EGPA at Diagnosis: A Comprehensive Single-Center Profile of Laboratory Findings and Clinical Evidence

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare vasculitis. A key bio-logical hallmark is peripheral blood eosinophilia while antineutrophil cytoplasmic an-tibody (ANCA) positivity is not always present. Therefore, an early phase suspicion of EGPA leading to a correct diagnosis can be challenging. We performed an observa-tional cross-sectional study limited to baseline data on 38 patients between December 2019 and December 2025 at the Allergy and Clinical Immunology Unit, Messina, Italy. Data collection included eosinophil, neutrophil, and lymphocyte counts; ANCAs and antinuclear antibodies (ANAs); erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) determination; and the Birmingham vasculitis activity score (BVAS) questionnaire: Median eosinophil counts were 685 cells/µL, the neutro-phil-to-lymphocyte ratio (NLR) was 2.29, ESR median values were 24 mm/h, and CRPs were 1.99 mg/L. ANCAs were positive in five patients, and ANAs in 20. The trend in ANA+ patients was of lower median eosinophil counts and higher ESR and CRP me-dian values and median BVASs. General, nervous system, and ENT BVAS domains had higher scores.: Disease activity in EGPA at diagnosis can be difficult to recognize. We defined it as chameleon-like and could not be captured by specific immunological sig-natures. Therefore, an early diagnosis needs multidimensional assessment, integrating laboratory parameters with clinical scores. In our EGPA cohort, ANAs were detected in just over half the patients, suggesting that rather than acting as bystanders, these could help clinicians, together with eosinophil counts, NLRs, and BVASs, to suspect EGPA at an early stage for referral to specialized medical centers.