The Rare Complication and Diagnostic Challenges of Pulmonary Eosinophilia in Graft versus Host Disease Patients after Hematopoietic Stem Cell Transplantation

Purpose: Chronic graft versus host disease (cGvHD) is a common complication of hematopoietic stem cell transplantation (HSCT). Eosinophilic lung disease is a rare poorly understood complication in HSCT patients with cGvHD. These patients present similarly to those with Acute Eosinophilic Pneumonia (AEP). The purpose of this study is to better elucidate the presentation and potential treatment of this phenomenon. Methods: We reviewed over 170 bronchoscopies in post-HSCT patients with respiratory symptoms. Of these, four patients, whose course was complicated by cGvHD, presented with respiratory symptoms, diffuse ground-glass opacities (GGO) on chest computerized tomography (CT), bronchoalveolar lavage (BAL) eosinophilia, and no evidence of infection. The clinical course of these patients was reviewed. Results: Despite clinical presentation similar to AEP, not all patients had > 25% eosinophils on BAL, one criterion for AEP, however all improved with steroids. Steroid initiation was often delayed in favor of empiric antibiotics despite negative infectious workup. Several patients had recurrent episodes. Regarding possible associations, we examined but found no link between particular demographics, reason for HSCT, chemotherapy, immunosuppressants, or peripheral eosinophil count and pulmonary eosinophilia in these patients. GGO present on initial CT imaging became chronic in several of these patients. Conclusion: We propose that in post-HSCT patients with GvHD presenting with respiratory symptoms, GGO on CT, BAL eosinophilia of > 10%, and negative respiratory cultures, an autoimmune eosinophilic process may be occurring. Earlier recognition and initiation of corticosteroids in these patients may improve their outcomes as an autoimmune diagnosis was often delayed in favor of antibiotics.