Pulmonary complications after T-cell-depleted allogeneic stem cell transplantation: low incidence and strong association with acute graft-versus-host disease

Clinical characteristics of late-onset interstitial pneumonia after allogeneic hematopoietic stem cell transplantation

Non-infectious pulmonary complications after allogeneic hematopoietic stem cell transplantation (HSCT) remain fatal. In particular, information regarding late-onset interstitial lung disease predominantly including organizing pneumonia and interstitial pneumonia (IP) is limited. A retrospective nationwide survey was conducted using data collected from the Japanese transplant outcome registry database from 2005 to 2010. This study focused on patients (n = 73) with IP diagnosed after day 90 post-HSCT. A total of 69 (94.5%) patients were treated with systemic steroids, and 34 (46.6%) experienced improvement. The presence of chronic graft-versus-host disease at the onset of IP was significantly associated with non-improvement of symptoms (odds ratio [OR] 0.35). At the time of last follow-up (median, 1471 days), 26 patients were alive. Of the 47 deaths, 32 (68%) were due to IP. The 3-year overall survival (OS) and non-relapse mortality (NRM) rates were 38.8% and 51.8%, respectively. In the multivariate analysis, the predictive factors for OS were comorbidities at IP onset (hazard ratio [HR]: 2.19) and performance status (PS) score of 2-4 (HR 2.77). Furthermore, cytomegalovirus reactivation requiring early intervention (HR 2.04), PS score of 2-4 (HR 2.63), and comorbidities at IP onset (HR 2.90) were also significantly associated with increased risk of NRM.

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.

Risk factors and prognosis of non-infectious pulmonary complications after allogeneic hematopoietic stem cell transplantation

Non-infectious pulmonary complications (NIPCs) following allogeneic hematopoietic stem cell transplantation (HSCT) are relatively rare, but frequently fatal. This study investigated the pre-transplant risk factors for developing NIPCs using Japanese transplant registry database entries from 2001 to 2009. Among 13,573 eligible patients, 535 experienced NIPCs (3.9%). Multivariate analysis identified high recipient age (60 + years: HR 1.85, P = 0.003), HLA mismatch (HR 1.61, P < 0.001), female to male HSCT (HR 1.54, P < 0.001), and unrelated bone marrow transplantation (UR-BMT) (HR 3.88, P < 0.001) as significantly associated with an increased risk of NIPCs. In contrast, a non-total body irradiation (TBI) regimen with reduced intensity conditioning (RIC) were associated with a decreased risk of NIPCs compared with a cyclophosphamide (CY) + TBI regimen (busulfan + CY: HR 0.67, P = 0.009, other non-TBI: HR 0.46, P < 0.001), fludarabine-based RIC (HR 0.52, P < 0.001), and other RIC (HR 0.42, P = 0.003). The mortality rate was significantly worse for patients with NIPCs than those without (HR 1.54, 71 P < 0.001). This large-scale retrospective study suggests that both allo-reactions to donor cells and conditioning regimen toxicity contributed to NIPCs following HSCT.

Pulmonary Toxicity After Total Body Irradiation - Critical Review of the Literature and Recommendations for Toxicity Reporting

INTRODUCTION

Total body irradiation is an effective conditioning regimen for allogeneic stem cell transplantation in pediatric and adult patients with high risk or relapsed/refractory leukemia. The most common adverse effect is pulmonary toxicity including idiopathic pneumonia syndrome (IPS). As centers adopt more advanced treatment planning techniques for TBI, total marrow irradiation (TMI), or total marrow and lymphoid irradiation (TMLI) there is a greater need to understand treatment-related risks for IPS for patients treated with conventional TBI. However, definitions of IPS as well as risk factors for IPS remain poorly characterized. In this study, we perform a critical review to further evaluate the literature describing pulmonary outcomes after TBI.

