Noninfectious pneumonitis after blood and marrow transplant

Endothelial Dysfunction Syndromes after Allogeneic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the only therapy with a curative potential for a variety of malignant and non-malignant diseases. The major limitation of the procedure is the significant morbidity and mortality mainly associated with the development of graft versus host disease (GVHD) as well as with a series of complications related to endothelial injury, such as sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD), transplant-associated thrombotic microangiopathy (TA-TMA), etc. Endothelial cells (ECs) are key players in the maintenance of vascular homeostasis and during allo-HSCT are confronted by multiple challenges, such as the toxicity from conditioning, the administration of calcineurin inhibitors, the immunosuppression associated infections, and the donor alloreactivity against host tissues. The early diagnosis of endothelial dysfunction syndromes is of paramount importance for the development of effective prophylactic and therapeutic strategies. There is an urgent need for the better understanding of the pathogenetic mechanisms as well as for the identification of novel biomarkers for the early diagnosis of endothelial damage. This review summarizes the current knowledge on the biology of the endothelial dysfunction syndromes after allo-HSCT, along with the respective therapeutic approaches, and discusses the strengths and weaknesses of possible biomarkers of endothelial damage and dysfunction.

Management of Acute Respiratory Failure in Patients With Hematological Malignancy

Acute respiratory failure (ARF) is the leading cause of intensive care unit admission in patients with hematologic malignancies and is associated with a high mortality. The main causes of ARF are bacterial and opportunistic pulmonary infections and noninfectious lung disorders. Management consists of a systematic clinical evaluation aimed at identifying the most likely cause, which in turn determines the best first-line empirical treatments. The need for mechanical ventilation is a major determinant of prognosis. Beneficial outcomes have been demonstrated with early use of noninvasive ventilation (NIV) in selected patients with hematologic malignancies. However, most of these studies did not control the time between onset of ARF to NIV implementation nor accounted for the etiology of ARF or the presence of associated organ dysfunction at the time of NIV initiation. Moreover, the benefits demonstrated with NIV in these patients were derived from studies with high mortality rates of intubated patients. Additional studies are therefore warranted to determine the appropriate patients with hematologic malignancy and ARF who may benefit from prophylactic or curative NIV.

Early Lung Computed Tomography Scan after Allogeneic Hematopoietic Stem Cell Transplantation

A lung computed tomography (CT) scan is essential for diagnosing lung diseases in hematopoietic stem cell transplantation (HSCT) recipients. As a result, lung CT scans are increasingly prescribed in the early phase after allogeneic HSCT, with no assessment of the added value for global patient management. Among 250 patients who underwent allogeneic HSCT in our center over a 2-year period, we evaluated 68 patients who had at least 1 lung CT scan within the first 30 days post-transplantation. The median interval between allogeneic HSCT and lung CT scan was 8.5 days. Patients who underwent an early lung CT scan were more immunocompromised and had a more severe course. Fever was the main indication for the CT scan (78%). The lung CT scan was abnormal in 52 patients, including 17 patients who had an abnormal pre-HSCT CT scan. A therapeutic change was noted in 37 patients (54%) within 24 hours after the lung CT scan. The main changes included the introduction of corticosteroids (n = 23; 62%), especially in patients with a normal CT scan (89%). In univariate models, we found that a normal pretransplantation CT scan (P = .002), the absence of either dyspnea (P = .029) or hypoxemia (P = .015), and a serum C-reactive protein level <10 mg/L (P = .004) were associated with a normal post-HSCT lung CT scan. We found that the association of these variables could predict the normality of early post-HSCT lung CT scans. Pretransplantation lung CT scans are useful for the interpretation of subsequent lung CT scans following allogeneic HSCT, which are frequently abnormal. Early post-HSCT lung CT scans are helpful in patient management, but prescriptions could be more targeted.

