The following is a summary of “Severe Eosinophilic Asthma or Eosinophilic Granulomatosis with Polyangitis: potential biomarkers for novel diagnostic strategies,” published in the August 2024 issue of Allergy and Immunology by Latorre et al.
Severe Eosinophilic Asthma (SEA) is increasingly recognized as a potential precursor to Eosinophilic Granulomatosis with Polyangiitis (EGPA), a rare and complex autoimmune disorder. Despite this, the early identification of EGPA within the spectrum of severe asthma still needs to be explored. This study aims to identify a comprehensive panel of clinical and biological markers that could aid in detecting patients with SEA who may be in the prodromal phase of EGPA and to develop a strategic framework for diagnostic decision-making.
In this study, researchers enrolled 30 patients diagnosed with EGPA and 49 with SEA. Each participant underwent thorough pulmonary, otolaryngologic, and rheumatologic evaluations. A range of biomarkers was assessed, including blood markers such as eosinophil count, eosinophilic cationic protein (ECP), IL-5, IL-4, total IgE, IgG4, and anti-neutrophil cytoplasmic antibody (ANCA). Additionally, sputum samples were analyzed for eosinophil count, periostin, IL-8, and granulocyte-macrophage colony-stimulating factor (GM-CSF), while nasal smears were evaluated for eosinophilia. The study group employed several patient-reported outcome measures to complement these assessments, including the Asthma Control Test, Short Form-36, Sino-Nasal Outcome Test-22, and the Asthma Quality of Life Questionnaire.
The results revealed that patients with SEA exhibited poorer asthma control (p<0.001) and elevated levels of sputum eosinophils (p<0.002). In contrast, patients with EGPA had a history of significantly higher blood eosinophil levels. Notably, sputum GM-CSF emerged as a distinctive biomarker, showing significantly elevated levels in patients with EGPA compared to those with SEA (p<0.0001). Furthermore, among patients with SEA, those who exhibited suggestive but non-diagnostic criteria for EGPA, particularly tissue eosinophilic infiltrates, demonstrated higher levels of sputum GM-CSF (p<0.0005) as well as increased blood and sputum eosinophils (p<0.0006 and p<0.011, respectively) compared to their counterparts.
These findings suggest that sputum GM-CSF and eosinophil counts may serve as valuable biomarkers in the early identification of EGPA among patients with SEA. Integrating these markers into clinical practice could enhance diagnostic accuracy and inform treatment decisions, ultimately improving patient outcomes in this challenging subset of asthma. This study underscores the importance of early detection and the potential of targeted biomarker analysis in refining the management of patients at risk for EGPA.
Source: sciencedirect.com/science/article/abs/pii/S2213219824008274
