Serum IgG4 Antibodies in Pediatric Subjects with Eosinophilic Esophagitis Treated with Cow's Milk Elimination Diet or Swallowed Fluticasone: High Levels of Specific IgG4 to Cow's Milk Components Despite Low to Negative IgE Antibodies
Monday, March 7, 2016
South Exhibit Hall H (Convention Center)
Alexander J. Schuyler, BS BA, Anubha Tripathi, MD, Patrice G. Kruszewski, DO, John M. Russo, MD, Lisa J Workman, BA, Thomas A.E. Platts-Mills, MD PhD FAAAAI, Elizabeth A. Erwin, MD
Rationale: High titer IgG4 antibodies to relevant food allergens have been reported in adults with eosinophilic esophagitis (EoE).  Responsiveness to cow’s milk elimination diet alone (i.e., without swallowed steroid) has been demonstrated in children with EoE mediated by this food, including those with <0.35 IU/mL of IgE antibodies to cow’s milk.  Here we investigate serum IgG4 levels to cow’s milk components among pediatric EoE patients in relation to IgE antibodies and the results of cow’s milk elimination.

Methods:  ImmunoCAP for specific IgE antibodies to cow’s milk and IgG4 antibodies to cow’s milk components Bos d 4 (alpha-lactalbumin), Bos d 5 (beta-lactoglobulin), Bos d 6 (bovine serum albumin; BSA), and Bos d 8 (caseins) were performed on sera collected before and after treatment with either cow’s milk elimination diet or fluticasone.

Results:  In subjects treated with cow’s milk elimination diet, a reduction in IgG4 antibodies to alpha-lactalbumin, beta-lactoglobulin, BSA, and caseins was observed. Diet nonresponders (n=3/9) had higher levels of IgG4 antibodies to cow’s milk components at baseline compared to responders (n=6/9).  There was a general increase in allergen-specific IgG4 antibodies in subjects with low to negative serum IgE to cow’s milk (i.e., <0.35 IU/mL).  Conversely, serum IgG4 antibodies to cow’s milk components decreased, irrespective of treatment, in subjects with ≥0.35 IU/mL of IgE to cow’s milk.

Conclusions: The results indicate that IgG4 antibodies are often present in sera with low to undetectable IgE to the same protein, and that the response to cow’s milk avoidance is unrelated to IgE antibodies to cow’s milk components.