Low-, medium- and high-dose steroids with or without aminocaproic acid in adult hematopoietic SCT patients with diffuse alveolar hemorrhage

Diffuse alveolar hemorrhage (DAH) is a poorly understood complication of transplantation carrying a high mortality. Patients commonly deteriorate and require intensive care unit (ICU) admission. Treatment with high-dose steroids and aminocaproic acid (ACA) has been suggested. The current study examined 119 critically ill adult hematopoietic transplant patients treated for DAH. Patients were subdivided into low-, medium- and high-dose steroid groups with or without ACA. All groups had similar baseline characteristics and severity of illness scores. Primary objectives were 30, 60, 100 day, ICU and hospital mortality. Overall mortality (n=119) on day 100 was high at 85%. In the steroids and ACA cohort (n=82), there were no significant differences in 30, 60, 100, day, ICU and hospital mortality between the dosing groups. In the steroids only cohort (n=37), the low-dose steroid group had a lower ICU and hospital mortality (P=0.02). Adjunctive treatment with ACA did not produce differences in outcomes. In the multivariate analysis, medium- and high-dose steroids were associated with a higher ICU mortality (P=0.01) as compared with the low-dose group. Our data suggest that treatment strategies may need to be reanalyzed to avoid potentially unnecessary and potentially harmful therapies.

High-resolution CT can differentiate between alloimmune and nonalloimmune lung disease early after hematopoietic cell transplantation

OBJECTIVE

The purpose of this study was to develop a simple semiquantitative high-resolution CT (HRCT) scoring system to differentiate alloimmune-mediated lung syndromes (allo-LS) from other lung diseases early after hematopoietic cell transplantation. Allo-LS should be differentiated from other abnormalities, such as infections and toxicity, because they are life threatening and require prompt and specific treatment.

MATERIALS AND METHODS

In 52 pediatric hematopoietic cell transplant recipients with early symptoms of pulmonary disease, a clinical diagnosis was made by an expert physician. HRCT studies were scored by two independent radiologists for various airway and parenchyma abnormalities. HRCT scores were compared with the final clinical diagnoses.

RESULTS

Patients with allo-LS had significantly higher HRCT severity scores for ground-glass pattern and airtrapping compared with patients with nonalloimmune disease. A combined score was constructed (the "allo-score") that appeared to have good predictive capacity for clinical allo-LS (AUC = 0.82). HRCT scoring was reproducible for all items except airway wall thickening and septal thickening.

CONCLUSION

A simple HRCT severity score can be helpful to differentiate allo-LS from other pulmonary complications early after hematopoietic cell transplantation.

Diffuse alveolar hemorrhage in patients with hematological malignancies: HRCT patterns of pulmonary involvement and disease course

OBJECTIVE

To analyze high-resolution computed tomography (HRCT) patterns of lung involvement and disease course in patients with hematological malignancies experiencing diffuse alveolar hemorrhage (DAH) after chemotherapy ± allogeneic stem cell transplantation (allo-SCT).

MATERIALS AND METHODS

Sixteen patients experiencing DAH after chemotherapy ± allo-SCT were enrolled. A total of 74 computed tomography (CT) scans obtained before, during, and after onset of DAH were evaluated retrospectively.

RESULTS

CT features of DAH are each, by oneself, nonspecific. However, conjoint bilateral, diffuse, and dependent ground glass opacity ± crazy paving, accompanied by airspace bronchograms, should suggest this complication. The HRCT course comprises a wide range of trends that are not predictive for patient's outcome, but progression of parenchymal consolidations at follow up was more often detrimental.

Distribution of aerosols in murine obliterative bronchiolitis lungs by fluorescent imaging

ABSTRACT Background: Obliterative bronchiolitis (OB) is a major obstacle to the success of lung transplantation and is also a serious complication of hematopoietic stem cell transplant. It has few therapeutic options and respiratory delivery of potential therapeutic drugs is hindered by the narrowed and occluded airways.

