Detecting asthma in its earliest stages remains a challenge, leading scientists to examine inflammatory biomarkers in adults with unexplained respiratory symptoms and normal lung function. In their quest for answers, Canadian researchers discovered that commonly used blood-based markers of type 2 (T2) airway inflammation, such as IL-4, IL-5 and IL-13, were largely undetectable in this population, raising questions about their reliability for early diagnosis.
Their work, “Early Detection of Asthma: Exploring Inflammatory Biomarkers in Symptomatic Adults With Normal Spirometry,” was published in the Journal of Asthma and Allergy. The study analyzed data from 128 adults across Canada who exhibited respiratory symptoms but had normal spirometry results. While 35% showed signs of T2 airway inflammation based on sputum eosinophils and FeNO levels, blood tests revealed low or absent concentrations of most biomarkers. Only eotaxin and eotaxin-3 demonstrated weak correlations with lung function and FeNO, suggesting limited diagnostic value.
Authors noted that their findings highlight the complexity of asthma pathophysiology and the limitations of systemic biomarkers for early detection. They emphasized that inflammation in early-stage asthma may remain localized in the airways, making blood tests less effective. They further called for longitudinal follow-up and the integration of airway sampling to better understand disease progression.
Up to 70% of asthma cases remain undiagnosed, according to the study, often due to mild symptoms and normal lung function tests. Early detection is critical to prevent severe respiratory events and improve long-term outcomes. Researchers suggested that future strategies include optimized biomarker panels, novel noninvasive techniques and targeted interventions for high-risk populations.
