Pre-hematopoietic stem cell transplant lung function and pulmonary complications in children

Evaluation of Children with Malignancies for Blood and Marrow Transplantation: A Report from the ASTCT Committee on Practice Guidelines

Evaluation of a candidate for hematopoietic cell transplantation (HCT) is a complex process with substantial intercenter variability. Although literature providing guidance for evaluating the eligibility of adults is well established, similar guidance for children is lacking. To address gaps between adult recommendations and the specific needs of children, we convened a panel of pediatric HCT experts from a wide geographic range of American Society of Transplantation and Cellular Therapy (ASTCT) member institutions to offer recommendations for pediatric-focused pre-HCT evaluation. In this report from the ASTCT Committee on Practice Guidelines, we present a practical framework for evaluating children with malignancies who are candidates for HCT. We also highlight key differences from adults and emphasize areas of unmet need that require additional research to delineate best practices.

Expanded HCT-CI Definitions Capture Comorbidity Better for Younger Patients of Allogeneic HCT for Nonmalignant Diseases

Allogeneic hematopoietic cell transplantation (HCT) can cure many nonmalignant conditions, but concern for morbidity and mortality remains. To help physicians estimate patient-specific transplant mortality risk, the HCT comorbidity index (HCT-CI) is used. However, pediatric physicians use the HCT-CI less frequently than adult counterparts. We used the Center for International Blood and Marrow Transplant Research database to expand the HCT-CI comorbidity definitions to be more inclusive of children and adolescent and young adult (AYA) patients, adding history of mechanical ventilation, history of invasive fungal infection, assessment of chronic kidney disease (CKD) by estimated glomerular filtration rate, expanding the definition of obesity, and adding an underweight category. A total of 2815 children and AYAs (<40 years old) who received first allogeneic HCT for nonmalignant diseases from 2008 to 2017 were included to create an expanded youth nonmalignant HCT-CI (expanded ynHCT-CI) and a simplified non-malignant (simplified ynHCT-CI) HCT-CI. The expanded comorbidities occurred frequently-history of mechanical ventilation (9.6%), history of invasive fungal infection (5.9%), mild CKD (12.2%), moderate/severe CKD (2.1%), obesity (10.9%), and underweight (14.5%). Thirty-nine percent of patients had an increase in their comorbidity score using the expanded ynHCT-CI, leading to a redistribution of scores: ynHCT-CI score 0 (35%), 1-2 (36.4%), and ≥3 (28.6%). Patients with an increase in their comorbidity score had an increased hazard of mortality compared to those whose score remained the same (hazard ratio = 1.41; 95% confidence interval, 1.01-1.98). Modifications to the HCT-CI can benefit children and AYA patients with nonmalignant diseases, creating a risk assessment tool that is clinically relevant and better captures comorbidity in this younger population.

Pulmonary microbiome and gene expression signatures differentiate lung function in pediatric hematopoietic cell transplant candidates

Impaired baseline lung function is associated with mortality after pediatric allogeneic hematopoietic cell transplantation (HCT), yet limited knowledge of the molecular pathways that characterize pretransplant lung function has hindered the development of lung-targeted interventions. In this study, we quantified the association between bronchoalveolar lavage (BAL) metatranscriptomes and paired pulmonary function tests performed a median of 1 to 2 weeks before allogeneic HCT in 104 children in The Netherlands. Abnormal pulmonary function was recorded in more than half the cohort, consisted most commonly of restriction and impaired diffusion, and was associated with both all-cause and lung injury-related mortality after HCT. Depletion of commensal supraglottic taxa, such as Haemophilus, and enrichment of nasal and skin taxa, such as Staphylococcus, in the BAL microbiome were associated with worse measures of lung capacity and gas diffusion. In addition, BAL gene expression signatures of alveolar epithelial activation, epithelial-mesenchymal transition, and down-regulated immunity were associated with impaired lung capacity and diffusion, suggesting a postinjury profibrotic response. Detection of microbial depletion and abnormal epithelial gene expression in BAL enhanced the prognostic utility of pre-HCT pulmonary function tests for the outcome of post-HCT mortality. These findings suggest a potentially actionable connection between microbiome depletion, alveolar injury, and pulmonary fibrosis in the pathogenesis of pre-HCT lung dysfunction.

