Blood Samples for the Study of Peanut, Tree Nut and Other Food Allergies

Food allergies are now a major problem. These experiments involve getting blood from people with food allergies and from people without food allergies. The blood collected will be used to answer questions and find information about peanut and other food allergies. Samples will come from: * People signed up by the investigators at the University of Colorado Denver * University of North Carolina, Massachusetts General Hospital, Children's Hospital of Colorado and the Immune Tolerance Network (Benaroya Research Institute) where people have been treated for peanut allergies * University of North Carolina, Massachusetts General Hospital, National Jewish Health and The Children's Hospital in Denver where people have taken part or will take part in clinically indicated oral food challenges. Blood and health histories from the University of North Carolina, Massachusetts General Hospital, National Jewish Health, The Children's Hospital and the Immune Tolerance Network will not have personal information linked. The specific aims of this experiment are: 1. Come up with a lab test that will predict how bad an allergic reaction will be to peanuts. 2. Find out what part of a peanut causes allergic reactions. 3. Come up with preventions that can block peanut allergies. 4. Find the strongest proteins in walnuts.