Molecular biology of cytokines in allergic diseases and asthma

The repertoire of cytokines produced in response to an immune insult determines whether an immune response develops and whether the response will be humoral, cell-mediated, or allergic. Several cytokines particularly important in generating the allergic phenotype include those responsible for the IgE isotope switch (interleukin [IL]-4 and [IL]-13); eosinophil proliferation, recruitment, and activation (IL-5, IL-3, GM-CSF, RANTES, and MIP-1), and mast cell proliferation and activation (IL-3, IL-9, stem cell factor, RANTES, and MCP-1). Cytokines mediate cellular activation through a unique superfamily of receptors. These receptors transduce the biologic activity of their respective cytokines through a unique activation cascade termed the Jak-STAT pathway. Recognition of the importance of cytokines in allergic inflammation has led to the development of pharmacologic agents that modulate cytokine function and show promise in the treatment of allergic diseases.