Review Question - QID 100865

The patient has asthma and his symptoms are due to factors released following mast cell Fc-receptor cross-linking and degranulation. The antibodies that bind to mast cells, IgE, are brought about by IL-4-mediated class-switching in B-cells.

In asthma, a stimulus leads to the secretion of IL-4 (amongst other cytokines) by Th2 T-cells. IL-4 leads to B cell class-switching and the production of IgE antibodies. These antibodies bind to mast cells and, in subsequent exposures, the antibody-receptor complexes aggregate and cross-link, resulting in degranulation of the mast cells. This culminates in bronchoconstriction and other symptoms of asthma.

Pollart et al. discuss the management of acute exacerbations of asthma and describe the use of short-acting beta-2 agonists as an essential form of therapy. They also discuss the usefulness of corticosteroids (prednisolone) and leukotriene antagonists (montelukast) in decreasing symptoms.

Barnes discusses the pathophysiology of asthma and highlights the importance of cytokines in directing the inflammatory reaction. The author goes on to note that factors released from airway epithelial cells also play a critical role in the inflammatory reaction, therefore they are possible therapeutic targets.

Illustration A depicts several of the hallmarks of asthma: thickened basement membrane, mucus in the airways, increased mucous glands, etc.

Incorrect Answers:
Answer 1: The actions of IL-2 are more consistent with stimulating the growth of T-cells.
Answer 3: The actions of IL-5 are more consistent in the activation of eosinophils.
Answer 4: The actions of IL-10 are more consistent with suppressing the development of Th1 T-cells.
Answer 5: The actions of IL-13 are more consistent with promoting increased mucus secretion in the airways.