Egg allergy is a common pediatric allergy, and is usually outgrown by elementary school age. There is, therefore, a need to perform an oral food challenge (OFC) to establish the presence of food allergy to egg. In this study, we conducted a retrospective review of 2304 OFCs at a pediatric center and analyzed the severity of reactions during egg OFCs and compared them with other foods. The gastrointestinal system (GI) has been reported as more affected in egg food challenge. This study confirmed that 11% of patients undergoing egg OFC had GI symptoms vs. 7% undergoing food challenges for other foods or compared to milk, peanut and tree nut, individually. However, the involvement of lower respiratory tract was less frequent with egg than observed in peanut and tree nut OFC and similar to observed rate in milk. In conclusion, our study confirmed that OFC to egg causes more GI symptoms and less respiratory symptoms compared to other foods, in particular peanuts and tree nuts. However, 27% of children who failed egg OFC had lower respiratory tract reactions and required the use of epinephrine, similarly to children undergoing milk challenge. Full article

Invariant Natural killer T cell (iNKT cells) are a subset of T cells, which are narrowly defined as a T cell lineage expressing a semi-invariant CD1d-restricted T cell Receptors (TCRs) composed by Vα24-Jα18/Vβ11 in human, and Vα14-Jα18/Vβ8,Vβ7, and Vβ2 in mouse. Unlike conventional T cells which recognize peptides bound to highly polymorphic major histocompatibility complex (MHC) class I and II molecules, iNKT cells recognize lipid antigens, such as glycolipids, presented by CD1d, a non-polymorphic non-classical MHC class I molecule. Lipids derived from microbes, tumors, and allergens, as well as self lipids have been shown to be able to activate iNKT cells. Early on, in an immune response, ligation of the iNKT cell TCR leads to rapid and copious secretion of prototypical Th1 and Th2 cytokines. Moreover, like NK cells, iNKT cells express cytotoxic granules, such as perforin and granzyme that polarize upon activation of TCR and are able to kill target cells. Therefore iNKT cells are a very interesting subset of T cells that may bridge the innate and adaptive immune systems. Indeed, iNKT cells can mount specific responses to antigen with cytokine production and cytotoxic activity, however, their TCR evolved to recognize different glycolipid antigens in a conserved manner and to perform innate-like rather than adaptive functions. iNKT cells are now recognized as important players in atopic, autoimmune, infectious diseases, and cancer. Full article