Clinical features of allogeneic hematopoietic stem cell transplantation-associated organizing pneumonia

CT strain metrics allow for earlier diagnosis of bronchiolitis obliterans syndrome after hematopoietic cell transplant

ABSTRACT

Bronchiolitis obliterans syndrome (BOS) after hematopoietic cell transplantation (HCT) is associated with substantial morbidity and mortality. Quantitative computed tomography (qCT) can help diagnose advanced BOS meeting National Institutes of Health (NIH) criteria (NIH-BOS) but has not been used to diagnose early, often asymptomatic BOS (early BOS), limiting the potential for early intervention and improved outcomes. Using pulmonary function tests (PFTs) to define NIH-BOS, early BOS, and mixed BOS (NIH-BOS with restrictive lung disease) in patients from 2 large cancer centers, we applied qCT to identify early BOS and distinguish between types of BOS. Patients with transient impairment or healthy lungs were included for comparison. PFTs were done at month 0, 6, and 12. Analysis was performed with association statistics, principal component analysis, conditional inference trees (CITs), and machine learning (ML) classifier models. Our cohort included 84 allogeneic HCT recipients, 66 with BOS (NIH-defined, early, or mixed) and 18 without BOS. All qCT metrics had moderate correlation with forced expiratory volume in 1 second, and each qCT metric differentiated BOS from those without BOS (non-BOS; P < .0001). CITs distinguished 94% of participants with BOS vs non-BOS, 85% of early BOS vs non-BOS, 92% of early BOS vs NIH-BOS. ML models diagnosed BOS with area under the curve (AUC) of 0.84 (95% confidence interval [CI], 0.74-0.94) and early BOS with AUC of 0.84 (95% CI, 0.69-0.97). qCT metrics can identify individuals with early BOS, paving the way for closer monitoring and earlier treatment in this vulnerable population.

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

ABSTRACT

Organizing pneumonia (OP) is a known noninfectious pulmonary complication following allogeneic hematopoietic cell transplant (HCT) and represents a significant risk factor for nonrelapse mortality in HCT recipients. Unlike bronchiolitis obliterans syndrome, it is not universally acknowledged as a distinctive pulmonary manifestation of chronic graft-versus-host disease (cGVHD) and, therefore, its diagnostic criteria and management approach are lacking. Given its shared similar clinical features and radiological and histologic findings to OP in the non-HCT population, the diagnostic approach and treatment strategy for OP in HCT recipients is largely adapted from the non-HCT population. In this article, we aim to enhance the understanding of OP within the context of cGVHD following HCT and distinguish its clinical features and treatment strategy from non-HCT counterparts, thereby reinforcing its recognition as a pulmonary manifestation of graft-versus-host disease. We will propose the diagnostic criteria and outline our approach in diagnosis and treatment strategy, highlighting the potential challenges that may arise in each process. Finally, we will discuss knowledge gaps in this field and identify the area of need for future research.

High-Dose Busulfan-Fludarabine Conditioning and Low Alveolar Volume as Predictors of Pulmonary Complications after Allogeneic Peripheral Blood Stem Cell Transplantation in Children

This study was conducted to investigate risk factors and predictors of infectious and noninfectious pulmonary complications (PCs) after allogeneic hematopoietic stem cell transplantation in children. We conducted a retrospective analysis of the post-transplantation PCs of 240 patients who underwent allogeneic peripheral blood stem cell transplantation (allo-PBSCT) between 2009 and 2018. Transplantation-related variables, pretransplantation baseline spirometry, body plethysmography, and CO diffusing capacity were analyzed for association with the development of infectious PCs (IPCs) and noninfectious PCs (NIPCs). Compared with the control group, the PC group had statistically significantly lower overall survival (50.6% versus 77.8%; P < .001), higher disease-related mortality (26.6% versus 54.4%; P < .001), and higher nonrelapse mortality (31.6% versus 5.9%; P < .001). A greater number of patients received pretransplantation conditioning with high-dose busulfan (520 mg/m²; Bu 520) and fludarabine (160 mg/m²; Flu 160) in both the IPC and NIPC groups. In the multivariate Cox hazard regression analysis, Bu 520 significantly increased the risk of NIPCs (hazard ratio [HR], 1.99; 95% confidence interval [CI], 1.13 to 3.49; P = .016), and Flu 160 was a predictor of IPCs (HR, 1.99; 95% CI, 1.13 to 3.49; P = .016). The Bu 520 + Flu 160 regimen was associated with a statistically significant increase in the risk of NIPC (HR, 1.92; 95% CI, 1.09 to 3.37; P = .023). In a multivariate analysis using pretransplantation baseline lung function, alveolar volume (VA) grades 3 and 4 and lung function score (LFS) VA categories III and IV were associated with increased risk for both IPCs and NIPCs. Our data identify receipt of the high-dose Bu-Flu conditioning regimen as an independent risk factor for NIPCs after allo-PBSCT. Impaired CO diffusing capacity before transplantation, especially VA reduction, contributes to the risk of post-transplantation pulmonary complications, and pretransplantation risk can be estimated by grading the degree of insufficiency of VA and LFS VA.

