Obliterative Bronchiolitis

Interventional anti-reflux management for gastro-oesophageal reflux disease in lung transplant recipients: a systematic review and meta-analysis

INTRODUCTION

Gastroesophageal reflux disease (GORD) and aspiration are risk factors in the development of bronchiolitis obliterans syndrome (BOS) in the lung transplant population. The aim of this study was to investigate if allograft function and survival improved after anti-reflux surgery (ARS) in lung transplant recipients.

METHODS

In accordance with PRISMA guidelines, we conducted a systematic search of MEDLINE, Embase, and the Cochrane library databases from inception until 13/01/2024. Articles reporting outcomes of ARS following lung transplantation were included. A random effects model was used for meta-analysis.

RESULTS

The search identified 20 which were used for quantitative analysis. Overall, FEV1 and rate of change of FEV1 had improved following ARS by 0.141 L/s (95% CI; -02.82, -0.001) and -1.153 mL/d (95% CI; -12.117, -0.188), respectively. Survival hazard ratio post-ARS was 0.39 (95% CI; 0.19, 0.60). Nissen fundoplication was the most effective anti-reflux procedure with the greatest effect on reduction in the rate of change of FEV1, with an improvement of -2.353 mL/d (95% CI; -3.058, -1.649).

CONCLUSION

ARS in lung transplant recipients improves allograft function and survival. Given the increased incidence of GORD in lung transplant recipients, there should be a low threshold for investigation of GORD and subsequent ARS.

Assessment of the Therapeutic Potential of Enhancer of Zeste Homolog 2 Inhibition in a Murine Model of Bronchiolitis Obliterans Syndrome

Bronchiolitis obliterans syndrome (BOS) is a chronic complication following lung transplantation that limits the long-term survival. Although the enhancer of zeste homolog 2 (EZH2) is involved in post-transplantation rejection, its involvement in BOS pathogenesis remains unclear. We aimed to investigate the therapeutic potential of EZH2 inhibition in BOS. 3-deazaneplanocin A (DZNep) was administered intraperitoneally to heterotopic tracheal transplant recipient model mice. Tracheal allografts were obtained on days 7, 14, 21, and 28 after transplantation. The obstruction ratios of the DZNep and control groups on days 7, 14, 21, and 28 were 15.1% ± 0.8% vs. 20.4% ± 3.6% (p = 0.996), 16.9% ± 2.1% vs. 67.7% ± 11.5% (p < 0.001), 47.8% ± 7.8% vs. 92.2% ± 5.4% (p < 0.001), and 60.0% ± 9.6% vs. 95.0% ± 2.3% (p < 0.001), respectively. The levels of interleukin (IL)-6 and interferon-γ on day 7 and those of IL-2, tumor necrosis factor, and IL-17A on days 14, 21, and 28 were significantly reduced following DZNep treatment. DZNep significantly decreased the number of infiltrating T-cells on day 14. In conclusion, DZNep-mediated EZH2 inhibition suppressed the inflammatory reactions driven by pro-inflammatory cytokines and T cell infiltration, thereby alleviating BOS symptoms.

Clinical observation on the safety and efficacy of umbilical cord mesenchymal stem cells in the treatment of bronchiolitis obliterans after allogeneic haematopoietic stem cell transplantation

Graft-versus-host disease (GVHD) is caused by a pathologic and destructive response of the organism as a result of the interaction between donor immunocompetent T lymphocytes and the recipient tisular antigens1. Graft-versus-host disease is considered a serious complication of hematopoietic stem cell transplantation. The skin, oral cavity and lungs are commonly affected organs. Among these complications bronchiolitis obliterans syndrome is a serious complication, which even can be life-threatening. Therefore, this research aims to do a clinical observation on the safety and efficacy of umbilical cord mesenchymal stem cells in the treatment of bronchiolitis obliterans after allogeneic haematopoietic stem cell transplantation. Fifteen patients were included in this study, who received allogeneic hematopoietic stem cell transplantation. Among these patients, both of them were treated with azithromycin, montelukast, glucocorticoid and pirfenidone. Two of them did not receive second line anti-rejection treatment due to economic reasons, and three of them were treated with mesenchymal stem cells. These bronchiolitis obliterans syndrome-related symptoms such as shortness of breath, chest tightness and wheezing have improved. Two of them died due to bronchiolitis obliterans syndrome related complications such as respiratory failure. Two of them not only improve the symptoms but also increased the FEV1/FVC, who were treated with mesenchymal stem cells. The comprehensive treatment regimen containing imatinib and ruxolitinib is safe and effective and mesenchymal stem cell is a promising treatment option to improve the prognosis of post-HSCT BOS.

Exhaled nitric oxide is associated with inflammatory biomarkers and risk of acute respiratory exacerbations in children with HIV-associated chronic lung disease

OBJECTIVES

Chronic lung disease is a recognized complication in children with HIV. Acute respiratory exacerbations (ARE) are common among this group and cause significant morbidity. Exhaled nitric oxide (eNO) is a known marker of local airway inflammation. We investigated the association between eNO and ARE, biomarkers of systemic inflammation, and the effect of azithromycin on eNO levels.

METHODS

Individuals aged 6-19 years with HIV-associated chronic lung disease in Harare, Zimbabwe, were enrolled in a placebo-controlled randomized trial investigating the effect of 48-week azithromycin treatment on lung function and ARE. eNO levels and biomarkers were measured at inclusion and after treatment in a consecutively enrolled subset of participants. Linear regression and generalized linear models were used to study associations between eNO and ARE, biomarkers, and the effect of azithromycin on eNO levels.

RESULTS

In total, 172 participants were included in this sub-study, 86 from the placebo group and 86 from the azithromycin group. Participants experiencing at least one ARE during follow-up had significantly higher eNO levels at baseline than participants who did not (geometric mean ratio 1.13, 95% confidence interval [CI] 1.03-1.24, p = 0.015), adjusted for trial arm, age, sex and history of tuberculosis. Matrix metalloproteinase (MMP)-3, -7, and -10 were significantly associated with higher baseline eNO levels. At 48 weeks, azithromycin treatment did not affect eNO levels (geometric mean ratio 0.86, 95% CI 0.72-1.03, p = 0.103).

CONCLUSION

Higher baseline eNO levels were a risk factor for ARE. eNO was associated with proinflammatory biomarkers previously found to contribute to the development of chronic lung disease. The potential use of eNO as a marker of inflammation and risk factor for ARE in HIV-associated chronic lung disease needs further investigation.

Risk factors for the development of bronchiolitis obliterans in children after suffering from adenovirus pneumonia

Introduction

Bronchiolitis obliterans (BO) is an irreversible chronic obstructive lung disease in small airways. The aim of this study was to identify the relevant risk factors for the development of BO in children after suffering from adenovirus (ADV) pneumonia.