METHODS

OB was induced in mice using an established protocol and lung function was assessed by plethysmograph. Mice were exposed to four different aerosols of aluminum phthalocyanine tetrasulfonic acid (AlPCS) that ranged in concentration and median particle size distribution (0.2-4.0 μm). The fluorescent intensity and number of pixels were measured for the trachea and lobes at two different compressional thicknesses. With analysis of the fluorescent intensity, the concentration and attenuation coefficient were estimated for each lobe and the trachea as well as individual pixels. The latter allowed generation of images reflective of the concentration.

RESULTS

Lungs/trachea from OB mice had lower deposition, which correlated with lung function measurements, and apparent greater variability in the intensity compared to controls. The estimated lung volumes measured by plethysmograph were not different between the OB group and controls; however, total inflational lung capacity was reduced in OB mice.

CONCLUSIONS

Despite the variability in disease induction, there is a clear link between aerosol deposition and lung function, which was revealed by fluorescent imaging. The modulation of aerosol deposition in lungs with restrictive airway disease underscores the importance of tailoring aerosolization to optimize drug delivery.

High-dose corticosteroids with or without etanercept for the treatment of idiopathic pneumonia syndrome after allo-SCT

Idiopathic Pneumonia Syndrome (IPS) is a common complication after allo-SCT and results in high mortality rates. Conventional treatment for IPS typically includes supportive care and high-dose corticosteroids (CS). Data suggests that TNF-α is important in the pathogenesis of IPS and that the TNF-α inhibitor etanercept may be useful for IPS treatment. We performed a retrospective comparison of consecutive patients treated at our center for IPS with CS only from 1999 to 2003 (group 1, n=22) or CS plus etanercept from 2004 to 2007 (group 2, n=17). In all, 18% of patients in group 1 vs 53% in group 2 were successfully taken off respiratory support and discharged from the hospital (P=0.039). OS was significantly better for recipients of CS plus etanercept (P=0.003). The estimated survival at 28 days and 2 years after IPS was 36.4% (95% CI 17-56%) and 9.1% (95% CI 2-25%) for group 1 and 88.2% (95% CI 61-97%) and 18% (95% CI 4-38%) for group 2, respectively. Our retrospective comparison suggests that the addition of etanercept to CS for IPS improves response rates and OS. However, outcomes remain limited in both groups, highlighting the need for more effective interventions to treat early and late complications of IPS.

Pleuroparenchymal fibroelastosis in patients with pulmonary disease secondary to bone marrow transplantation

This study presents four patients who underwent bone marrow transplantation and subsequently developed pleuroparenchymal fibroelastosis, hitherto reported as an idiopathic condition. All presented clinically with pneumothorax and subpleural fibrosis on high-resolution computed tomography. In addition to the expected obliterative bronchiolitis, histopathology showed coexistent subpleural changes, and the relationship of pathology in multiple anatomic compartments in post bone marrow transplantation pulmonary disease is discussed.

An official American Thoracic Society research statement: noninfectious lung injury after hematopoietic stem cell transplantation: idiopathic pneumonia syndrome

RATIONALE

Acute lung dysfunction of noninfectious etiology, known as idiopathic pneumonia syndrome (IPS), is a severe complication following hematopoietic stem cell transplantation (HSCT). Several mouse models have been recently developed to determine the underlying causes of IPS. A cohesive interpretation of experimental data and their relationship to the findings of clinical research studies in humans is needed to better understand the basis for current and future clinical trials for the prevention/treatment of IPS.

OBJECTIVES

Our goal was to perform a comprehensive review of the preclinical (i.e., murine models) and clinical research on IPS.

METHODS

An ATS committee performed PubMed and OVID searches for published, peer-reviewed articles using the keywords "idiopathic pneumonia syndrome" or "lung injury" or "pulmonary complications" AND "bone marrow transplant" or "hematopoietic stem cell transplant." No specific inclusion or exclusion criteria were determined a priori for this review.

