Eosinophil-linked pulmonary circulation in EGPA Improves under anti-IL-5/R therapy: A longitudinal study

Background Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare systemic vasculitis characterized by eosinophilic inflammation and potential cardiovascular involvement. The relationship between eosinophil burden and subclinical cardiopulmonary vascular dysfunction remains unclear. Methods 27 EGPA patients were evaluated. Peripheral eosinophil counts (PEC) at diagnosis were analysed in relation to echocardiographic markers of pulmonary vascular load and right ventricular–pulmonary artery (RV–PA) coupling. Patients initiating anti–IL-5/R therapy (mepolizumab or benralizumab) underwent echocardiography assessing pulmonary artery systolic pressure (PAPs), tricuspid annular plane systolic excursion (TAPSE), TAPSE/PAPs ratio, and tricuspid regurgitation velocity (TRV) at diagnosis, treatment initiation (Baseline), and 24-month follow-up (T24) to assess temporal changes. Patients were stratified by median PEC. Multivariable regression and ROC analyses were performed. Results At Baseline, 33% of patients exhibited elevated PAPs (>25 mmHg) despite absence of clinical pulmonary hypertension. Higher PEC were associated with increased PAPs (p = 0.04) and reduced TAPSE/PAPs ratio (p = 0.03). Pulmonary vascular load worsened from diagnosis to T0 and improved after anti-IL-5/R therapy, with PAPs decreasing from 27.5 [18.0–30.0] mmHg to 18.0 [11.75–20.0] mmHg (p = 0.002) and TRV from 2.30 [1.65–2.48] to 1.80 [1.28–1.92] m/s (p = 0.005). Baseline PEC moderately discriminated patients with intermediate/high echocardiographic probability of pulmonary hypertension (AUC 0.751). Conclusion Elevated PEC may signal early pulmonary vascular dysfunction and RV–PA uncoupling EGPA, which may be partially reverted with anti-IL-5/R therapy. These findings support the importance of early cardiovascular surveillance in eosinophil-rich EGPA.