Surveillance bronchoscopy in lung transplant recipients: risk versus benefit

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

Background

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.

Methods

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.

Results

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.

Conclusion

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.

Effects of donor smoking history on early post-transplant lung function measured by oscillometry

Introduction

Prior studies assessing outcomes of lung transplants from cigarette-smoking donors found mixed results. Oscillometry, a non-invasive test of respiratory impedance, detects changes in lung function of smokers prior to diagnosis of COPD, and identifies spirometrically silent episodes of rejection post-transplant. We hypothesise that oscillometry could identify abnormalities in recipients of smoking donor lungs and discriminate from non-smoking donors.

Methods

This prospective single-center cohort study analysed 233 double-lung recipients. Oscillometry was performed alongside routine conventional pulmonary function tests (PFT) post-transplant. Multivariable regression models were constructed to compare oscillometry and conventional PFT parameters between recipients of lungs from smoking vs non-smoking donors.

Results

The analysis included 109 patients who received lungs from non-smokers and 124 from smokers. Multivariable analysis identified significant differences between recipients of smoking and non-smoking lungs in the oscillometric measurements R5-19, X5, AX, R5z and X5z, but no differences in %predicted FEV1, FEV1/FVC, %predicted TLC or %predicted DLCO. An analysis of the smoking group also demonstrated associations between increasing smoke exposure, quantified in pack years, and all the oscillometry parameters, but not the conventional PFT parameters.

Conclusion

An interaction was identified between donor-recipient sex match and the effect of smoking. The association between donor smoking and oscillometry outcomes was significant predominantly in the female donor/female recipient group.

Center variability in the prognostic value of a cumulative acute cellular rejection "A-score" for long-term lung transplant outcomes

The acute rejection score (A-score) in lung transplant recipients, calculated as the average of acute cellular rejection A-grades across transbronchial biopsies, summarizes the cumulative burden of rejection over time. We assessed the association between A-score and transplant outcomes in 2 geographically distinct cohorts. The primary cohort included 772 double lung transplant recipients. The analysis was repeated in 300 patients from an independent comparison cohort. Time-dependent multivariable Cox models were constructed to evaluate the association between A-score and chronic lung allograft dysfunction or graft failure. Landmark analyses were performed with A-score calculated at 6 and 12 months posttransplant. In the primary cohort, no association was found between A-score and graft outcome. However, in the comparison cohort, time-dependent A-score was associated with chronic lung allograft dysfunction both as a time-dependent variable (hazard ratio, 1.51; P < .01) and when calculated at 6 months posttransplant (hazard ratio, 1.355; P = .031). The A-score can be a useful predictor of lung transplant outcomes in some settings but is not generalizable across all centers; its utility as a prognostication tool is therefore limited.

[The role of surveillance bronchoscopy after lung transplantation]

The role of surveillance bronchoscopy after lung transplantation. Lung transplantation is currently accepted as a potential treatment for end-stage respiratory diseases. That said, airway complications and the onset of chronic lung allograft dysfunction remain major causes of morbidity and mortality subsequent to lung transplantation and a significant obstacle to long-term survival. In this article, we discuss the advantages and limitations of bronchial endoscopy in post-lung transplant monitoring.

Circulating donor-derived cell-free DNA as a marker for rejection after lung transplantation

Objective

Recently, circulating donor-derive cell free DNA (dd-cfDNA) has gained growing attention in the field of solid organ transplantation. The aim of the study was to analyze circulating dd-cfDNA levels in graft rejection, ACR and AMR separately for each rejection type compared with non-rejection, and assessed the diagnostic potential of dd-cfDNA levels in predicting graft rejection after lung transplantation.

Methods

A systematic search for relevant articles was conducted on Medline, Web of Science, China National Knowledge Infrastructure (CNKI), and Wanfang databases without restriction of languages. The search date ended on June 1, 2023. STATA software was used to analyze the difference between graft rejection, ACR, AMR and stable controls, and evaluate the diagnostic performance of circulating dd-cfDNA in detecting graft rejection.

Results

The results indicated that circulating dd-cfDNA levels in graft rejection, ACR, and AMR were significantly higher than non-rejection (graft rejection: SMD=1.78, 95% CI: 1.31-2.25, I2 = 88.6%, P< 0.001; ACR: SMD=1.03, 95% CI: 0.47-1.59, I2 = 89.0%, P < 0.001; AMR: SMD= 1.78, 95% CI: 1.20-2.35, I2 = 89.8%, P < 0.001). Circulating dd-cfDNA levels distinguished graft rejection from non-rejection with a pooled sensitivity of 0.87 (95% CI: 0.80-0.92) and a pooled specificity of 0.82 (95% CI: 0.76-0.86). The corresponding SROC yield an AUROC of 0.90 (95% CI: 0.87-0.93).

Conclusion

Circulating dd-cfDNA could be used as a non-invasive biomarker to distinguish the patients with graft rejection from normal stable controls.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42023440467.

Prophylactic epinephrine attenuates severe bleeding in lung transplantation patients undergoing transbronchial lung biopsy: Results of the PROPHET randomized trial

BACKGROUND

Severe hemorrhage is an uncommon yet potentially life-threatening complication of transbronchial lung biopsy. Lung transplantation recipients undergo multiple bronchoscopies with biopsy and are considered to be at an increased risk for bleeding from transbronchial biopsy, independent of traditional risk factors. We aimed to evaluate the efficacy and safety of endobronchial administration of prophylactic topical epinephrine in attenuating transbronchial biopsy-related hemorrhage in lung transplant recipients.

METHODS

The Prophylactic Epinephrine for the Prevention of Transbronchial Lung Biopsy-related Bleeding in Lung Transplant Recipients study was a 2-center, randomized, double blind, placebo-controlled clinical trial. Participants undergoing transbronchial lung biopsy were randomized to receive 1:10,000-diluted topical epinephrine vs saline placebo administered prophylactically into the target segmental airway. Bleeding was graded based on a clinical severity scale. The primary efficacy outcome was incidence of severe or very severe hemorrhage. The primary safety outcome was a composite of 3-hours all-cause mortality and an acute cardiovascular event.

RESULTS

A total of 66 lung transplantation recipients underwent 100 bronchoscopies during the study period. The primary outcome of severe or very severe hemorrhage occurred in 4 cases (8%) in the prophylactic epinephrine group and in 13 cases (24%) in the control group (p = 0.04). The composite primary safety outcome did not occur in any of the study groups.

