Gene expression analysis of nasal mucosa in birch pollen allergic and non-allergic individuals upon nasal provocation with birch pollen

Birch pollen is a significant cause of allergic rhinitis, yet the mechanisms of sensitization is to be understood completely. Here, we investigate the changes in gene expression of birch pollen allergic and non-allergic individuals that occur as a result of nasal provocation with birch pollen. Overall design: This study was conducted specifically outside the birch pollen season to ensure that the results obtained are due to the nasal provocation alone and not to the exposure to birch pollen in the environment. 11 birch pollen allergic and 12 birch pollen non-allergic individuals participated in the study. All participants made two visits where they were subjected to nasal provocation with saline solution at visit 1 (baseline) and birch pollen solution at visit 2. At visit 1, nasal scrapings were collected 15 minutes following nasal provocation. The participants were randomized into four groups according to the time point of sample collection (15, 30, 60 or 120 minutes) following nasal provocation at visit 2. Nasal scrapings were collected at the respective time points. Total RNA was isolated from the nasal scrapings, Sequencing libraries from total RNA were prepared at the Core Facility Genomics, Medical University of Vienna, using the QuantSeq FWD protocol (Lexogen) and the pooled libraries were sequenced on a NextSeq500 instrument (Illumina) in 1x75bp single-end sequencing mode.