Monitoring Ara h 1, 2 and 3-sIgE and sIgG4 antibodies in peanut allergic children receiving oral rush immunotherapy.

BACKGROUND

The aim was to study the clinical efficacy and safety of rush oral immunotherapy (OIT) for severe peanut-allergic children and to measure the antibody responses.

METHODS

Eighteen Japanese children were enrolled after a positive double-blind, placebo-controlled food challenge (DBPCFC). The patients ingested peanuts up to 3-5 times a day every 30 min, increasing the dose by 20% every time. The goal dose was 3.5-7 g. IgE, IgG, and IgG4 antibody levels to peanut, and peanut allergen components were measured during up to 3 yr of maintenance treatment.

RESULTS

Two children dropped out due to side effects. Sixteen patients (14 boys and two girls, median: 9 yr range: 5-14 yr) achieved the goal dose after a median of 11 days (range: 4-19 days). Their median threshold dose at DBPCFC was 0.20 g (range: 0.015-1.0 g). All were sensitized to Ara h 2. Fourteen of them had a history of previous anaphylaxis. In total, 173 adverse events were observed during the treatment (27% of the total ingestions) of which 74 needed medications. The median IgE, IgG, and IgG4 antibody levels to peanut increased during rush OIT. The IgG4 levels were high during the whole maintenance phase. IgE and IgG4 antibodies to Ara h 2 dominated the serological response during the treatment.

CONCLUSIONS

The present rush OIT protocol for children with severe peanut allergy was effective and relatively safe. A sustained Ara h 2-specific IgG4 antibody response characterized the treatment.