CONCLUSIONS

In lung transplantation recipients undergoing transbronchial lung biopsy, prophylactic administration of 1:10,000-diluted topical epinephrine into the target segmental airway before biopsy attenuates the incidence of significant endobronchial hemorrhage without conveying a significant cardiovascular risk. (ClinicalTrials.gov identifier: NCT03126968).

Interventional pulmonology techniques in lung transplantation

Lung transplantation is a key therapeutic option for several end-stage lung diseases. Interventional pulmonology techniques, mostly bronchoscopy, play a key role throughout the whole path of lung transplantation, from donor evaluation to diagnosis and management of post-transplant complications. We carried out a non-systematic, narrative literature review aimed at describing the main indications, contraindications, performance characteristics and safety profile of interventional pulmonology techniques in the context of lung transplantation. We highlighted the role of bronchoscopy during donor evaluation and described the debated role of surveillance bronchoscopy (with bronchoalveolar lavage and transbronchial biopsy) to detect early rejection, infections and airways complications. The conventional (transbronchial forceps biopsy) and the new techniques (i.e. cryobiopsy, biopsy molecular assessment, probe-based confocal laser endomicroscopy) can detect and grade rejection. Several endoscopic techniques (e.g. balloon dilations, stent placement, ablative techniques) are employed in the management of airways complications (ischemia and necrosis, dehiscence, stenosis and malacia). First line pleural interventions (i.e. thoracentesis, chest tube insertion, indwelling pleural catheters) may be useful in the context of early and late pleural complications occurring after lung transplantation. High quality studies are advocated to define endoscopic standard protocols and thus help improving long-term prognostic outcomes of lung transplant recipients.

PD-1 expression in transbronchial biopsies of lung transplant recipients is a possible early predictor of rejection

Introduction

Chronic lung allograft dysfunction (CLAD) is the main cause of the reduced survival of lung transplanted (LTx) patients. The possible role of immune checkpoint molecules in establishing tolerance has been scarcely investigated in the setting of lung transplantation.

Methods

We conducted a retrospective, observational pilot study on a consecutive series of transbronchial cryobiopsies (TCB) obtained from 24 patients during LTx follow-up focusing on PD-1, one of the most investigated immune checkpoint molecules.

Results

Results showed that PD-1-expressing T lymphocytes were present in all TCB with a histological diagnosis of acute rejection (AR; 9/9), but not in most (11/15) of the TCB not resulting in a diagnosis of AR (p=0.0006). Notably, the presence of PD-1-expressing T lymphocytes in TCB resulted in a 10-times higher risk of developing chronic lung allograft dysfunction (CLAD), the main cause of the reduced survival of lung transplanted patients, thus being associated with a clearly worst clinical outcome.

Discussion

Results of this pilot study indicate a central role of PD-1 in the development of AR and its evolution towards CLAD and suggest that the evaluation of PD-1-expressing lymphocytes in TCB could offer a prognostic advantage in monitoring the onset of AR in patients who underwent lung transplantation.

Utility of microbiologic testing in surveillance bronchoscopy following lung transplantation: A retrospective cohort study

BACKGROUND

The utility of surveillance bronchoscopy (SB) for the clinical management of lung transplant recipients (LTRs) is undefined. This study evaluates the role of SB in the monitoring and care of LTRs.

METHODS

We retrospectively analyzed all LTRs who had SB at Henry Ford Hospital in Detroit, Michigan between August 2014 and August 2019. Bronchoscopies performed for clinical symptoms, new radiographic abnormalities, and to assess stents or acute rejection were excluded. A total of 107 LTRs and 449 bronchoscopies were analyzed. The primary outcome was the rate of change in clinical care based on microbiologic and pathologic test results. Secondary outcomes were rates of microbiologic and pathologic test positivity and rates of adverse effects.

RESULTS

The most common microbiologic tests performed on bronchoalveolar lavage were bacterial (96.9%), fungal (95.3%), and acid-fast bacillus (95.1%) stains and cultures. Of 2560 microbiologic tests, 22.0% were positive and resulted in therapy changes for 2.9%. Positive galactomannan, acid-fast bacillus tests, and Pneumocystis jirovecii antigen/polymerase chain reaction did not result in therapy changes. Of the 370 transbronchial biopsies performed, 82.2% were negative for acute rejection and 13% were positive for A1/A2 rejection. Immunosuppressive therapy changes occurred after 15.8% with reduction in immunosuppression due to positive microbiologic tests in 16.9%. Adverse events occurred in 8.0% of patients.

CONCLUSION

Diagnostic stewardship is warranted when performing SB in LTRs.

Why Cell-Free DNA Can Be a “Game Changer” for Lung Allograft Monitoring for Rejection and Infection

Purpose of Review

Although there has been improvement in short-term clinical outcomes for patients following lung transplant (LT), advances have not translated into longer-term allograft survival. Furthermore, invasive biopsies are still standard of practice for monitoring LT recipients for allograft injury. We review the relevant literature supporting the role of using plasma donor-derived cell-free DNA (dd-cfDNA) as a non-invasive biomarker for LT allograft injury surveillance and discuss future research directions.

Recent Findings

Accumulating data has demonstrated that dd-cfDNA is associated with molecular and cellular injury due to acute (cellular and antibody-mediated) rejection, chronic lung allograft dysfunction, and relevant infectious pathogens. Strong performance in distinguishing rejection and allograft injury from stable patients has set the stage for clinical trials to assess dd-cfDNA utility for surveillance of LT patients. Research investigating the potential role of dd-cfDNA methylation signatures to map injured tissue and cell-free DNA in detecting allograft injury-related pathogens is ongoing.

Summary

There is an amassed breadth of clinical data to support a role for dd-cfDNA in monitoring rejection and other forms of allograft injury. Rigorously designed, robust clinical trials that encompass the diversity in patient demographics are paramount to furthering our understanding and adoption of plasma dd-cfDNA for surveillance of lung allograft health.

Circulating Donor Lung-specific Exosome Profiles Enable Noninvasive Monitoring of Acute Rejection in a Rodent Orthotopic Lung Transplantation Model

BACKGROUND

There is a critical need for development of biomarkers to noninvasively monitor for lung transplant rejection. We investigated the potential of circulating donor lung-specific exosome profiles for time-sensitive diagnosis of acute rejection in a rat orthotopic lung transplant model.

