D2.292 - Effects of Milk Oral Immunotheraphy on Human Basophils in Children with Cow’s Milk Protein Allergy

Milk oral immunotherapy (OIT) is used to induce desensitization in patients with cow’s milk protein allergy (CMPA). This study evaluated the effects of OIT on basophil activation test (BAT).

In patients with CMPA, BAT was performed during the initial, dose escalation, and maintenance phases of OIT using anti-FcεRI, fMLP, and casein (10, 100, and 1000 ng/mL) as stimuli. Basophils were identified by CCR3 expression, and basophil activation was determined by CD63 expression

Forty-five children with CMPA were enrolled, but 18 were excluded due to high basophil activation in the negative control. Fourteen patients were analyzed in the initial phase, seven in the dose escalation phase, and four in the maintenance phase of OIT. Total IgE, milk and casein sIgE were similar at three phases of OIT; however, eosinophil percentage and count were significantly different (p=0.035, p=0.011, respectively).BAT results showed no significant differences in the conditions of unstimulated, fMLP and FcεRI stimulation among the three OIT phases.

Following stimulation with 100 ng/mL casein, the median basophil CD63 expression was 31.4 (interquartile range:5.8–46.4), 4.5 (0–16.6), and 0.6 (0.1–6.1), respectively (p=0.130; p for trend=0.040). After stimulation with 1000 ng/mL casein, CD63 expression was 31.9 (18.7–71.3), 8.6 (2.8–20.7), and 2.4 (0.1–6.1), respectively (p=0.016; p for trend=0.004).

In the initial phase 14 children showed significant correlation between total IgE and CD63 at 100 and 1000 ng/mL casein (p=0.047 and p=0.002; r=0.366 and r=0.797) respectively). Additionally, significant correlations were observed between milk sIgE levels and CD63 expressions at three casein concentrations (r=0.635, r=0.614 and r=0.711, p=0.026, p=0.034, and p=0.01, respectively). A significant correlation was observed between casein sIgE and CD63 at 10 and 1000 ng/mL casein (r=0.635, p=0.026 and r=0.637, p=0.018). 

Our results show that milk OIT leads to a consistent reduction in BAT with 10, 100, and 1000 ng/mL casein as the OIT phases progress. Furthermore, CD63 expression in BAT shows significant correlation with milk and casein sIgE in the initial phase. In conclusion BAT offers a promising monitoring strategy for evaluating the efficiency of milk OIT.