Evaluation of tryptase levels in anaphylaxis

Aims: Tryptase is a serine protease released from mast cells during an acute allergic reaction. Levels of serum tryptase vary among healthy individuals, and there has been a growing debate about the normal and abnormal ranges of tryptase depending on the numbers of mast cells, basal secretion rate, and renal function. To adress this point, serum tryptase levels were analysed in subjects with a prediagnosis or absolute diagnosis of anaphylaxis. Methods: This was a retrospective, one-centered study performed in a Tertiary Hospital in Turkey. Patient recruiment criteria was that files of patients with tryptase levels between 2020 and 2023 were evaluated detailly. Serum tryptase levels that is moment at reaction (RT) and as basal (BT) were analyzed with the same method with ImmunoCAP (Pharmacia, Uppsala, Sweden). The age, gender and reasons for admission of the patients were examined one by one. Results: Out of approximately 400 test entries, there were valid results of 300. A ratio of 62% of the patients were female (n: 186) and 38% were male (n: 114). The mean age was 18-89 (41.5±14.7)/year. Serum levels of tryptase was measured at the time of reaction in 12.7% of the patients, 4.3% had both reaction and baseline tryptase levels, and the rest had only baseline tryptase analyses. A statistically significant difference was found between the tryptase levels during the reaction in males and females (p: 0.02, Female/Male: 7.26±4.91/16.93±11.11 µg/L). We found that approximately 90.3% of the patients had serum tryptase levels lower than 11.5 µg/L. There was a statistically significant difference between reaction time (RT) and baseline tryptase (BT) in drug-induced hypersensitivity reactions (p: 0.02), but no difference was found in venom hypersensitivity reactions (p: 0.47). There was no correlation between age and tryptase during reaction, but a positive correlation was found between baseline tryptase (p: 0.01 r: 0.162). Conclusion: There may be many reasons for high serum tryptase levels. For doctors, it is important to quickly recognize anaphylaxis and manage the treatment process quickly. In this study, we reviewed all tryptase results retrospectively and addressed the etiology of the cases we encountered in our center. We showed that age is a baseline variable in determining tryptase levels. Tryptase can be used as a useful biomarker in diagnosis.