METHODS

Left lungs from Wistar transgenic rats expressing human CD63-GFP, an exosome marker, were transplanted into fully MHC-mismatched Lewis recipients or syngeneic controls. Recipient blood was collected between 4 h and 10 d after transplantation, and plasma was processed for exosome isolation by size exclusion column chromatography and ultracentrifugation. Circulating donor exosomes were profiled using antihuman CD63 antibody quantum dot on the nanoparticle detector and via GFP trigger on the nanoparticle flow cytometer.

RESULTS

In syngeneic controls, steady-state levels of circulating donor exosomes were detected at all posttransplant time points. Allogeneic grafts lost perfusion by day 8, consistent with acute rejection. Levels of circulating donor exosomes peaked on day 1, decreased significantly by day 2, and then reached baseline levels by day 3. Notably, decrease in peripheral donor exosome levels occurred before grafts had histological evidence of acute rejection.

CONCLUSIONS

Circulating donor lung-specific exosome profiles enable an early detection of acute rejection before histologic manifestation of injury to the pulmonary allograft. As acute rejection episodes are a major risk factor for the development of chronic lung allograft dysfunction, this biomarker may provide a novel noninvasive diagnostic platform that can translate into earlier therapeutic intervention for lung transplant patients.

Acute rejection and post lung transplant surveillance

Purpose

The purpose of this review is to summarize the current evidence on the evaluation and treatment of acute rejection after lung transplantation.

Results

Despite significant progress in the field of transplant immunology, acute rejection remains a frequent complication after transplantation. Almost 30% of lung transplant recipients experience at least one episode of acute cellular rejection (ACR) during the first year after transplant. Acute cellular rejection, lymphocytic bronchiolitis, and antibody-mediated rejection (AMR) are all risk factors for the subsequent development of chronic lung allograft dysfunction (CLAD). Acute cellular rejection and lymphocytic bronchiolitis have well-defined histopathologic diagnostic criteria and grading. The diagnosis of antibody-mediated rejection after lung transplantation requires a multidisciplinary approach. Antibody-mediated rejection may cause acute allograft failure.

Conclusions

Acute rejection is a risk factor for development of chronic rejection. Further investigations are required to better define risk factors, surveillance strategies, and optimal management strategies for acute allograft rejection.

Complications of Lung Transplantation: Update on Imaging Manifestations and Management

As lung transplantation has become the most effective definitive treatment option for end-stage chronic respiratory diseases, yearly rates of this surgery have been steadily increasing. Despite improvement in surgical techniques and medical management of transplant recipients, complications from lung transplantation are a major cause of morbidity and mortality. Some of these complications can be classified on the basis of the time they typically occur after lung transplantation, while others may occur at any time. Imaging studies, in conjunction with clinical and laboratory evaluation, are key components in diagnosing and monitoring these conditions. Therefore, radiologists play a critical role in recognizing and communicating findings suggestive of lung transplantation complications. A description of imaging features of the most common lung transplantation complications, including surgical, medical, immunologic, and infectious complications, as well as an update on their management, will be reviewed here. Keywords: Pulmonary, Thorax, Surgery, Transplantation Supplemental material is available for this article. © RSNA, 2021.

Rapid molecular detection of airway pathogens in lung transplant recipients

BACKGROUND

Airway infections are difficult to distinguish from acute rejection in lung transplant recipients. Traditional culture techniques take time that may delay treatment. We hypothesized that a rapid multiplex molecular assay could improve time to diagnosis and appropriate clinical decision making.

METHODS

In a prospective observational study of recipients undergoing bronchoscopy, we assessed the BioFire® FilmArray® Pneumonia Panel (BFPP) in parallel to standard of care (SOC) diagnostics. Research clinicians performed shadow (research only) clinical decision making in real time. Time to report and interpretation were reported as median and interquartile ranges and compared by Wilcoxon signed-ranked test. Agreement was defined based on detection of any species targeted in the molecular assay.

RESULTS

For the 150 enrolled subjects, BFPP results were available 3.8 hours (IQR 2.8-5.1) following bronchoscopy, compared to 13 hours for viral SOC (IQR 10-34, P < .001) results and 48 hours for bacterial SOC (IQR 46-70, P < .001) results. Positive BFPP results were interpreted in 9 hours (IQR 5-20) following bronchoscopy, compared to 74 hours for SOC (IQR 37-110, P < .001). Assays agreed for 138 (92%) of the 150 subjects. Of 22 BFPP diagnoses, five (23%) resulted in a shadow antibiotic recommendation. Notable BFPP deficiencies included fungal species and H parainfluenzae, accounting for 15 (27%) and 13 (23%) of the 56 actionable SOC results, respectively.

CONCLUSIONS

This molecular diagnostic including bacterial targets has the potential to shorten time to diagnosis and augment current clinical decision making but cannot replace SOC culture methods.

Bronchoalveolar lavage cytokine-based risk stratification of minimal acute rejection in clinically stable lung transplant recipients

BACKGROUND

Acute cellular rejection (ACR) remains the most significant risk factor for chronic lung allograft dysfunction (CLAD). While clinically significant or higher-grade (≥A2) ACR is generally treated with augmented immunosuppression (IS), the management of clinically stable grade A1 ACR remains controversial. At our center, patients with clinically stable grade A1 ACR are routinely not treated with augmented IS. While the overall outcomes in this group of patients at our center are equivalent to patients with stable A0 pathology, CLAD and death rates remain overall high. We hypothesized that a distinct cytokine signature at the time of early minimal rejection state would be associated with worse outcomes. Specifically, we aimed to determine whether bronchoalveolar lavage (BAL) biomarkers at the time of first clinically stable grade A1 ACR (CSA1R) are predictive of subsequent CLAD or death.

METHODS

Among all adult, bilateral, first lung transplants, performed 2010-2016, transbronchial biopsies obtained within the first-year post-transplant were categorized as clinically stable or unstable based on the presence or absence of ≥10% concurrent drop in forced expiratory volume in 1 second (FEV₁). We assessed BAL samples obtained at the time of CSA1R episodes, which were not preceded by another ACR (i.e., first episodes). Twenty-one proteins previously associated with ACR or CLAD were measured in the BAL using a multiplex bead assay. Association between protein levels and subsequent CLAD or death was assessed using Cox Proportional Hazards models, adjusted for relevant peri-transplant clinical covariates.

RESULTS

We identified 75 patients with first CSA1R occurring at a median time of 98 days (range 48.5-197) post-transplant. Median time from transplant to CLAD or death was 1247 (756.5-1921.5) and 1641 days (1024.5-2326.5), respectively. In multivariable models, levels of MCP1/CCL2, S100A8, IL10, TNF-receptor 1, and pentraxin 3 (PTX3) were associated with both CLAD development and death (p < 0.05 for all). PTX3 remained significantly associated with both CLAD and death after adjusting for multiple comparisons.

