Abstract Allogeneic stem cell transplantation (A-SCT) offers curative potential for various hematologic malignancies. However, its benefits are often limited by graft-versus-host disease (GVHD), which is a leading cause of late complications and mortality in survivors. Within its manifestations, pulmonary involvement, specifically bronchiolitis obliterans syndrome (BOS) is one the most severe presentation. Symptoms are often subtle and nonspecific, making diagnosis frequently delayed. Imaging commonly reveals mosaic attenuation, air trapping, or ground-glass opacities, and careful exclusion of infectious etiologies is necessary prior to diagnosis. A 41-year-old man with history of adult T-cell leukemia/lymphoma status post A-SCT for 1 year presented to the emergency department after developing fever, chills, sore throat, and dyspnea over the course of five days. The patient was found to be hypotensive, tachycardic, and tachypneic. Physical exam was remarkable for diffuse dry crackles and wheezing on auscultation. Imaging had no evidence of pulmonary embolism but revealed diffuse groundglass opacities, with interlobular septal thickening and intralobular interstitial thickening. Laboratories were remarkable for bicytopenia (anemia, severe thrombocytopenia) with anion gap metabolic acidosis due to lactatemia, highly elevated inflammatory markers, and transaminitis. He was started on IV fluid resuscitation, oxygen supplementation with 4 liters, broad-spectrum anti-microbials, and Prednisone 1 mg/kg daily with no improvement. Bronchoscopy with bronchoalveolar lavage revealed no abnormal findings; biopsy was deferred due to severe thrombocytopenia. Thorough infectious workup, including next-generation sequencing of microbial cell-free DNA was negative for any pathogens. Additionally, bone marrow biopsy, 1 month before hospitalization, showed no evidence of disease. In view of these findings, patient was started on Belumosudil with inhaled Fluticasone, Azithromycin, and Montelukast for bronchiolitis obliterans syndrome with marked improvement over the course of hospitalization. This case highlights the importance of maintaining a high index of suspicion for noninfectious etiologies of respiratory decline in post-transplant patients, especially when infectious evaluations are unrevealing and imaging suggests small-airway involvement. Prompt recognition and early initiation of appropriate therapy are essential to prevent permanent pulmonary damage. The patient’s notable recovery with Belumosudil, alongside inhaled Fluticasone, Azithromycin, and Montelukast, illustrates the emerging value of targeted therapies that address the fibrotic and immune mechanisms underlying chronic GVHD. Ongoing clinical awareness and timely management remain key to improving prognosis in this high-risk population. This abstract is funded by: None
Chahin et al. (Fri,) studied this question.