Significance of alveolar nitric oxide concentration in the airway of patients with organizing pneumonia after allogeneic hematopoietic stem cell transplantation

Organizing pneumonia (OP) is a complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT) and a manifestation of peripheral airway/alveolar inflammation. Recently, alveolar nitric oxide concentration (Calv) has been revealed as a noninvasive marker of peripheral airway inflammation; however, whether Calv levels are associated with OP and peripheral airway in patients after allo-HSCT remains unclear. Herein, we evaluated whether Calv levels could reflect the presence of OP and structural airway changes in patients after allo-HSCT. We measured the eNO levels of 38 patients (6 with OP and 32 without OP) who underwent allo-HSCT. Three-dimensional computed tomography (CT) analysis of the airway was performed in 19 patients. We found that in patients with OP, Calv levels were significantly higher than in those without OP (10.6 vs. 5.5 ppb, p < 0.01). Receiver-operating characteristic analyses revealed a Calv cut-off value for OP detection of 10.2 ppb. No significant differences in the patient characteristics, except for the presence of OP (p < 0.01), were noted between the two groups stratified by the Calv cut-off value. Three-dimensional CT images of the airway revealed gradually increasing positive correlations between Calv levels and airway wall area of the third-, fourth-, and fifth-generation bronchi (r = 0.20, 0.31, 0.38; p = 0.42, 0.19, 0.038, respectively), indicating that Calv levels are strongly correlated with the wall thickness of the distal bronchi. Our results suggest that the Calv level may be a useful noninvasive detectable marker for OP after an allo-HSCT.

Bronchoscopic features, associations, and outcomes of organizing pneumonia following allogeneic hematopoietic stem cell transplantation

Organizing pneumonia (OP) is a poorly understood complication of hematopoietic stem cell transplant (HSCT). We identified 15 patients diagnosed with OP following HSCT and described their clinical course. CT chest findings were remarkable for multifocal infiltrates that were predominantly consolidating or ground glass opacities. Bronchoalveolar lavage (BAL) was performed on 14 patients with five having lymphocytosis (> 25% lymphocytes), three with eosinophilia (> 5% eosinophils), three with neutrophilia (> 30% neutrophils), and three with normal cell counts. Flow cytometry was analyzed on BAL fluid in 13 patients with 11 having a CD4/CD8 of < 0.9. Initial treatment with 0.3–1.0 mg/kg prednisone resulted in improvement in symptoms, in radiographic findings, and in pulmonary function testing for the majority of patients. Six patients had recurrence of OP after completing treatment. Eleven patients had evidence of extra-pulmonary graft-versus-host disease prior to diagnosis of OP, and seven patients were diagnosed with an upper respiratory tract infection (URI) within 8 weeks of OP diagnosis. Most patients respond well to prednisone with significant improvement in pulmonary function, but risk of recurrence is high after cessation of steroid treatment. Risk factors for the development of OP may include prior URI.