CONCLUSION

Our data indicate that a focused BAL protein signature, with PTX3 having the strongest association, may be useful in determining a subset of CSA1R patients at increased risk and may benefit from a more aggressive management strategy.

Surveillance Bronchoscopy for the Care of Lung Transplant Recipients: A Retrospective Single Center Analysis

INTRODUCTION

Lung transplantation is often the only treatment for end-stage lung disease. Following lung transplantation, infections and transplant rejections are major obstacles to short- and long-term success. Therefore, close monitoring for these complications is required after lung transplantation. The role of prescheduled surveillance bronchoscopies after lung transplantation is controversial. Thus, we aimed to retrospectively analyze the therapeutic implications of surveillance bronchoscopies in 110 consecutive lung transplant recipients.

MATERIALS AND METHODS

Results of 400 prescheduled surveillance bronchoscopies of 110 consecutive lung transplant recipients were analyzed. Positive results (pathologic histology, microbiology, or virology) were further investigated for their effect on clinical decision making. Additionally, cellular composition of bronchoalveolar lavage (BAL) was analyzed.

RESULTS

Two hundred five surveillance bronchoscopies showed pathologic findings. In 81 cases clinical treatment was changed based on the results. That is, 20% of all prescheduled bronchoscopies directly influenced clinical decision making. Furthermore, analyses of BAL indicate that increased alveolar eosinophils are associated with an increased risk of transplant rejection.

CONCLUSIONS

Prescheduled surveillance bronchoscopies identify clinically unsuspected but therapeutically relevant pathologic findings in approximately 20% of cases. BAL cell composition may confer additional information, especially in cases when biopsy is not possible.

Usefulness of a preoperative inflammatory marker as a predictor of asymptomatic acute rejection after lung transplantation: a Japanese single-institution study

Background

Surveillance bronchoscopy (SB) is performed as routine follow-up after lung transplantation (LTx), primarily for the early detection of clinically asymptomatic acute rejection (AR). To identify appropriate candidates for SB over a long period, we explored risk factors of asymptomatic AR after LTx.

Method

This study is a single-center and retrospective cohort study. Forty-five patients underwent cadaveric LTx between 2000 and 2016 in our institution. All enrolled patients had at least three months of follow-up. SB is scheduled at 1, 2, 3, 6, and 12 months after LTx routinely and annually thereafter until 5 years after LTx. A histological assessment for AR was performed according to the International Society for Heart and Lung Transplantation (ISHLT) criteria. The analysis of potential risk factors for AR was performed using a chi-square test and logistic regression analysis.

Results

The median period of follow-up after LTx for the entire cohort was 64 months. Asymptomatic AR (grade A1-A3) was detected in 22 patients, 14 of whom showed severe AR (worse than grade A2). The percentage of patients with AR was 5–24% at each time point, and 15% of patients still showed severe AR (A2 and A3) at 24 months after LTx. Potential risk factors included recipient factors (diagnosis, age, gender, BMI), donor factors (age, gender, smoking history, cause of brain death), HLA mismatch, operation-related factors, neutrophil-to-leucocyte ratio (NLR), platelet-to-leucocyte ratio (PLR), and other scores. Patients with a higher NLR showed a higher incidence of AR after LTx than others during follow-up (P=0.01).

Conclusions

An increased perioperative NLR was significantly associated with a higher odds ratio of AR during follow-up. Patients with a high NLR seem to be good candidates for long-term SB.

Airway Oscillometry Detects Spirometric-Silent Episodes of Acute Cellular Rejection

Rationale: Acute cellular rejection (ACR) is common during the initial 3 months after lung transplant. Patients are monitored with spirometry and routine surveillance transbronchial biopsies. However, many centers monitor patients with spirometry only because of the risks and insensitivity of transbronchial biopsy for detecting ACR. Airway oscillometry is a lung function test that detects peripheral airway inhomogeneity with greater sensitivity than spirometry. Little is known about the role of oscillometry in patient monitoring after a transplant.Objectives: To characterize oscillometry measurements in biopsy-proven clinically significant (grade ≥2 ACR) in the first 3 months after a transplant.Methods: We enrolled 156 of the 209 double lung transplant recipients between December 2017 and March 2019. Weekly outpatient oscillometry and spirometry and surveillance biopsies at Weeks 6 and 12 were conducted at our center.Measurements and Main Results: Of the 138 patients followed for 3 or more months, 15 patients had 16 episodes of grade 2 ACR (AR2) and 44 patients had 64 episodes of grade 0 ACR (AR0) rejection associated with stable and/or improving spirometry. In 15/16 episodes of AR2, spirometry was stable or improving in the weeks leading to transbronchial biopsy. However, oscillometry was markedly abnormal and significantly different from AR0 (P < 0.05), particularly in integrated area of reactance and the resistance between 5 and 19 Hz, the indices of peripheral airway obstruction. By 2 weeks after biopsy, after treatment for AR2, oscillometry in the AR2 group improved and was similar to the AR0 group.Conclusions: Oscillometry identified physiological changes associated with AR2 that were not discernible by spirometry and is useful for graft monitoring after a lung transplant.

Risk Factors for Acute Rejection in the First Year after Lung Transplant. A Multicenter Study

Rationale: Acute rejection, manifesting as lymphocytic inflammation in a perivascular (acute perivascular rejection [AR]) or peribronchiolar (lymphocytic bronchiolitis [LB]) distribution, is common in lung transplant recipients and increases the risk for chronic graft dysfunction.Objectives: To evaluate clinical factors associated with biopsy-proven acute rejection during the first post-transplant year in a present-day, five-center lung transplant cohort.Methods: We analyzed prospective diagnoses of AR and LB from over 2,000 lung biopsies in 400 newly transplanted adult lung recipients. Because LB without simultaneous AR was rare, our analyses focused on risk factors for AR. Multivariable Cox proportional hazards models were used to assess donor and recipient factors associated with the time to the first AR occurrence.Measurements and Main Results: During the first post-transplant year, 53.3% of patients experienced at least one AR episode. Multivariable proportional hazards analyses accounting for enrolling center effects identified four or more HLA mismatches (hazard ratio [HR], 2.06; P ≤ 0.01) as associated with increased AR hazards, whereas bilateral transplantation (HR, 0.57; P ≤ 0.01) was associated with protection from AR. In addition, Wilcoxon rank-sum analyses demonstrated bilateral (vs. single) lung recipients, and those with fewer than four (vs. more than four) HLA mismatches demonstrated reduced AR frequency and/or severity during the first post-transplant year.Conclusions: We found a high incidence of AR in a contemporary multicenter lung transplant cohort undergoing consistent biopsy sampling. Although not previously recognized, the finding of reduced AR in bilateral lung recipients is intriguing, warranting replication and mechanistic exploration.

