{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Tryptase is the most abundant secretory granule-derived serine proteinase contained in mast cells and has recently been used as a marker for mast cell activation. It is involved in allergenic response and is suspected to act as a mitogen for fibroblast lines. Elevated levels of serum tryptase occur in both anaphylactic and anaphylactoid reactions, but a negative test does not exclude anaphylaxis. Mast cells contain a number of preformed chemical mediators such as histamine, chymase, carboxypeptidase and proteolytic tryptase."}]}]}