Tryptase in type I hypersensitivity

Tryptase is currently the main mast cell biomarker available in medical practice. Tryptase determination is a quantitative test performed in serum or plasma for the diagnosis, stratification, and follow-up of mast cell-related conditions. The continuous secretion of monomeric a and b protryptases forms the baseline tryp-tase level. Transient, activation-induced release of tryptase is known as acute tryptase. Because mast cells are tis-sue-resident cells, the detection of an acute tryptase release in the bloodstream is protracted, with a delay of 15 to 20 minutes after the onset of symptoms and a peak at approximately 1 hour. Constitutive release of tryptase is a marker of mast cell number and activity status, whereas transient release of mature tryptase is a marker of mast cell degranulation. Although consensual as a concept, the application of this statement in clinical practice has only been clarified since 2020. For baseline tryptase to be used as a biomarker, reference values need to be established. In contrast, defining a transient increase using acute tryptase can only be achieved as a function of the baseline status. (c) 2022 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Automated summary

Tryptase is currently the main mast cell biomarker used for diagnosis, stratification, and follow-up of mast cell-related conditions. The baseline tryptase level is formed by the continuous secretion of monomeric a and b protryptases, while the transient activation-induced release of tryptase is known as acute tryptase.