 production by human basophils found in the lung following segmental allergen challenge.

Author information

1
Johns Hopkins Asthma & Allergy Center, Department of Medicine, Division of Clinical Immunology, Baltimore, Md 21224, USA.

Abstract

BACKGROUND:

Human blood basophils secrete high levels of IL-4 following activation with specific allergen, yet their role as cytokine-producing cells in allergic lesions has not been described.

OBJECTIVE:

Our objective was to investigate whether and under what conditions basophils infiltrating allergic lesions in the lung secrete IL-4 in vitro.

METHODS:

Bronchoalveolar lavage (BAL) cells were recovered 20 hours after segmental allergen challenge. Basophils were enriched with Percoll using a protocol commonly used for blood basophils. IL-4 and histamine were measured in culture supernatants following activation with a variety of stimuli. Two-color flow cytometry was performed to detect intracellular IL-4.

RESULTS:

IL-4 protein was detected in all basophil culture supernatants following a 4- to 5-hour incubation in medium alone; the levels obtained did not significantly increase with the addition of anti-IgE. BAL basophils failed to release histamine in response to specific allergen but showed nearly 60% histamine release with N-formyl-methionyl-leucyl-phenylalanine, suggesting that they were desensitized to IgE-mediated stimuli as a result of their activation in vivo. Using these same conditions, IL-4 was not detected in BAL cell fractions enriched for lymphocytes and eosinophils. Ionomycin induced IL-4 secretion by BAL basophils, and this response was reduced with the addition of phorbol myristate acetate. In contrast, phorbol myristate acetate promoted the secretion of IL-4 by BAL cells enriched for lymphocytes; both findings are identical to those reported for basophils and lymphocytes purified from blood. Flow cytometry confirmed the secretion of IL-4 by BAL basophils.

CONCLUSIONS:

These data suggest that basophils migrating to the lung following allergen challenge represent a major source of IL-4.

PMID:
11174192
DOI:
10.1067/mai.2001.112846
[Indexed for MEDLINE]

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