Bronchiolitis Obliterans Research Articles

Adenoviral infection in children admitted with severe acute respiratory infection at tertiary care hospital from North India: A case series

Abstract There has been a recent surge in adenoviral infections with poor outcomes. This case series describes the clinical profile and outcome of 38 children admitted with adenovirus infection with severe acute respiratory illness (SARI). The majority (68.4%) were infants, 25 (65.7%) were immunocompetent, and 13 (34.2%) had an underlying comorbidity. Twenty-seven (71%) patients required mechanical ventilation and 5 (13.1%) were managed on a heated high-flow nasal cannula. Nine (23.6%) children developed acute respiratory distress syndrome and four (10.5%) cases developed postinfectious bronchiolitis obliterans (PIBO). The median duration of mechanical ventilation was 24 days interquartile range [11.5–34.5] days. Eleven (28.9%) children in the study population expired.

Clinical impact of airflow obstruction after allogeneic hematopoietic stem cell transplantation

Criteria for airflow obstruction (AFO) at one year after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in pulmonary function tests (PFTs) are more stringent than the bronchiolitis obliterans syndrome (BOS) criteria of the National Institutes of Health. This single-center, retrospective cohort study evaluated the clinical impact of the AFO criteria at any time after transplantation. In 132 patients who underwent allo-HSCT from 2006 to 2016, the 2-year cumulative incidence of AFO was 35.0%, and the median time to diagnosis of AFO was 101 days after transplantation (range 35–716 days). Overall chronic graft-versus-host disease (cGVHD) incidence was significantly higher in patients with AFO than in those without AFO (80.4% vs. 47.7%, P < 0.01); notably, 37.0% of patients with AFO developed cGVHD after AFO diagnosis. AFO patients developed BOS with a 5-year cumulative incidence of 49.1% after AFO onset. The 5-year cumulative incidence of non-relapse mortality in the AFO group was higher than that in the non-AFO group (24.7% vs. 7.1%, P < 0.01). These results suggest that closely monitoring PFTs within two years after allo-HSCT, regardless of cGVHD status, is important for early detection of AFO and prevention of progression to BOS. (192words).

Diagnostic challenges in patients with Castleman disease, a single center experience from Hungary.

Castleman disease is a rare and atypical lymphoproliferative disorder characterized by diverse clinical manifestations. It has both unicentric and multicentric forms, the latter with further subdivisions, i.e., human herpesvirus 8-associated and idiopathic forms. The diagnosis of Castleman disease is often delayed, as it is rare, and because it shares clinical features with different autoimmune, inflammatory, and malignant lymphoproliferative disorders. The first-line treatment in unicentric form is mainly surgical, while in idiopathic Castleman disease, anti-interleukin-6 treatment is the therapy of choice. In virus-associated diseases, antiretroviral therapy and rituximab are recommended. In Hungary, only a few cases of Castleman disease have been published. This report presents our twodecades of experience in the challenging diagnosis and management of this rare disorder, most properly underdiagnosed in Hungary. We provide insights into seven unicentric and five idiopathic multicentric Castleman disease cases, the latter ones especially highlighting the diagnostic and therapeutic challenges due to the variable and unique clinical features both of patients and diseases, e.g., bronchiolitis obliterans, stage IV diabetic renal failure, anti-HBc positivity, siltuximab treatment period, respectively.

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

AbstractBronchiolitis 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.

Chronic Lung Allograft Dysfunction: Clinical Manifestations and Immunologic Mechanisms.

The term "chronic lung allograft dysfunction" has emerged to describe the clinical syndrome of progressive, largely irreversible dysfunction of pulmonary allografts. This umbrella term comprises 2 major clinical phenotypes: bronchiolitis obliterans syndrome and restrictive allograft syndrome. Here, we discuss the clinical manifestations, diagnostic challenges, and potential therapeutic avenues to address this major barrier to improved long-term outcomes. In addition, we review the immunologic mechanisms thought to propagate each phenotype of chronic lung allograft dysfunction, discuss the various models used to study this process, describe potential therapeutic targets, and identify key unknowns that must be evaluated by future research strategies.

