Swedish cohort
BAMSE is a population-based Swedish cohort which recruited 4089 newborn children between 1994-1996. The participants have been followed repeatedly with questionnaires on lifestyle, exposures and symptoms of allergic disease, and have attended regular clinical follow-ups. At the 16-year follow-up, gene expression levels were measured (256 individuals of mean age 16.7 years) with the Affymetrix Human Transcriptome Array 2.0 (HTA).[17] Whole blood was collected from study subjects in PAXgene tubes, and RNA was extracted batch-wise (QIAGEN, Courtaboeuf, France). RNA yield and quality were assessed. RNA of highest quality was selected for amplification, labelling, and hybridization on HTA with WT PLUS kit (Affymetrix Inc). Gene expression levels were normalized with the Robust Multi-array Average (RMA) algorithm and transcript clusters were annotated as previously described.[17]