How I diagnose and treat organizing pneumonia in hematopoietic cell transplant recipients

In this elegant paper, the authors describe four case reports of patients to whom a diagnosis of OP was assigned based on clinical-radiological data and BAL execution. However, in none of these cases was a lung biopsy performed to confirm the diagnosis accurately, nor was this diagnostic modality mentioned in the diagnostic summary. Recommendations from major scientific societies mention it as a method for the diagnostic approach, particularly if a confident diagnosis is not possible1.
Pulmonary complications after HCT persist in up to 30–60% of HCT recipients despite improvements in supportive care and remain fatal. Among non-infectious complications, idiopathic pneumonia syndrome (IPS), diffuse alveolar haemorrhage (DAH), peri-engraftment respiratory distress syndrome, nonspecific interstitial pneumonia (NSIP), lymphoid interstitial pneumonia (LIP), and OP2 can occur. These conditions can inherently exhibit clinical features like both infectious and other non-infectious conditions, often requiring a lung biopsy for definitive diagnosis3, so doing to avoid improper therapy.
We believe it is important to emphasize that, particularly in atypical presentation cases where the clinical, radiological findings do not allow for a highly confident diagnosis of OP, lung biopsy should be included in the diagnostic workup. In fact, in these specific cases, prolonged corticosteroid therapy or immunosuppression therapy may be more harmful for the patient than undergoing a lung biopsy.
Transbronchial lung cryobiopsy (TBLC) has recently been recognized as a valid and less invasive alternative to SLB for diagnosing interstitial lung diseases (ILDs). TBLC allows for the collection of larger and higher-quality lung tissue samples without the crush artifacts typically associated with conventional transbronchial lung biopsy performed with flexible forceps4.
Moreover, recent randomized clinical trials have demonstrated an acceptable safety profile for TBLC when performed even in intensive care unit settings, both in terms of haemorrhage and pneumothorax, particularly when conducted by experienced pulmonologists5.


References
1. Cherian SV, Patel D, Machnicki S, et al. Algorithmic Approach to the Diagnosis of Organizing Pneumonia: A Correlation of Clinical, Radiologic, and Pathologic Features. Chest. 2022 Jul;162(1):156-178. doi: 10.1016/j.chest.2021.12.659.
2. Bondeelle L, Bergeron A. Managing pulmonary complications in allogeneic hematopoietic stem cell transplantation. Expert Rev Respir Med. 2019;13(1):105-119. doi:10.1080/17476348.2019.1557049
3. Patel SS, Ahn KW, Khanal M, et al. Noninfectious Pulmonary Toxicity after Allogeneic Hematopoietic Cell Transplantation. Transplantation and Cellular Therapy, Official Publication of the American Society for Transplantation and Cellular Therapy. 2022;28(6):310-320. doi:10.1016/j.jtct.2022.03.015
4. Ravaglia C, Poletti V. Transbronchial lung cryobiopsy for the diagnosis of interstitial lung diseases. Curr Opin Pulm Med. 2022;28(1):9-16. doi:10.1097/MCP.0000000000000848
5. Loor K, Culebras M, Sansano I, et al. Lung allograft transbronchial cryobiopsy for critical ventilated patients: a randomised trial. European Respiratory Journal. 2023;61(1). doi:10.1183/13993003.02354-2021