Methods

An observational cohort study that included 112 children suffering from ADV pneumonia in our institution from March 2019 to March 2020 was performed. We divided the children into a BO group and a non-BO group based on whether they did develop BO or not. Univariate analysis and multivariate logistic regression analysis were applied to identify risk factors for the development of BO. The prediction probability model was evaluated by receiver operating characteristic (ROC) curve analysis.

Results

Twenty-eight children (25%) did develop BO after suffering from ADV pneumonia, while 84 children did not. Respiratory support (OR 6.772, 95% CI 2.060-22.260, P = 0.002), extended length of wheezing days (OR 1.112, 95% CI 1.040-1.189, P = 0.002) and higher lactic dehydrogenase (LDH) levels (OR 1.002, 95% CI 1.000-1.003, P = 0.012) were independently associated with the development of BO. The predictive value of this prediction probability model was validated by the ROC curve, with an area under the curve of 0.870 (95% CI 0.801-0.939, P < 0.001), a standard error of 0.035, a maximum Youden's index of 0.608, a sensitivity of 0.929, and a specificity of 0.679.

Conclusions

After suffering an ADV pneumonia, children who have needed respiratory support, had a longer length of wheezing days or had higher LDH levels are more likely to develop BO.

Castleman disease of plasma cell type accompanied with bronchiolitis obliterans: a case report and review of the literature

BACKGROUND

Castleman disease, also known as giant lymph node hyperplasia or angiofollicular lymph node hyperplasia, is a highly heterogeneous clinicopathological entity that belongs to the family lymphoproliferative disorders. Castleman disease accompanied by bronchiolitis obliterans is uncommon and often poses a great diagnostic challenge, which is easily confused with respiratory diseases and impeding the correct diagnosis and treatment. The main aim in presenting such rare case studies is to raise awareness and expand the diagnostic horizon of clinicians for appropriate management.

CASE PRESENTATION

Here, we present a 69-year-old Chinese male who was admitted to our hospital due to right chest pain for 6 months, accompanied by cough, expectoration, and fever. Laboratory examinations revealed elevated immunoglobulin G and C-reactive protein, and normal serum levels of tumor markers and interleukin-6. Computed tomography scan detected diffuse bronchial wall thickening and patchy area of air trapping consistent with small airway disease. Pulmonary function test showed mild small airway obstructive ventilation dysfunction and moderate decrease in diffusion capacity. The pathological result of the right axillary lymph node was consistent with the plasma cell type Castleman disease. According to the above examinations, the patient was finally diagnosed with the plasma cell type Castleman disease accompanied with bronchiolitis obliterans. He received immunosuppressive medication after surgery and has been followed up for 11 months. Now the patient is currently in stable condition without recurrence.

CONCLUSION

Castleman disease is a rare lymphoproliferative disorder with a variety of symptoms. At present, the treatment of Castleman disease accompanied with bronchiolitis obliterans is mostly based on experiences or previous case reports, and there is no standard treatment. Here, we report an uncommon case of Castleman disease accompanied with bronchiolitis obliterans in which the patient received immunosuppressive medication after surgery and has been followed up for 11 months without experiencing a recurrence, which may deepen and extend our understanding of this disease.

Rabbit Antithymocyte Globulin for Treatment of Corticosteroid Refractory Acute Cellular Rejection After Lung Transplantation

BACKGROUND

Chronic lung allograft dysfunction (CLAD) remains a major cause of death after the first year posttransplant, with acute cellular rejection (ACR) being a major risk factor for CLAD. We evaluated the use of rabbit antithymocyte globulin (rATG) for corticosteroid refractory ACR in lung transplant recipients.

METHODS

We retrospectively identified 112 adult lung transplant recipients who received rATG for refractory ACR after lung transplantation. The primary endpoint was the incidence of ACR on follow-up transbronchial biopsy. Secondary endpoints included freedom from ACR within 1 y post-rATG, CLAD progression at 1 y post-rATG, and all-cause mortality at 1 y post-rATG.

RESULTS

A complete resolution of ACR was observed in 60.2% of patients, an improvement but not complete resolution in 22.1%, and no response on follow-up biopsy in 17.8%. Mean A grade 1 y post-rATG was 0.51 in complete responders, 1.01 in partial responders, and 2.19 in nonresponders ( P  < 0.001). Complete responders had significantly less new or worsening CLAD at 1 y than partial responders (17% versus 40%; P  = 0.02). All-cause mortality rate was 14.9% in complete responders, 40% in partial responders, and 30% in nonresponders ( P  < 0.01).

CONCLUSIONS

rATG appears to be an effective treatment of refractory ACR in lung transplant recipients. Failure to respond to rATG carries an increased risk of early CLAD and death.

Laparoscopic fundoplication after lung transplantation does not appear to alter lung function trajectory

BACKGROUND

The primary aim of this study was to determine if allograft function in lung transplant (LTx) recipients improves or stabilizes after laparoscopic fundoplication (LF). The secondary aim was to examine the differences in forced expiratory volume in 1 second (FEV1) before and after LF for various subgroups to identify patients who obtained a superior respiratory outcome after LF, and potential predictive factors for this outcome.

METHODS

Retrospective analysis of consecutive LTx recipients undergoing LF at a single centre in Brisbane, Australia between 2004 and 2018. 149/431 proceeded to LF after clinical review and pH study. Regular pre- and post-fundoplication pulmonary function tests were collected from participants. Data were analyzed with linear mixed models, random intercept models, the Reliable Change Index (RCI), and graphical and visual analysis of the trajectory of FEV1.

RESULTS

There was 100% follow-up. After Bonferroni adjustment for multiple comparison was performed, none of the models demonstrated statistical significance. The Reliable Change Index showed one patient had a significant improvement in lung function across that time period, while nine had a significant reduction. The rate of change before and after LF was similar for the 132/149 patients for whom the first and last pre- and post-LF FEV1 values were available. A subset of patients had a considerable reduction in their FEV1 in the peri-operative period (i.e., a large difference between the first measurement post-LF and the final measurement pre-LF).

CONCLUSION

In the largest published cohort to date, LF performed in a high-volume center did not appear to alter the reduction in allograft function seen with time.

Bronchiolitis obliterans syndrome associated with an immune checkpoint inhibitor in a patient with non-small cell lung cancer

A 75-year-old woman was admitted to our hospital with progressive dyspnea 7 months after second-line treatment with pembrolizumab for advanced non-small cell lung cancer. Chest radiography revealed hyperinflation in both lung fields, and pulmonary function tests revealed severe obstructive dysfunction without bronchodilator reversibility. There were no identifiable causes such as infections or autoimmune diseases. Therefore, bronchiolitis obliterans syndrome associated with immune checkpoint inhibitors was clinically diagnosed. Pembrolizumab was discontinued, but the respiratory dysfunction was irreversible and resulted in death. Bronchiolitis obliterans syndrome is an extremely rare but potentially severe adverse event associated with immune checkpoint inhibitor-related lung disease.

