Hydroxychloroquine as a novel therapeutic approach in mast cell activation diseases

International audience; There is no therapeutic agent approved in cutaneous mastocytosis and mast cell activation syndrome. We report the efficacy of hydroxychloroquine in four patients with cutaneous mastocytosis (n = 2) and mast cell activation syndrome (n = 2). We show that this molecule reduces the long-term survival of primary human mast cells, interferes with lysosome function and leads to the accumulation of non-functional tryptase in the mast cell granules. Furthermore, hydroxychloroquine decreases the production of pro-inflammatory mediators.