MATERIALS AND METHODS

A search of publications from 1960-2020 was undertaken in PubMed, Embase, and Cochrane Library. Search terms included "total body irradiation", "whole body radiation", "radiation pneumonias", "interstitial pneumonia", and "bone marrow transplantation". Demographic and treatment-related data was abstracted and evidence quality supporting risk factors for pulmonary toxicity was evaluated.

RESULTS

Of an initial 119,686 publications, 118 met inclusion criteria. Forty-six (39%) studies included a definition for pulmonary toxicity. A grading scale was provided in 20 studies (17%). In 42% of studies the lungs were shielded to a set mean dose of 800cGy. Fourteen (12%) reported toxicity outcomes by patient age. Reported pulmonary toxicity ranged from 0-71% of patients treated with TBI, and IPS ranged from 1-60%. The most common risk factors for IPS were receipt of a TBI containing regimen, increasing dose rate, and lack of pulmonary shielding. Four studies found an increasing risk of pulmonary toxicity with increasing age.

CONCLUSIONS

Definitions of IPS as well as demographic and treatment-related risk factors remain poorly characterized in the literature. We recommend routine adoption of the diagnostic workup and the definition of IPS proposed by the American Thoracic Society. Additional study is required to determine differences in clinical and treatment-related risk between pediatric and adult patients. Further study using 3D treatment planning is warranted to enhance dosimetric precision and correlation of dose volume histograms with toxicities.

[Application of bronchoalveolar lavage fluid in patients with pulmonary complications after allogeneic hematopoietic stem cell transplantation]

Objective: To evaluate the diagnostic value of bronchoalveolar lavage (BAL) for pulmonary complications in patients after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and its safety. Methods: Patients with pulmonary complications after allo-HSCT underwent BAL. Microbiological smears, culture, PCR of CMV-DNA, EBV-DNA and TB-DNA, macro genomes new generation sequencing (mNGS) techniques were performed to detect pathogens in BAL fluid (BALF) . Results: A total of 73 allo-HSCT patients with 86 times of pulmonary complications enrolled this prospective study. They underwent 132 times of BAL procedures. The clinical diagnoses of 88.4% cases were made based on BALF analysis. Of them, 67 cases (77.9%) had infectious pulmonary complications, including 29 cases (33.7%) of fungal infection, 18 cases (20.9%) of mixed infection, 11 cases (12.8%) of viral infection and 9 cases (10.5%) of bacterial infection. The other 9 cases (10.5%) of non-infectious pulmonary complications included 8 cases (9.3%) of idiopathic pneumonia syndrome (IPS) and 1 case (1.2%) of pulmonary infiltration of lymphoma. The diagnoses of the remaining 10 cases (11.6%) were not determined. The platelet counts of 33 patients were less than 50×10(9)/L before BAL. None of them developed severe bleeding complications during or after BAL. Transient fever occurred in 10 patients after BAL. Blood cultures showed staphylococcal bacteremia in them and anti-infection therapies were effective. No life-threatening complications occurred in all of the patients during or after BAL. Conclusion: BALF analysis was informative for the diagnosis of pulmonary complication and safe for patients with pulmonary complications after allo-HSCT.

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.

Positive stool culture could predict the clinical outcomes of haploidentical hematopoietic stem cell transplantation

We aimed to identify the effect of positive stool cultures (PSCs) on the clinical outcomes of patients undergoing haploidentical hematopoietic stem cell transplantation (haplo-HSCT) (n = 332). PSCs were observed in 61 patients (PSC group, 18.4%). Enterobacteriaceae in stool specimens was associated with a higher risk of bloodstream infection, and Candida in stool specimens was related to a higher risk of platelet engraftment failure. The cumulative incidence of infection-related mortality 1 year after haplo-HSCT in the PSC group was higher than that of the patients who showed persistently negative stool cultures (NSC group; 19.2% vs. 8.9%, P = 0.017). The probabilities of overall survival (71.4% vs. 83.8%, P = 0.031) and disease-free survival (69.6% vs. 81.0%, P = 0.048) 1 year after haplo-HSCT for the PSC group were significantly lower than those for the NSC group, particularly for patients who had Candida in their stool specimens. In multivariate analysis, Candida in stool specimens significantly increased the risk of mortality and was associated with poorer survival. Our results showed that PSC influenced the clinical outcomes after haplo-HSCT, particularly those who had Candida in their stool specimens.

