The epithelium is the outermost layer of cells in an organ and provides a strong barrier function in order to prevent or treat allergic diseases. In the case of an allergy, this cell layer of the skin, nose or lungs becomes permeable. From studies with patients suffering from eczema, asthma or rhinitis, researchers from Area D have learnt that the barrier function of the particular epithelium does not operate properly.
The focus has been placed on tight junctions (TJs). Tight junctions (TJs) are narrow bands of proteins that hold together the outermost cells of a tissue and thereby form a barrier. This prevents penetration by substances from the environment, e.g. allergens, pollutants and bacterial toxins. Defects in the TJs disrupt this barrier function in the airways and lungs therefore play an important role in the development and existence of asthma.
It was suspected that one of the most effective approaches to allergy prevention is to maintain the functionality of these TJs and thereby ensure the tissue does not become permeable.
Early detection of permeability of the epithelium can consequently be used as early diagnosis in allergy-prone children and can help in taking the first necessary precautions. In an initial step, new methods of performing this analysis are being addressed. Thus treatment to protect the barrier function may become the method of choice for some patients with atopic dermatitis or other allergic diseases.
Researchers from Area D have studied the regulation of these TJs by a cell group that is typical of allergies (denTh2 cells) and their released messengers in both healthy and asthmatic individuals. The data showed that these Th2 cells and their messengers reduce the integrity of the TJs and hence the outermost barrier of cells. However, if one specific enzyme (HDAC) has been blocked, the defective barrier function could be restored as the cells increase the formation of TJ molecules.
Four new molecules have been identified which are responsible for the development of eczema in allergy patients. Furthermore, new and promising approaches to the diagnostic criteria and the treatment of the serious form of atopic dermatitis have been defined.