A protein in mice known as RGS13 suppresses allergic reactions, including the severe, life-threatening allergic reaction known as anaphylaxis, according to scientists at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH). Because RGS13 is also a protein found in humans and is expressed in only a limited number of cells — including the immune system’s mast cells that are central to allergic reactions — scientists believe the protein may be an attractive target for developing new drugs to treat and prevent certain allergic reactions, including anaphylaxis.