Markers of Bronchiolitis Obliterans Syndrome after Lung Transplant: Between Old Knowledge and Future Perspective

Bronchiolitis obliterans syndrome (BOS) is the most common form of CLAD and is characterized by airflow limitation and an obstructive spirometric pattern without high-resolution computed tomography (HRCT) evidence of parenchymal opacities. Computed tomography and microCT analysis show abundant small airway obstruction, starting from the fifth generation of airway branching and affecting up to 40-70% of airways. The pathogenesis of BOS remains unclear. It is a multifactorial syndrome that leads to pathological tissue changes and clinical manifestations. Because BOS is associated with the worst long-term survival in LTx patients, many studies are focused on the early identification of BOS. Markers may be useful for diagnosis and for understanding the molecular and immunological mechanisms involved in the onset of BOS. Diagnostic and predictive markers of BOS have also been investigated in various biological materials, such as blood, BAL, lung tissue and extracellular vesicles. The aim of this review was to evaluate the scientific literature on markers of BOS after lung transplant. We performed a systematic review to find all available data on potential prognostic and diagnostic markers of BOS.

[Factors associated with long-term survival in critically ill patients following surgery for solid tumors complicated with paraneoplastic pemphigus]

OBJECTIVE

Critically ill patients with solid tumors complicated with paraneoplastic pemphigus are usually treated in intensive care units (ICU) for perioperative management after surgical treatment. In this study, the clinical characteristics and predictors of long-term prognosis of these critically ill patients were analyzed.

METHODS

the clinical and laboratory data of 63 patients with solid tumors complicated with paraneoplastic pemphigus admitted to ICU from 2005 to 2020 were retrospectively analyzed, and the survival status of the patients were followed up.

RESULTS

Among the 63 patients, 79.4% had Castleman disease as the primary tumor, and 20.6% with other pathological types; 69.8% had severe-extensive skin lesions, and 30.2% had other skin lesions; the patients with bronchiolitis obliterans accounted for 44.4%, and 55.6% were not merged. Postoperative fungal infection occurred in 23.8% of the patients, and 76.2% without fungal infection. The median follow-up time was 95 months, and 25 patients died during the study period. The 1-year, 3-year and 5-year survival rates were 74.6% (95%CI 63.8%-85.4%), 67.4% (95%CI 55.6%-79.2%) and 55.1% (95%CI 47.9%-62.3%), respectively. The log-rank univariate analysis showed that the patients had age>40 years (P=0.042), preoperative weight loss>5 kg (P=0.002), preoperative albumin < 30 g/L (P < 0.001), paraneoplastic pemphigus complicated with bronchiolitis obliterans (P=0.002), and perioperative fungal infection (P < 0.001) had increased mortality. Cox univariate analysis showed that preoperative weight loss >5 kg (P=0.005), preoperative albumin < 30 g/L (P < 0.001), paraneoplastic pemphigus complicated with bronchiolitis obliterans (P=0.009), preoperative bacterial pulmonary infection (P=0.007), prolonged surgical time (P=0.048), postoperative oxygenation index (P=0.012) and low albumin (P=0.010) and hemoglobin concentration (P=0.035) in ICU, acute physiology and chronic health evaluation (APACHE Ⅱ) score (P=0.001); sequential organ failure assessment (SOFA) score (P=0.010), and postoperative fungal infection (P < 0.001) were risk factors for long-term survival. Cox regression model for multivariate analysis showed that preoperative weight loss > 5 kg (HR 4.44; 95%CI 1.47-13.38; P=0.008), and preoperative albumin < 30 g/L (HR 4.38; 95%CI 1.72-11.12; P=0.002), bronchiolitis obliterans (HR 2.69; 95%CI 1.12-6.50; P=0.027), and postoperative fungal infection (HR 4.85; 95%CI 2.01-11.72; P < 0.001) were independent risk factors for postoperative mortality.

CONCLUSION

The 5-year survival rate of critically ill patients undergoing surgery for paraneoplastic pemphigus combined with solid tumors is approximately 55.1%, with preoperative weight loss > 5 kg, albumin < 30 g/L, bronchiolitis obliterans and postoperative fungal infection were associated with an increased risk of near- and long-term postoperative mortality.

Pulmonary effects of e-liquid flavors: a systematic review

Electronic cigarettes (ECs) are purported to be tobacco harm-reduction products whose degree of harm has been highly debated. EC use is considered less hazardous than smoking but is not expected to be harmless. Following the banning of e-liquid flavors in countries such as the US, Finland, Ukraine, and Hungary, there are growing concerns regarding the safety profile of e-liquid flavors used in ECs. While these are employed extensively in the food industry and are generally regarded as safe (GRAS) when ingested, GRAS status after inhalation is unclear. The aim of this review was to assess evidence from 38 reports on the adverse effects of flavored e-liquids on the respiratory system in both in vitro and in vivo studies published between 2006 and 2021. Data collected demonstrated greater detrimental effects in vitro with cinnamon (9 articles), strawberry (5 articles), and menthol (10 articles), flavors than other flavors. The most reported effects among these investigations were perturbations of pro-inflammatory biomarkers and enhanced cytotoxicity. There is sufficient evidence to support the toxicological impacts of diacetyl- and cinnamaldehyde-containing e-liquids following human inhalation; however, safety profiles on other flavors are elusive. The latter may result from inconsistencies between experimental approaches and uncertainties due to the contributions from other e-liquid constituents. Further, the relevance of the concentration ranges to human exposure levels is uncertain. Evidence indicates that an adequately controlled and consistent, systematic toxicological investigation of a broad spectrum of e-liquid flavors may be required at biologically relevant concentrations to better inform public health authorities on the risk assessment following exposure to EC flavor ingredients.

Idiopathic Obliterative Bronchiolitis in a Young Woman: A Rare Case of a Transbronchial Lung Biopsy Contributing to the Diagnosis

Idiopathic obliterative bronchiolitis (OB) is a rare disease that usually requires a surgical lung biopsy. A 25-year-old woman with progressive exertional dyspnea for several months showed a severe mixed restrictive and obstructive pattern on spirometry. Chest computed tomography showed a mosaic pattern, and pulmonary ventilation-perfusion scintigraphy showed a matched defect. The bronchoscopic specimens obtained from both the alveolar and bronchiolar regions of the predicted lesion area contributed to the diagnosis of OB. She had no underlying causes of secondary OB, and she was diagnosed with idiopathic OB. Since lung transplantation was indicated, she was referred to a lung transplantation-certified hospital.

Effect of azithromycin on bronchiolitis obliterans syndrome in posttransplant recipients: A systematic review and meta-analysis

BACKGROUND

Bronchiolitis obliterans syndrome (BOS) is a devastating complication that occurs after transplantation. Although azithromycin is currently used for the treatment of BOS, the evidence is sparse and controversial. The aim of this meta-analysis is to evaluate the effects of azithromycin on forced expiratory volume in 1 second (FEV1) and patient's survival.

