Anaphylaxis Research Today is a free monthly online journal that collates and summarizes the latest research about Anaphylaxis, including details on food allergies, diagnosis, treatment, causes.

Tryptase genetics and anaphylaxis.

Caughey GH

Cardiovascular Research Institute and Department of Medicine, University of California at San Francisco, CA 94121, USA. George.Caughey@ucsf.edu

Tryptases secreted by tissue mast cells and basophils can enter the bloodstream. In human subjects tryptases are encoded by several genes and alleles, including alpha, beta, gamma, and delta. Common variations include complete absence of alpha genes. Until recently, alpha tryptase was considered to be the major tryptase secreted at baseline and in mastocytosis. However, lack of alpha tryptase genes has little effect on circulating tryptase levels, which are now thought mainly to consist of inactive pro-beta tryptase secreted constitutively rather than stored in granules with mature tryptases. Pro-beta tryptase levels thus might reflect total body mast cell content. In contrast, mature beta tryptase can increase transiently in severe systemic anaphylaxis and confirm the diagnosis. However, it might fail to increase in food anaphylaxis or might increase nonspecifically in samples acquired after death. Thus pro- and mature beta tryptase measurements are useful but associated with false-negative and false-positive results, which need to be considered in drawing clinical conclusions in cases of suspected anaphylaxis.

Published 5 June 2006 in J Allergy Clin Immunol, 117(6): 1411-4.
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