Human mast cell tryptase in biology and medicine.

The most abundant prestored enzyme of human mast cell secretory granules is the serine-protease tryptase. In humans, there are four tryptase isoforms, but only two of them, namely the alpha and beta tryptases, are known as medically important. Low levels of continuous tryptase production as an immature monomer makes up the major part of the baseline serum tryptase levels, while transient release of mature tetrameric tryptase upon mast cell degranulation accounts for the anaphylactic rise of serum tryptase levels. Serum tryptase determination contributes to the diagnosis or monitoring of mast cell disorders including mast cell activation - induced anaphylaxis, mastocytosis and a number of myeloproliferative conditions with mast cell lineage involvement. Baseline serum tryptase levels are predictive of the severity risk in some allergic conditions.