The overall objective of this grant is to complement Dr. Marichal’s expertise in basic and translational Allergy and Immunology. He will therefore integrate an outstanding laboratory in this area (Pr. Stephen J. Galli’s laboratory) at Stanford University School of Medicine, a world leader in medical education, training and research. Scientifically, Dr. Marichal will acquire cutting-edge knowledge in the detailed mechanistic understanding of allergic disorders, which are increasingly recognized as a major global public health problem. Indeed, the current proposal aims to evaluate in depth the contribution of mast cells in early immune and late inflammatory responses associated with skin eczema, the most complex allergic skin disorder. To address this question, two complementary genetic approaches of mast-cell deficient mice will be used in combination with a clinically relevant mouse model of skin eczema. In addition, Dr. Marichal will learn and take advantage of the innovative tool of Gene Set Enrichment Analysis to assess to relevance of the findings to the human disease. This challenging project is possible thanks to Dr. Marichal’s previous experience, in combination with the financial and technical resources of the host laboratory, as well as the scientific and training environment that will be provided. Pr. Galli has indeed a long history of highly successful training of postdoctoral researchers. Moreover, Dr. Marichal will benefit from many training and educational programs, enabling him to gain essential skills at the level of leadership, project management and financial independency and helping him in growing as an independent researcher. Finally, it is the goal of the outgoing and return host laboratories to create a strong international collaboration and a worldwide network of experts in the fields covered by the project, thereby addressing societal challenges and training needs at the worldwide scale.