Patterns of onset and outcome of cryptogenic organizing pneumonia after allogeneic hematopoietic stem cell transplantation

Cryptogenic organizing pneumonia (COP) after allogeneic hematopoietic stem cell transplantation (HSCT) is characterized by frequent recurrence. Few studies have examined onset and recurrence patterns of COP after HSCT. We investigated the clinical features of COP after HSCT in a single-center retrospective study including 165 consecutive patients who underwent allogeneic HSCT. Eighteen patients (11%) developed COP after HSCT. Hypoxemia and pleural effusion at the onset of COP were significantly associated with umbilical cord blood transplantation (P = 0.002 and P = 0.002, respectively). Recurrence of COP was observed in six patients and significantly associated with the presence of chronic graft-versus-host disease (cGVHD; P = 0.013) and stem cell sources other than umbilical cord blood (P = 0.038). Four patients with COP died of pulmonary failure after recurrence of COP. No patients who underwent umbilical cord blood transplantation experienced recurrence of COP. These findings suggest that the clinical features at the onset of COP may depend on stem cell sources. Moreover, both stem cell source and the absence or presence of cGVHD may affect COP recurrence, indicating the need to develop treatment strategies against COP according to stem cell source and risk of cGVHD.

Bronchiolitis Obliterans Syndrome and Other Late Pulmonary Complications After Allogeneic Hematopoietic Stem Cell Transplantation

As more individuals survive their hematologic malignancies after allogeneic hematopoietic stem cell transplantation (HSCT), there is growing appreciation of the late organ complications of this curative procedure for malignant and nonmalignant hematologic disorders. Late noninfectious pulmonary complications encompass all aspects of the bronchopulmonary anatomy. There have been recent advances in the diagnostic recognition and management of bronchiolitis obliterans syndrome, which is recognized as a pulmonary manifestation of chronic graft-versus-host disease. Organizing pneumonia and other interstitial lung diseases are increasingly recognized. This article provides an update on these entities as well as pleural and pulmonary vascular disease after allogeneic HSCT.

Pulmonary Clinicopathological Correlation after Allogeneic Hematopoietic Stem Cell Transplantation: An Autopsy Series

Pulmonary complications are a significant cause of morbidity, mortality, and resource utilization after hematopoietic stem cell transplantation (HSCT). The objective of this study was to compare antemortem clinical suspicion of pulmonary complications and postmortem findings in a modern HSCT cohort. All patients who underwent allogeneic HSCT at our institution (n = 1854) between January 1, 2000 and June 30, 2010 were reviewed and patients who died of any cause greater than 1 year after HSCT and had an unrestricted autopsy available for analysis were included. Presence of pulmonary graft-versus-host disease (GVHD) was assessed by a pathologist blinded to the autopsy report, as previously described by Yousem (1995). A total of 35 (1.9%) patients had autopsies available for review. Airway disease, vascular disease, and interstitial disease were all clinically under-recognized compared with the pathological findings on autopsy. Varying degrees of pathological changes were detected, including 10 (28.6%) patients having bronchiolitis obliterans (BO) and 12 (34.3%) patients having pulmonary veno-occlusive disease (PVOD). Pulmonary manifestations of chronic GVHD, particularly BO and PVOD, were clinically under-recognized in our cohort. Our results suggest that PVOD, which has traditionally been considered a rare complication, may be clinically and histologically under-recognized.

A call to arms: a critical need for interventions to limit pulmonary toxicity in the stem cell transplantation patient population

Noninfectious pulmonary toxicity after allogeneic hematopoietic stem cell transplantation (allo-HSCT) causes significant morbidity and mortality. Main presentations are idiopathic pneumonia syndrome (IPS) in the acute setting and bronchiolitis obliterans syndrome (BOS) and cryptogenic organizing pneumonia (COP) at later time point. While COP responds well to corticosteroids, IPS and BOS often are treatment refractory. IPS, in most cases, is rapidly fatal, whereas BOS progresses over time, resulting in chronic respiratory failure, impaired quality of life, and eventually, death. Standard second-line treatments are currently lacking, and current approaches, such as augmented T cell-directed immunosuppression, B cell depletion, TNF blockade, extracorporeal photopheresis, and tyroskine kinase inhibitor therapy, are unsatisfactory with responses in only a subset of patients. Better understanding of underlying pathophysiology hopefully results in the identification of future targets for preventive and therapeutic strategies along with an emphasis on currently underutilized rehabilitative and supportive measures.

