Cow's milk protein allergy: Immunological response in children with cow's milk protein tolerance

Abstract

Objective: To study changes in immunological responses in patients with CMPA during symptomatic and asymptomatic episodes of cow's milk protein tolerance status. Methods: 27 CMPA patients were enrolled and underwent diagnostic evaluation, including CM challenge test, skin prick test and specific IgE to CM. Blood samples were collected in two periods from those who became tolerant (n = 13) and those with persistent CMA (n = 14), in order to measure in vitro PBMC responses to cow's milk protein (IL-10, IFN-γ, IL-5), IgG4 to β- lactoglobulin, casein, BLG-IgG4/IgE ratio and the CAS-IgG4/IgE ratio. Results: Seventy percent of CMPA patients in our study were male with a mean age at diagnosis of 8 months and mean age of onset of 3 months. The reaction time to CM ranged from within 7 minutes to within 14 days. Positive IgEsensitization was defined as either a specific IgE to CM of more than 0.35 kUA/L (N=11) or SPTs positive for CM and/or fresh cow milk (N=20). Forty-eight percent of the patients (n = 13) could tolerate CM by 13.38 months (8 - 19 months). Mean specific-IgE levels to CM were 4.1 kUA/L (range 0.35 - 14.3 kUA/L). Determination of the cytokine (IL-10, IFN-γ, IL-5) response to BLG revealed significantly higher IL-10 levels during the tolerance phase (212.93 vs 142.46 pg/ml, P =.011). There was a significant increase in BLGIgG4 and the BLG-IgG4/IgE ratio in the tolerance phase when compared to the symptomatic phase. Conclusions: IL-10, BLG-IgG4 and the BLGIgG4/ IgE ratio were higher in CMPA patients during the tolerance phase compared to the symptomatic phase.