METHODS

PubMed, Embase, Cochrane library, Web of Science databases, and the ClinicalTrials.gov registry were systematically searched from inception until December 2020 for relevant original research articles. Random-effects models were used to calculate pooled-effect estimates.

RESULTS

Searches identified 15 eligible studies involving 694 participants. For FEV1 (L), there was a significant increase after short-term (≤12 weeks; P = .00) and mid-term (12-24 weeks; P = .01) administration of azithromycin. For FEV1 (%) compared to baseline, there was a significant increase after short-term (≤12 weeks) administration of azithromycin (P = .02), while there were no statistically significant differences in the medium and long term. When pooled FEV1% was predicted, it exhibited a similar trend to FEV1 (%) compared to baseline. In addition, we discovered that azithromycin reduced the risk of death (hazard ratio = 0.26; 95% confidence interval = 0.17 to 0.40; P = .00) in patients with BOS post-lung transplantation.

CONCLUSIONS

Azithromycin therapy is both effective and safe for lung function improvement in patients with posttransplant BOS after the short- and medium-term administration. Additionally, it has been demonstrated a significant survival benefit among patients with BOS post-lung transplant. Higher quality randomized controlled trials and more extensive prospective cohort studies are needed to confirm the effect of azithromycin on patients with posttransplant BOS.

Risk factors for lower respiratory tract disease and outcomes in allogeneic hematopoietic stem cell transplantation recipients with influenza virus infection

INTRODUCTION

Influenza virus infection (IVI) is frequent in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients, and reports from several countries indicate high morbidity and mortality from progression to lower respiratory tract disease (LRTD). However, there have been no reports on IVI clinical characteristics, treatment outcomes, and risk factor for progression to LRTD among allo-HSCT recipients in Japan.

METHODS

We retrospectively reviewed the medical charts of allo-HSCT recipients who developed IVI between 2012 and 2019.

RESULTS

Forty-eight cases of IVI following allo-HSCT were identified at our institution. The median age was 42 years, and median time from allo-HSCT to IVI was 25 months. Thirty-seven patients (77.1%) were administered neuraminidase inhibitors (NAIs) as antiviral therapy within 48 h of symptom onset (early therapy), whereas 11 (22.9%) received NAI over 48 h after onset (delayed therapy). Subsequently, 12 patients (25.0%) developed LRTD after IVI. Multivariate analysis identified older age (hazard ratio [HR], 7.65; 95% confidence interval [CI], 2.22-26.3) and bronchiolitis obliterans (HR, 5.74; 95% CI, 1.57-21.0) as independent risk factors for progression to LRTD. Moreover, land-mark analysis showed that early therapy prevented progression to LRTD (11.8% vs. 45.5%, P = 0.013). The IVI-related mortality rate was 2.1%.

CONCLUSIONS

Early NAI treatment is recommended for reducing the risk of LRTD progression due to IVI in allo-HSTC recipients, particularly for older patients and those with bronchiolitis obliterans.

Risk Factors for Post-infectious Bronchiolitis Obliterans in Children: A Systematic Review and Meta-Analysis

BACKGROUND

Post-infectious bronchiolitis obliterans (PIBO) is a long-term sequela after an initial insult to the lower respiratory tract. A comprehensive understanding of the factors that contribute to a high risk of developing PIBO is important to help define therapeutic strategies and improve prognosis.

METHODS

We performed a systematic review of published literature available in the online databases including PubMed, Embase, Web of Science, CNKI, Wan Fang, and VIP, with the last search updated on 27 January 2022. Observational studies and case-control studies that provide sufficient data to examine associations between potential risk factors and PIBO were included. Pooled odds ratio (OR) or mean difference (MD) with 95% confidence interval (CI) and heterogeneity were calculated.

RESULTS

A total of 14 risk factors were selected from 9 studies included in the analysis. The strongest risk factors were hypoxemia, mechanical ventilation, tachypnea, and wheezing. Hypoxemia conferred the greatest risk with pooled OR of 21.54 (95% CI: 10-46.36, p < 0.001). Mechanical ventilation ranked second (pooled OR 14.61, 95% CI: 7.53-28.35, p < 0.001). Use of γ-globulin, use of glucocorticoids, co-infection of bacteria, a history of wheezing, and being male were other prominent risk factors. The effects of premature birth, allergic rhinitis, and imaging finding (pulmonary consolidation, atelectasis, pleural effusion) are less clear and require further confirmation. Cases that developing PIBO had a lower age compared with controls (MD, -8.76 months, 95% CI: -16.50 to -1.02, p = 0.03). No significant differences were observed in the duration of fever (MD, 1.74 days, 95% CI: -0.07 to 3.54, p = 0.06). Children diagnosed with PIBO had higher LDH levels (MD, 264.69 U/L, 95% CI: 67.43 to 461.74, p = 0.008) and duration of hospitalization (MD, 4.50 days, 95% CI: 2.63 to 6.37, p < 0.001).

CONCLUSION

In this study, we found that the strongest risk factors for PIBO were hypoxemia, mechanical ventilation, tachypnea, and wheezing. Use of glucocorticoids, γ-globulin, co-infection of bacteria, a history of wheezing, and being male may also play a role. The factors discussed above can inform the generation of a clinical prediction model for the developing PIBO in children.

Bioinspired carbon monoxide delivery using artificial blood attenuates the progression of obliterative bronchiolitis via suppression of macrophage activation by IL-17A

Carbon monoxide (CO) is expected to attenuate the progression of obliterative bronchiolitis (OB), which is a serious complication after lung transplantation. However, issues in terms of feasible exogenous CO supply, such as continuousness and safety, remain unsolved. Here, we applied nano red blood cells, namely hemoglobin vesicles (Hb-V), as a CO cargo based on the biomimetic concept and investigated the therapeutic potential of CO-loaded Hb-V on OB in orthotopic tracheal transplant model mice. The CO-loaded Hb-V was comprised of negatively charged liposomes encapsulating carbonylhemoglobin with a size of ca. 220 nm. The results of histological evaluation showed that allograft luminal occlusion and fibrosis were significantly ameliorated by treatment with CO-loaded Hb-V compared to treatment with saline, cyclosporine, and Hb-V. The therapeutic effects of CO-loaded Hb-V on OB were due to the suppression of M1 macrophage activation in tracheal allografts, resulting from decreased IL-17A production. Furthermore, the expression of TNF-α and TGF-β in tracheal allografts was decreased by CO-loaded Hb-V treatment but not saline and Hb-V treatment, indicating that CO liberated from CO-loaded Hb-V inhibits epithelial-mesenchymal transition. These findings suggest that CO-loaded Hb-V exerts strong therapeutic efficacy against OB via the regulation of macrophage activation by IL-17A and TGF-β-driven epithelial-mesenchymal transition.

