GI Alpha-Gal Study
This is a double-blind, crossover food challenge study using pork with and without α-gal in patients with a clinical diagnosis of gastrointestinal (GI)- α-gal allergy, and to investigate the pathophysiology underlying their symptoms.
- EligibilityCriteria: Inclusion Criteria:  The subject is at least 18 years of age. The subject has a history of gastrointestinal alpha-gal allergy defined by elevated test for α-gal allergy (α-gal IgE >0.1 U/L) due to complaints of either abdominal pain or discomfort, diarrhea, nausea with or without vomiting, or a combination of those complaints, within the last 5 years. The subjects must have experienced one or more of the four symptoms at least once monthly for at least two months. The subjects will fill out a symptom questionnaire of the presence of these four symptoms (abdominal pain or discomfort, diarrhea, nausea, vomiting), frequency and severity (mild, moderate, or severe) for the 3 months prior to diagnosis. The subject has experienced symptomatic improvement on a mammalian meat-free diet over at least a month's time, defined by saying "yes" to the following question: "On the alpha-gal avoidant diet, have you had adequate relief of gastrointestinal symptoms?" The subject has elevated α-gal IgE titer on screening for the trial if they do not have a positive titer within 3 months of enrollment. The subject is willing to not take nonsteroidal anti-inflammatory medications, leukotriene modifiers or steroids 14 days prior to challenge. The subject is willing to sign the informed consent form.  Exclusion Criteria:  The subject has health conditions that would pose a significant threat in the face of anaphylaxis or treatment for anaphylaxis (e.g., cardiac disease, unstable angina pectoris, arrhythmias). The subject is allergic to mannitol. If female, the subject is pregnant. The subject has a history of chronic GI conditions, including inflammatory bowel disease, celiac disease, chronic pancreatitis with continued symptoms (experience moderate-severe abdominal pain, diarrhea, or nausea/vomiting that occur more frequently than once weekly) The subject has diarrhea (one or more loose stools that conform to the container), moderate to severe abdominal pain, or vomiting within 10 days prior to the challenge. The subject has a history of severe allergic reaction on mammalian meat ingestion (respiratory distress, chest pain or cardiopulmonary compromise) The subject is unwilling to receive intramuscular epinephrine. The subject is anticipated to use omalizumab within 6 months of enrollment. The subject is anticipated to use systemic steroids within 28 days of food challenge. The subject is anticipated to use leukotriene modifier within 14 days of food challenge. The subject is unable to not use nonsteroidal anti-inflammatory drugs for 14 days prior to challenge.  Additional Exclusion Criteria for Subjects Undergoing Transnasal Endoscopy and Biopsy  Known conditions that are contraindications to transnasal endoscopy, or in the opinion of the investigator any condition that would interfere with the study objectives. History of head and neck malignancy or anatomical deformities of the nasopharynx Severe anxiety - HealthyVolunteers: No - Gender: All - MinimumAge: 18 Years - StdAgeList: Adult, Older Adult