The Impact of Donor-Recipient Human Leukocyte Antigen Matching on Bronchiolitis Obliterans-Free Survival Among Lung Transplant Recipients With Connective Tissue Diseases.

The development of connective tissue disease-associated lung diseases (CTD-LD) occurs in association with specific human leukocyte antigens (HLA). For CTD-LD patients who require lung transplant, it is unknown whether utilization of donor organs expressing these same HLA impacts posttransplant outcomes. Using the Scientific Registry of Transplant Recipients, we assessed whether CTD-LD lung transplant recipients in the United States have worse bronchiolitis obliterans (BOS)-free survival based on the degree of donor HLA matching. This included overall degree of donor-recipient HLA matching, donor-recipient matching at DR loci, and recipient matching with specific donor HLA antigens associated with the development of pulmonary disease in their condition. Among 1413 patients with CTD-ILD, highly HLA-matched donor-recipients did not have worse adjusted survival (hazard ratio [HR]=0.93, 95% confidence interval [CI]=0.58-1.51, p=0.77). Recipients who were fully matched at HLA DR did not have worse survival (HR=0.82, 95% CI=0.56-1.19, p=0.29). Finally, among individual CTD-LD, including rheumatoid arthritis, systemic sclerosis, the idiopathic inflammatory myopathies, and systemic lupus erythematous, transplant with a donor expressing HLA antigens associated with lung manifestations in these conditions was not associated with worse BOS-free survival. Among transplant recipients with CTD-LD, HLA donor-recipient matching, including at the DR loci, does not result in worse BOS-free survival. Based on these findings, there is no reason to treat these as unacceptable antigens when considering donor offers for CTD-LD candidates.

The Impact of Prelung Transplant HLA Antibodies on Post-transplant Outcomes in Recipients With Autoimmune Lung Disease

IntroductionPatients with advanced lung disease who have HLA antibodies against potential donors have reduced opportunities for transplant. Not all HLA antibodies, however, have the same impact on post-transplant outcomes. It is unknown whether HLA antibodies arising in the context of autoimmune lung disease are associated with increased antibody mediated rejection (AMR) or bronchiolitis obliterans stage 1 (BOS1)-free survival. MethodsThis study used retrospective data from SRTR to examine BOS1-free survival and AMR among sensitized recipients with autoimmune ILD compared to sensitization recipients with nonautoimmune ILD, accounting for other sources of sensitization such as pregnancy and blood transfusions. This study did not use organs from prisoners and participants were neither coerced nor paid. ResultsSensitized recipients with autoimmune ILD did not have differences in BOS1-free survival when adjusting for sensitizing exposures (HR = 0.90, 95% CI: 0.70-1.16) or clinical covariates (HR = 0.96, 95% CI: 0.83-1.12). There was also no difference in AMR (OR = 1.92, 95% CI: 1.04-3.52). ConclusionsHLA antibodies arising in the context of autoimmune ILD do not appear to have a differential impact on BOS1-free survival or AMR. This provides further evidence that patients sensitized via autoimmune lung diseases do not require separate decision-making regarding HLA antibody status compared to the overall sensitized population.

Effects of inflammatory stimuli on the development of Mycoplasma bovis pneumonia in experimentally challenged calves

Many cattle infected with Mycoplasma bovis remain healthy while others develop severe chronic respiratory disease. We hypothesized that inflammatory stimuli such as co-pathogens worsen disease outcomes in M. bovis-infected calves. Calves (n=24) were intrabronchially inoculated with M. bovis and either killed bacterial lysate, transient M. haemolytica infection, or saline. Caseonecrotic lesions developed in 7/7 animals given M. haemolytica and M. bovis compared to 2/8 given M. bovis with no inflammatory stimulus, and 6/9 animals given bacterial lysate and M. bovis (P=0.01). Animals receiving M. haemolytica and M. bovis had more caseonecrotic foci in lungs than those receiving M. bovis with no inflammatory stimulus (median = 21 vs 0; P = 0.01), with an intermediate response (median = 5) in animals given bacterial lysate. In addition to caseonecrotic foci, infected animals developed neutrophilic bronchiolitis that appeared to develop into caseonecrotic foci, peribronchiolar lymphocytic cuffs that were not associated with the other lesions, and 4 animals with bronchiolitis obliterans. The data showed that transient lung inflammation at the time of M. bovis infection provoked the development of caseonecrotic bronchopneumonia, and the severity of inflammation influenced the number of caseonecrotic foci that developed. In contrast, caseonecrotic lesions were few or absent in M. bovis-infected calves without a concurrent inflammatory stimulus. These studies provide insight into how caseonecrotic lesions develop within the lung of M. bovis-infected calves. This and other studies suggest that controlling co-pathogens and harmful inflammatory responses in animals infected with M. bovis could potentially minimize development of M. bovis caseonecrotic bronchopneumonia.