MEASUREMENTS AND MAIN RESULTS

Experimental models that reproduce the various patterns of lung injury observed after HSCT have identified that both soluble and cellular inflammatory mediators contribute to the inflammation engendered during the development of IPS. To date, 10 preclinical murine models of the IPS spectrum have been established using various donor and host strain combinations used to study graft-versus-host disease (GVHD). This, as well as the demonstrated T cell dependency of IPS development in these models, supports the concept that the lung is a target of immune-mediated attack after HSCT. The most developed therapeutic strategy for IPS involves blocking TNF signaling with etanercept, which is currently being evaluated in clinical trials.

CONCLUSIONS

IPS remains a frequently fatal complication that limits the broader use of allogeneic HSCT as a successful treatment modality. Faced with the clinical syndrome of IPS, one can categorize the disease entity with the appropriate tools, although cases of unclassifiable IPS will remain. Significant research efforts have resulted in a paradigm shift away from identifying noninfectious lung injury after HSCT solely as an idiopathic clinical syndrome and toward understanding IPS as a process involving aspects of both the adaptive and the innate immune response. Importantly, new laboratory insights are currently being translated to the clinic and will likely prove important to the development of future strategies to prevent or treat this serious disorder.

Organizing pneumonia primed by high-dose chemotherapy and lung irradiation: two pediatric cases

A 9-year-old and a 17-year-old male patients affected by metastatic Ewing sarcoma developed an organizing pneumonia after high-dose chemotherapy with autologous peripheral blood stem cell transplantation followed by total-lung irradiation. They were successfully treated with high-dose corticosteroid for 6 months slowly tapered, with a significant clinical and radiologic response. Organizing pneumonia is a nonspecific response to various forms of lung injury such as high-dose chemotherapy and radiotherapy. For this reason, even if rare, has to be considered in children affected by lung metastatic Ewing sarcoma with persisting pulmonary symptoms after peripheral blood stem cell transplantation and total-lung irradiation. This report provides a useful description for the evaluation and treatment of pediatric patients with pulmonary infiltrates after chemotherapy and radiotherapy.

Pleiotropic effects of transforming growth factor-β in hematopoietic stem-cell transplantation

Transforming growth factor (TGF)-β is a pleiotropic cytokine with beneficial and detrimental effects posthematopoietic stem-cell transplantation. TGF-β is increased in specific sites postengraftment and can suppress immune responses and maintain peripheral tolerance. Thus, TGF-β may promote allograft acceptance. However, TGF-β is also the central pathogenic cytokine in fibrotic disease and likely promotes pneumonitis. Although TGF-β can enhance leukocyte recruitment and IgA production, it inhibits both innate and adaptive immune cell function and antiviral host defense posthematopoietic stem-cell transplantation. This review will focus on the current understanding of TGF-β biology and the numerous ways it can impact outcomes posttransplant.

Idiopathic pneumonia syndrome in mice after allogeneic bone marrow transplantation: association between idiopathic pneumonia syndrome and acute graft-versus-host disease

OBJECTIVE

To explore the association between idiopathic pneumonia syndrome (IPS) and acute graft-versus-host disease (aGVHD) in allogeneic hematopoietic stem cell transplantation.

METHODS

Established acute GVHD model of C57BL/6-->BALB/c mice. Chest computed tomography (CT) scans were dynamically performed in recipient mice after transplant. Lung histopathology and cytokine levels (including TNF-alpha and IFN-gamma) were examined in three experimental groups: mice receiving simple irradiation, syngeneic transplants, and allogeneic transplants.

RESULTS

All allogeneic transplant mice developed aGVHD. On CT, most aGVHD mice had bilateral diffuse lung infiltrates, while syngeneic transplant mice had normal lungs. On histopathology, aGVHD mice had acute pneumonitis. On immunohistochemistry, the infiltrates were mainly CD4+ T cells during aGVHD onset, but CD8+ T cells predominated during aGVHD progression. Lung TNF-alpha and IFN-gamma levels were higher in the three experimental groups than in normal controls on days +3 and +7 post-transplant. On day +7, TNF-alpha levels were higher in allogeneic than in syngeneic transplant mice; IFN-gamma levels were not different. On days +12 and +16, TNF-alpha levels were higher but IFN-gamma levels were lower in allogeneic mice than in syngeneic transplant mice.

