Assessment of food-specific IgG4 directed elimination diet in eosinophilic oesophagitis

30 Patients with diagnosed with EoE will be recruited through the outpatient clinic, endoscopy unit and motility laboratory; Department of Gastroenterology & Hepatology, Royal Adelaide Hospital. 20 patients with other indications for endoscopy and oesophageal biopsies (eg. Oesophageal reflux, dysphagia) will also be recruited. Study Design: 1. Serum samples from eosinophilic oesophagitis (EoE) patients will be taken for: (a) total IgG4 and IgE levels; (b) specific IgG4 and IgE (sIgG4 and sIgE), and sIgE to milk, wheat, soy, egg white, nut mix (fx1 peanut, hazelnut, almond), seafood mix (fx2 Fish, Shrimp, Blue mussel, Tuna, Salmon); (c) sIgG4 and sIgE to additional foods if suspected on history. 2. Skin Prick Testing (SPT) will be performed to (a) commercial extracts of milk, wheat, soy, egg white, peanut, hazelnut, almond, codfish, shrimp; (b) additional foods if indicated on history (using commercial extracts or fresh/frozen food samples); (c) commercial extracts of common aeroallergens (ryegrass pollen, olive tree pollen, alternaria mould, cat dander, house dust mite) to confirm atopy in those with a history of atopic disease. SPT will be performed and interpreted by an Allergist, Allergy/Immunology advanced trainee, or experienced Allergy Nurse, and in keeping with ASCIA standards outlined in ‘ASCIA Skin prick testing for the diagnosis of allergic disease’ handbook. 3. Comprehensive examination and assessment of EoE including: a) Patients will undergo an upper endoscopy (routine sedative protocol) using an Olympus ‘Gastro-videoscopes’. This will allow assessment of oesophageal mucosa, wall thickness, and tissue acquisition using biopsy forceps through an accessory channel within the endoscope. The duration of the procedure is expected to be approximately 20 minutes. Total IgG4 (T-IgG4), and Food Specific IgG4 (FS-IgG4) will be measured in oesophageal homogenates. b) Baseline bloods including complete blood picture and electrolytes c) Symptomatic survey 4. If FS-IgG4 is detected in baseline serum samples, patients will be offered 6 weeks of elimination of the allergen. Patients will meet a dietitian for education regarding their restricted diet based on IgG4 testing. If dietary contamination occurs, their restricted diet will be extended an additional 6 weeks. 5. Dietitian will undertake an initial nutritional assessment that will include: a) Nutritional status; b) Anthropometric measures including weight, height, Body Mass Index and weight history; c) Diet history; and d) Other factors influencing diet including patient lifestyle, social supports and motivation for dietary compliance. The dietitian will educate the patient on dietary avoidance of identified food(s). The dietitian will review patient dietary compliance after 6 weeks of dietary avoidance and the patient will then undergo a repeat endoscopy before further education. 6. If no FS-IgG4 is detected in baseline serum sample, patients will be offered empirical 6 food elimination diet (6FED) instead under the guidance of a dietitian, administered for 6 weeks. This involves the elimination of 6 of the most common food allergens: milk, wheat, soy, eggs, nuts, and fish. Dietician will also educate the patient on what types of foods to avoid and how to identify foods with allergens, and provide potential food alternatives. Adherence to 6FED will be monitored via food diaries. The dietitian will review patient dietary compliance after 6 weeks. 7. Patients who decline dietary elimination will undertake medical therapy with oral proton-pump inhibitor (PPI), Pantoprazole, and topical corticosteroid, Budesonide. Patient will then have a repeat examination and assessment of EoE: a) EoE endoscopic reference score and biopsy including tissue IgG4 b) Bloods and serum IgG4 c) Symptomatic questionnaire All patients enrolled in the study would like the targeted dietary intervention, but if they do not qualify (no raised FS-IgG4) then they will either have the six-food elimination diet, or 40mg Pantoprazole twice daily (as per guidelines) or Budesonide slurry (1mg/2ml slurry mixed with sucralose). This will occur for 6 weeks before repeat endoscopy to assess for response. Adherence will only be via patient questionnaire, and for the diet, this will be via a diary (with the dietitian). There are no physical or informational materials involved. The dietitian will discuss with patients regarding which foods to be avoided depending on our FS-IgG4 results. If there is histological improvement following dietary restriction, then patients can continue dietary avoidance of this food.