Gut Microbiota Predict Pulmonary Infiltrates after Allogeneic Hematopoietic Cell Transplantation

RATIONALE

Pulmonary complications (PCs) cause significant morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HCT). Shifts in gut microbiota have been linked to HCT outcomes; however, their effect on PCs is unknown.

OBJECTIVES

To investigate whether changes in gut microbiota are associated with PCs after HCT.

METHODS

A single-center observational study was performed on 94 patients who underwent HCT from 2009 to 2011 and who were previously enrolled in a protocol for 16S ribosomal RNA sequencing of fecal microbiota. The primary endpoint, PC, was defined by new abnormal parenchymal findings on chest imaging in the setting of respiratory signs and/or symptoms. Outcomes were collected up to 40 months after transplant. Clinical and microbiota risk factors for PCs and mortality were evaluated using survival analysis.

MEASUREMENTS AND MAIN RESULTS

One hundred twelve PCs occurred in 66 (70.2%) subjects. A high comorbidity index (hazard ratio [HR], 2.30; 95% confidence interval [CI], 1.30-4.00; P = 0.004), fluoroquinolones (HR, 2.29, 95% CI, 1.32-3.98; P = 0.003), low baseline diversity (HR, 2.63; 95% CI, 1.22-5.32; P = 0.015), and γ-proteobacteria domination of fecal microbiota (HR, 2.64; 95% CI, 1.10-5.65; P = 0.031), which included common respiratory pathogens, predicted PCs. In separate analyses, low baseline diversity was associated with PCs that occurred preengraftment (HR, 6.30; 95% CI, 1.42-31.80; P = 0.016), whereas γ-proteobacteria domination predicted PCs postengraftment (HR, 3.68; 95% CI, 1.49-8.21; P = 0.006) and overall mortality (HR, 3.52; 95% CI, 1.28-9.21; P = 0.016). Postengraftment PCs were also independent predictors of death (HR, 2.50; 95% CI, 1.25-5.22; P = 0.009).

CONCLUSIONS

This is the first study to demonstrate prospective changes in gut microbiota associated with PCs after HCT. Postengraftment PCs and γ-proteobacteria domination were predictive of mortality. This suggests an adverse relationship between the graft and lung, which is perhaps mediated by bacterial composition in the gut. Further study is warranted.