Hb-adjusted DLCO with GLI reference predicts long-term survival after HSCT in children

This study aimed to evaluate the pretransplant diffusing capacity as a predictor of outcomes in pediatric allogeneic hematopoietic stem cell transplantation (allo-HSCT). Retrospective cohort study of 176 children followed outcomes for 5 years after allo-HSCT. We conducted an analysis of PFTs include spirometry, body plethysmography, and diffusing capacity prior to allo-HSCT. We analyzed the probabilities of overall survival (OS), disease-related mortality (DRM), and non-relapse mortality (NRM). Of all carbon monoxide diffusing capacity (DLCO) parameters obtained using the Global Lung Function Initiative (GLI)-2017, univariate analysis showed that the grade 3, 4 of DLCOadj and Category III, IV of LFS significantly increase NRM (p = 0.003 and p = 0.008). Multivariate analysis indicated that a significant increase in the risk of NRM is associated with grades 3, 4 DLCOadj (hazard ratio [HR] = 4.90, p = 0.020). Kaplan-Meier analyses showed that a significant stepwise increase in NRM was observed with both worse pretransplant DLCOadj grades and LFS categories (p < 0.001 and p = 0.003). A compromised pretransplant diffusing capacity and a high LFS significantly increase the risk of NRM. Especially, DLCOadj before transplantation can be used as an important predictor of NRM after allo-HSCT in children with malignancy.

The pulmonary metatranscriptome prior to pediatric HCT identifies post-HCT lung injury

Lung injury after pediatric allogeneic hematopoietic cell transplantation (HCT) is a common and disastrous complication that threatens long-term survival. To develop strategies to prevent lung injury, novel tools are needed to comprehensively assess lung health in HCT candidates. Therefore, this study analyzed biospecimens from 181 pediatric HCT candidates who underwent routine pre-HCT bronchoalveolar lavage (BAL) at the University Medical Center Utrecht between 2005 and 2016. BAL fluid underwent metatranscriptomic sequencing of microbial and human RNA, and unsupervised clustering and generalized linear models were used to associate microbiome gene expression data with the development of post-HCT lung injury. Microbe-gene correlations were validated using a geographically distinct cohort of 18 pediatric HCT candidates. The cumulative incidence of post-HCT lung injury varied significantly according to 4 pre-HCT pulmonary metatranscriptome clusters, with the highest incidence observed in children with pre-HCT viral enrichment and innate immune activation, as well as in children with profound microbial depletion and concomitant natural killer/T-cell activation (P < .001). In contrast, children with pre-HCT pulmonary metatranscriptomes containing diverse oropharyngeal taxa and lacking inflammation rarely developed post-HCT lung injury. In addition, activation of epithelial-epidermal differentiation, mucus production, and cellular adhesion were associated with fatal post-HCT lung injury. In a separate validation cohort, associations among pulmonary respiratory viral load, oropharyngeal taxa, and pulmonary gene expression were recapitulated; the association with post-HCT lung injury needs to be validated in an independent cohort. This analysis suggests that assessment of the pre-HCT BAL fluid may identify high-risk pediatric HCT candidates who may benefit from pathobiology-targeted interventions.

Lung Function Predicts Outcome in Children With Obstructive Lung Disease After Hematopoietic Stem Cell Transplantation

