Abstract
in
English,
German
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Background:
Allergen-specific immunotherapy (AIT) is a causative treatment in allergic airway disease, comprising long-term allergen administration and requiring three years of treatment. Mechanisms and biomarkers that translate into clinical efficacy remain urgently needed.
Methods:
In an exploratory observational allergy cohort we phenotyped 32 grass-pollen allergic patients with hayfever undergoing AIT for over three years and controls using local and systemic samples for ex vivo FACS, nasal transcriptomes and in vitro phleum-stimulation at critical time windows six hours after therapeutic allergen administration and during peak-season responses.
Findings:
The up-dosing phase is marked by increased IL-10+ B-cells with allergen-specific PD-L1 up-regulation, while effector Th1/Th17 cells and CCR6+IL-17+FoxP3+T-cells decrease. The conversion phase exhibits Th17 recovery in the absence of Th2 cells. The tolerance-mounting phase after three years of treatment is characterized by induction of Tregs while Th2 and phleum-specific Th17 responses decrease. Notably, high ratios of circulating Breg/Th17 following initial AIT correlate significantly with clinical improvement after three years.
Interpretation:
Our exploratory data hypothezise differential shifts in the hierarchy of tolerance in three distinct phases of AIT characterized by conversion of regulatory against pro-inflammatory mechanisms, of which the Breg/Th17 ratio after initial treatment emerges as potential early prediction of AIT efficacy.
Fund:
This study was partially funded by Allergopharma GmbH & Co. KG, intramural funding and the German Center for Lung Research (DZL).
Keywords:
Allergic Rhinitis; Allergy; Biomarker; Prediction; Regulatory B-cells (Bregs); Regulatory T-cells (Tregs); Specific Immunotherapy; Surrogate; Tolerance.