Il4

Asthma Free Forever

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Th2-type cytokines such as IL-4, IL-5, and IL-13 orchestrate a cascade of events during development of an allergic inflammatory response. This is demonstrated both clinically and in preclinical animal models (404, 405). IL-4 plays a critical role in the early commitment of ThO cells to Th2 cells and regulates IgE secretion by B-cells. It also induces V-CAM expression on endothelial cells, promotes eosinophilic inflammation, and increases airway mucus production.

In asthmatic patients there is an increase in serum and bronchoalveolar lavage fluid IL-4 levels, and atopic individuals have a higher frequency of IL-4-producing T-cells (406, 407). Genetic studies have linked asthma and atopy to the chromosome region 5q31-33, which includes IL-4, IL-5, IL-9, and the IL-13 genes (408). Thus, aberrant production of IL-4, or excessive response to this cytokine resulting from genetic defects, might contribute to the pathogenesis of asthma.

IL-4 is a 20-kDa secreted glycoprotein and its expression is highly tissue specific. IL-4 is produced by Th2 cells and natural killer cells in response to stimulation through the T-cell receptor (409). IL-4 binds to two types of receptor complexes, type I and type II receptors. Type I receptor complexes are formed by the IL-4 receptor a chain (IL-4Ro:) and the common y chain (yC), whichform part of the many other cytokine receptor complexes. The type II receptor consists of the IL-4Ra chain and the IL-13R« chain. In both cases signaling occurs through the JAK/STAT pathway, more specifically through activation of STAT6 (410).

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Coping with Asthma

Coping with Asthma

If you suffer with asthma, you will no doubt be familiar with the uncomfortable sensations as your bronchial tubes begin to narrow and your muscles around them start to tighten. A sticky mucus known as phlegm begins to produce and increase within your bronchial tubes and you begin to wheeze, cough and struggle to breathe.

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