Obstructive lung disease (OLD) that develops after hematopoietic stem cell transplantation (HSCT) has a significant impact on morbidity and mortality. We investigated the role of pulmonary function tests (PFTs) in the prediction of prognosis of OLD in children who have undergone HSCT. We retrospectively reviewed 538 patients who underwent allogenic HSCT in the Department of Pediatrics, Seoul St. Mary's Hospital, South Korea, from April 2009 to July 2017. OLD was identified on PFTs or chest computed tomography scans obtained from 3 months after HSCT onwards. OLD developed after HSCT in 46 patients (28 male individuals, median age: 11.2 y). The group that developed OLD with an unfavorable prognosis (n=23) had a lower forced vital capacity (FVC) (% of predicted, 78.53±24.00 vs. 97.71±16.96, P=0.01), forced expiratory volume in 1 second (FEV1) (% of predicted, 52.54±31.77 vs. 84.44±18.59, P=0.00), FEV1/FVC (%, 59.28±18.68 vs. 79.94±9.77, P=0.00), and forced expiratory flow at 25% to 75% of forced vital capacity (FEF25-75) (% of predicted, 30.95±39.92 vs. 57.82±25.71, P=0.00) at diagnosis than the group that developed OLD with a favorable prognosis (n=23). The group that developed OLD with an unfavorable prognosis had significant reductions in FVC, FEV1, FEV1/FVC, and FEF25-75 at 2 years after diagnosis. Children who develop OLD with an unfavorable prognosis after HSCT already have poor lung function at the time of diagnosis. Additional treatment should be considered in patients who develop OLD after HSCT according to their PFTs at diagnosis.

American Thoracic Society 2019 Pediatric Core Curriculum

The American Thoracic Society Pediatric Core Curriculum updates clinicians annually in pediatric pulmonary disease in a 3 to 4 year recurring cycle of topics. The 2019 course was presented in May during the Annual International Conference. An American Board of Pediatrics Maintenance of Certification module and a continuing medical education exercise covering the contents of the Core Curriculum can be accessed online at www.thoracic.org.

Xenon-129 MRI detects ventilation deficits in paediatric stem cell transplant patients unable to perform spirometry

BACKGROUND

Early detection of pulmonary morbidity following haematopoietic stem cell transplantation (HSCT) remains an important challenge for intervention, primarily due to the insensitivity of spirometry to early change, and in paediatrics, patient compliance provides additional challenges. Regional lung ventilation abnormalities in paediatric HSCT patients were quantified using hyperpolarised xenon-129 (129Xe) magnetic resonance imaging (MRI) and compared to spirometry.

METHODS

Medically stable, paediatric allogeneic HSCT patients (n=23, ages 6-16 years) underwent an outpatient MRI scan where regional ventilation was quantified with a breath-hold of hyperpolarised 129Xe gas. Ventilation deficits, regions of the lung that ventilate poorly due to obstruction, were quantified as a ventilation defect percentage (VDP) and compared to forced expiratory volume in 1 s (FEV1), FEV1/forced vital capacity (FVC) ratio, and forced expiratory flow at 25-75% of FVC (FEF25-75%) from spirometry using linear regression.

RESULTS

The mean±sd 129Xe VDP was 10.5±9.4% (range 2.6-41.4%). 129Xe VDP correlated with FEV1, FEV1/FVC ratio and FEF25-75% (p≤0.02 for all comparisons). Ventilation deficits were detected in patients with normal spirometry (i.e. FEV1 >80%), supporting the sensitivity of 129Xe MRI to early obstruction reported in other pulmonary conditions. Seven (30%) patients could not perform spirometry, yet ventilation deficits were observed in five of these patients, detecting abnormalities that otherwise may have gone undetected and untreated until advanced.

CONCLUSION

Lung ventilation deficits were detected using hyperpolarised 129Xe gas MRI in asymptomatic paediatric HSCT patients and in a subgroup who were unable to perform reliable spirometry. 129Xe MRI provides a reliable imaging-based assessment of pulmonary involvement in this potentially difficult to diagnose paediatric population.

Impact of Lung Function on Bronchiolitis Obliterans Syndrome and Outcome after Allogeneic Hematopoietic Cell Transplantation with Reduced-Intensity Conditioning

