Bronchoalveolar lavage (BAL) immune cells from patients with asthma treated with a short-acting beta-agonist demonstrated changes in gene expression that may not relate to disease mechanisms or be immediately matched by protein expression, according to the results of a study published in the American Journal of Respiratory and Critical Care Medicine.
Epithelial cell gene expression from BAL immune cells was profiled from both patients with asthma and healthy controls. Correlations between BAL immune cell gene expression profiles and participant and sample traits were examined. Of interest were severity-related gene expression determined by correlating transcripts and coexpression networks to lung function, emergency department visits, or hospitalizations.
Of the 154 patients with asthma and controls, 100 had accompanying airway epithelial cell gene expression data available. Overall, changes in BAL immune cell expression were linked to age, sex, race, cell proportions, and medications. Individuals with severe asthma were more likely to have changes in the cyclic adenosine monophosphate signaling pathway. An in vitro cellular model demonstrated that this was likely caused by upregulation in cyclic adenosine monophosphate-related expression in nonsevere and beta-agonist-naive patients given a beta-agonist before cell collection.
“Gene expression in BAL immune cells is influenced by factors seldom considered,” the authors wrote. “[F]uture gene expression research should consider all factors that affect gene expression, particularly the influence of any medication used prior to sampling.”
Weathington N, O’Brien ME, Radder JE, et al. Bronchoalveolar lavage cell gene expression in severe asthma reveals mechanisms of severe disease and influences of medications [published June 4, 2019]. Am J Respir Crit Care Med. doi:10.1164/rccm.201811-2221OC