PD27 - Specific antibodies in oral immunotherapy for cow’s milk allergy: kinetics and prediction of clinical outcome

BACKGROUND METHODS for predicting the clinical outcome of specific oral immunotherapy (OIT) would improve the safety of the therapy. METHODS We investigated 40 children aged 6-17 years with IgE-mediated cow's milk allergy (CMA) who either successfully completed OIT (n = 32) or discontinued the therapy due to adverse reactions (n = 8). From sera drawn before and after OIT, we analyzed specific IgA, IgG, IgG1 and IgG4 to cow's milk (CM), casein, β-lactoglobulin and ovalbumin (with enzyme-linked immunosorbent assay) and IgE to CM and hen's egg white [with enzymatic fluoroimmunoassay (Phadia ThermoFisher Scientific CAP system)]. As a reference, we also analyzed serum samples from 8- to 9-year-old children who either had no history of CMA (n = 76) or who had spontaneously recovered from IgE-mediated CMA (n = 56). RESULTS Levels of specific IgA, IgG, IgG1 and IgG4 to CM and casein, and CM-specific IgE prior to OIT were higher in children who discontinued the therapy than in those who achieved desensitization (p < 0.05). Adverse reactions in the entire population were associated with low IgG and IgG4, but high IgG1 levels to ovalbumin (p < 0.05). Specific IgA, IgG, IgG1 and IgG4 to CM proteins significantly increased and IgE to CM decreased during OIT in children who achieved desensitization (p < 0.01). In those who discontinued OIT, only IgG, IgG1 and IgG4 to CM increased significantly (p < 0.03) and CM IgE remained unchanged. CONCLUSIONS High specific IgE, IgA and IgG-class antibodies to CM proteins appear to predict failure to achieve desensitization in CM OIT. Specific IgA and IgG-class antibodies to CM increase and CM IgE decreases during desensitization.