Some chemoattractant molecules such as eotaxin-3, immunoglobulin G4 (IgG4), and CC chemokine ligand 17 (CCL17/TARC) have been found at elevated levels in active EGPA compared to HCs and inactive EGPA and have a potential role as a diagnostic biomarker [70]. This evidence concerns the gene CCL26 and eosinophilic granulomatosis with polyangiitis.