Pulmonary Nocardia nova infection after allogeneic hematopoietic stem cell transplantation

We herein report the case of a 68-year-old man with a history of allogeneic hematopoietic stem cell transplantation for acute myelocytic leukemia in whom graft-versus-host disease (GVHD) developed in the gastrointestinal tract and liver five months after transplantation. In that same period, chest computed tomography showed infiltration in both upper lungs. We performed bronchoscopy to clarify the GVHD and pulmonary infection. Nocardia nova was identified in the bronchoalveolar lavage fluid, and we diagnosed the patient as having pulmonary nocardiosis. Because the differential diagnosis is important for the medical management of GVHD and pulmonary infection, performing bronchoscopy is essential for making an appropriate and rapid diagnosis.

Pre-transplant risk factors for cryptogenic organizing pneumonia/bronchiolitis obliterans organizing pneumonia after hematopoietic cell transplantation

Cryptogenic organizing pneumonia (COP), previously known as bronchiolitis obliterans organizing pneumonia (BOOP), is a significant complication after allogeneic hematopoietic SCT (HCT). However, the pathogenesis of this complication has not yet been elucidated. Therefore, we identified the pre-transplant risk factors for the development of COP/BOOP using the Japan transplant registry database between 2005 and 2009. Among 9550 eligible recipients, 193 experienced COP/BOOP (2%). HLA disparity (odds ratio (OR) 1.51, P=0.05), female-to-male HCT (OR 1.53, P=0.023), and PBSC transplant (OR 1.84, P=0.0076) were significantly associated with an increased risk of COP/BOOP. On the other hand, BU-based myeloablative conditioning (OR 0.52, P=0.033), or fludarabine-based reduced-intensity conditioning (OR 0.50, P=0.0011) in comparison with a TBI-based regimen and in vivo T-cell depletion (OR 0.46, P=0.055) were associated with a lower risk. Of the 193 patients with COP/BOOP, 77 died, including non-relapse death in 46 (59%). Pulmonary failure and fatal infection accounted for 41% (n=19) and 26% (n=12) of the non-relapse death. Allogeneic immunity and conditioning toxicity could be associated with COP/BOOP. Prospective studies are required to elucidate the true risk factors for COP/BOOP and to develop a prophylactic approach.

Management of noninfectious lung injury following hematopoietic cell transplantation

PURPOSE OF REVIEW

Over the past 20 years, tremendous strides have been made to decrease treatment-related morbidity and mortality following allogeneic transplant, including management of acute and chronic lung injury. Within this context, three distinct entities are recognized, idiopathic pneumonia syndrome (IPS), bronchiolitis obliterans syndrome (BOS), and bronchiolitis obliterans organizing pneumonia (BOOP). Management options for each of these disorders are now reviewed.

RECENT FINDINGS

A recent pilot study and subsequent phase II trial suggest that tumor necrosis factor (TNF) inhibitors hold promise in treating IPS. A randomized phase III trial ended prematurely, without a definitive conclusion regarding TNF inhibitors established. Few prospective trials for BOS have been performed, with current therapy based on observational studies and small case reports. Therapy for BOOP is based upon minimal clinical evidence.

SUMMARY

Although corticosteroids remain the backbone of therapy for IPS, BOS, and BOOP, TNF inhibition may augment management of IPS and potentially BOS as well. Diagnostic criteria for IPS and BOS have been established, although optimal treatment strategies will ultimately require consensus monitoring and response criteria, coupled with an improved understanding of the pathophysiology underlying each disorder. For BOS and BOOP in particular, therapy has been based upon a paucity of data and anecdotal experiences.

Cytomegalovirus pneumonia in hematopoietic stem cell recipients

Cytomegalovirus (CMV) is a frequently encountered infection following hematopoietic cell transplantation, and tissue invasive pneumonia is a dreaded complication of the virus in this population. In this review of CMV pneumonia, we address epidemiology, pathogenesis, diagnostics, current therapy, and strategies to prevent the development of CMV. We also review emerging treatment and prevention options for this challenging disease.

Organizing pneumonia in recipients of hematopoietic stem cell transplantation: CT features in 16 patients

PURPOSE

To evaluate computed tomographic (CT) scans of patients with organizing pneumonia (OP) complicating hematopoietic stem cell transplantation (HSCT).

MATERIALS AND METHODS

A review of patients who underwent HSCT at our institution identified 16 patients who had documented OP on biopsy. Computed tomographic scans were reviewed by 2 thoracic radiologists.

