TIgG antibody titer determination
Four milliliters of venous blood from each subject was drawn in the early morning at baseline and at the end of the study. Serum was used for testing. IgG antibodies reactive with 14 types of food (cow's milk, wheat, beef, chicken, codfish, corn; crab, eggs, mushroom, milk, pork, rice, shrimp, soybean, and tomato) were semi‐quantitatively detected with the IgG food testing kit produced by Biomerica (Allerquant™ 14 Foods IgG Elisa Kit). An IgG antibody titer of greater than 50 U/mL for one of the foods was defined as a positive IgG titer to that food. For each patient tested, the positive IgG antibody titers of all 14 foods tested with the kit were added together. The resulting value was designated as ‘total positive IgG antibody titer (TIgG titer)’ for that patient. The percent decrease in TIgG titer was calculated by dividing the difference between the original and final TIgG titer by the original titer and multiplication by 100%. TIgG titer < 50 U/mL, 50 U/mL ≤ TIgG titer < 100 U/mL, 100 U/mL ≤ TIgG titer < 200 U/mL and TIgG titer ≥ 200 U/mL were designated as TIgG titer grades: negative, mild, moderate, and severe, respectively.