Lung function deterioration contributes to treatment-related morbidity and mortality in patients after allogeneic hematopoietic cell transplantation (allo-HCT). Better understanding of impaired lung function including bronchiolitis obliterans syndrome (BOS) as chronic manifestation of graft-versus-host disease (GVHD) might improve outcomes of patients after allo-HCT. To detect early pulmonary function test abnormalities associated with BOS incidence and outcome after allo-HCT, we performed a retrospective analysis of homogenous-treated 445 patients (median age, 61.9 years; range, 19 to 76 years) with a reduced intensity/toxicity conditioning protocol. The cumulative incidence of BOS was 4.1% (95% confidence interval [CI], 2.6 to 6.4) at 1 year and 8.6% (95% CI, 6.3 to 11.6) at 5 years after allo-HCT with a median follow-up of 43.2 months (range, 3.3 to 209 months). In multivariate analysis, pre-existence of moderate small airway disease reflected by decreased midexpiratory flows before allo-HCT was associated with increased risk for BOS development. In addition, severe small airway disease before allo-HCT and combined restrictive/obstructive lung disease at day +100 after allo-HCT were associated with higher risk for nonrelapse mortality (NRM) due mainly to pulmonary cause of death. In summary, we identified novel pulmonary function test abnormalities prior and after allo-HCT associated with BOS development and NRM. These findings might help to identify a risk population and result in personalized GVHD prophylaxis and preventive or early therapeutic interventions.

Recovery of Pulmonary Function after Allogeneic Hematopoietic Cell Transplantation in Children is Associated with Improved Survival

Abnormal pulmonary function is prevalent in survivors of allogeneic hematopoietic cell transplantation (HCT). Post-transplantation recovery of pulmonary function, and its effect on survival, in children are not known. This retrospective cohort study of 308 children followed for 10 years after HCT at a single institution included 2 groups of patients. Group 1 comprised 188 patients with 3 or more pulmonary function test (PFT) results, of which at least 1 was abnormal, and group 2 comprised 120 patients with 3 or more PFTs, all of which were normal. Pulmonary function normalized post-transplantation in 51 patients (27%) in group 1. Obstructive lung disease, restrictive lung disease, mixed lung disease, and normal pattern were seen in 43%, 25%, 5%, and 27% of patients, respectively, at a median of 5 years (range, 0.5 to 11.9 years) post-transplantation. Lung volumes recovered better than spirometric indices. Pulmonary complications were seen in 80 patients (43%) in group 1. Patients who recovered pulmonary function had better overall survival (P = .006), which did not differ significantly from that in patients in group 2 with normal lung function post-transplantation (P = .80). After adjusting for duration of follow-up, pulmonary complications (P = .01), and lower pretransplantation forced vital capacity z-scores (P = .01) were associated with poor recovery. T cell depletion (P < .001), lower pretransplantation forced expired volume in 1 second z-scores (P = .006), and chronic graft-versus-host disease (P < .001) increased the risk for pulmonary complications. Nonrecovery of lung function with pulmonary complications (P = .03), acute graft-versus-host disease (P = .004), and mechanical ventilation (P < .001) were risk factors for nonrelapse mortality. Normalization of pulmonary function is possible in long-term survivors of allogeneic HCT. Strategies to decrease the risk of pulmonary complications may improve outcomes.

Pulmonary Function and Pretransplant Evaluation of the Hematopoietic Cell Transplant Candidate

Pretransplant pulmonary function tests provide baseline data by which to reference subsequent respiratory impairment, as well as important prognostic information, for the hematopoietic cell transplant (HCT) recipient. Abnormalities in forced expiratory volume in 1 second and diffusing capacity of carbon monoxide are associated with early respiratory failure and increased all-cause mortality after allogeneic HCT. These parameters have been incorporated into risk assessment calculators that may aid in clinical decision making. This article discusses the clinical implications of pulmonary function parameters and other risk factors for pulmonary complications in the context of evolving allogeneic HCT practice.

Pulmonary Function after Treatment for Childhood Cancer. A Report from the St. Jude Lifetime Cohort Study (SJLIFE)

RATIONALE

The relationship between treatment-related impairment of pulmonary function in adult survivors of childhood cancer and subsequent physical function has not been studied.

OBJECTIVES

In this prospective evaluation of 606 adult survivors of childhood cancer, we sought to determine the risk factors for, as well as the functional impact of, clinically ascertained pulmonary function impairment.