RESULTS

Ground glass opacities (GGO) were seen in 15 patients, consolidation in 8 patients, linear opacities in 8 patients, traction bronchiectasis in 2 patients, and septal thickening in 2 patients. Ground glass opacity was the dominant abnormality in 7 patients, consolidation in 4 patients, and linear opacities in 5 patients. Peribronchovascular distribution was found in 4 patients, peripheral in 2 patients, diffuse in 3 patients; upper lung predominance was found in 10 patients, and lower lung predominance in 5 patients.

CONCLUSION

The principal computed tomographic features of OP after HSCT are ground glass opacities, consolidation and linear opacities, with upper lung predominance. Allowing for a possible sampling bias, these findings differ from those reported in cryptogenic OP and OP from other causes.

Pneumonia in allogeneic stem cell transplantation recipients: a multicenter prospective study

Pneumonia is a common cause of mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT) but updated and prospective information is partial. The aim of this nationwide prospective study is to determine the current epidemiology, etiology, and outcome of pneumonia in allo-HSCT recipients. From September-2003 to November-2005, 112 episodes in 427 consecutive allo-HSCT recipients were included (incidence 52.2 per 100 allo-HSCT/yr), and 72 of them (64.3%) were microbiologically defined pneumonia. Bacterial pneumonia (44.4%) was more frequent than fungal (29.2%) and viral pneumonia (19.4%). The most frequent microorganisms in each group were: Escherichia coli (n = 7, 8.9%), Streptococcus pneumoniae (n = 4, 5.0%), cytomegalovirus (n = 12, 15.4%), and Aspergillus spp. (n = 12, 15.4%). The development of pneumonia and chronic graft-versus-host disease (GVHD) was associated with increased mortality after allo-HSCT, and the probability of survival was significantly lower in patients that had at least one pneumonia episode (p < 0.01). Pneumonia development in the first 100 d after transplantation, fungal etiology, GVHD, acute respiratory failure, and septic shock were associated with increased mortality after pneumonia. Our results show that pneumonia remains a frequent infectious complication after allo-HSCT, contributing to significant mortality, and provide a large current experience with the incidence, etiology and outcome of pneumonia in these patients.

Tacrolimus-induced pulmonary injury in rheumatoid arthritis patients

BACKGROUND

Tacrolimus (TAC) was approved in Japan in 2005 for rheumatoid arthritis (RA) patients having inadequate response to other disease-modifying anti-rheumatic drugs. As of May 2007, spontaneous reports identified twenty-seven cases of exacerbation or new development of interstitial pneumonia among RA patients given TAC in Japan.

OBJECTIVE

To describe the clinical and radiological characteristics of TAC-induced pulmonary injury (TIPI).

PATIENTS AND METHODS

Eleven RA patients diagnosed with de novo pulmonary injury or exacerbation of IP during treatment with TAC were identified. Clinical, radiological, and laboratory data of ten of these cases were retrospectively analyzed.

RESULTS

Baseline data for the ten patients were a mean age of 69.7 years; gender, 70% female; mean RA disease duration, 9.1 years; and pulmonary comorbidities, 90%. Six cases were classified as presumptive TAC-induced pulmonary injury (TIPI) and four as probable TIPI. Among the six presumptive cases, TIPI developed at an average of 84 days after initiation of treatment (n = 5) or four days after reinstitution of TAC (n = 1). Five cases were an exacerbation of pre-existing interstitial pneumonia and one was a de novo pulmonary injury. Radiological patterns of thoracic computed tomography (CT) scans of patients in the presumptive TIPI cases were hypersensitivity pneumonia like-pattern (n = 3), ground-glass opacity (n = 2), and organizing pneumonia-pattern (n = 1). All patients with presumptive TIPI were treated with high dosage glucocorticosteroids and one received concomitant immunosuppressants. Two of the six presumptive TIPI patients died.

CONCLUSION

Rheumatologists should be aware of this rare but potentially life-threatening adverse event in RA patients receiving TAC.

Clinical features of late onset non-infectious pulmonary complications following pediatric allogeneic hematopoietic stem cell transplantation

BACKGROUND

Late onset non-infectious pulmonary complications (LONIPCs) are major causes of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We evaluated the incidence and the outcomes of LONIPCs in children who underwent allo-HSCT.

METHODS

Data for 143 children who underwent allo-HSCT at Asan Medical Center between April 2002 and April 2009 were reviewed, and the 127 who survived more than three months were enrolled.