The importance of central airway dilatation in patients with bronchiolitis obliterans

Background

Bronchiolitis obliterans (BO) is a clinical syndrome characterised by progressive small airway obstruction, causing significant morbidity and mortality. Central airway dilatation is one of its radiological characteristics, but little is known about the clinical and pathological associations between airway dilatation and BO.

Methods

This retrospective study consecutively included patients who underwent lung transplantation due to BO at Kyoto University Hospital from 2009 to 2019. Demographic and histopathological findings of the resected lungs were compared between patients with and without airway dilatation measured by chest computed tomography (CT) at registration for lung transplantation.

Results

Of a total of 38 included patients (median age, 30 years), 34 (89%) had a history of hematopoietic stem-cell transplantation, and 22 (58%) had airway dilatation based on CT. Patients with airway dilatation had a higher frequency of Pseudomonas aeruginosa isolation with greater residual volume than those without airway dilatation. Quantitative CT analysis revealed an increase in lung volume to predictive total lung capacity and a percentage of low attenuation volume <−950 HU at inspiration in association with the extent of airway dilatation. Airway dilatation on CT was associated with an increased number of bronchioles with concentric narrowing of the lumen and thickening of the subepithelium of the walls on histology.

Conclusions

In patients with BO, airway dilatation may reflect increased residual volume or air trapping and pathological extent of obstructive bronchioles, accompanied by a risk of Pseudomonas aeruginosa isolation. More attention should be paid to the development of airway dilatation in the management of BO.

In patients with bronchiolitis obliterans (BO), airway dilatation may reflect air trapping and the pathological extent of obstructive bronchioles. More attention should be paid to airway dilatation in the management of BO.https://bit.ly/3w7cRV6

Interleukin-18: A Novel Participant in the Occurrence, Development, and Drug Therapy of Obliterative Bronchiolitis Postlung Transplantation

Background

Obliterative bronchiolitis (OB) was a main cause of deterioration of long-term prognosis in lung transplant recipients after the first posttransplant year. Proinflammatory cytokine interleukin-18 (IL-18) strengthened both the natural immunity and acquired immunity and played an important role in organ transplantation. The roles of IL-18 in the occurrence, development, and drug treatment of OB remained unclear.

Methods

Small interfering RNA (siRNA) against mouse IL-18 (siRNA-IL-18) was used to silence IL-18 expression. Mouse heterotopic tracheal transplantation model was used to simulate OB. Recipient mice were divided into 5 groups (n = 12) according to donor mouse strains and drug treatment: isograft group, allograft group, allograft+tacrolimus group, allograft+azithromycin group, and allograft+tacrolimus+azithromycin group. The luminal obliteration rates were pathological evaluation. Expressions of cytokines and MMPs were detected by real-time PCR, western blot, and enzyme chain immunosorbent assay (ELISA).

Results

The luminal obliteration rates of IL-18 of the siRNA-IL-18 group were significantly lower than those of the negative control group (p < 0.0001) and the blank control group (p = 0.0002). mRNA expressions of IFN-γ, EMMPRIN, MMP-8, and MMP-9 of the siRNA-IL-18 group were significantly lower than those of the negative and blank control groups. No tracheal occlusion occurred in grafts of the isograft group. The rates of tracheal occlusion of the allograft group, allograft+tacrolimus group, allograft+azithromycin group, and allograft+tacrolimus+azithromycin group were 72.17 ± 4.66%, 40.33 ± 3.00%, 38.50 ± 2.08%, and 23.33 ± 3.24%, respectively. There were significant differences between the 4 groups (p < 0.001). Serum protein expressions of IL-17 (p = 0.0017), IL-18 (p = 0.0036), IFN-γ (p = 0.0102), and MMP-9 (p = 0.0194) were significantly decreased in the allograft+tacrolimus+azithromycin group compared to the allograft group.

Conclusions

IL-18 could be a novel molecular involved in the occurrence, development, and drug treatment of OB.

Overexpression of the MSK1 Kinase in Patients With Chronic Lung Allograft Dysfunction and Its Confirmed Role in a Murine Model

BACKGROUND

Chronic lung allograft dysfunction (CLAD) and its obstructive form, the obliterative bronchiolitis (OB), are the main long-term complications related to high mortality rate postlung transplantation. CLAD treatment lacks a significant success in survival. Here, we investigated a new strategy through inhibition of the proinflammatory mitogen- and stress-activated kinase 1 (MSK1) kinase.

METHODS

MSK1 expression was assessed in a mouse OB model after heterotopic tracheal allotransplantation. Pharmacological inhibition of MSK1 (H89, fasudil, PHA767491) was evaluated in the murine model and in a translational model using human lung primary fibroblasts in proinflammatory conditions. MSK1 expression was graded over time in biopsies from a cohort of CLAD patients.

RESULTS

MSK1 mRNA progressively increased during OB (6.4-fold at D21 posttransplantation). Inhibition of MSK1 allowed to counteract the damage to the epithelium (56% restoration for H89), and abolished the recruitment of MHCII+ (94%) and T cells (100%) at the early inflammatory phase of OB. In addition, it markedly decreased the late fibroproliferative obstruction in allografts (48%). MSK1 inhibitors decreased production of IL-6 (whose transcription is under the control of MSK1) released from human lung fibroblasts (96%). Finally, we confirmed occurrence of a 2.9-fold increased MSK1 mRNA expression in lung biopsies in patients at 6 months before CLAD diagnosis as compared to recipients with stable lung function.

CONCLUSIONS

These findings suggest the overall interest of the MSK1 kinase either as a marker or as a potential therapeutic target in lung dysfunction posttransplantation.

Microvasculature in murine tracheal allografts after combined therapy with clopidogrel and everolimus

OBJECTIVES

Survival after lung transplantation is mainly limited by the development of chronic lung allograft dysfunction. Previous studies have suggested T-cell mediated proliferation and microvascular changes in experimental small airways models as potential therapeutic targets. The aim of this study was to assess microvascular changes in murine orthotopic tracheal allografts after treatment with everolimus alone or in combination with clopidogrel.

METHODS

C57Bl/6 (H-2b) donor tracheas were orthotopically transplanted into CBA (H-2k) recipients. Mice received daily injections of everolimus (0.05 mg/kg) alone or combined with clopidogrel (1 mg/kg). Twenty-eight days after transplantation, ratio of the thickness of tracheal epithelium and lamina propria was measured as an indicator for chronic rejection. Additionally, graft oxygenation and graft perfusion were detected on postoperative days 4, 10 and 28. Quantitative reverse transcription polymerase chain reaction analysis was used for gene expression analysis.