METHODS

We measured FEV1, FVC, total lung capacity (TLC), and single-breath diffusing capacity of the lung for carbon monoxide corrected for hemoglobin (DlCOcorr), expressing the results as percent predicted and lower limit of normal (LLN) values, and we also assessed functional exercise capacity (6-minute-walk distance). Lung radiation exposure was expressed as the estimated percentage of lung tissue that received at least 10 Gy (V10). Associations of clinical and treatment factors with pulmonary function measures were assessed using log-binomial regression to calculate relative risks and 95% confidence intervals.

MEASUREMENTS AND MAIN RESULTS

The participants' median age at evaluation was 34.2 years, and the median elapsed time from diagnosis was 21.9 years. Among the sample population, 50.7% had an FEV1 percent predicted less than 80%, 47.2% had an FVC percent predicted less than 80%, 31.2% had a TLC percent predicted less than 75%, and 44.6% had DlCOcorr percent predicted less than 75%. Also, 49.0% had FEV1 less than the LLN on the basis of the Global Lung Function Initiative (GLI) criteria, and 45.4% had FVC less than LLN. Obstructive lung defects (FEV1/FVC, <0.7) were found in 0.8%, but none had obstructive lung defects on the basis of the GLI criterion of FEV1/FVC less than the LLN. Restrictive lung defects (TLC, <75%) were found in 31.2% of participants. V10 and elapsed time since diagnosis were associated with abnormal FEV1 and FVC based on the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.03 criteria, and with abnormal FEV1 using the GLI criterion. Age at diagnosis was an additional risk factor for abnormal FVC based on the GLI criteria. Age at diagnosis and V10 were associated with abnormal TLC. Increased body mass index, V10, and elapsed time since diagnosis were risk factors for abnormal DlCOcorr. Abnormal pulmonary function tests were associated with decreased 6-minute walk distance.

CONCLUSIONS

Impaired pulmonary function in adult survivors of childhood cancer is associated with decreased physical function. These patients may benefit from interventions designed to preserve and/or improve pulmonary function.

A randomized clinical trial of a parent-focused social-cognitive processing intervention for caregivers of children undergoing hematopoetic stem cell transplantation

OBJECTIVE

Providing care to one's child during and after a hematopoietic stem cell transplant (HSCT) is a universally stressful experience, but few psychological interventions have been developed to reduce caregiver distress. The goal of this study was to test the efficacy of a brief cognitive-behavioral intervention delivered to primary caregivers.

METHOD

Two hundred eighteen caregivers were assigned either best-practice psychosocial care (BPC) or a parent social-cognitive intervention program (P-SCIP). The 5 session P-SCIP was delivered during the HSCT hospitalization. Caregivers completed measures of distress, optimism, coping, and fear appraisals preintervention, 1, 6 months, and 1 year.

RESULTS

P-SCIP reduced caregiver's distress significantly more than BPC between the pretransplant assessment (Time 1) and 1-month follow-up assessment (Time 2). P-SCIP had a stronger effect than BPC among caregivers who began the hospitalization reporting higher depression and anxiety, and among caregivers whose children developed graft-versus-host disease (GvHD). Long-term treatment effects of P-SCIP were seen in traumatic distress among caregivers who reported higher anxiety pretransplant as well as among caregivers whose children had GvHD at HSCT discharge.

CONCLUSIONS

Screening caregivers for elevations in pretransplant anxiety and targeting interventions specifically to these caregivers, as well as targeting caregivers to children who develop GvHD, may prove beneficial.

A Critical Care and Transplantation-Based Approach to Acute Respiratory Failure after Hematopoietic Stem Cell Transplantation in Children

Acute respiratory failure contributes significantly to nonrelapse mortality after allogeneic hematopoietic stem cell transplantation. Although there is a trend of improved survival over time, mortality remains unacceptably high. An understanding of the pathophysiology of early respiratory failure, opportunities for targeted therapy, assessment of the patient at risk, optimal use of noninvasive positive pressure ventilation, strategies to improve alveolar recruitment, appropriate fluid management, care of the patient with chronic lung disease, and importantly, a team approach between critical care and transplantation services may improve outcomes.

•

Outcomes from acute respiratory failure after hematopoietic stem cell transplantation remain unacceptably high.

•

The review focuses on strategies to improve these outcomes.