International Society for Heart and Lung Transplantation consensus statement for the standardization of bronchoalveolar lavage in lung transplantation

Bronchoalveolar lavage (BAL) is a key clinical and research tool in lung transplantation (LTx). However, BAL collection and processing are not standardized across LTx centers. This International Society for Heart and Lung Transplantation-supported consensus document on BAL standardization aims to clarify definitions and propose common approaches to improve clinical and research practice standards. The following 9 areas are covered: (1) bronchoscopy procedure and BAL collection, (2) sample handling, (3) sample processing for microbiology, (4) cytology, (5) research, (6) microbiome, (7) sample inventory/tracking, (8) donor bronchoscopy, and (9) pediatric considerations. This consensus document aims to harmonize clinical and research practices for BAL collection and processing in LTx. The overarching goal is to enhance standardization and multicenter collaboration within the international LTx community and enable improvement and development of new BAL-based diagnostics.

Surveillance for acute cellular rejection after lung transplantation

Acute cellular rejection (ACR) is a common complication following lung transplantation (LTx), affecting almost a third of recipients in the first year. Established, comprehensive diagnostic criteria exist but they necessitate allograft biopsies which in turn increases clinical risk and can pose certain logistical and economic problems in service delivery. Undermining these challenges further, are known problems with inter-observer interpretation of biopsies and uncertainty as to the long-term implications of milder or indeed asymptomatic episodes. Increased risk of chronic lung allograft dysfunction (CLAD) has long been considered the most significant consequence of ACR. Consensus is lacking as to whether this applies to mild ACR, with contradictory evidence available. Given these issues, research into alternative, minimal or non-invasive biomarkers represents the main focus of research in ACR. A number of potential markers have been proposed, but none to date have demonstrated adequate sensitivity and specificity to allow translation from bench to bedside.

The impact of first untreated subclinical minimal acute rejection on risk for chronic lung allograft dysfunction or death after lung transplantation

Acute cellular rejection (ACR) is a significant risk factor for chronic lung allograft dysfunction (CLAD). Although clinically manifest and higher grade (≥A2) ACR is generally treated with augmented immunosuppression, management of minimal (grade A1) ACR remains controversial. In our program, patients with subclinical and spirometrically stable A1 rejection (StA1R) are routinely not treated with augmented immunosuppression. We hypothesized that an untreated first StA1R does not increase the risk of CLAD or death compared to episodes of spirometrically stable no ACR (StNAR). The cohort was drawn from all consecutive adult, first, bilateral lung transplantations performed between 1999 and 2017. Biopsies obtained in the first-year posttransplant were paired with (forced expiratory volume in 1 second FEV₁ ). The first occurrence of StA1R was compared to a time-matched StNAR. The risk of CLAD or death was assessed using univariable and multivariable Cox proportional hazards models. The analyses demonstrated no significant difference in risk of CLAD or death in patients with a first StA1R compared to StNAR. This largest study to date shows that, in clinically stable patients, an untreated first A1 ACR in the first-year posttransplant is not significantly associated with an increased risk for CLAD or death. Watchful-waiting approach may be an acceptable tactic for stable A1 episodes in lung transplant recipients.

Detection, classification, and management of rejection after lung transplantation

Rejection is a major complication following lung transplantation. Acute cellular rejection, lymphocytic bronchiolitis, and antibody-mediated rejection (AMR) are all risk factors for the subsequent development of chronic lung allograft dysfunction (CLAD). Acute cellular rejection and lymphocytic bronchiolitis have well defined histopathologic diagnostic criteria and grading. Diagnosis of AMR requires a multidisciplinary approach. CLAD is the major barrier to long-term survival following lung transplantation. The most common phenotype of CLAD is bronchiolitis obliterans syndrome (BOS) which is defined by a persistent obstructive decline in lung function. Restrictive allograft dysfunction (RAS) is a second phenotype of CLAD and is associated with a worse prognosis. This article will review the diagnosis, staging, clinical presentation, and treatment of acute rejection, AMR, and CLAD following lung transplantation.

Acute cellular rejection in lung transplantation

Lung transplantation is an important therapy for end-stage respiratory failure in patients who have exhausted other therapeutic options. The lung is unique among solid-organ transplants in that it is exposed to the outside environment, and undergoes continuous stimulation from infectious and non-infectious agents, which may play a part in upregulating the immune response to the allograft. Despite induction immunosuppression and the use of aggressive maintenance regimens, acute allograft rejection is still a major problem, especially in the first year after transplant, with important diagnostic and therapeutic challenges. As well as being responsible for early graft failure and death, acute rejection also initiates alloimmune responses that predispose patients to chronic lung allograft dysfunction, in particular bronchiolitis obliterans syndrome. Cellular responses to human leukocyte antigens (HLAs) on the allograft have traditionally been considered the main mechanism of acute rejection, although the influence of humoral immunity is increasingly recognised. Here, we present two cases of acute cellular rejection (ACR) in the early post-transplant period and review the pathophysiology, diagnosis, clinical presentation and treatment of ACR.

Parenteral administration of oral medications in lung transplant recipients: An underrecognized problem

Microcrystalline cellulose (MCC) is an insoluble material commonly used as a binder and filler in oral medications. Identification of pulmonary intravascular deposition of MCC in transbronchial biopsies from lung transplant (LT) recipients following parenteral injection of oral medications has only been reported once. A search of our surgical pathology electronic database was performed from January 1, 2000 to November 1, 2017 using the text "transplant transbronchial." The diagnosis field for all cases retrieved was then searched for the text "cellulose." These cases were queried for patient demographics and outcomes. Between January 1, 2000 and November 1, 2017, 1558 lung transplants were performed in 1476 individual patients at our institution; 12 were identified to have MCC in their lung tissue. Patients with MCC identified on biopsies were more likely to be transplanted for cystic fibrosis versus other indications and younger versus older. MCC identified in 2 of our cases was favored to be donor derived. Of the 12 patients, 6 (50%) are deceased. MCC within the pulmonary vasculature may be an indicator of increased complications, mortality, or shortened survival in LT recipients. Detecting intravascular MCC and distinguishing it from aspirated foreign material can be challenging. Awareness of the differential diagnosis for pulmonary foreign material is of paramount importance for the pathologist.

