title: Cytokines in asthma.
abstract: The airway inflammation underlying asthma is regulated by a network of mutually interacting cytokines. The exact functional role of each individual cytokine in the pathogenesis of the disease remains to be fully established. Type 2 T-helper cells are currently considered to play a crucial role in this process. In vivo animal data suggest a sequential involvement of interleukin (IL)-4 and IL-5 in the induction of allergen-induced airway changes. The potential role of other type 2 T-helper cell-like cytokines in asthma is increasingly being recognized. In particular, IL-4 and -13 display a large degree of redundancy. Whereas IL-4 seems to be crucial in the primary allergen sensitization process, IL-13 might be more important during secondary exposure to aerosolized allergen. Animal models also indicate that T-cell-derived cytokine production, rather than eosinophil influx or immunoglobulin-E synthesis, is causally related to altered airway behaviour. An important aspect when evaluating the functional role of cytokines in a complex disease such as asthma is the interaction with other cytokines in the microenvironment. Increased expression of pro-inflammatory cytokines such as tumour necrosis factor-alpha can further enhance the inflammatory process, and is increasingly linked to disease severity. In addition, decreased expression of immunoregulatory cytokines, including interleukin-12, interleukin-18 or interferon gamma could also strengthen the type 2 T-helper cell-driven inflammatory process.
authors.affiliation: Dept Respiratory Diseases, Ghent University Hospital, Belgium.
authors.forename: J C
authors.initials: JC
authors.lastname: Kips
mesh_terms: D000818:Animals; D001249:Asthma / Q000209:etiology / Q000503:physiopathology*; D016207:Cytokines / Q000276:immunology* / Q000502:physiology*; D006801:Humans; D018793:Interleukin-13 / Q000276:immunology / Q000502:physiology; D015847:Interleukin-4 / Q000276:immunology / Q000502:physiology; D015848:Interleukin-5 / Q000276:immunology / Q000502:physiology; D012680:Sensitivity and Specificity; D018418:Th2 Cells / Q000276:immunology* / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000502:physiology
chemical_list: D016207:Cytokines; D018793:Interleukin-13; D015848:Interleukin-5; D014409:Tumor Necrosis Factor-alpha; D015847:Interleukin-4