Measurement of serum tryptase in the diagnosis of systemic allergic reactions

Abstract

Background: Mast cell plays a central role in the allergic responses, in which chemical mediators are released by allergen and IgE binding on the surface, and direct liberating agents including opiates, aspirin, salicylate, and foods. Among chemical mediators, tryptase is a tetrametric serine protease released only from mast cells, and therefore serum tryptase level has been used as a marker for systemic mast cell degranulation. The aim of this study was to evaluate clinical significance of serum tryptase level for identifying episodes of anaphylaxis in patients attending emergency room with clinical signs of generalized allergic reactions. Methods: Eighty three patients with symptoms of immediate allergic reactions who visited the emergency room for one year were enrolled. They were classified into three groups: Group I includes the patient presenting anaphylaxis at initial visit (n=19, 22.9%). Group II includes respiratory symptoms, generalized urticaria and angioedema (n=21, 25.3%). Group III includes generalized urticaria and angioedema (n=43, 51.8%) without major organ symptoms. The serum tryptase level was measured by CAP system (Pharmacia, Sweden). Results: Tryptase levels of group I were significantly higher than those of group II and III (p<0.05 respectively). The significantly increased level of tryptase (13.5 ㎍/L) was noted in 63% of group I compared to 28% of group II, 11% of group III with statistical significant differences (p<0.05). The major causes to induce systemic allergic symptoms were drugs (43%), foods (38%) and bee stings (8%), which were similar in three groups. Conclusion: Measurement of serum tryptase during symptom development can be used as a marker to represent systemic allergic response in this country.