Molecular assessment of rejection and injury in lung transplant biopsies

BACKGROUND

Improved understanding of lung transplant disease states is essential because failure rates are high, often due to chronic lung allograft dysfunction. However, histologic assessment of lung transplant transbronchial biopsies (TBBs) is difficult and often uninterpretable even with 10 pieces.

METHODS

We prospectively studied whether microarray assessment of single TBB pieces could identify disease states and reduce the amount of tissue required for diagnosis. By following strategies successful for heart transplants, we used expression of rejection-associated transcripts (annotated in kidney transplant biopsies) in unsupervised machine learning to identify disease states.

RESULTS

All 242 single-piece TBBs produced reliable transcript measurements. Paired TBB pieces available from 12 patients showed significant similarity but also showed some sampling variance. Alveolar content, as estimated by surfactant transcript expression, was a source of sampling variance. To offset sampling variation, for analysis, we selected 152 single-piece TBBs with high surfactant transcripts. Unsupervised archetypal analysis identified 4 idealized phenotypes (archetypes) and scored biopsies for their similarity to each: normal; T-cell‒mediated rejection (TCMR; T-cell transcripts); antibody-mediated rejection (ABMR)-like (endothelial transcripts); and injury (macrophage transcripts). Molecular TCMR correlated with histologic TCMR. The relationship of molecular scores to histologic ABMR could not be assessed because of the paucity of ABMR in this population.

CONCLUSIONS

Molecular assessment of single-piece TBBs can be used to classify lung transplant biopsies and correlated with rejection histology. Two or 3 pieces for each TBB will probably be needed to offset sampling variance.

Critical Care after Lung Transplantation

Since the first successful lung transplantation in 1983, there have been many advances in the field. Nevertheless, the latest data from the International Society for Heart and Lung Transplantation revealed that the risk of death from transplantation is 9%. Various aspects of postoperative management, including mechanical ventilation, could affect intensive care unit stay, hospital stay, and immediate postoperative morbidity and mortality. Complications such as reperfusion injury, graft rejection, infection, and dehiscence of anastomosis increase fatal adverse side effects immediately after surgery. In this article, we review the possible immediate complications after lung transplantation and summarize current knowledge on prevention and treatment.

Surveillance Transbronchial Biopsy Program to Evaluate Acute Rejection After Lung Transplantation: A Single Institution Experience

BACKGROUND

There is no unanimity in the literature regarding the value of transbronchial biopsies (TBBs) performed at a scheduled time after lung transplantation (surveillance TBBs [SBs]), compared to biopsies performed for suspected clinical acute rejection (clinically indicated TBBs [CIBs]). This study exposes an assessment of our experience over the last 4 years through a retrospective analysis of the data collected.

METHODS

In our center, SBs are performed at 3, 6, and 12 months after a transplant. Data from 110 patients who underwent a TBB were collected from January 2013 to November 2017. Clinical and functional data along with the histologic results and complications were collected.

RESULTS

Overall 251 procedures were performed: 223 for surveillance purposes and 28 for clinical indications. The SBs diagnostic rate was 84%. A grade 2 acute rejection (AR) was detected in 9 asymptomatic patients, all of whom were medically treated, with downgrading of AR documented in all cases. The rate of medical intervention in the SB group was 8%. The CIBs diagnostic rate was 96%. The rate of AR detected by CIBs was significantly higher than by SBs (36% versus 4%; P < .0001). Overall the major complication rate was 4%; no patients required transfusions and no mortality occurred in the patient cohort.

CONCLUSIONS

The surveillance protocol did not eliminate the necessity of CIBs, but in 8% of patients early rejection was histologically assessed. The correlation between histologic and clinical data allows a more careful approach to transplanted patients.

Delayed Pneumothorax: A Potential Complication Of Transbronchial Lung Biopsy

The purpose of this article is to report a case of secondary tension pneumothorax presenting seven weeks post Transbronchial Lung biopsy. A 62 year old male with a known history of germ cell tumor was found to have a left-sided pneumothorax which later complicated to a tension pneumothorax.To the best of our knowledge this is the second case being reported for a delayed pneumothorax post a Transbronchial Lung Biopsy .The purpose of this case report is to create awareness among physicians to consider this diagnosis even at a later stage and the importance of patient education regarding the signs and symptoms of pneumothorax. Our case adds to the medical literature, a new presentation of a rare complication of delayed pneumothorax post TBB.

Acute rejection

Despite induction immunosuppression and the use of aggressive maintenance immunosuppressive regimens, acute allograft rejection following lung transplantation is still a problem with important diagnostic and therapeutic challenges. As well as causing early graft loss and mortality, acute rejection also initiates the chronic alloimmune responses and airway-centred inflammation that predispose to bronchiolitis obliterans syndrome (BOS), also known as chronic lung allograft dysfunction (CLAD), which is a major source of morbidity and mortality after lung transplantation. Cellular responses to human leukocyte antigens (HLAs) on the allograft have traditionally been considered the main mechanism of acute rejection, but the influence of humoral immunity is increasingly recognised. As with other several other solid organ transplants, antibody-mediated rejection (AMR) is now a well-accepted and distinct clinical entity in lung transplantation. While acute cellular rejection (ACR) has defined histopathological criteria, transbronchial biopsy is less useful in AMR and its diagnosis is complicated by challenges in the measurement of antibodies directed against donor HLA, and a determination of their significance. Increasing awareness of the importance of non-HLA antigens further clouds this issue. Here, we review the pathophysiology, diagnosis, clinical presentation and treatment of ACR and AMR in lung transplantation, and discuss future potential biomarkers of both processes that may forward our understanding of these conditions.

Complications and discomfort of bronchoscopy: a systematic review

Objective

To identify bronchoscopy-related complications and discomfort, meaningful complication rates, and predictors.

Method

We conducted a systematic literature search in PubMed on 8 February 2016, using a search strategy including the PICO model, on complications and discomfort related to bronchoscopy and related sampling techniques.

Results

The search yielded 1,707 hits, of which 45 publications were eligible for full review. Rates of mortality and severe complications were low. Other complications, for instance, hypoxaemia, bleeding, pneumothorax, and fever, were usually not related to patient characteristics or aspects of the procedure, and complication rates showed considerable ranges. Measures of patient discomfort differed considerably, and results were difficult to compare between different study populations.