Prophylaxis with palivizumab in a six-year-old girl with Down syndrome and postinfectious obliterative bronchiolitis.

Prophylaxis with palivizumab in a six-year-old girl with Down syndrome and postinfectious obliterative bronchiolitis.

Bronchiolitis Obliterans Organizing Pneumonia After Breast Radiation Therapy

Presented here is a case report of a 77-year-old woman affected by rheumatoid arthritis who underwent breast-conserving surgery followed by radiation therapy (RT) for left-breast cancer and developed bronchiolitis obliterans organizing pneumonia (BOOP) after RT and during a COVID-19 vaccination campaign. BOOP incidence is an uncommon morbidity after breast RT (1.2%-2.9%); however, specific predisposing factors can play a role. In this patient, both rheumatoid arthritis and the vaccine may have predisposed her to an increased risk of organizing pneumonia, probably by triggering a proinflammatory cascade. Our report highlights the importance of factors that influence the occurrence of uncommon radiation-induced morbidities, such as BOOP, in specific subsets of patients. Further studies are necessary to evaluate factors increasing radiation sensitivity.

Dual Role of microRNA-146a in Experimental Inflammation in Human Pulmonary Epithelial and Immune Cells and Expression in Inflammatory Lung Diseases.

microRNA (miR)-146a emerges as a promising post-transcriptional regulator in various inflammatory diseases with different roles for the two isoforms miR-146a-5p and miR-146a-3p. The present study aimed to examine the dual role of miR-146a-5p and miR-146a 3p in the modulation of inflammation in human pulmonary epithelial and immune cells in vitro as well as their expression in patients with inflammatory lung diseases. Experimental inflammation in human A549, HL60, and THP1 via the NF-kB pathway resulted in the major upregulation of miR-146a-5p and miR-146a-3p expression, which was partly cell-specific. Modulation by transfection with miRNA mimics and inhibitors demonstrated an anti-inflammatory effect of miR-146a-5p and a pro-inflammatory effect of miR-146a-3p, respectively. A mutual interference between miR-146a-5p and miR-146a-3p was observed, with miR-146a-5p exerting a predominant influence. In vivo NGS analyses revealed an upregulation of miR-146a-3p in the blood of patients with cystic fibrosis and bronchiolitis obliterans, while miR-146a-5p levels were downregulated or unchanged compared to controls. The reverse pattern was observed in patients with SARS-CoV-2 infection. In conclusion, miR-146a-5p and miR-146a-3p are two distinct but interconnected miRNA isoforms with opposing functions in inflammation regulation. Understanding their interaction provides important insights into the progression and persistence of inflammatory lung diseases and might provide potential therapeutic options.

Impact of Transplant Body Mass Index and Post-Transplant Weight Changes on the Development of Chronic Lung Allograft Dysfunction Phenotypes

Chronic lung allograft dysfunction (CLAD) is a lung transplant complication for which four phenotypes are recognized: Bronchiolitis obliterans syndrome (BOS), Restrictive allograft syndrome (RAS), mixed and undefined phenotypes. Weight gain is common after transplant and may negatively impact lung function. Study objectives were to describe post-transplant weight trajectories of patients who developed (or did not) CLAD phenotypes and examine the associations between BMI at transplant, post-transplant changes in weight and BMI, and the risk of developing these phenotypes. Adults who underwent a bilateral lung transplant between 2000 and 2020 at our institution were categorized as having (or not) one of the four CLAD phenotypes based on the proposed classification system. Demographic, anthropometric, and clinical data were retrospectively collected from medical records and analyzed. Study population included 579 recipients (412 [71.1%] CLAD-free, 81 [14.0%] BOS, 20 [3.5%] RAS, 59 [10.2%] mixed, and 7 [1.2%] undefined phenotype). Weight gains of greater amplitude were seen in recipients with restrictive phenotypes than CLAD-free and BOS patients within the first five years post-transplant. While the BMI category at transplant was not statistically associated with the risk of developing CLAD phenotypes, an increase in weight (Hazard ratio [HR]: 1.04, 95% CI [1.01-1.08]; P = .008) and BMI (HR: 1.13, 95% CI [1.03-1.23]; P = .008) over the post-transplant period was associated with a greater risk of RAS. Post-LTx gain in weight and BMI modestly increased the risk of RAS, adding to the list of unfavorable outcomes associated with weight gain following transplant.

