New Asthma Phenotypes Identified In Smokers

A new study has uncovered the existence of 2 distinct phenotypes with different biological pathways that may be associated with fixed airflow limitation in smokers with severe asthma.

For their study, the researchers assessed 127 individuals with severe asthma, of whom 59 were current or former smokers. Cluster analysis was performed using clinical variables collected during a 2-day hospital stay. Subsequently, the clinical clusters were biologically characterized using the sputum levels of 14 molecules.
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The researchers identified 5 clinical clusters, including 2 that were characterized by low forced expiratory volume in 1 second/forced vital capacity. Following comparison of these 2 clusters, they found notable differences between both. One cluster consisted of high levels of circulating eosinophils, high immunoglobulin E levels, and a high sinus score, whereas the second cluster was reflected low levels of the aforementioned parameters. Cytokine/chemokine patters were also different between these 2 groups.

The researchers noted that the remaining 3 clusters were consistent with those previously reported: young onset and atopic; nonsmoker and less eosinophilic; and female and obese.

“This study reveals 2 distinct phenotypes with potentially different biological pathways contributing to fixed airflow limitation in cigarette smokers with severe asthma,” the researchers concluded.

—Christina Vogt

Reference:

Konno S, Taniguchi N, Makita H, et al; HiCARAT Investigators. Distinct phenotypes of smokers with fixed airflow limitation identified by cluster analysis of severe asthma. Ann Am Thorac Soc. 2018;15(1). https://doi.org/10.1513/AnnalsATS.201701-065OC.