Early Onset Noninfectious Pulmonary Syndromes after Hematopoietic Cell Transplantation

Recent advancements in hematopoietic stem cell transplantation in Taiwan

Hematopoietic stem cell transplantation (HSCT) can cure malignant and nonmalignant hematological disorders. From 1983 to 2022, Taiwan performed more than 10,000 HSCT transplants. The Taiwan Blood and Marrow Transplantation Registry collects clinical information to gather everyone's experience and promote the advances of HSCT in Taiwan to gather everyone's experience and promote advances of HSCT in Taiwan. Compared with matched sibling donors, transplants from matched unrelated donors exhibited a trend of superior survival. In Taiwan, transplant donors showed remarkable growth from unrelated (24.8%) and haploidentical (10.5%) donors. The number of older patients (17.4%; aged ≥61 years) who underwent transplantation has increased markedly. This review summarizes several significant developments in HSCT treatment in Taiwan. First, the use of Anti-thymocyte globulin (ATG) and intravenous busulfan regimens were important risk factors for predicting hepatic sinusoidal obstruction syndrome. Second, a new, machine learning-based risk prediction scoring system for posttransplantation lymphoproliferative disorder has identified five risk factors: aplastic anemia, partially mismatched related donors, fludarabine use, ATG use, and acute skin graft-versus-host disease. Third, although the incidence of idiopathic pneumonia syndrome was low (1.1%), its mortality rate was high (58.1%). Fourth, difficult-to-treat mantle cell and T-cell lymphomas treated with autologous HSCT during earlier remission had higher survival rates. Fifth, treatment of incurable multiple myeloma with autologous HSCT showed a median progression-free survival and overall survival of 46.5 and 70.4 months, respectively. Sixth, different haploidentical transplantation strategies were compared. Seventh, caution should be taken in administering allogeneic HSCT treatment in older patients with myeloid leukemia with a Charlson Comorbidity Index ≥3 because of a higher risk of nonrelapse mortality.

Metformin pretreatment ameliorates busulfan-induced liver endothelial toxicity during haematopoietic stem cell transplantation

The success of Haematopoietic cell transplantation (HCT) is often limited by regimen-related toxicity (RRT) caused by conditioning regimen drugs. Among different conditioning drugs, busulfan (Bu) and treosulfan (Treo), although widely used in HCT, exhibit different toxicity profiles, the mechanism of which is still unclear. Here we investigated the effects of Bu and Treo in endothelial cells. While both Bu and Treo induced DNA damage in endothelial cells, we observed Bu alone to induce oxidative stress and sustained activation of phospho-ERK1/2, leading to apoptosis. However, Treo-treated cells exhibited no oxidative stress/apoptosis of endothelial cells. Screening of pharmacological inhibitors of both ROS and p-ERK revealed that metformin effectively ameliorates Bu-mediated toxicity in endothelial cells. In Balb/c mice, we observed a significant reduction in bone marrow endothelial cells in Bu-treated mice compared to Treo-treated mice. Further, liver sinusoidal endothelial cells (LSEC) was damaged by Bu, which is implicated in liver vasculature and their functional capacity to uptake FITC-albumin. However, Treo-treated mice liver vasculature was morphologically and functionally normal. When mice were pretreated with metformin followed by Bu, LSECs damage was ameliorated morphologically and functionally. Bone marrow transplants done on these mice did not affect the engraftment of donor cells.

Incidence and predictors of idiopathic pneumonia syndrome in hematopoietic stem cell transplant patients: a nationwide registry study

Idiopathic pneumonia syndrome (IPS) is a rare but deadly complication of hematopoietic stem cell transplantation (HSCT). This study characterized the incidence and risk factors for IPS after HSCT in Taiwan. Data from January 2009 to February 2019 was collected from the Taiwan Society of BMT national registry. Forty-three (1.1%) of 3924 HSCT patients who developed IPS were identified. Incidence of IPS was lower in patients who received autologous HSCT than patients who received allogeneic HSCT (0.68% vs 1.44%, P = 0.022). Multivariate analysis showed that use of TBI and intravenous busulfan in the conditioning regimen were each independent predictor of IPS after HSCT. In addition, development of IPS was significantly associated with increased risk of death in the first 120 days post-HSCT (HR, 2.09; 95% CI, 1.08 to 4.05, P = 0.029) and 2 years post-HSCT (HR, 1.65; 95% CI, 1.07 to 2.542, P = 0.023), but not beyond 2 years post-HSCT. However, survival outcomes did not differ significantly between patients with IPS who received autologous versus allogeneic HSCT (P = 0.52). In conclusion, despite the relatively low incidence of post-HSCT IPS in Taiwan, mortality remains high. The results of this study will help to identify high-risk patients for early intervention and guide future therapeutic research.

Case Report: Severe Acute Pulmonary COVID-19 in a Teenager Post Autologous Hematopoietic Stem Cell Transplant

Pulmonary severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in children is generally described as mild, and SARS-CoV-2 infection in immunocompromised children are observed as generally mild as well. A small proportion of pediatric patients will become critically ill due to (cardio)respiratory failure and require intensive care treatment. We report the case of a teenager with Hodgkin's lymphoma who acquired SARS-CoV-2 (detected by PCR) on the day of her autologous stem cell transplant and developed acute respiratory distress syndrome, successfully treated with a combination of antivirals, immunomodulation with steroids and biologicals, and ECMO.

