The function and properties of human lung mast cells

Area of Science:

• Immunology
• Pulmonology
• Cell Biology

Background:

• Mast cells in the airways play a role in allergic responses.
• Bronchoalveolar lavage is a method to collect airway cells.
• Asthma involves airway inflammation and bronchoconstriction.

Purpose of the Study:

• To investigate the characteristics and mediator release of bronchoalveolar mast cells (BAMCs) in human subjects.
• To compare BAMCs from asthmatic and non-asthmatic individuals.
• To explore the role of BAMCs in asthma pathogenesis.

Main Methods:

• Bronchoalveolar lavage to obtain human mast cells.
• In vitro challenge of BAMCs with IgE-dependent stimuli (anti-IgE) and antigens.
• Measurement of histamine, leukotriene C4 (LTC4), and prostaglandin D2 (PGD2) release.
• Investigation of non-immunological histamine release using mannitol.

Main Results:

• BAMCs release histamine in an IgE-dependent, dose-, time-, and energy-dependent manner.
• Asthmatic subjects have higher percentages of BAMCs and increased histamine releasability compared to controls.
• Spontaneous histamine release from asthmatic BAMCs is significantly higher.
• Mannitol induces dose-dependent histamine release, inhibited by sodium cromoglycate.
• Anti-IgE challenge releases LTC4 and PGD2 from normal BAMCs, with PGD2 release correlating with histamine release.

Conclusions:

• BAMCs exhibit distinct functional characteristics and are increased in asthmatic airways.
• Increased releasability and spontaneous histamine release from asthmatic BAMCs suggest a role in asthma.
• Non-immunological mechanisms contribute to histamine release.
• Mediator release from BAMCs, accessible to inhaled antigens, is relevant to asthma pathogenesis.