Proteome Profiling in Lung Injury after Hematopoietic Stem Cell Transplantation

Pulmonary complications due to infection and idiopathic pneumonia syndrome (IPS), a noninfectious lung injury in hematopoietic stem cell transplant (HSCT) recipients, are frequent causes of transplantation-related mortality and morbidity. Our objective was to characterize the global bronchoalveolar lavage fluid (BALF) protein expression of IPS to identify proteins and pathways that differentiate IPS from infectious lung injury after HSCT. We studied 30 BALF samples from patients who developed lung injury within 180 days of HSCT or cellular therapy transfusion (natural killer cell transfusion). Adult subjects were classified as having IPS or infectious lung injury by the criteria outlined in the 2011 American Thoracic Society statement. BALF was depleted of hemoglobin and 14 high-abundance proteins, treated with trypsin, and labeled with isobaric tagging for relative and absolute quantification (iTRAQ) 8-plex reagent for two-dimensional capillary liquid chromatography (LC) and data dependent peptide tandem mass spectrometry (MS) on an Orbitrap Velos system in higher-energy collision-induced dissociation activation mode. Protein identification employed a target-decoy strategy using ProteinPilot within Galaxy P. The relative protein abundance was determined with reference to a global internal standard consisting of pooled BALF from patients with respiratory failure and no history of HSCT. A variance weighted t-test controlling for a false discovery rate of ≤5% was used to identify proteins that showed differential expression between IPS and infectious lung injury. The biological relevance of these proteins was determined by using gene ontology enrichment analysis and Ingenuity Pathway Analysis. We characterized 12 IPS and 18 infectious lung injury BALF samples. In the 5 iTRAQ LC-MS/MS experiments 845, 735, 532, 615, and 594 proteins were identified for a total of 1125 unique proteins and 368 common proteins across all 5 LC-MS/MS experiments. When comparing IPS to infectious lung injury, 96 proteins were differentially expressed. Gene ontology enrichment analysis showed that these proteins participate in biological processes involved in the development of lung injury after HSCT. These include acute phase response signaling, complement system, coagulation system, liver X receptor (LXR)/retinoid X receptor (RXR), and farsenoid X receptor (FXR)/RXR modulation. We identified 2 canonical pathways modulated by TNF-α, FXR/RXR activation, and IL2 signaling in macrophages. The proteins also mapped to blood coagulation, fibrinolysis, and wound healing-processes that participate in organ repair. Cell movement was identified as significantly over-represented by proteins with differential expression between IPS and infection. In conclusion, the BALF protein expression in IPS differed significantly from infectious lung injury in HSCT recipients. These differences provide insights into mechanisms that are activated in lung injury in HSCT recipients and suggest potential therapeutic targets to augment lung repair.

Pneumonia After Hematopoietic Stem Cell Transplantation

Pneumonia is the main cause of morbidity and mortality after hematopoietic stem cell transplantation. Two thirds of pneumonias observed after both autologous and allogeneic stem cell transplantations are of infectious origin, and coinfections are frequent. One third is due to noninfectious process, such as alveolar hemorrhage, alveolar proteinosis, or alloimmune pulmonary complications such as bronchiolitis obliterans or idiopathic interstitial pneumonitis. Most of these noninfectious complications may require treatment with corticosteroids which may be deleterious in infection. On the other hand, these complications either mimic or may be complicated with infections. Therefore, a precise diagnosis of pneumonia is of crucial importance to decide of the optimal treatment. CT scan is the best procedure for imaging of the lung. Although several indirect biomarkers, such as serum or plasma galactomannan or (1-3) β(beta)-G-glucan, can help in the etiological diagnosis, only direct invasive investigations provide the best chance to identify the cause(s) of pneumonia. Bronchoalveolar lavage (BAL) under fiberoptic bronchoscopy is the procedure of choice to identify the cause of pulmonary infection. It is safe and reproducible, and its diagnostic yield is around 50 % if the BAL fluid is processed at the laboratory according to a prespecified protocol established between the transplanter, the infectious diseases’ specialist, the pneumologist, and the laboratory, allowing the identification of the most likely hypotheses. Transbronchial biopsy does not provide significant additional information to BAL in most cases and more often complicates with bleeding and pneumothorax. In case of a noncontributory BAL, the decision to proceed to a second BAL, a transthoracic biopsy, or a surgical biopsy should be cautiously weighted in a multidisciplinary approach in regard to the benefits and risks of invasive procedures versus empirical treatment.

The association between platelet transfusion and idiopathic pneumonia syndrome is unaffected by platelet product type

BACKGROUND

Methods used to produce platelet (PLT) components, pooling of PLT-rich plasma (PRP-PLT) and apheresis (AP-PLT), may variably contribute to the pathogenesis and severity of idiopathic pneumonia syndrome (IPS).

STUDY DESIGN AND METHODS

We performed a retrospective cohort study of 906 allogeneic hematopoietic cell transplant recipients to examine associations between PLT product type and risks of developing IPS and dying after IPS onset. Proportional hazards models included separate terms for the sum of all PLT transfusions and the sum of PRP-PLT units received in the 3 or 7 days before IPS onset. Similarly constructed models analyzed the outcome of time to death after IPS onset. All analyses were adjusted for known IPS risk factors.

