Secondary Pulmonary Alveolar Proteinosis Associated With Ruxolitinib After Bone-Marrow Transplantation: A Case With...

Ruxolitinib is a Janus kinase (JAK) 1/2 inhibitor used to treat steroid-refractory graft-versus-host disease, wherein pulmonary alveolar proteinosis (PAP) is a rare complication. We report the case of a 47-year-old woman developing respiratory failure 8 months after commencing ruxolitinib treatment. Chest computed tomography revealed bilateral ground-glass opacities. Bronchoalveolar lavage fluid was milky and periodic acid-Schiff-positive, and Mycobacterium intracellulare was detected. Anti-granulocyte-macrophage colony-stimulating factor antibodies were negative, and the patient was diagnosed with secondary PAP. Ruxolitinib withdrawal led to initial radiological and clinical improvement, prior to initiating antimycobacterial therapy. To date, only three cases of ruxolitinib-associated secondary PAP have been reported, all complicated by nontuberculous mycobacterial infection. This case represents a unique clinical course of ruxolitinib-associated secondary PAP, wherein initial radiological and clinical improvements occurred following drug withdrawal, prior to antimycobacterial therapy. This case highlights the need to consider PAP as a rare complication in patients receiving ruxolitinib.