IL4 and mastocytosis: The hallmark of the TH2 response is the production of type 2 cytokines such as interleukin-4 (IL-4), IL-5, IL-9, and IL-13, goblet cell (GC) hyperplasia and subsequent mucus production, mastocytosis, expansion of eosinophils and basophils as well as alternatively activated macrophages (AAM), which contribute to fibrosis and tissue repair [25–27].