Mast cell tryptase-role in the investigation of acute hypersensitivity reactions

摘要

Mast cells are granulocytes found in peripheral tissues that play a central role in acute hypersensitivity reactions. Tryptase, a neutral serine protease, is the most abundant mediator stored in mast cell granules. The release of tryptase is a characteristic feature of mast cell degranulation. beta-tryptase has a role in airway homeostasis, angiogenesis, vascular relaxation and contraction, gastrointestinal smooth muscle activity and intestinal transport, mediated by activation of protease-activated receptor (PAR) type 2. Serum mast cell beta-tryptase is increased in anaphylaxis and other allergic conditions. Increased tryptase levels are highly suggestive of an immunologically mediated reaction but may reflect direct histamine release. Patients with increased mast cell tryptase levels must be investigated for an allergic cause. However, if the clinical picture suggests severe anaphylaxis, investigations for an allergic cause must be undertaken in patients even if their mast cell tryptase levels are not increased.