Conclusion

More research on safety aspects of bronchoscopy is needed to conclude on complication rates and patient- and procedure-related predictors of complications and discomfort.

New Nodule-Newer Etiology

AIM: To evaluate frequency and temporal relationship between pulmonary nodules (PNs) and transbronchial biopsy (TBBx) among lung transplant recipients (LTR).

METHODS: We retrospectively reviewed 100 records of LTR who underwent flexible bronchoscopy (FB) with TBBx, looking for the appearance of peripheral pulmonary nodule (PPN). If these patients had chest radiographs within 50 d of FB, they were included in the study. Data was compared with 30 procedures performed among non-transplant patients. Information on patient’s demographics, antirejection medications, anticoagulation, indication and type of lung transplantation, timing of the FB and the appearance and disappearance of the nodules and its characteristics were gathered.

RESULTS: Nineteen new PN were found in 13 procedures performed on LTR and none among non-transplant patients. Nodules were detected between 4-47 d from the procedure and disappeared within 84 d after appearance without intervention.

CONCLUSION: FB in LTR is associated with development of new, transient PPN at the site of TBBx in 13% of procedures. We hypothesize that these nodules are related to local hematoma and impaired lymphatic drainage. Close observation is a reasonable management approach.

Bronchoscopic procedures and lung biopsies in pediatric lung transplant recipients

Bronchoscopy remains a pivotal diagnostic and therapeutic intervention in pediatric patients undergoing lung transplantation (LTx). Whether performed as part of a surveillance protocol or if clinically indicated, fibre-optic bronchoscopy allows direct visualization of the transplanted allograft, and in particular, an assessment of the patency of the bronchial anastomosis (or tracheal anastomosis following heart-lung transplantation). Additionally, bronchoscopy facilitates differentiation of infective processes from rejection episodes through collection and subsequent assessment of bronchoalveolar lavage (BAL) and transbronchial biopsy (TBBx) samples. Indeed, the diagnostic criteria for the grading of acute cellular rejection is dependent upon the histopathological assessment of biopsy samples collected at the time of bronchoscopy. Typically, performed in an out-patient setting, bronchoscopy is generally a safe procedure, although complications related to hemorrhage and pneumothorax are occasionally seen. Airway complications, including stenosis, malacia, and dehiscence are diagnosed at bronchoscopy, and subsequent management including balloon dilatation, laser therapy and stent insertion can also be performed bronchoscopically. Finally, bronchoscopy has been and continues to be an important research tool allowing a better understanding of the immuno-biology of the lung allograft through the collection and analysis of collected BAL and TBBx samples. Whilst new investigational tools continue to evolve, the simple visualization and collection of samples within the lung allograft by bronchoscopy remains the gold standard in the evaluation of the lung allograft. This review describes the use and experience of bronchoscopy following lung transplantation in the pediatric setting.

Cell-Free DNA: An Upcoming Biomarker in Transplantation

After organ transplantation, donor-derived cell-free DNA (ddcfDNA) can be detected in the recipient's blood and urine. Different ddcfDNA quantification techniques have been investigated but a major breakthrough was made with the introduction of digital droplet PCR and massive parallel sequencing creating the opportunity to increase the understanding of ddcfDNA kinetics after transplantation. The observations of increased levels of ddcfDNA during acute rejection and even weeks to months before histologic features of graft rejection point to a possible role of ddcfDNA as an early, noninvasive rejection marker. In this review, we summarize published research on ddcfDNA in the transplantation field thereby elaborating on its clinical utility.

Results of surveillance bronchoscopy after cadaveric lung transplantation: a Japanese single-institution study

BACKGROUND

The prevention and early detection of post-transplantation rejection and infection are key clinical points to achieve long-term survival after lung transplantation. Although surveillance bronchoscopy (SB) is performed in many transplantation centers, it is still controversial because of its undefined clinical significance and its possible complications. We evaluated the clinical utility of SB after cadaveric lung transplantation in Japan, where bilateral transplantation is officially limited to patients medically requiring bilateral grafts.

PATIENTS AND METHODS

Twenty-eight patients who underwent cadaveric lung transplantation followed by SB were retrospectively analyzed with reference to the results of bronchoscopy. SB is routinely performed at 1, 2, 3, 6, and 12 months after lung transplantation and annually thereafter. Clinically indicated bronchoscopy (CIB) is considered in patients with suspected rejection or airway infection, and for follow-up examination after treatment for acute rejection.

RESULTS

There were 206 bronchoscopies, including 189 SBs and 17 CIBs, performed in 28 patients who underwent cadaveric lung transplantation between 2000 and 2013 at Osaka University Hospital. Among SBs, 92 (49%) showed positive results of transbronchial lung biopsy (TBLB) or bronchoalveolar lavage (BAL), and intervention was applied following 34 SBs (18%). Among CIBs, 8 (47%) showed positive results of TBLB or BAL, with intervention performed in 3 patients (18%). A2-3 and B2R findings according to the revised International Society for Heart and Lung Transplantation (ISHLT) rejection score and airway infection/colonization were frequently observed within a year following lung transplantation. Cytomegalovirus infection was found in 7 SBs (6%) by TBLB only within 2 months after transplantation. Regarding complications, moderate bleeding occurred in 21 (11%), pneumothorax in 2 (1%), prolonged hypoxemia in 1 (0.5%), and pneumonia in 1 (0.5%) among the 189 SBs.

CONCLUSION

SB frequently detects rejection and airway infection or colonization with minimum complications, especially within 12 months after cadaveric lung transplantation.

Noninvasive assessment for acute allograft rejection in a rat lung transplantation model

After lung transplantation, early detection of acute allograft rejection is important not only for timely and optimal treatment, but also for the prediction of chronic rejection which is a major cause of late death. Many biological and immunological approaches have been developed to detect acute rejection; however, it is not well known whether lung mechanics correlate with disease severity, especially with pathological rejection grade. In this study, we examined the relationship between lung mechanics and rejection grade development in a rat acute rejection model using the forced oscillation technique, which provides noninvasive assessment of lung function. To this end, we assessed lung resistance and elastance (R_L and E_L) from implanted left lung of these animals. The perivascular/interstitial component of rejection severity grade (A‐grade) was also quantified from histological images using tissue fraction (TF; tissue + cell infiltration area/total area). We found that TF, R_L, and E_L increased according to A‐grade. There was a strong positive correlation between E_L at the lowest frequency (E_low; E_L at 0.5 Hz) and TF (r² = 0.930). Furthermore, the absolute difference between maximum value of E_L (E_max) and E_low (E_het; E_max − E_low) showed the strong relationship with standard deviation of TF (r² = 0.709), and A‐grade (Spearman's correlation coefficients; r_s = 0.964, P < 0.0001). Our results suggest that the dynamic elastance as well as its frequency dependence have the ability to predict A‐grade. These indexes should prove useful for noninvasive detection and monitoring the progression of disease in acute rejection.