RESULTS

While syngeneic grafts showed a stable tissue pO2 and undisturbed microvascular perfusion, rejecting allografts had a drastic decline in both parameters as well as a flattened epithelium and an increased thickness of the lamina propria. Treatment with everolimus reduced allogeneic fibroproliferation, but had no protective effects on the microvasculature; polymerase chain reaction analysis indicated hypoxic stress and inflammation. Combining everolimus with clopidogrel improved microvascular integrity in the tracheal grafts, but had no synergistic effect in preventing obliterative bronchiolitis development.

CONCLUSIONS

These data demonstrate that the ability of everolimus to reduce the development of post-transplant obliterative bronchiolitis is not caused by microvascular protection and has no synergistic effects with clopidogrel in acute airway rejection.

Effect of human umbilical cord-derived mesenchymal stem cells on murine model of bronchiolitis obliterans like injury

BACKGROUND

Bronchiolitis obliterans is a fatal respiratory disease characterized by the obliteration of small airways. Mesenchymal stem cells (MSCs) is a promising candidate for cell-based therapy.

OBJECTIVE

To evaluate the therapeutic effect of human umbilical cord-derived mesenchymal stem cells (HUC-MSCs) on a murine model of bronchiolitis obliterans like injury (BOLI).

METHOD

The murine model of BOLI was established by administrating of diacetyl (DA) via intratracheal instillation. Treatment of HUC-MSCs or HUC-MSCs culture medium (HUC-MSCs-CM) was conducted in the BOLI model.

RESULTS

The pathogenic manifestations, lung function, and the number of neutrophils were similar between the oropharyngeal inhalation DA group (OPI-DA), intratracheal instillation group (ITI-DA); however, less reduction of weight and higher survival rate were observed in ITI-DA groups. Compared with the control groups, the trend of weight loss was significantly reduced (p < .05), and the pulmonary function was significantly improved (p < .05) in HUC-MSCs and HUC-MSCs-CM groups. Masson staining and hematoxylin and eosin staining showed that the deposition of collagen around bronchioles and blood vessels is less and airway epithelial cells and basal cells in lung tissue repaired better in HUC-MSCs and HUC-MSCs-CM groups compared with the control groups. Immunofluorescence shows the expression of E-cadherin and cytokeratin 5 (CK-5) were significantly higher in HUC-MSCs and HUC-MSCs-CM groups compared with control groups, while HUC-MSCs themselves did not express E-cadherin or CK-5. The DiI label showed HUC-MSCs gradually reduced after 2 days in the bronchus and 4 days in bronchiole.

CONCLUSION

HUC-MSCs could help to repair airway epithelial cells in a murine model of BOLI. It might be related to paracrine factors of HUC-MSCs.

Vitamin D and its therapeutic relevance in pulmonary diseases

Vitamin D is customarily involved in maintaining bone and calcium homeostasis. However, contemporary studies have identified the implication of vitamin D in several cellular processes including cellular proliferation, differentiation, wound healing, repair and regulatory systems inclusive of host defence, immunity, and inflammation. Multiple studies have indicated corelations between low serum levels of vitamin D, perturbed pulmonary functions and enhanced incidences of inflammatory diseases. Almost all of the pulmonary diseases including acute lung injury, cystic fibrosis, asthma, COPD, Pneumonia and Tuberculosis, all are inflammatory in nature. Studies have displayed strong inter-relations with vitamin D deficiency and progression of lung disorders; however, the underlying mechanism is still unknown. Vitamin D has emerged to possess inhibiting effects on pulmonary inflammation while exaggerating innate immune defenses by strongly influencing functions of inflammatory cells including dendritic cells, monocyte/macrophages, T cells, and B cells along with structural epithelial cells. This review dissects the effects of vitamin D on the inflammatory cells and their therapeutic relevance in pulmonary diseases. Although, the data obtained is very limited and needs further corroboration but presents an exciting area of further research. This is because of its ease of supplementation and development of personalized medicine which could lead us to an effective adjunct and cost-effective method of therapeutic modality for highly fatal pulmonary diseases.

Defining chronic rejection in vascularized composite allotransplantation-The American Society of Reconstructive Transplantation and International Society of Vascularized Composite Allotransplantation chronic rejection working group: 2018 American Society of Reconstructive Transplantation meeting report and white paper Research goals in defining chronic rejection in vascularized composite allotransplantation

Objectives:

This report summarizes a collaborative effort between the American Society of Reconstructive Transplantation and the International Society of Vascularized Composite Allotransplantation to establish what is known about chronic rejection in recipients of vascularized composite allografts, with an emphasis on upper extremity and face transplants. As a picture of chronic rejection in hand and face vascularized composite allografts emerges, the results will be applied to other types of vascularized composite allografts, such as uterine transplantation.

Methods:

The overall goal is to develop a definition of chronic rejection in vascularized composite allografts so that we can establish longitudinal correlates of factors such as acute rejection, immunosuppressive therapy, de novo donor-specific antibody and trauma/infection and other external factors on the development of chronic rejection. As Dr Kanitakis eloquently stated at the 2017 International Society of Vascularized Composite Allotransplantation meeting in Salzburg, “Before we can correlate causative factors of chronic rejection, we have to define what chronic rejection in VCA is.”

Results:

The first meeting report was presented at the sixth Biennial meeting of the American Society of Reconstructive Transplantation in November 2018. Based on collaborative efforts and descriptions of clinical cases of chronic rejection in vascularized composite allograft recipients, a working definition of chronic rejection in vascularized composite allografts with respect to overt functional decline, subclinical functional decline, histologic evidence without functional decline, and normal allograft function in the absence of histologic evidence of chronic rejection is proposed.

Conclusions:

It is the intent of this collaborative working group that these working definitions will help to focus ongoing research to define the incidence, risk factors and treatment regimens that will identify mechanisms of chronic rejection in vascularized composite allografts. As with all good research, our initial efforts have generated more questions than answers. We hope that this is the first of many updates.

A case of imatinib-related obstructive bronchiolitis followed long term

Obstructive bronchiolitis (OB) is an intractable disease causing stenosis in the surrounding bronchiolar region and bronchiolar lumen obstruction. Causes of OB are lung and hematopoietic stem-cell transplantation, collagen diseases, infections, and foods, but there are very few reports of drug-induced OB [1]. Imatinib is a drug used for the treatment of leukemia, gastrointestinal stromal tumors, etc. Although there are some reports of imatinib-induced lung injury as a complication (Ohnishi et al., 2006; Ma et al., 2003; Yamasawa et al., 2008; Koide et al., 2011) [[2], [3], [4], [5]], OB has not been reported. We have encountered a patient with OB related to imatinib administered for chronic myelogenous leukemia, who we have followed for 10 years. Drug-induced OB is very rare, but our case demonstrates the importance of considering the possibility of airway lesions by evaluating pulmonary function and expiratory computed tomography in patients with respiratory symptoms despite no shading on imaging.

