Beschreibung:
<jats:title>Abstract</jats:title><jats:sec><jats:title>Background</jats:title><jats:p>Prevention of new IgE sensitizations has been described during allergen‐specific immunotherapy. However, prospective data using a preventive approach in very young children who would benefit most are missing. We initiated a prospective pilot study investigating the safety, immunomodulatory, and sensitization‐preventive effect of sublingual immunotherapy (<jats:styled-content style="fixed-case">SLIT</jats:styled-content>) in mono/oligoclonally sensitized, clinically asymptomatic children 2–5 yr of age.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>In this double‐blinded, randomized, placebo‐controlled pilot study, 31 mono‐/oligosensitized children to house‐dust mite or grass pollen were included. <jats:styled-content style="fixed-case">SLIT</jats:styled-content> with the respective source (n = 15) or placebo (n = 16) was applied. After dose‐up‐phase therapy was continued for 2 yr. Parents recorded clinical events, vaccinations, and drug intake in a diary. Skin prick testing and specific IgE and IgG measurements were recorded at baseline, 12 and 24 months. At the same time, allergen‐specific proliferation and <jats:styled-content style="fixed-case">IL</jats:styled-content>10‐ and <jats:styled-content style="fixed-case">TGF</jats:styled-content>β‐dependent Treg function were measured.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Preventive application of <jats:styled-content style="fixed-case">SLIT</jats:styled-content> in young children was safe (no relevant side effects in 21,170 single applications). After 12 and 24 months of treatment, the rate of allergen‐specific sensitization (specific IgE and <jats:styled-content style="fixed-case">SPT</jats:styled-content> reactivity) was comparable in the treatment and the placebo group. However, verum‐treated patients displayed a significant up‐regulation of allergen‐specific IgG (p < 0.05). Furthermore, <jats:styled-content style="fixed-case">IL</jats:styled-content>10‐dependent inhibition (p < 0.05) was observed <jats:italic>in vitro</jats:italic> in the treatment group but not in the placebo group.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>Preventive <jats:styled-content style="fixed-case">SLIT</jats:styled-content> is safe in children 2–5 yr of age and induces regulatory mechanisms involving allergen‐specific IgG and <jats:styled-content style="fixed-case">IL</jats:styled-content>10. Based on this pilot study, large‐scale trials will need to investigate the modulation of sensitization and clinically relevant allergy.</jats:p></jats:sec>