After lung transplantation, early detection of acute allograft rejection is important for both in timely treatment and prediction of chronic rejection which is a major cause of late death. We examined the relationship between lung mechanics and rejection grade development in a rat acute rejection model using the forced oscillation technique, which provides noninvasive assessment of lung function. Our results suggest that the dynamic elastance as well as its frequency dependence reflect the perivascular‐interstitial component of rejection severity grade (A‐grade), and this method should prove useful for noninvasive detection and monitoring the progression of disease in acute rejection.

Safety and efficacy of outpatient bronchoscopy in lung transplant recipients - a single centre analysis of 3,197 procedures

BACKGROUND

Bronchoscopy represents an important diagnostic and therapeutic tool in the management of lung transplant (LTx) recipients. Outpatient bronchoscopy reduces health costs and may improve quality of life amongst these patients. This retrospective study assessed the safety and efficacy of outpatient bronchoscopy including trans-bronchial biopsy.

METHODS

All outpatient bronchoscopies performed on lung transplant recipients between 1 August 2008 and 31 January 2011 were reviewed. Sample quality, duration and complications were recorded. Cost analysis was performed from local trust financial data.

RESULTS

A total of 3,197 bronchoscopies were performed on 571 LTx recipients under topical anaesthesia. Fourteen percent of examinations required intravenous sedation. In 79.8% of examinations no complications were observed. Most complications were minor (17.9%) including cough (5.3%) and minimal bleeding after trans-bronchial biopsy (7.8%). Major complications (2.3%) were pneumothorax, severe bleeding and severe desaturation. No attributable deaths were recorded during the observation period. Quality of examination based on bronchoalveolar lavage recovery median (>50%) and biopsy results was adequate at 75% and 77.4%, respectively. Independent risk factors associated with complication were long-term oxygen therapy, sedation before examination, balloon dilatation and transbronchial biopsy. After excluding high-risk procedures annual savings per patient (2.2 bronchoscopies per year) were 2140€.

CONCLUSIONS

Outpatient bronchoscopy after LTx is safe. The low complication rate could be attributed to withholding of intravenous sedation. Furthermore, it reduces health community costs.

Surveillance transbronchial biopsies in infant lung and heart-lung transplant recipients

There are limited published data on surveillance TBB for the identification of allograft rejection in infants after lung or heart-lung transplantation. We performed a retrospective review of children under one yr of age who underwent lung or heart-lung transplant at our institution. Since 2005, four infants were transplanted (three heart-lung and one lung). The mean age (±s.d.) at the time of transplant was 5.5 ± 2.4 (range 3-8) months. A total of 16 surveillance TBB procedures were completed in both inpatient and outpatient settings, with a range of 3-7 performed per patient. A minimum of five acceptable tissue pieces with expanded alveoli were obtained in 81% (13/16) of TBB procedures and a minimum of three pieces in 88% (14/16). There was no evidence of acute allograft rejection in 88% (14/16) of TBB procedures. One TBB procedure yielded two tissue specimens demonstrating A2 acute allograft rejection. One TBB procedure failed to yield tissue with sufficient alveoli. Additionally, B-grade assessment identified B0 in 50% (8/16), B1R in 12% (2/16), and BX (ungradeable or insufficient sample) in 38% (6/16) of biopsy procedures, respectively. In conclusion, TBB may be safely performed as an inpatient and outpatient procedure in infant lung and heart-lung transplant recipients and may provide adequate tissue for detecting acute allograft rejection and small airway inflammation.

T cell immunohistochemistry refines lung transplant acute rejection diagnosis and grading

Objective

Lung transplant volume has been increasing. However, inaccurate and uncertain diagnosis for lung transplant rejection hurdles long-term outcome due to, in part, interobserver variability in rejection grading. Therefore, a more reliable method to facilitate diagnosing and grading rejection is warranted.

Method

Rat lung grafts were harvested on day 3, 7, 14 and 28 post transplant for histological and immunohistochemical assessment. No immunosuppressive treatment was administered. We explored the value of interstitial T lymphocytes quantification by immunohistochemistry and compared the role of T cell immunohistochemistry with H&E staining in diagnosing and grading lung transplant rejection.

Results

Typical acute rejection from grade A1 to A4 was found. Rejection severity was heterogeneously distributed in one-third transplanted lungs (14/40): lesions in apex and center were more augmented than in the base and periphery of the grafts, respectively. Immunohistochemistry showed profound difference in T lymphocyte infiltration among grade A1 to A4 rejections. The coincidence rate of H&E and immunohistochemistry was 77.5%. The amount of interstitial T lymphocyte infiltration increased gradually with the upgrading of rejection. The statistical analysis demonstrated that the difference in the amount of interstitial T lymphocytes between grade A2 and A3 was not obvious. However, T lymphocytes in lung tissue of grade A4 were significantly more abundant than in other grades.

Conclusions

Rejection severity was heterogeneously distributed within lung grafts. Immunohistochemistry improves the sensitivity and specificity of rejection diagnosis, and interstitial T lymphocyte quantitation has potential value in diagnosing and monitoring lung allograft rejection.

Virtual slides

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1536075282108217.

Diagnostic bronchoscopy in solid-organ and hematopoietic stem cell transplantation

Fiberoptic bronchoscopy is a valuable diagnostic tool in solid-organ and hematopoietic stem cell transplant recipients presenting with a range of pulmonary complications. This article provides a comprehensive overview of the utility and potential adverse effects of diagnostic bronchoscopy for transplant recipients. Recommendations are offered on the selection of patients, the timing of bronchoscopy, and the samples to be obtained across the spectrum of suspected pulmonary complications of transplantation. Based on review of the literature, the authors recommend early diagnostic bronchoscopy over empiric treatment in transplant recipients with evidence of certain acute, subacute, or chronic pulmonary processes. This approach may be most critical when an underlying infectious etiology is suspected. In the absence of prompt diagnostic information on which to base effective treatment, the risks associated with empiric antimicrobial therapy, including medication side effects and the development of antibiotic resistance, compound the potential harm of delaying targeted management.