Mechanisms of allergy and clinical immunologyPersistence and evolution of allergen-specific IgE repertoires during subcutaneous specific immunotherapy

BackgroundSpecific immunotherapy (SIT) is the only treatment with proved long-term curative potential in patients with allergic disease. Allergen-specific IgE is the causative agent of allergic disease, and antibodies contribute to SIT, but the effects of SIT on aeroallergen-specific B-cell repertoires are not well understood.ObjectiveWe sought to characterize the IgE sequences expressed by allergen-specific B cells and track the fate of these B-cell clones during SIT.MethodsWe used high-throughput antibody gene sequencing and identification of allergen-specific IgE with combinatorial antibody fragment library technology to analyze immunoglobulin repertoires of blood and the nasal mucosa from aeroallergen-sensitized subjects before and during the first year of subcutaneous SIT.ResultsOf 52 distinct allergen-specific IgE heavy chains from 8 allergic donors, 37 were also detected by using high-throughput antibody gene sequencing of blood samples, nasal mucosal samples, or both. The allergen-specific clones had increased persistence, higher likelihood of belonging to clones expressing other switched isotypes, and possibly larger clone size than the rest of the IgE repertoire. Clone members in nasal tissue showed close mutational relationships.ConclusionIn the future, combining functional binding studies, deep antibody repertoire sequencing, and information on clinical outcomes in larger studies might aid assessment of SIT mechanisms and efficacy.