Promise of New Meds for Allergies
Help for sneezy, wheezy, itchy seasonal allergies may be at hand. Researchers at the University of Eastern Finland and Kuopio University Hospital, also in Finland, have identified several target molecules that are suitable for the development of new allergy drugs. The work, completed in a large-scale European Union project, was published in May 2014 in Journal of Allergy and Clinical Immunology.
A release from the university notes that immediate allergic reactions and allergic diseases such as allergic rhinitis (sinus), asthma, and urticarial (rashes) are extremely widespread in the population. Traditionally, drug therapy for allergy is based on the use of non-sedative antihistamines that block the histamine H1 receptors, but sometimes additional relief can be come from the use of blockers of the cysteinyl leukotriene receptor-1.
Antihistamines seek to prevent allergic symptoms caused by histamine released by mast cells. Mast cells, also known as "allergy cells", are cells of the immune system that become activated by environmental allergens.
The release quotes lead author Professor Ilkka Harvima as saying, "However, even high doses of H1 antihistamine drugs aren't enough to alleviate the symptoms of some patients. This is understandable, as when the mast cell becomes activated, several other strong mediators besides histamine get released, too. Histamine can also affect other receptors of the cell surface than the H1 receptor."
In the past, researchers have identified several mast cell molecules which can be targets of new drugs. Some of these have already proceeded to clinical trials. These targets include, for example, serine proteinases tryptase, chymase, cathepsin G, which are enzymes that break down proteins, as well as 5-lipoxygenase-activating protein FLAP, 15-lipoxygenase-1, prostaglandin-D2, and proinflammatory cytokines such as TNF-alpha, IL-4, IL-6 and IL-17. New drugs targeting the histamine H4 receptor are also undergoing clinical trials. In the near future, it is possible that drug therapy for allergy is a combination of H1 and H4 receptor blockers.
Certain target molecules have also been identified in intracellular signaling pathways and in cell survival proteins. Inhibiting these molecules can lead to the prevention of activation of the cell and to the prevention of mediator release. Various receptors, which can either activate or inhibit the cell, have been identified on cell surface. Different drug molecules make it possible to affect the function of these receptors and, consequently, to prevent cell activation and mediator release.