Clinical significance of food allergen-specific IgG antibody detection in chronic gastrointestinal diseases

Objectives To explore the correlation between 14 food allergen- specific IgG antibodies and chronic digestive diseases in children. Methods The food allergen- specific IgG antibodies in serum were measured by enzyme- linked immunosorbent assay (ELISA) in 40 children with chronic digestive diseases. Total serum IgE and serum IgG4 le- vels were analyzed at the ratio of 3 to 1 by chemiluminescent microparticle immunoassay (CMIA) and nephelometry respectively. Results The increased food allergen- specific IgG antibodies ranged from 1 to 6 types in all the children. Total positive rate was 100 % and 87.5 % children showed elevated levels of at least 2 types of antibodies. The most common elevated food allergen- specific IgG detected were that against egg (92.5 %) and cow's milk (72.5 %),followed by wheat (40.0 %) and soybean (27.5 %). No increase of IgG specific to chicken, pork and corn were detected. All the subjects adjusted their diet according to the assay results. Within 3 weeks, 62.5 % of the cases have significant symptomatic relief,32.5 % had moderate relief and no effect was observed in 5 % of the cases (total efficacy = 95.0 %). Total serum IgE was 17.5 % above the normal level and had no correlation with food allergen- specific IgG (r = -1.132, P =0.268). There was also no correlation between serum IgG4 level and food allergen- specific IgG (r = 0.863, P = 0.396), but a positive correlation between serum IgG4 level and age (r = 3.317, P = 0.003) was detected. Conclusions The measurement of 14 common food allergen- specific IgG might be very useful for diagnosis and treatment of chronic digestive diseases in children.