RESULTS

Eleven (8.7%) developed LONIPCs at a median eight months (range 3-14 months) after allo-HSCT, presenting with cough and dyspnea. Six had bronchiolitis obliterans and five had idiopathic pneumonia syndrome. FVC declined more significantly in LONIPC than in non-LONIPC patients three months after HSCT. A significant risk factor for the development of LONIPCs was chronic graft-versus-host disease (GVHD) (p = 0.002). At a median follow-up of 36 months, the three-yr overall survival rate in LONIPC patients was significantly lower than that of non-LONIPC patients (37.4% vs. 72.7%, p = 0.02). The major cause of death was respiratory failure.

CONCLUSIONS

Along with chronic GVHD, deterioration of pulmonary function at three months after HSCT may help in the early identification of patients at risk of subsequent LONIPCs. Considering the poor prognosis of LONIPC, strategies should be aimed at their prevention.

Pathology of small airways disease

CONTEXT

The term small airways disease encompasses a generally poorly understood group of lung diseases that may arise primarily within the small airways or secondarily from diseases primarily affecting the bronchi or lung parenchyma. Their histology may be confusing; however, because treatments and prognoses vary, correct pathologic diagnosis is important.

OBJECTIVE

To present a nonexhaustive review of the pathology of primary and secondary small airways diseases, including small airways disease related to tobacco; to various other exposures, including mineral dusts; to diseases involving other areas of the lung with secondary bronchiolar involvement; and to recently described bronchiolitic disorders.

DATA SOURCES

Current literature is reviewed.

CONCLUSIONS

Small airways diseases include a wide variety of diseases of which the pathologist must consider. Uncommon conditions such as diffuse idiopathic neuroendocrine cell hyperplasia and diffuse panbronchiolitis may show relatively specific diagnostic features histologically; however, most small airways diseases exhibit nonspecific histologic features. Conditions not considered primary pulmonary diseases, such as collagen vascular diseases, bone marrow transplantation, and inflammatory bowel disease, must also be considered in patients with small airways changes histologically. Clinical and radiologic correlation is important for obtaining the best possible diagnosis.

A high risk of life-threatening infectious complications in mycophenolate mofetil treatment for acute or chronic graft-versus-host disease

We describe herein the clinical courses and outcomes of 26 patients who received oral mycophenolate mofetil (MMF) for the treatment of steroid-resistant refractory or steroid-dependent acute or chronic graft-versus-host disease (GVHD) in a single institution. In most cases, 1,500 mg/day of MMF is a median dose (range 500-3,000 mg/day) and administered for 116.5 days (range 9-584 days) along with calcineurin inhibitors and steroids. Although 20 patients (77%) showed rapid improvement of GVHD symptoms, of 15 patients, 13 (87%) showed acute GVHD; of 11 patients, 7 (64%) showed chronic GVHD; most patients (54%) experienced infection during MMF administration, including 5 cases with life-threatening infection. Positive cytomegalovirus (CMV) antigenemia was also observed in 19 patients (73%), but no patients developed CMV infection. Within the median follow-up of 12.5 months (range 0.5-67 months), 10 patients (39%) died. This small study demonstrates that MMF offers an alternative tool for rescuing steroid-refractory or steroid-dependent GVHD, but increases the risk of developing life-threatening infection.

Eosinophilic pulmonary syndrome as a manifestation of GVHD following hematopoietic stem cell transplantation in three patients

Eosinophilic pulmonary syndrome is an uncommon problem in SCT recipients that can mimic an infectious process. We report the occurrence of eosinophilic pulmonary syndrome in three patients following allogeneic hematopoietic stem cell transplantation (HSCT), and postulate that this entity is part of the clinicopathologic spectrum of pulmonary GVHD. In all three cases, active chronic GVHD of the skin preceded or coincided with the development of pulmonary involvement. Other common features included peripheral blood eosinophilia, diffuse bilateral pulmonary infiltrates and lung biopsies showing pronounced infiltrates of eosinophils involving the small bronchioles. All patients responded promptly to systemic steroid therapy, with improvement of their pulmonary symptoms and the resolution of peripheral blood eosinophilia. Clinicians should be aware that eosinophilic pulmonary syndrome can occur following HSCT, may be associated with other manifestations of chronic GVHD, and generally responds well to corticosteroid therapy.