[Role of tumor necrosis factor-alpha in allergic inflammation and airway hyperresponsiveness].

TNF-alpha is a potent multifunctional cytokine that plays a central role in the pathogenesis of many inflammatory diseases such as asthma and allergic rhinitis. This proinflammatory cytokine is produced by a variety of cells in the airways and is released via the IgE-dependent activation of mast cells. The elevated levels of TNF-alpha can be detected in the airways, bronchoalveolar lavage (BAL) fluid and nasal lavage from asthmatic and rhinitic patients. Leucocytes and monocytes isolated from BAL fluid of asthmatics were shown to release more TNF-alpha than cells from control subjects. Recent research indicates that TNF-alpha maybe associated with acquired airway hyperresponsiveness a pathophysiological hallmark of asthma. It was suggested that TNF-alpha upregulates adhesion molecules and is directly responsible for transendothelial migration of inflammatory cells a central feature underlying the inflammatory response. A direct chemotactic effect has also been attributed to TNF-alpha. This cytokine is a chemoatractant for neutrophils and monocytes, can also induce transepithelial migration of neutrophils through production of IL-8.