Detection of Bronchiolitis Obliterans Syndrome after Pediatric Hematopoietic Stem Cell Transplantation: An Official American Thoracic Society Clinical Practice Guideline.

Background: Many children undergo allogeneic hematopoietic stem cell transplantation (HSCT) for the treatment of malignant and nonmalignant conditions. Unfortunately, pulmonary complications occur frequently post-HSCT, with bronchiolitis obliterans syndrome (BOS) being the most common noninfectious pulmonary complication. Current international guidelines contain conflicting recommendations regarding post-HSCT surveillance for BOS, and a recent NIH workshop highlighted the need for a standardized approach to post-HSCT monitoring. As such, this guideline provides an evidence-based approach to detection of post-HSCT BOS in children. Methods: A multinational, multidisciplinary panel of experts identified six questions regarding surveillance for, and evaluation of, post-HSCT BOS in children. A systematic review of the literature was undertaken to answer each question. The Grading of Recommendations, Assessment, Development, and Evaluation approach was used to rate the quality of evidence and the strength of recommendations. Results: The panel members considered the strength of each recommendation and evaluated the benefits and risks of applying the intervention. In formulating the recommendations, the panel considered patient and caregiver values, the cost of care, and feasibility. Recommendations addressing the role of screening pulmonary function testing and diagnostic tests in children with suspected post-HSCT BOS were made. Following a Delphi process, new diagnostic criteria for pediatric post-HSCT BOS were also proposed. Conclusions: This document provides an evidence-based approach to the detection of post-HSCT BOS in children while also highlighting considerations for the implementation of each recommendation. Further, the document describes important areas for future research.

Iron Overload-induced Ferroptosis as a Target for Protection against Obliterative Bronchiolitis after Orthotopic Tracheal Transplantation in Mice.

The major complication of Obliterative Bronchiolitis (OB) is characterized by epithelial cell loss, fibrosis, and luminal occlusion of the terminal small airways, which limits the long-term survival of the recipient after lung transplantation. However, the underlying mechanisms are still not fully clarified. This research aims to investigate whether iron overload-induced ferroptosis is involved in OB development and provide a new target for OB prevention. Allograft orthotopic tracheal transplantation in mice was applied in our study. Ferrostatin-1 and deferoxamine were administrated to inhibit ferroptosis and get rid of ferric iron, while iron dextran was used to induce an iron overload condition in the recipient. The histological examination, luminal occlusion rate, collagen deposition, iron level, ferroptosis marker (GPX4, PTGS2), and mitochondrial morphological changes of the graft were evaluated in mice. Our research indicated that ferroptosis and iron overload contribute to OB development, while ferroptosis inhibition and iron chelator could reverse the changes. Iron overload exacerbated OB development after orthotopic tracheal transplantation via promoting ferroptosis. Overall, this research demonstrated that iron overload-induced ferroptosis is involved in OB, which may be a potential therapeutic target for OB after lung transplantation.

Bronchiolite obliterante post-infettiva (PIBO), chi è costei?

