Steroids May Increase Inflammation in Patients with Severe Asthma
A recent study found that increased levels of the inflammatory protein CXCL10 in patients with severe asthma was associated with resistance to corticosteroid treatment.
In prior studies, researchers found that 50% of patients with severe asthma had increased IFN-y levels—the marker of Th1/type 1 inflammation—in airways despite treatment with corticosteroids. They hypothesized that CXCL10, an inflammatory protein induced by IFN-γ, was an important factor in asthma control and unresponsiveness to corticosteroids.
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The study assessed levels of CXCL10 in 18 patients with mild or moderate asthma, 17 patients with severe asthma, and 12 healthy controls. Patients with severe asthma had higher levels of CXCL10 compared with patients with mild or moderate asthma.
Among patients with severe asthma, 50% had elevated CXCL10 and those who had elevated CXCL10 had worse asthma control, determined by more emergency department visits and asthma flares in the past year.
In addition, the researchers examined cultured immune cells and found that corticosteroids failed to suppress CXCL10 gene expression by stabilizing the signal from IFN-y, which stimulates CXCL10 production.
“While corticosteroids are the mainstay asthma treatment, our findings suggest that these medications are of limited help to patients with high levels of interferon-gamma and CXCL10, and may even be harmful over time,” the researchers concluded.2
—Melissa Weiss
Reference:
1) Gauthier M, Chakraborty K, Oriss TB, et al. Severe asthma in humans and mouse model suggests a CXCL10 signature underlies corticosteroid-resistant Th1 bias [published online July 6, 2017]. JCI Insight. doi:10.1172/jci.insight.94580.
2) Steroids may do more harm than good in some cases of severe asthma [press release]. Pittsburg, PA: University of Pittsburg, July 6, 2017. http://www.upmc.com/media/NewsReleases/2017/Pages/asthma-ray.aspx. Accessed July 10, 2017.