Mesalazine-induced airway obstruction: Utility of pulmonary function testing in drug-induced lung diseases

Mesalazine is a standard therapeutic agent for the treatment of inflammatory bowel diseases. A rare case of mesalazine-induced airway obstruction documented by pulmonary function testing is reported herein. The patient had Crohn's disease and was treated with mesalazine; she subsequently developed a high fever, cough, and chest pain with centrilobular nodular shadows on chest computed tomography (CT). After cessation of mesalazine, the abnormal CT findings as well as the decreased forced expiratory volume in 1 second improved. Based on these findings, pulmonary function testing appears to be a useful tool, even in the acute phase, along with chest CT in drug-induced lung diseases.

FK506 combined with GM6001 prevents tracheal obliteration in a mouse model of heterotopic tracheal transplantation

BACKGROUND

Obliterative bronchiolitis (OB) is the major complication limiting the long-term survival of allografts after lung transplantation. In this study, we investigated the effect of tacrolimus (FK506) combined with GM6001，a matrix metalloproteinase (MMP) inhibitor， on the formation of OB using a mouse heterotopic tracheal transplantation model.

METHODS

Syngeneic tracheal grafts were transplanted heterotopically from BALB/c mice to BALB/c mice. Allografts from C57BL/6 mice were transplanted to BALB/c mice. Isograft group, allograft group, allograft+FK506 group, allograft +GM6001 group and allograft+FK506 + GM6001 group was given respectively intraperitoneal injection of saline, saline, FK506, GM6001 and FK506 + GM6001 once a day. At 28 day after transplantation, OB incidence was determined by hematoxylin-eosin staining and the expressions of MMPs and cytokines were assessed using enzyme linked immunosorbent assay, immunohistochemical assays and western blot assay.

RESULTS

The tracheal occlusion rates of isograft group, allograft group, allograft+FK506 group, allograft+GM6001 group and allograft+FK506 + GM6001 group were 0, 74.1 ± 9.79%, 34.4 ± 6.04%, 40.3 ± 8.77% and 26.5 ± 5.73% respectively. There were significant differences between the latter two groups (P < .001). The serum MMP-8 and MMP-9 levels of allograft group were significantly higher than those of isograft group (P < .05) and had no significant decrease when treated by FK506. The serum MMP-8 and MMP-9 levels of allograft+FK506 + GM6001 group were significantly lower than those of allograft+FK506 group (P < .05). MMP-8 and MMP-9 protein expression in the grafts of allograft+FK506 + GM6001 group were lower than those of allograft+FK506 group verified by immunohistochemical staining and western blotting.

CONCLUSION

FK506 combined with GM6001 could alleviate tracheal obliteration in mouse heterotopic tracheal transplantation model, due to its inhibitory effect on MMPs.

Impairments in dyspnea, exercise capacity, physical activity and quality of life of allogeneic hematopoietic stem cell transplantation survivors compared with healthy individuals: a cross sectional study

Background: A limited number of studies have reported impairments in physical activity, exercise capacity and quality of life (QOL) in allogeneic hematopoietic stem cell transplantation (allogeneic-HSCT) recipients. We aimed to compare dyspnea, exercise capacity, physical activity and QOL in allogeneic-HSCT recipients with age-gender matched healthy individuals, since this has not been investigated hitherto. Methods: A total of 80 allogeneic-HSCT recipients (>100 days status post-transplantation) (38.88 ± 13.25 years) and 60 healthy individuals (35.92 ± 10.83 years) were compared. Exercise capacity [6-minute walk test (6-MWT)], physical activity level (total and active energy expenditure, moderate and severe physical activity duration, number of steps, average metabolic equivalent, lying down and sleeping duration) [metabolic holter], QOL [European Organization for Research and Treatment of Cancer QOL Questionnaire (EORTCQOL)], dyspnea [Modified Medical Research Council Dyspnea scale] and pulmonary functions [spirometry] were evaluated. Clinical trials #NCT03606005. Results: Six-MWT distance, energy expenditure, physical activity duration, number of steps, average metabolic equivalent, global health status, functional and social function subscales of EORTCQOL were significantly lower in recipients compared with controls; dyspnea score, lying down, sleep durations, symptom and fatigue subscales of EORTCQOL were significantly higher in recipients compared with controls (p < 0.05). Conclusion: Dyspnea during daily living activities, exercise capacity, physical activity level and QOL are considerably impaired in allogeneic-HSCT recipients during post-engraftment period. To improve impaired outcomes, allogeneic-HSCT recipients should be oriented to cardiopulmonary rehabilitation programs.

Precision medicine: integration of genetics and functional genomics in prediction of bronchiolitis obliterans after lung transplantation

PURPOSE OF REVIEW

Lung transplantation (LTx) can be a life saving treatment in end-stage pulmonary diseases, but survival after transplantation is still limited. Posttransplant development of chronic lung allograft dysfunction with bronchiolits obliterans syndrome (BOS) as the major subphenotype, is the main cause of morbidity and mortality. Early identification of high-risk patients for BOS is a large unmet clinical need. In this review, we discuss gene polymorphisms and gene expression related to the development of BOS.

RECENT FINDINGS

Candidate gene studies showed that donor and recipient gene polymorphisms affect transplant outcome and BOS-free survival after LTx. Both selective and nonselective gene expression studies revealed differentially expressed fibrosis and apoptosis-related genes in BOS compared with non-BOS patients. Significantly, recent microarray expression analysis of blood and broncho-alveolar lavage suggest a role for B-cell and T-cell responses prior to the development of BOS. Furthermore, 6 months prior to the development of BOS differentially expressed genes were identified in peripheral blood cells.

SUMMARY

Genetic polymorphisms and gene expression changes are associated with the development of BOS. Future genome wide studies are needed to identify easily accessible biomarkers for prediction of BOS toward precision medicine.

Heterogeneity of Pulmonary Stem Cells

Epithelial stem cells reside within multiple regions of the lung where they renew various region-specific cells. In addition, there are multiple routes of regeneration after injury through built-in heterogeneity within stem cell populations and through a capacity for cellular plasticity among differentiated cells. These processes are important facets of respiratory tissue resiliency and organism survival. However, this regenerative capacity is not limitless, and repetitive or chronic injuries, environmental stresses, or underlying factors of disease may ultimately lead to or contribute to tissue remodeling and end-stage lung disease. This chapter will review stem cell heterogeneity among pulmonary epithelia in the lower respiratory system, discuss recent findings that may challenge long-held scientific paradigms, and identify several clinically relevant research opportunities for regenerative medicine.