The paper presents the case of a 14-month-old child with a persistent respiratory distress with wheezing and diffuse crackles on chest auscultation. Symptoms appeared after a viral pneumonia caused by Adenovirus. The recent history, the clinical manifestations and the lung CT (Computed Tomography) scans, which showed a diffuse mosaic pattern, with air trapping, bronchiectasis and peribronchial inflammation, led to the diagnosis of Post-infectious Bronchiolitis Obliterans (PIBO). PIBO is a rare chronic paediatric pulmonary disease characterized by irreversible fibrotic narrowing of the small airways. It can present with a broad severity spectrum, and the evolution of this condition is not predictable in the single patient. Adenovirus is by far the most common cause of this lung pathology, and during the post Covid-19 pandemic an unprecedented rise in PIBO cases triggered by Adenovirus lower respiratory infections was observed. The treatment of PIBO is empirical, and a defined protocol does not exist yet. Therapeutic approaches range from nil to methylprednisolone pulse therapy, which would seem effective especially if performed early and if peribronchitis is found on imaging. Some studies evaluated the administration of intravenous immunoglobulins, while in more advanced cases showing fibrotic transformation of the parenchyma, the use of antifibrotic drugs (hydroxychloroquine, nintedanib) may be tried

Empowering caregivers of children with bronchiolitis obliterans: The effectiveness of an internet-based follow-up platform

ObjectiveLimited evidence on home care and need for long-term individualized follow-up highlight the importance of developing an Internet-based follow-up platform to support caregivers of children with Bronchiolitis Obliterans (BO). This Study aims to explore and test the potential benefits of this platform by comparing family management, medication compliance and clinical systems. Study design and methodsA two-arm, single-blind randomized controlled trial was conducted on 168 children with BO and their families from January 2022 to October 2022. Families were randomly divided into Internet-based follow-up group and conventional follow-up group with a ratio of 1:1. Scores of family management measures (FaMM), 8-item of Morisky Medication Adherence (8-MMAS) and BO clinical symptoms of both groups were collected at three points of time: the day of discharge (T1), 3 months after discharge (T2), and 6 months after discharge (T3). The changes of each group due to intervention were compared by repeated-measures ANOVA. Results90 families completed the trial, including 48 in the Internet-based follow-up group and 42 in the conventional follow-up group. The results showed a significant difference in the group-by-time interaction on the scores of Child's Daily Life, Condition Management Ability and Parental Mutuality (p < 0.05). No group-by-time effect was found on the scores of View of Condition Impact and Family Life Difficulty. Scores of BO clinical symptoms and MMAS-8 showed intra-group, inter-group, and group-by-time effects. ConclusionsThe Internet-based follow-up platform can empower caregivers in enhancing effective family management, improving medication compliance in children with BO, and relieving patients’ clinical symptoms. Trial registrationChinese Clinical Trials Registry of ChiCTR2200065121 (04/28/2022).

Efficacy of surveillance bronchoscopy versus clinically indicated bronchoscopy for detection of acute lung transplant rejection: a systematic review and meta-analysis.

Acute allograft rejection after lung transplantation significantly increases the risk of developing bronchiolitis obliterans syndrome, a form of chronic lung allograft dysfunction and the leading cause of mortality beyond the initial post-transplantation year. There are two diagnostic approaches available for monitoring lung transplant recipients: clinically indicated bronchoscopy (CIB) and surveillance bronchoscopy (SB). The efficacy of both methods and their relative superiority in detecting acute rejection have not been conclusively determined. We systematically searched the MEDLINE, Embase, Cochrane and Scopus databases from inception until 10 October 2023 for prospective studies comparing the efficacy of SB and CIB. Meta-analysis using a random effects model was performed for three observational cohort studies, totalling 122 patients with 527 bronchoscopies. Overall, neither SB nor CIB had a higher likelihood of detecting acute lung transplant rejection of any grade. Subsequent subgroup analyses showed no advantage for SB in detecting minimal rejection (grade A1), but an inverse association was observed for higher-grade rejection. In conclusion, our study found no significant difference in detecting acute lung transplant rejection between SB and CIB. However, due to the limited number of studies and small sample sizes, larger prospective studies are urgently needed to definitely determine whether there truly exists no difference between SB and CIB in detecting acute rejection, particularly A1 minimal rejection.

Respiratory Syncytial Virus Sequelae Among Adults in High-Income Countries: A Systematic Literature Review and Meta-analysis.

