Natural History and Genetics of Food Allergy and Related Conditions
Background: \- About 15 million Americans have a food allergy. Because there are no cures or effective prevention or treatment for food allergies, researchers want to learn more about them.
Objective: \- To learn more about the causes and effects of food allergy and related conditions.
Eligibility: * People ages 2 99 who have food allergy and/or a related genetic or other condition * Their relatives * Healthy relatives and volunteers
Design: * Participants will have at least 3 visits over 1 2 years, and then once a year for up to 12 years. Each may last a day or longer. * Participants will be screened with medical history, physical exam, and questionnaires. * Participants may have the following: * Blood tests * Allergy skin prick tests: Drops of allergens are placed on the back or arm. The skin is scratched under each drop. * Leukapheresis: blood is taken from a needle in one arm, passed through a machine, and returned through a needle in the other arm. * X-rays * Esophageal string test: One end of a string is taped to the cheek and the other end is packed into a capsule. When the capsule is swallowed, the string unwinds; it is left in for at least 1 hour. * EGD and colonoscopy: Biopsies are taken from the gastrointestinal system. * Tiny biopsies of skin * Photographs of the body * Collection of cells through: * Swab of nose, inside of cheek, or skin * Gentle skin scrape * Tape stripping: piece of tape is put on the skin and pulled off.
⁃ All participants must meet the following criteria:
• Be 2 to 99 years-old at the time of enrollment for participants who will be seen at the NIH CC; be 0 (newborn) to 99 years-old at the time of enrollment for participants who will submit mail-in samples or participate in telehealth visits. Only viable neonates will be enrolled.
• Willing to allow storage of blood, buccal swabs, saliva, nasal swabs, stool samples, and other clinically appropriate tissue specimens for future use in medical research
• Required to have a primary care or other physician who will manage all health conditions related or unrelated to the study objectives
⁃ ADDITIONAL INCLUSION CRITERIA FOR AFFECTED PARTICIPANTS
⁃ In addition to the general criteria listed above, affected participants must meet 1 of the following criteria:
• Have a clinical history of an immediate hypersensitivity reaction to food(s) and be sensitized to food allergen(s) (as evidenced by positive SPT or allergen-specific IgE testing)
• Be sensitized (as evidenced by positive SPT or allergen-specific IgE testing) to food allergen(s) but have no overt clinical history of IgE-mediated symptoms when they eat that food(s)
• Have a suspected genetic or congenital disorder potentially associated with food allergy or related condition, as determined by the principal investigator (PI) or associate investigators (AIs)
• Have a diagnosis of eosinophilic esophagitis (EoE), or clinical suspicion for EoE as determined by the principal investigator (PI) or associate investigators (AIs)
• Have a history of atopic dermatitis based on self-report or physician assessment.
⁃ ADDITIONAL INCLUSION CRITERIA FOR UNAFFECTED RELATIVES:
⁃ In addition to the general criteria listed above, unaffected relatives must meet the following criteria:
• Be a relative of an affected participant
• Be unaffected by food allergy (as determined by clinical history and/or allergy testing) or be unaffected by the genetic condition under study
⁃ ADDITIONAL INCLUSION CRITERIA FOR HEALTHY VOLUNTEERS
⁃ In addition to the general criteria listed above , healthy volunteers must meet the following criteria:
• Be unrelated to an affected participant
• Be unaffected by food allergy (as determined by clinical history and/or allergy testing) or be unaffected by the genetic condition under study
⁃ ADDITIONAL PROCEDURE- SPECIFIC INCLUSION CRITERIA:
⁃ The following additional inclusion criteria apply for participants undergoing leukapheresis:
• Age greater than or equal to 18 years
• Stable hematologic parameters (definition: white blood cell count \> 2,500/microL, hemoglobin \> 10 g/dL, and platelet count \> 75,000/microL)