Administration of a probiotic with peanut oral immunotherapy: A randomized trial.

This was a double-blind, placebo-controlled randomized trial in children aged 1 to 10 years with peanut allergy conducted at the Royal Children's Hospital allergy and immunology outpatient clinics in Australia. The PPOIT active arm included 31 participants.

The active regimen combined Lactobacillus rhamnosus CGMCC 1.3724 at a fixed oral dose of 2 × 10^10 colony-forming units once daily with peanut oral immunotherapy using peanut flour (50% peanut protein) once daily for 18 months. The peanut OIT protocol used a 1-day rush induction, build-up updosing every 2 weeks to a maintenance dose of 2 g peanut protein over 8 months, then a 10-month maintenance phase; the control group received placebo (maltodextrin).

The combined probiotic-plus-peanut oral immunotherapy regimen was highly effective for inducing sustained unresponsiveness and desensitization in peanut-allergic children. Sustained unresponsiveness occurred in 23/28 PPOIT-treated participants (82.1%) versus 1/28 placebo recipients (3.6%) (RR 23, 95% CI 3.33-158.8; P < .001), and desensitization occurred in 26/29 (89.7%) versus 2/28 (7.1%) (RR 12.55, 95% CI 3.28-47.99; P < .001). Peanut skin-prick test wheal size was also markedly lower with PPOIT at T1 and T3 than with placebo, and the authors reported immune changes consistent with modulation of peanut-specific responses, including reduced peanut-specific IgE reactivity and increased peanut-specific IgG4. Severe adverse events were not significantly different between groups (45.2% vs 32.3%, P = .3), but the regimen was associated with serious events in some participants. The authors concluded that PPOIT shows promise, while the separate contribution of the probiotic component remains unclear.

The trial was relatively small and conducted at a single pediatric center, which limits generalizability. The intervention combined probiotic therapy with peanut oral immunotherapy, so the independent effect of the probiotic cannot be separated from the OIT effect. Safety interpretation is also constrained by the occurrence of serious adverse events and by limited follow-up for durability of sustained unresponsiveness.