RESULTS

Patients received a median of three PRP-PLT transfusions (interquartile range [IQR], 0-6) and five AP-PLT transfusions (IQR, 1-13) while at risk for IPS. Seventy-five patients (8%) developed IPS by Posttransplant Day 120. The proportion of PRP-PLT transfusions was not associated with risk of developing IPS (3-day hazard ratio [HR] 0.98, 95% CI 0.74-1.29, p = 0.86; 7-day HR 1.00, 95% CI 0.86-1.15, p = 0.95) or dying after IPS onset (3-day HR 0.99, 95% CI 0.75-1.31, p = 0.97; 7-day HR 0.98, 95% CI 0.78-1.12, p = 0.47).

CONCLUSION

The association between PLT transfusions and risk of developing IPS or dying after IPS onset does not differ according to PLT product type. Further research is required to identify potentially modifiable steps in PLT component production that contribute to IPS.

Hyperexpansion of Functional Viral-Specific CD8+ T Cells in Lymphopenia-Associated MCMV Pneumonitis

Cytomegalovirus (CMV) is a significant cause of morbidity and mortality in immunocompromised hosts, many of whom undergo significant periods of lymphopenia. However, the impact of lymphopenia and subsequent immune reconstitution on T cell responses and pulmonary pathology are poorly understood. Using a model of primary murine CMV infection in mice treated with cyclophosphamide (CY), the relationship of CD8+ T cell reconstitution to pneumonitis pathology was studied. Female BALB/c mice were infected with murine CMV (MCMV) with/without CY on day 1 post-infection. Lung pathology and viral specific T cell responses were assessed on days 7-28. T cell lymphocyte subsets, effector responses, and MCMV specificity were assessed at baseline and after in vitro stimulation of cells with immediate-early peptide pp89. CY treatment of MCMV-infected mice resulted in interstitial pneumonitis not seen with MCMV alone. Compared to MCMV alone, on day 14, MCMV/CY mice had greater number of CD8+ T cells, a fourfold increase in absolute number of pp89 tetramer-specific CD8+ cells, and an eightfold increase in MCMV specific T cell effector responses (IFN-γ; p<0.001). This expansion was preceded by transient lymphopenia, increased viral titers, and, most strikingly, a 10-fold increased proliferative capacity in MCMV/CY mice. In the setting of CY-associated lymphopenia, concurrent MCMV infection alters immune reconstitution toward a hyperexpanded MCMV-specific CD8+ effector T cell pool that correlates with significant lung immunopathology.

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.

Stem cell transplantation and lung dysfunction

PURPOSE OF REVIEW

To identify factors that impact the incidence and severity of lung dysfunction after haematopoietic stem cell transplantation (HSCT) for preventive and therapeutic purposes.

RECENT FINDINGS

Respiratory failure from lung dysfunction after HSCT is a serious and often fatal transplant-related complication, but recent data reveal decreasing incidence and improving outcome over time. Idiopathic pneumonia syndrome (IPS) and bronchiolitis obliterans are now recognized as part of a spectrum of post-HSCT lung diseases involving both aspects of innate and adaptive immune responses, but may differ in the main lung structure affected: alveolar versus airway epithelium. There exists a strong association between acute graft-versus-host disease (GVHD) and IPS, and bronchiolitis obliterans is pathognomonic of chronic GVHD. Experimental models of IPS and bronchiolitis obliterans have proven useful to test strategies designed to limit lung injury including the effects of allogeneity, chemoradiotherapy and stem cell therapy. Recent advances in critical care practices, early diagnosis and utilizing ARDS Network ventilatory and conservative fluid management recommendations have also contributed to better outcome from lung dysfunction after HSCT.

SUMMARY

Understanding the factors that contribute to post-HSCT lung injury should lead to safer transplant practices that will allow the broader use of HSCT for sicker children with comorbidities.

