Asthma population
Subjects with asthma were recruited from the Asthma Clinic at the
University of Alberta following written informed consent. This asthma
study was approved by the University of Alberta Human Ethics Review
Board (PRO1784). Lung function testing was performed and blood obtained
for complete blood count (CBC), serum IgE measurement, immune cell
profiling and whole blood RNA preparation. Severe asthma was defined as
patients on high dose inhaled corticosteroids (ICS, ≥ 1000 µg/day
fluticasone equivalent), a 2nd line controller
(long-acting β agonist,
leukotriene modifier, theophylline, tiotropium), anti-type 2 therapy
(anti-IgE, anti-IL-5) and/or oral corticosteroid (OCS) therapy for ≥
50% of the previous year whose symptoms remain uncontrolled despite
this therapy [2].