PEANUT oral immunotherapy (POIT) initiated during infancy was associated with substantial reductions in markers of peanut allergy over the first two years of treatment, according to findings from an NHS service at St George’s Hospital, UK. The study examined immunological changes in 16 infants who began treatment before 12 months of age, with the aim of characterising responses during the first two years.
Researchers collected skin prick test (SPT) results, peanut-specific immunoglobulin E (IgE), and Ara h 2-specific IgE at baseline and at the end of the first and second years of treatment. Descriptive analyses were used to assess changes over time.
After 12 months, mean peanut-specific IgE decreased from 12.9 kUA/L at baseline to 2.7 kUA/L among the 16 infants. Ara h 2-specific IgE fell from 11.6 kUA/L to 1.4 kUA/L, while mean SPT responses decreased from 7.6 mm to 1.3 mm.
Among the five infants with available two-year data, reductions in all three immunological markers were sustained. Mean peanut-specific IgE declined from 17.6 kUA/L at baseline to 5.6 kUA/L after two years. Ara h 2-specific IgE decreased from 12.8 kUA/L to 2.1 kUA/L, while mean SPT responses fell from 8.6 mm to 2.2 mm.
These findings indicate that the reductions observed during the first year persisted in the small group with longer follow-up. However, the limited number of infants with two-year data means that the longer-term results should be interpreted cautiously.
Food challenge outcomes provided additional evidence of clinical responses to treatment. After 12 months, seven infants had a negative food challenge to a total of 4,000 mg of peanut protein, administered in 1,000 mg and 3,000 mg doses. Four infants whose repeat immunological results were considered too high for a challenge at 12 months subsequently had negative food challenges after 24 months. The remaining five infants had repeat results considered suitable for a challenge after 12 months and were awaiting appointments.
The authors concluded that POIT initiated in infancy was associated with substantial and sustained reductions in key immunological markers, alongside negative food challenge outcomes in some infants. They noted that a formal study assessing sustained unresponsiveness is needed to establish whether these changes persist beyond treatment.
Reference
Wells R et al. Immunological changes in infants undergoing peanut oral immunotherapy during the first two years of treatment. Abstract A205. BSACI Meeting, 11-13 October, 2026.
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