[1][2][3][4][5] Club cells contain tryptase, which is believed to be responsible for cleaving the hemagglutinin surface protein of influenza A virus, thereby activating it and causing the symptoms of flu.

[7] Elevated levels of serum tryptase occur in both anaphylactic and anaphylactoid reactions, but a negative test does not exclude anaphylaxis.

Tryptase is less likely to be elevated in food allergy reactions as opposed to other causes of anaphylaxis.

[8][9] Tryptase is involved with allergenic response and is suspected to act as a mitogen for fibroblast lines.

[10] Mast cell tryptase-6 is involved in Trichinella spiralis infection in mice through linking adaptive and innate immunity.