Healing chronic idiopathic eosinophilic pneumonia using mepolizumab alone without corticosteroids.

While glucocorticoids remain the standard first-line treatment for chronic idiopathic eosinophilic pneumonia (CIEP), the long-term use is marred by significant side effects. This case study explores the effectiveness of mepolizumab, an anti-interleukin‑5 (IL-5) monoclonal antibody, as a novel corticosteroid-free alternative in treating CIEP. A 50-year-old woman presented with a 3-week history of progressive shortness of breath, dry cough and night sweats. The blood tests showed eosinophilia, and chest radiography identified lung consolidations. The CIEP was confirmed, ruling out other conditions through a detailed clinical and bronchoscopic work-up. The patient declined to be treated with systemic glucocorticoids. Treatment with mepolizumab was remarkable for effectively resolving symptoms and improving radiological findings without any prior or concurrent glucocorticoid therapy. Notably, the patient remained relapse-free over a 2-year follow-up, underscoring mepolizumab's efficacy as a corticosteroid-free treatment for CIEP. This case study calls for further research into anti-IL‑5 treatment of rare respiratory conditions.