Unravelling maintenance mechanisms of immune tolerance after termination of venom immunotherapy by means of clonal mast cell diseases

ended

Anaphylaxis is the most severe form of a systemic hypersensitivity reaction, which can be fatal within minutes after exposure to a trigger such as wasp venom. VIT has been the only treatment available to prevent subsequent anaphylactic wasp-sting reactions even years after treatment termination. The goal of this project is to understand molecular mechanisms of maintained immune tolerance (MIT) after completing venom immunotherapy (VIT). We aim to find biomarkers for MIT that could be specifically triggered to increase efficiency of VIT. In contrast to wasp venom anaphylactic patients of the general population, wasp venom anaphylactic patients with a clonal mast cell disease (CMD) do not maintain immune tolerance after VIT termination. These patients carry a clonal D816V point mutation in the tyrosine kinase receptor KIT. We hypothesize that the MIT in wasp venom anaphylactic CMD patients is dysregulated due to the carriage of KIT D816V mutation in immune cells. We will, therefore, compare blood plasma proteins and blood cells of venom-induced anaphylaxis patients with a CMD to patients without a CMD. This project addresses our hypothesis with three specific objectives: Firstly, we will identify plasma proteins (in work package 1; WP1) and, secondly, blood cell types (WP2) that are crucial for MIT. Thirdly, we will study the role of the identified candidates from WP1 and WP2 in maintaining immune tolerance (WP3) and investigate whether or not the detected dysregulations are due to KIT D816V (WP3). We estimate that our results will, therefore, be directly relevant for 0.3% of the European population who experience anaphylaxis and bares potential to be also beneficial for patients suffering from other allergic diseases, which account for a significant part of the population worldwide.