Transfusion-Related Acute Lung Injury: 36 years of Progress (1985-2021)

The term transfusion-related acute lung injury (TRALI) was coined in 1985 to describe acute respiratory distress syndrome (ARDS) after transfusion, when another ARDS risk factor was absent; TRALI cases were mostly associated with donor leukocyte antibody. In 2001, plasma from multiparous donors was implicated in TRALI in a randomized controlled trial in Sweden. In 2003 and in many years thereafter, the FDA reported that TRALI was the leading cause of death from transfusion in the United States. In 2003, the United Kingdom was the first among many countries to successfully reduce TRALI using male-predominant plasma. These successes are to be celebrated. Nevertheless, questions remain about the mechanisms of non-antibody TRALI, the role of blood products in the development of ARDS in massive transfusion patients, the causes of unusual TRALI cases, and how to reduce inaccurate clinical diagnoses of TRALI in clinical practice. Regarding the latter, a study in 2013-2015 at 169 US hospitals found that many TRALI diagnoses did not meet clinical definitions. In 2019, a consensus panel established a more precise terminology for clinical diagnosis: TRALI type I and TRALI type II are cases where transfusion is the likely cause, and ARDS are cases where transfusion is not the likely cause. For accurate diagnosis using these clinical definitions, critical care expertise is needed to distinguish between permeability versus hydrostatic pulmonary edema, to determine whether an ARDS risk factor is present and, if so, whether respiratory function was stable within the 12 hours before transfusion.

Noninfectious complications of hematopoietic cell transplantation

Noninfectious lung diseases contribute to nonrelapse mortality. They constitute a spectrum of diseases that can affect the parenchyma, airways, or vascular pulmonary components and specifically exclude cardiac and renal causes. The differential diagnoses of these entities differ as a function of time after hematopoietic cell transplantation. Specific diagnosis, prognosis, and optimal treatment remain challenging, although progress has been made in recent decades.

Late Noninfectious Pulmonary Complications in Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation (HSCT) is an established therapeutic modality for a number of malignant and nonmalignant conditions. Pulmonary complications following HSCT are associated with increased mortality and morbidity. These complications may be classified into infectious versus noninfectious, and early versus late based on the time of occurrence post-transplant. Thus, exclusion of infectious etiologies is the first step in the diagnoses of pulmonary complications. Late onset noninfectious pulmonary complications typically occur 3 months post-transplant. Bronchiolitis obliterans is the major contributor to late-onset pulmonary complications, and its clinical presentation, pathogenesis, and current therapeutic approaches are discussed. Idiopathic pneumonia syndrome is another important complication which usually occurs early, although its onset may be delayed. Organizing pneumonia is important to recognize due to its responsiveness to corticosteroids. Other late onset noninfectious pulmonary complications discussed here include pulmonary venoocclusive disease, pulmonary cytolytic thrombi, pleuroparenchymal fibroelastosis, thoracic air leak syndrome, and posttransplant lymphoproliferative disorders.

Managing pulmonary complications in allogeneic hematopoietic stem cell transplantation

Introduction: Progress in allogeneic hematopoietic stem cell transplantation (HSCT) procedures has been associated with improved survival in HSCT recipients. However, they have also brought to light organ-specific complications, especially pulmonary complications. In this setting, pulmonary complications are consistently associated with poor outcomes, and improved management of these complications is required. Areas covered: We review the multiple infectious and noninfectious lung complications that occur both early and late after allogeneic HSCT. This includes the description of these complications, risk factors, diagnostic approach and outcome. A literature search was performed using PubMed-indexed journals. Expert commentary: Multiple lung complications after allogeneic HSCT can be diagnosed concomitantly and require a multidisciplinary approach. A specific clinical evaluation including a precise analysis of a lung CT scan is necessary. Management of these lung complications, especially the noninfectious ones, is impaired by the lack of prospective, randomized control trials, suggesting preventive strategies should be developed.

Lung histopathology of non-infectious pulmonary complications after allogeneic haematopoietic stem cell transplantation

AIMS

Non-infectious pulmonary complications (NIPCs) occur frequently following allogeneic haematopoietic stem cell transplantation (HSCT). As there is no consensus on the description of the related pulmonary pathological lesions, pathologist reports and clinical conclusions are largely inconsistent in routine practice. The aim of our study was to provide an accurate overview of post-allogeneic HSCT NIPCs from a large number of lung biopsies.

METHODS AND RESULTS

We reviewed 61 lung biopsies in patients with an NIPC, including 51 surgical lung biopsies, four post-mortem biopsies and six lung explants. We found both bronchiolar (n = 59) and alveolar/interstitial pathologies (n = 27). We describe two types of bronchiolar lesions: bronchiolectasies (n = 37) and fibrous and cellular lesions with luminal narrowing (n = 43). We found a wide spectrum of airway/interstitial pathologies that were labelled using the terminology of the 2013 American Thoracic Society and European Respiratory Society (ATS/ERS) classification of idiopathic interstitial pneumonias (IIPs), including the following: organising pneumonia (OP, n = 8), non-specific interstitial pneumonia (NSIP, n = 9), diffuse alveolar damage (DAD, n = 6), lymphoid interstitial pneumonia (LIP, n = 1) and pleuroparenchymal fibroelastosis (PPFE, n = 2), as well as one instance of associated PPFE and NSIP.

CONCLUSIONS

Interstitial pathology was associated with bronchiolar lesions in 41% of the cases reviewed (n = 25). Lung airway and interstitial inflammation was still present in lung explants from patients who underwent lung transplantation for post-allogeneic HSCT end-stage respiratory insufficiency. Herein, we describe a wide spectrum of pathological lung lesions encountered in post-allogeneic HSCT NIPCs.