Lung transplantation in children following bone marrow transplantation: a multi-center experience

Allogenic BMT has been successfully performed as a treatment for hematologic diseases with an expected long-term survival. This survival is truncated by respiratory complications including airway obstruction especially BO. Chronic GVHD has been reported to precede almost all cases reported. LTx has become a therapeutic life-saving option for patients with end-stage lung disease that maybe offered for the treatment of GVHD. We report a multi-center experience of pediatric LTx following BMT in 11 patients age- and gender-matched with 11 controls who received LTx for end-stage lung disease secondary to CF. Overall death was 36.4% over a follow-up period of 19 months (range 3-36 months) for the cases and 27.3% for the control group followed for 17 months (range 8-32 months). Median FEV1 one yr post-transplant for the cases was 78% predicted compared with 67.3% predicted for the controls. The median for episodes of infection was comparable at a median of one episode per patient through the entire follow-up period among both groups. Acute rejection episodes were significantly higher in the control group with a median of one episode per patient in the control group compared to none within the cases. Our data suggest that LTx may be a valuable therapeutic option for children with end-stage lung disease post-BMT with comparable survival outcome to that after LTx in children for other indications such as CF. Hospital stay was significantly longer in our case group. Infection rate was comparable between groups albeit type of infection varied. Significantly and of interest is that acute rejection episodes were non-existent in these cases.

Lethal pulmonary complications after pediatric allogeneic hematopoietic stem cell transplantation

INTRODUCTION

Hematopoietic stem cell transplantation (HSCT) in children is accompanied by a transplant-related mortality of 10% to 30%, which is the result of lethal pulmonary complications (LPCs) in many cases.

METHODS

We retrospectively assessed prevalence and risk factors of LPC following 234 allogeneic HSCTs in 228 patients for malignant or nonmalignant diseases at a single institution.

RESULTS

Pulmonary complications (PCs) were observed following 81 of 234 transplants (35%). LPCs were observed in 4% of HSCT within 100 days and in 14% within 5 years after HSCT. Late PCs after day 100 were lethal in 56% (22/39) of the patients with PCs, who are 11% (22/202) of all evaluable patients still alive after day +100. Causes of LPC after day 100 were viral (10 cases), bacterial (1 case), fungal (5 cases) pulmonary infection, or noninfectious (6 cases) PCs. Abnormal pretransplant pulmonary function test was not associated with an increased risk of LPC. Children older than 10 years and those undergoing a second HSCT had an increased incidence of overall LPC. T-cell depletion and mismatched donor HSCT (P = 0.001), but not age, were associated with an increased risk of lethal viral pneumonia.

CONCLUSIONS

Transplant-related mortality up to 5 years after HSCT in children was associated with LPC in 14%. There were more late (>100 days) than early LPCs, predominantly due to infectious etiologies and affecting children >10 years of age.

The diagnostic utility of routine chest radiography in the evaluation of the initial fever in patients undergoing hematopoietic stem cell

BACKGROUND

A routine chest radiograph is often performed to evaluate initial fever in patients undergoing hematopoietic stem cell transplantation (HSCT) given the signs and symptoms of infectious pulmonary pathology may be subtle or absent. Studies in patients receiving conventional chemotherapy have shown that chest radiographs do not appear to be helpful in the evaluation of asymptomatic patients with febrile neutropenia. We performed a retrospective review of pediatric stem cell transplant recipients to determine if chest radiographs are useful in the evaluation of initial fever.

PROCEDURE

We retrospectively identified 81 consecutive pediatric hematopoietic stem transplant recipients who had a chest radiograph performed as a routine part of the evaluation of initial fever during stem cell transplantation.

RESULTS

Seventy-six (94%) of the chest radiographs performed had no evidence of pulmonary infiltrate. Of the five children with positive radiographs, three had symptomatic respiratory infection and two (40%) were asymptomatic. One asymptomatic patient had a history of pulmonary infection with persistent stable infiltrates prior to transplantation. This patient did not have any evidence of pneumonia during the transplant. The second asymptomatic patient had subsequent resolution of the infiltrate with antibiotic administration. None of the patients had a change made in the empiric antibiotic regimen based upon the results of the chest film.

