Bronchiolitis obliterans syndrome following SARS-CoV-2 infection in an allogeneic hematopoietic stem cell recipient

Peripheral allogeneic hematopoietic stem cell transplant recipients are the most vulnerable patients to community-acquired respiratory viruses such as respiratory syncytial virus, influenza virus, or others. These patients are likely to develop severe acute viral infections; community-acquired respiratory viruses have also been identified as triggers of bronchiolitis obliterans (BO). BO is a manifestation of pulmonary graft-versus-host disease, most often leading to irreversible ventilatory impairment. To date, there are no data on whether Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could be a trigger for BO. Here, we report the first report of a case of bronchiolitis obliterans syndrome following SARS-CoV-2 infection occurring 10 months after allogeneic hematopoietic stem cell transplant with a flare of underlying extra thoracic graft-versus-host disease. This observation provides a new perspective and should be of particular interest to clinicians, suggesting the need for close monitoring of pulmonary function test (PFTs) after SARS-CoV-2 infection. The mechanisms leading to bronchiolitis obliterans syndrome after SARS-CoV-2 infection require further investigation.