CONCLUSIONS

The underlying cause of IPS is aGVHD. T cells and TNF-alpha may play a role in the pathogenesis of aGVHD-induced IPS. IPS progression may be associated with decreasing lung IFN-gamma levels.

Effect and mechanism of acute graft versus host disease on early diffuse murine lung injury following allogeneic stem cell transplantation

To explore the effect and pathogenssis of acute graft-versus-host disease (aGVHD) on early diffuse lung injury in allogeneic hematopoietic stem cell transplantation (allo-HSCT), we established an aGVHD model of C(57)BL/6-->BALB/c mice. Chest computed tomography (CT) scans, histopathology and the levels of cytokines including tumor necrosis factor alpha (TNFalpha) and Interferon (IFNgamma) in lungs were dynamically detected in recipient mice after transplantation. The incidence of aGVHD was respectively 0%, 0% and 100% in simple irradiation group (A), syngeneic transplant group(B) and allogeneic transplant group (C). Chest CT scans of recipient mice were normal in 3 groups on days +3 and +7 after transplantation. CT showed that two of ten mice had bilateral lung diffuse infiltrate on day +12 (on the brink of death) in group A and 6 of 10 mice had bilateral lung diffuse infiltrate on day +14 (3 d after aGVHD occurring) in group C, and were normal on days +12 and +14 in group B after transplantation. Histopathology of lungs in the 3 groups was similar, consisting of minor interstitial pneumonitis on day +3. Group A showed edema, hyperplasia of epithelial cells and widened alveolar interval on day +7, and epithelial cell necrosis, lymphocyte infiltration, hemorrhage, protein leakage, and local consolidation on day +12. The histopathology of group B showed slight edema of epithelial cells on +7 day, which were slighter than that on day +3, and virtually normal on day +14. The histopathology in group C was characterized by the significant expansion and congestion of capillaries, and lymphocyte infiltration on day +7, the acute pneumonitis was present involving tissue edema, lymphocyte and macrophage infiltration, protein leakage and perivascular inflammation on day +14. In group A, the levels of TNFalpha were lower on day +7 than on day +3. In group B, the levels of TNFalpha attained a peak on day +3, which decreased on days +7 and +14. In group C, the levels of TNFalpha were highest on day +7 and there was a significant difference between those on days +7 and +14 (P=0.816). In group A, the levels of IFNgamma on day +7 were higher than on day +3. In group B, the levels of IFNgamma increased progressively, but the comparison of IFNgamma levels in different times had no statistical significance (P=0.521, 0.118, 0.340). In group C, the levels of IFNgamma attained a peak by day +7 and decreased on day +14. aGVHD is the main cause of early non-infectious lung injury. T lymphocytes and TNFalpha are possibly implicated in the pathogenesis of acute GVHD-induced lung injury. The decreased levels of IFNgamma in lung tissues following transplantation might be associated with pulmonary fibrosis in late non-infectious pulmonary complications.

Idiopathic pneumonia syndrome after bone marrow transplantation presenting with "crazy-paving" pattern on high-resolution computed tomography: a case report

The authors present the high-resolution computed tomography findings of a patient with idiopathic pneumonia syndrome after bone marrow transplantation. The main finding consisted of extensive ground-glass opacities superimposed to mild interlobular septal thickening, resulting in the appearance termed "crazy-paving". Following the clinical, laboratorial and imaging criteria, the diagnosis of idiopathic pulmonary syndrome was defined and corticosteroids were introduced. The clinical symptoms improved in the following days, and the patient was discharged from the hospital.