Respiratory syncytial virus (RSV) can cause severe respiratory infections in adults; however, information on associated sequelae is limited. This systematic literature review aimed to identify sequelae in adults within 1year following RSV-related hospitalization or resolution of acute infection. Studies were identified from Embase, MEDLINE, LILACS, SciELO, and grey literature. Random-effects meta-analyses using restricted maximum likelihood were used to calculate the proportions and relative risks of sequelae in patients with RSV compared with controls (patients with RSV-negative influenza-like illness, influenza, and parainfluenza) per follow-up period, population, and treatment setting, where possible. Twenty-one relevant studies covering the period from 1990 to 2019 were included. Among the general population, the most frequent clinical sequela was sustained function loss (33.5% [95%CI 27.6-39.9]). Decline in lung function and cardiovascular event or congestive heart failure were also identified. Utilization sequelae were readmission (highest at > 6months after discharge) and placement in a skilled nursing facility. The only subpopulation with data regarding sequelae was transplant patients. Among lung transplant patients, the most frequently reported clinical sequelae were decline in lung function, followed by graft dysfunction and bronchiolitis obliterans syndrome. Pooled relative risks were calculated for the following sequela with controls (primarily influenza-positive patients): cardiovascular event (general population) and pulmonary impairment (hematogenic-transplant patients) both 1.4 (95%CI 1.0-2.0) and for readmission (general population) 1.2 (95%CI 1.1-1.3). Although less data are available for RSV than for influenza or other lower respiratory tract infections, RSV infection among adults is associated with medically important sequelae, with a prevalence similar to other respiratory pathogens. RSV sequelae should be included in disease burden estimates.

Late-Onset Noninfectious Pulmonary Complications After Allogeneic Hematopoietic Stem Cell Transplantation: Single-Center Experience.

We aimed to reveal the incidence of lateonset noninfectious pulmonary complications and bronchiolitis obliterans syndrome and risk factors involved in development. In this cross-sectional study, we retrospectively investigated 745 patients who underwent allogeneic hematopoietic stem cell transplantation in our hospital between January 2000 and December 2020. We evaluated demographic characteristics, comorbidities, and hematopoietic stem cell transplantation characteristics to determine possible risk factors affecting development of lateonset noninfectious pulmonary complications and bronchiolitis obliterans syndrome. Of 745 patients, 8.9% (n = 66) had late-onset noninfectious pulmonary complications. Complications included 38 patients with bronchiolitis obliterans syndrome, 13 with venous thromboembolism, 8 with cryptogenic organizing pneumonia, 5 with pneumothorax, 4 with interstitial lung disease-restrictive graft-versus-host disease, 5 with bronchiectasis, 2 with pneumomediastinum, and 1 with pleural effusion. Patients with and without complications were not significantly differentin terms of smoking history, hematopoietic stem cell transplantation characteristics, and conditioning regimens. Patients with complications had higher busulfan and lower antithymocyte globulin use than those without complications (both P<.05). Patients with complications more commonly had hematopoietic stem cell transplantation from related donors and chronic graft-versus-host disease (P < .05). Patients with bronchiolitis obliterans syndrome had more frequent use of busulfan (P <.05) but less frequent use of total body irradiation (P <.05) and antithymocyte globulin (P <.05) than those without this syndrome. Rate of hematopoietic stem cell transplantation from a related donor (P < .05) and frequency of chronic graftversus-host disease (P < .001) were significantly higher in patients with bronchiolitis obliterans syndrome, presented with bronchiectasis (78.6%), air trapping (67.9%), bronchial wallthickening (53.6%), and mosaic attenuation (39.3%) in thorax computed tomography. Pretransplant spirometry did not predict bronchiolitis obliterans syndrome development. Determining risk factors for late-onset noninfectious pulmonary complications is needed to aid in prevention and follow-up.

Postinfectious bronchiolitis obliterans: An uncommon complication of severe viral pneumonia in an infant: A case report

Postinfectious bronchiolitis obliterans (PIBO) is a rare, chronic form of obstructive lung disease characterized by obliteration of small airways leading to clinical and radiological manifestations of smaller airway obstruction. Adenovirus is the most common viral pathogen associated with PIBO in the pediatric population. We report a 7-month-old male who developed PIBO following severe viral pneumonia to highlight the significance of early diagnosis, challenges faced during the clinical course, treatment of acute exacerbations, and long-term care.