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]