Blood protein identified as potential lung disease biomarker in AAV
Study links high levels of CXCL6 with lung damage
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A study linked high levels of a blood protein called CXCL6 with lung disease in people with ANCA-associated vasculitis (AAV), pointing to the protein as a potential biomarker to diagnose the condition and monitor its progression.
Data indicate that people with AAV who have inflammatory lung disease tend to have higher CXCL6 levels, and higher levels of CXCL6 are associated with higher levels of inflammatory markers and a greater risk of disease progression in AAV patients with lung disease.
An early-access version of the study, “Serum CXCL6 as a biomarker for diagnosing and predicting progression of interstitial lung disease in ANCA-associated vasculitis,” was published in Arthritis Research & Therapy.
AAV is an autoimmune disorder characterized by inflammation of blood vessels. In some patients, this can lead to interstitial lung disease (ILD), a broad term for disorders marked by inflammation and fibrosis (scarring) of the lungs. This can result in life-threatening problems with breathing.
CXCL6 is a cytokine, a signaling molecule that helps to coordinate the activity of inflammatory immune cells. Recent studies in people with idiopathic pulmonary fibrosis, another disorder marked by lung inflammation and scarring, have indicated that elevated CXCL6 levels are abnormally high, with higher levels associated with worse clinical outcomes.
Measuring protein
A team of scientists in China wondered if the inflammatory protein might also be associated with lung disease outcomes for people with AAV. To find out, they measured CXCL6 levels in serum samples from 292 people with AAV, just under half of whom had ILD. They also analyzed CXCL6 levels in serum samples from 82 people without AAV for comparison. Serum is the part of blood that doesn’t contain blood cells.
Results showed that AAV patients had higher CXCL6 levels than people without AAV, and among AAV patients, levels of the inflammatory molecule were higher in those with ILD. The researchers noted that CXCL6 levels were comparable in people with different types of AAV.
CXCL6 levels were not significantly associated with lung function measures, but they did correlate significantly with markers of systemic (body-wide) inflammation. Analyses also indicated that people with AAV-related ILD who had high CXCL6 levels were more likely to experience lung disease progression.
“Multivariate analysis revealed that serum CXCL6 was independently associated with ILD progression in patients with AAV-ILD,” the researchers wrote. “These findings indicate a significant association between serum CXCL6 and ILD in AAV patients, suggesting CXCL6 may serve as a potential [blood] marker for disease activity and ILD progression in AAV.”
The scientists stressed a need for additional, larger studies to validate and expand on the findings.
