Objectives: The purpose of this study was to evaluate the utility of alpha-lactalbumin (ALA) specific IgE levels using 3gallergy in predicting clinical tolerance in patients with milk allergy.
Method: Forty-three (43) patients with milk allergy (30 boys and 13 girls, age 12 months to 13 years, median 4 years old) were examined for ALA specific IgE levels using 3gAllergy and ImmunoCAPspecific IgE assay (ImmunoCAP). In addition, specific IgE for cow’s milk, casein, and beta-lactoglobulin (BLG) were measured by 3gAllergy and ImmunoCAP. Subjects were categorized into 3 groups according to how much heated milk the patient could tolerate, group A, less than 10ml (n=14), group B, 10ml to 100ml (n=15), and group C, 100ml or more (n=14). Two patients had avoided cow’s milk product strictly because of severe anaphylactic history with milk intake and others had been undertaking oral immunotherapy with heated milk. Since all data were not assumed Gaussian distributions, they were shown as (median, range(minimum - maximum), and were analyzed by Spearman’s method or one-way ANOVA with Dunn’s multiple comparisons.
Results: The levels of cow’s milk specific IgE using 3gAllergy were significantly correlated to the levels using ImmunoCAP (r=0.958, p< 0.0001). Likewise, the casein, BLG, and ALA specific IgE levels showed similar correlations: (r=0.9766, p< 0.0001, r=0.9793, p< 0.0001, and r=0.821, p<0.0001, respectively). Month of age and serum total IgE levels were not significantly different among the groups.
The ALA specific IgE levels with 3gAllergy in group A (44.6 UA/ml, (2.92-478)) and in group B (8.43 UA/ml, (1.09-152) were significantly higher than those in group C (0.994 UA/ml, (<0.1-53.1), p< 0.0001 and p<0.05). but there was no significant difference between levels in group A and in group B. Levels of milk, casein, and BLG showed similar results. However, the ALA specific IgE - total IgE ratios in group A (0.05, (0.0132-0.1146) were significantly higher than those in group B (0.0155 (0.0024-0.0691)) and those in group C (0.0034 (0.0007-0.0234), p< 0.0001 and p<0.05), as well as the ratios in group B were significantly higher than those in group C, (p< 0.05). On the other hand, there were no significant differences of ALA data using ImmunoCAP among the groups.
Conclusions: The ALA specific IgE levels using 3gAllergy is useful to evaluate the clinical tolerance of milk allergy, especially when considered influence of total IgE levels.