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Mast cell hyperplasia in experimental hypersensitivity pneumonitis
P J Haley1, M Schuyler, K Gott
1Lovelace Inhalation Toxicology Research Institute, Albuquerque, N. Mex.
International Archives of Allergy and Applied Immunology
|January 1, 1991
Summary
Repeated exposure to Micropolyspora faeni antigen in guinea pigs increases lung mast cells and histamine levels, indicating their role in experimental hypersensitivity pneumonitis (EHP).
Area of Science:
- Immunology
- Pulmonary Medicine
- Pathology
Background:
- Experimental hypersensitivity pneumonitis (EHP) is an immune-mediated lung disease.
- Mast cells play a role in allergic and inflammatory responses.
- Understanding the cellular mechanisms in EHP is crucial for developing treatments.
Purpose of the Study:
- To investigate the role of mast cells in a guinea pig model of EHP.
- To assess changes in mast cell numbers and histamine levels following Micropolyspora faeni exposure.
Main Methods:
- Guinea pigs were subjected to weekly intratracheal challenges with Micropolyspora faeni antigen.
- Mast cell counts were determined in lung tissue.
- Histamine levels in bronchoalveolar lavage fluid were measured.
- Serum antibodies against M. faeni were analyzed.
Main Results:
- Significant increases in lung mast cells were observed after 8 challenges compared to 2 or 4 challenges.
- Mast cells accumulated around airways, blood vessels, and alveolar septa.
- Degranulating mast cells were identified ultrastructurally.
- Histamine levels in bronchoalveolar lavage fluid increased after 8 challenges.
- Serum anti-M. faeni antibodies were present in all exposed animals.
Conclusions:
- Repetitive intratracheal challenge with M. faeni antigen leads to increased mast cell presence and degranulation in the lungs.
- Elevated histamine levels in bronchoalveolar lavage fluid correlate with increased mast cell activity.
- These findings support the involvement of mast cells and histamine in the pathogenesis of EHP.