Interplay of Cytokines in Asthma

Scientists at the Center of Allergy and Environment (ZAUM) of Helmholtz Zentrum München and Technische Universität München investigated the anti-inflammatory role of interferon-22 in allergic asthma in the framework of an international research group. 

The cytokine interleukin-22 may control the extent of asthmatic lung inflammation, according to a study by an international research team. The analysis of T-helper cells derived from the lungs of patients with asthma detected the presence of the T-helper cell type Th22, which was originally described in the skin. Interestingly, however, the lead cytokine of the Th22 cells, interleukin (IL)-22, was co-produced in a number of T cells with gamma interferon (IFN-γ).

IFN-γ  is considered to be pro-inflammatory because, among other things, it stimulates the production of adhesion molecules in epithelial cells, while interleukin-22 has the opposite effect – it promotes defense mechanisms and wound healing. In an in vitro model using human bronchial epithelial cells, the researchers examined the interaction of the two substances and demonstrated that IL-22 and IFN-γ  are apparently antagonists. In the presence of IFN-γ , IL-22 cannot fully develop its positive characteristics, and this leads to diminished wound healing responses. On the other hand, however, IL-22 also suppresses the pro-inflammatory effect of IFN-γ  in the inflammatory process. The results suggest that the therapeutic administration of interleukin-22 or measures that support its production could reduce the acute inflammatory response in asthma.

However, this protein is ambivalent in its effect. Too much IL-22 can lead to excessive proliferation of epithelial cells, a phenomenon that is e.g. observed in psoriasis. In addition, IL-22 interacts strongly with other interleukins, and these interactions are not yet sufficiently understood. As next step the scientists therefore want to study the interaction of IL-22 and IFN-γ  in the mouse model.

Both interleukins (IL-x) and interferons belong to the family of cytokines. They are endogenous tissue hormones, which act as communication factors between immune and tissue cells.