Association Between Promoter Polymorphisms in CD46 and CD59 in Kidney Donors and Transplant Outcome

Complement regulating proteins, including CD46, CD55, and CD59, protect cells against self-damage. Because of their expression on the donor endothelium, they are hypothesized to be involved in accommodation. Polymorphisms in their promoter regions may affect their expression. The aim of this study was to investigate if donor polymorphisms in complement regulating proteins influence kidney transplant outcomes. We included 306 kidney transplantations between 2005 and 2010. Five polymorphisms in the promoters of CD46, CD55, and CD59 were genotyped. A CD59 promoter polymorphism (rs147788946) in donors was associated with a lower 1-year rejection-free survival [adjusted hazard ratio (aHR) 2.18, 95% CI 1.12–4.24] and a trend toward impaired 5-year graft survival (p = 0.08). Patients receiving a kidney with at least one G allele for the CD46 promoter polymorphism rs2796267 (A/G) showed a lower rejection-free survival, though this became borderline significant after adjustment for potential confounders (aHR 1.87, 95% CI 0.96–3.65). A second CD46 promoter polymorphism (rs2796268, A/G), was also associated with a lower freedom from acute rejection in the presence of at least one G allele (aHR 1.95, 95% CI 1.03–3.68). Finally, the combined presence of both favorable genotypes of rs2796267 and rs147788946 had an additional protective effect both on acute rejection (p = 0.006) and graft survival (p = 0.03). These findings could help to identify patients who could benefit from intensified immunosuppressive therapy or novel complement inhibitory therapeutics.

Constrictive bronchiolitis presenting with a mixed obstructive and restrictive pattern, associated with acid reflux

A previously healthy 55-year-old woman presented with worsening dyspnoea on exertion. The patient lived at altitude, did not smoke and had no exposure to occupational or environmental toxins. Her physical examination, including pulmonary, was unremarkable. Pulmonary function tests showed forced expiratory volume in 1 s/forced vital capacity ratio 74% predicted, diffusing capacity for carbon monoxide (DLCO) 92% predicted and residual volume 213% predicted. Rheumatological workup was negative. Chest radiograph showed hyperinflation without consolidation, and high-resolution chest CT showed mosaic attenuation with air trapping on expiratory imaging. A decreasing DLCO lead to transbronchial biopsies that were inconclusive. A video-assisted thoracic surgery lung biopsy showed small airway disease suggestive of constrictive bronchiolitis. Oesophagram and a barium swallow showed a hiatal hernia with large volume gastro-oesophageal reflux to the level of the clavicles. The development of constrictive bronchiolitis in this patient was possibly secondary to hiatal hernia and silent gastroesophageal reflux disease (GERD). In the face of presumably idiopathic lung disease, clinicians should perform a GERD workup even in the absence of GERD symptoms.

Clinical and follow-up study of bronchiolitis obliterans in pediatric patients in China

Bronchiolitis obliterans (BO) is in general a rare and life-threatening form of non-reversible obstructive lung disease in which the bronchioles are compressed and narrowed by fibrosis and/or inflammation. The purpose of this study was to evaluate the clinical features of BO in pediatric patients and explore its risk factors. The medical records of 35 pediatric patients with BO at Guangzhou Women and Children’s Medical Center were evaluated. The age at onset of symptoms was 2–42 months (mean 13.3 ± 8.9 months), with age at diagnosis of 5 months–4 years (mean 17.8 ± 9.0 months). High-resolution computed tomography findings included mosaic pattern (100%), atelectasis (37.1%), air trapping (31.4%), and bronchiectasis (20.0%). Three patients received lung biopsies and mainly exhibited an inflammatory process surrounding the lumen of bronchioles. BO predominantly resulted from post-infectious causes (91.4%) which were primarily caused by adenovirus (50%), followed by Mycoplasma pneumoniae (46.7%) and influenza (20%). Pulmonary function tests (PFTs) showed severe and fixed airflow obstruction, decreased compliance, and increased resistance. No significant difference was found between before and after steroid treatment ( P > 0.05). Two patients died owing to severe pulmonary complications, one of whom had inherent immunodeficiency. Our study suggests that the occurrence of BO, especially post-infectious BO, in China is relatively high and might result from primary immunodeficiency diseases in severe cases. Recurrent aspiration pneumonia caused by congenital dysplasia of the larynx and vaccination not on schedule might be potential risk factors for persistent and recurrent BO.

Anesthetic Considerations in Transplant Recipients for Nontransplant Surgery

As solid organ transplantation increases and patient survival improves, it will become more common for these patients to present for nontransplant surgery. Recipients may present with medical problems unique to the transplant, and important considerations are necessary to keep the transplanted organ functioning. A comprehensive preoperative examination with specific focus on graft functioning is required, and the anesthesiologist needs pay close attention to considerations of immunosuppressive regimens, blood product administration, and the risk benefits of invasive monitoring in these immunosuppressed patients. This article reviews the posttransplant physiology and anesthetic considerations for patients after solid organ transplantation.

Long-term outcomes and management of lung transplant recipients

Lung transplantation is an established treatment for patients with end-stage lung disease. Improvements in immunosuppression and therapeutic management of infections have resulted in improved long-term survival and a decline in allograft rejection. Allograft rejection continues to be a serious complication following lung transplantation, thereby leading to acute graft failure and, subsequently, chronic lung allograft dysfunction (CLAD). Bronchiolitis obliterans syndrome (BOS), the most common phenotype of CLAD, is the leading cause of late mortality and morbidity in lung recipients, with 50% having developed BOS within 5 years of lung transplantation. Infections in lung transplant recipients are also a significant complication and represent the most common cause of death within the first year. The success of lung transplantation depends on careful management of immunosuppressive regimens to reduce the rate of rejection, while monitoring recipients for infections and complications to help identify problems early. The long-term outcomes and management of lung transplant recipients are critically based on modulating natural immune response of the recipient to prevent acute and chronic rejection. Understanding the immune mechanisms and temporal correlation of acute and chronic rejection is thus critical in the long-term management of lung recipients.

Azithromycin for the Treatment of Obliterative Bronchiolitis after Hematopoietic Stem Cell Transplantation: A Systematic Review and Meta-Analysis

Obliterative bronchiolitis (OB) is a major cause of morbidity and mortality in patients undergoing hematopoietic stem cell transplantation (HSCT). Our objective was to perform a systematic review and meta-analysis of the impact of azithromycin on change in forced expiratory volume in 1 second (FEV₁). We searched MEDLINE, EMBASE, Web of Science, Cochrane CENTRAL and Scopus databases and included studies that compared azithromycin with placebo or no intervention in the treatment of OB or bronchiolitis obliterans syndrome (BOS) in patients who had undergone allogeneic HSCT. Ninety-one unique publications were identified, and 4 studies met inclusion criteria, with a total of 90 patients. Changes in FEV₁ were measured between 12 and 24 weeks after initiation of treatment. The meta-analysis demonstrated a mean increase in FEV₁ of 30 mL (95% confidence interval, -260 to +330 mL; P = .82) after initiation of azithromycin. One patient death was reported but not attributed to azithromycin therapy. In conclusion, current evidence can neither support nor refute the use of azithromycin in the treatment of patients who develop OB/BOS after HSCT. Further studies are needed to determine whether azithromycin is beneficial for the treatment of OB/BOS in this setting.