CONCLUSIONS

Routine radiographs are not useful in the evaluation of asymptomatic children at the time of an initial febrile event while undergoing HSCT.

Risk factors and outcome of pulmonary complications after autologous hematopoietic stem cell transplant

BACKGROUND

Most reports addressing pulmonary complications (PCs) in hematopoietic stem cell transplant (HSCT) recipients have focused on allogeneics. This study describes the PCs, their risk factors, and the impact on mortality in autologous recipients.

METHODS

We reviewed the medical records of 1,243 adult autologous HSCT recipients. We collected pretransplant and posttransplant data and data on PC after transplant and long-term mortality.

RESULTS

Four hundred eighty-seven PC developed in 343 patients (27.6%): 173 infectious (13.9%), 127 noninfectious (10.2%), and 43 both infectious and noninfectious (3.5%). Bacterial, fungal, and viral pneumonias were the most common infectious complications. The main noninfectious complications were acute pulmonary edema (APE) (59 [4.7%]), diffuse alveolar hemorrhage (DAH) (26 [2.1%]), peri-engraftment respiratory distress syndrome (PERDS) (31 [2.5%]), and idiopathic pneumonia syndrome (IPS) (12 [1.0%]). Independent factors associated with PC included diffusing capacity of lung for carbon monoxide and indications for transplant. Factors associated with mortality included sex, history of pulmonary disease, disease status at the time of transplant, FVC, Karnofsky score, and underlying diagnosis. A Cox proportional hazards regression model with separate time-dependent predictors for the first 1 month, 1 to 2 months, 2 to 6 months, and 6 or more months showed an association with mortality at hazard ratios (HRs) of 32.39, 10.13, 4.29, and 0.98, respectively, compared with persons without PC.

CONCLUSIONS

More than 25% of autologous HSCT recipients develop PCs within 1 year of transplant. Most of the complications are infections. The most common noninfectious complications are APE, DAH, PERDS, and IPS. PCs increase the risk of death, with HR as high as 32.

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.

Increased morbidity and mortality in murine cytomegalovirus-infected mice following allogeneic bone marrow transplant is associated with reduced surface decay accelerating factor expression

Infection with cytomegalovirus (CMV) remains a significant cause of morbidity and mortality following allogeneic bone marrow transplantation (allo-BMT). The manifestations of CMV infection can range from neurological and haematological abnormalities to diminished graft survival and, in extreme cases, death. Many clinical studies have shown a direct correlation between cytomegalovirus infection and increased morbidity and mortality post allo-BMT, yet the exact mechanism is not well understood. Although driven primarily by T cell responses, the role of complement activation in acute and chronic graft-versus-host disease (GVHD) has also become more evident in recent years. The present studies were performed to examine the effects of murine cytomegalovirus (MCMV) infection on decay accelerating factor (DAF) and MCMVs role in exacerbating morbidity and mortality post-allo-BMT. Mice infected previously with a sublethal dose of MCMV (1 × 10⁵ plaque-forming units) have reduced expression of DAF on lung tissues and lymphocytes following allo-BMT. More importantly, mortality rates post-allo-BMT in recipient DAF knock-out mice receiving wild-type bone marrow are increased, similar to wild-type MCMV-infected recipient mice. Similarly, DAF knock-out mice showed greater intracellular interferon (IFN)-γ production by lung CD8 T cells, and infection with MCMV further exacerbated both intracellular IFN-γ production by CD8 T cells and mortality rates post-allo-BMT. Together, these data support the hypothesis that MCMV infection augments morbidity and mortality post-allo-BMT by reducing surface DAF expression.

