D3.279 - Biomarkers in anaphylaxis

Anaphylaxis is a potentially life-threatening, rapidly progressing systemic hypersensitivity reaction that can be triggered by even small amounts of allergens such as insect venom, foods, and medications. Measurement of acute serum tryptase, released by mast cells during activation, is a primary diagnostic tool for confirming an anaphylactic reaction. However, tryptase levels do not always rise, particularly in food-induced or medication-related anaphylaxis, occurring in up to 30% of cases. In search of a more reliable biomarker, the chemokine CCL2 has emerged as a promising candidate. This study compares the diagnostic value of tryptase and CCL2 in Slovenian individuals with anaphylactic reactions of varying severity and causes.

A total of 204 individuals with allergic reactions and 203 healthy controls were examined for two anaphylactic biomarkers: tryptase and CCL2. Among patients, 96 reactions were caused by insect stings, 54 by medications, 18 by food, and 36 by other triggers. By Brown grading, 126 experienced Grade 3 anaphylaxis, 58 had Grade 2, and 20 had Grade 1 reactions.

Tryptase exhibited higher sensitivity and specificity compared to CCL2: 70.1% vs 63.2% and 97.5% vs 93.6%, respectively. When both biomarkers were assessed sequentially, specificity increased to 82.4%. This trend was consistent across all severity grades and triggers. At Grade 3, the sensitivity and specificity of tryptase, CCL2, and combined tryptase/CCL2 were 79.4%, 73.0%, 89.7% and 97.5%, 93.6%, 92.6%, respectively. For Grade 2, these values were 62.1%, 51.7%, 75.9% and 97.5%, 93.6%, 92.6%, respectively, while at Grade 1, they were 35.0%, 35.0%, 55.0% and 97.5%, 93.6%, 92.6%, respectively. Regarding triggers, the highest sensitivity was observed in food-induced anaphylaxis (88.9%) with combined biomarkers, followed by insect stings (88.5%) and unknown triggers (75.0%). Medication-induced reactions had the lowest sensitivity at 72.2%.

Serum tryptase, demonstrated superior sensitivity compared to CCL2. This trend persisted across different grades and triggers of anaphylactic reactions. However, the highest sensitivity score was accomplished when using both biomarkers together. Our study underscores the importance of sequential biomarker assessment in enhancing the accuracy of anaphylactic reaction diagnosis, offering valuable insights for clinical practice and future research endeavours.