Monitoring of cytomegalovirus infection after allogeneic stem cell transplantation

Background/Aim. More than 90% of worldwide population is infected with human cytomegalovirus (CMV), one of the most common agents which complicate immunocompromised patients. Viral infections, in particular CMV ones are still a major cause of moratality and morbidity after stem cell transplantation (SCT). Monitoring is performed by detecting CMVAg or virus DNA in peripheral blood. Risk factors are donor/ recipient CMV status, type of transplant and acute graft versus host disease. The aim of the study was to determine the extent of validity of CMV infection monitoring after transplantation as a reliable parameter of further CMV replication course in patients with hematopoietic stem cell transplantation. Methods. A total of 49 patients with stem cell transplantation were studied prospectively during a 2-year period after transplantation for the presence of CMV DNA. Polymerase chain reaction (PCR) CMV DNA was performed on 222 full blood samples using Cobas Amplicor assay. Results. Activation of CMV was detected in 10/49 (20.48%) of the patients. The median posttransplantation time for the first positive PCR result was 6 weeks for the stem cell transplant patients. Viremia became negative in all the cases after the antiviral therapy with ganciclovir. Conclusion. Our data show that the level of CMV-DNA load at the time of initial CMV detection after transplantation could be a possible predictor for further course of CMV replication in patients receiving hematopoietic stem cell.

Early pulmonary complications after hematopoietic stem cell transplantation in pediatric patients: association with cytomegalovirus infection

Pulmonary complications resulting in high morbidity and mortality occur in a substantial proportion of hematopoietic stem cell transplantation (HSCT) recipients. We investigated the incidence, causes, and risk factors of pulmonary complications, early after HSCT in pediatric patients, and patient outcomes by retrospective analysis of patients who underwent HSCT at Seoul National University Children's Hospital between September 2003 and June 2007. A total of 145 patients were evaluated of whom 15 (10.3%) developed pulmonary complications. Eight patients were suspected to have infection-related pulmonary complications and 7 had noninfectious causes. In a multivariate analysis of allogeneic transplantation recipients, detection of cytomegalovirus antigenemia was significantly associated with the development of both pulmonary complications and acute respiratory distress syndrome. Eleven (73.3%) of the 15 patients developed acute respiratory distress syndrome, required mechanical ventilation and eventually died. Early use of methylprednisolone in 3 patients decreased the oxygenation index. Sixteen patients died due to treatment-related complications early after HSCT, and pulmonary complications accounted for a substantial portion of the mortality. Thus, improvement of prophylaxis and management for pulmonary complications is crucial to improve the overall outcome of HSCT. More aggressive prophylaxis and treatment of cytomegalovirus infection and judicious use of methylprednisolone at the appropriate time could be the means for such improvement.

Pulmonary function changes in experimental graft-versus-host disease of the lung

Pulmonary graft-versus-host disease (p-GVHD) is a serious complication after allogeneic stem cell transplantation (allo-SCT) of high morbidity and high mortality. We characterized breathing patterns and pulmonary function changes in correlation to lung histopathology and survival by using a well-established murine model of p-GVHD. Lethally irradiated B6D2F1 mice received SCT from either syngeneic B6D2F1 or allogeneic C57BL/6 animals. Within 6 weeks, severe p-GVHD developed in allogeneic recipients characterized by progressive interstitial, alveolar, peribronchial, and periluminal inflammatory cell infiltration, whereas in syngeneic recipients lung histology remained normal. Allogeneic recipients demonstrated decreased minute ventilation (MV), reduced peak inspiratory and expiratory flow rates as early as 1 week after SCT. In addition, allo-SCT resulted in restrictive pulmonary function changes as early as 7 days after transplantation and in progressive airflow obstruction within 6 weeks. Decreased breathing abilities and pulmonary function changes of allogeneic recipients were associated with increased mortality and the severity of acute graft-versus-host disease (aGVHD). These findings show that p-GVHD can be characterized by changes in pulmonary function and functional respiratory insufficiency. Furthermore, our data strengthen the understanding, that the lung is a critical target organ of aGVHD.

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.