Glen P. Westall

A Feasibility and Safety Study of Bronchoscopic Thermal Vapor Ablation: A Novel Emphysema Therapy

PURPOSE This study reports the feasibility and safety of novel second-generation bronchoscopic lung volume reduction (LVR) technology, independent of collateral ventilation. DESCRIPTION Eleven patients with severe heterogeneous emphysema underwent unilateral bronchoscopic application of vapor thermal energy (mean 4.9 cal/g alveolar tissue; range, 3 to 7.5) with bronchial thermal vapor ablation (BTVA) aiming to induce a controlled inflammatory airway and parenchymal response with resultant LVR. EVALUATION Nine women and 2 men, with a mean age of 61 years, forced expiratory volume in 1 second (FEV(1)) of 0.77 +/- 0.17 L (32% predicted), residual volume (RV) of 4.1 +/- 0.9 L (219% predicted), and gas transfer of 7.8 +/- 2.2 (34% predicted), underwent unilateral upper lobe treatments. Serious adverse events in 5 included probable bacterial pneumonia and exacerbations of airways disease in 2. Although no important FEV(1) or RV changes occurred during 6 months of follow-up, gas transfer improved, 16% to 9.0% +/- 2.1% (38% predicted), the Medical Research Council Dyspnoea Score improved from 2.6 to 2.1, and the St. George Respiratory Questionnaire Total Score improved from 64.4 at baseline to 49.1. CONCLUSIONS These preliminary data on unilateral BTVA therapy confirm feasibility, an acceptable safety profile, and the potential for efficacy.

Human Cytomegalovirus Load in Plasma and Bronchoalveolar Lavage Fluid: A Longitudinal Study of Lung Transplant Recipients

BACKGROUND In lung transplant recipients (LTRs), the measurement of human cytomegalovirus (HCMV) load dynamics in the local environment of the lung allograft may offer distinct advantages over their assessment in the peripheral blood compartment. METHODS We compared HCMV load in paired bronchoalveolar lavage (BAL) and plasma samples in a prospective cohort of LTRs. RESULTS In all, 182 paired samples were collected from 41 LTRs. Qualitative findings were concordant for 79.7% of the paired samples (virus load detected or absent in 8.1% and 71.5% of paired samples, respectively). In 35 paired samples (20.3%), HCMV was detected in the BAL but not the plasma sample; the converse was not found for any of the paired samples. HCMV inclusions were histologically detected in the lungs of 8 patients on 9 occasions. HCMV was detected in both BAL and plasma samples on 7 of the 9 occasions and in only the BAL sample on 2 occasions. Application of a threshold virus load in BAL samples, to predict histologically proven HCMV infection, was associated with improved diagnostic sensitivity and specificity. CONCLUSIONS Quantification of HCMV in the lung allograft correlates with histological detection and, in addition, offers the potential to monitor subclinical viral replication in the lung allograft.

Linking CMV Serostatus to Episodes of CMV Reactivation Following Lung Transplantation by Measuring CMV-Specific CD8+ T-Cell Immunity

CMV‐specific immunity was assessed in a longitudinal cohort of 39 lung transplant recipients (LTR) who were followed prospectively from the time of transplant using a novel assay. At the time of surveillance bronchoscopy, CMV‐specific CD8+ T‐cell responses were assessed in the peripheral blood, using the QuantiFERON®‐CMV assay, which measures IFN‐γ‐secreting T cells following stimulation with CMV peptides. In total, 297 samples were collected from 39 LTR (CMV D+/R−, n = 8; D+/R+, n = 18; D−/R+, n = 6; D−/R−, n = 7). CMV‐specific T‐cell immunity was not detected in any of the CMV D−/R− LTR. In CMV seropositive LTR levels of CMV immunity were lowest early posttransplant and increased thereafter. While levels of CMV‐specific immunity varied between LTR, measurements at any one time point did not predict episodes of CMV reactivation. In CMV mismatched (D+/R−) LTR, primary CMV immunity was not observed during the period of antiviral prophylaxis, but typically developed during episodes of CMV reactivation. Measuring CMV‐specific CD8+ T‐cell function with the QuantiFERON®‐CMV assay provides insights into the interrelationship between CMV immunity and CMV reactivation in individual LTR. A better understanding of these dynamics may allow the opportunity to individualize antiviral prophylaxis in the future.

Cytomegalovirus replication within the lung allograft is associated with bronchiolitis obliterans syndrome

Early studies reported cytomegalovirus (CMV) pneumonitis as a risk factor for development of bronchiolitis obliterans syndrome (BOS) following lung transplantation. While improvements in antiviral prophylaxis have resulted in a decreased incidence of CMV pneumonitis, molecular diagnostic techniques allow diagnosis of subclinical CMV replication in the allograft. We hypothesized that this subclinical CMV replication was associated with development of BOS. We retrospectively evaluated 192 lung transplant recipients (LTR) from a single center between 2001 and 2009. Quantitative (PCR) analysis of CMV viral load and histological evidence of CMV pneumonitis and acute cellular rejection was determined on 1749 bronchoalveolar lavage (BAL) specimens and 1536 transbronchial biopsies. CMV was detected in the BAL of 41% of LTR and was significantly associated with the development of BOS (HR 1.8 [1.1–2.8], p = 0.02). This association persisted when CMV was considered more accurately as a time‐dependent variable (HR 2.1 [1.3–3.3], p = 0.003) and after adjustment for significant covariates in a multivariate model. CMV replication in the lung allograft is common following lung transplantation and is associated with increased risk of BOS. As antiviral prophylaxis adequately suppresses CMV longer prophylactic strategies may improve long‐term outcome in lung transplantation.

Antibody-mediated rejection of the lung: A consensus report of the International Society for Heart and Lung Transplantation

Antibody-mediated rejection (AMR) is a recognized cause of allograft dysfunction in lung transplant recipients. Unlike AMR in other solid-organ transplant recipients, there are no standardized diagnostic criteria or an agreed-upon definition. Hence, a working group was created by the International Society for Heart and Lung Transplantation with the aim of determining criteria for pulmonary AMR and establishing a definition. Diagnostic criteria and a working consensus definition were established. Key diagnostic criteria include the presence of antibodies directed toward donor human leukocyte antigens and characteristic lung histology with or without evidence of complement 4d within the graft. Exclusion of other causes of allograft dysfunction increases confidence in the diagnosis but is not essential. Pulmonary AMR may be clinical (allograft dysfunction which can be asymptomatic) or sub-clinical (normal allograft function). This consensus definition will have clinical, therapeutic and research implications.

Bronchiolitis obliterans syndrome and early human cytomegalovirus Dnaaemia dynamics after lung transplantation

Background. Bronchiolitis obliterans syndrome (BOS) remains a major cause of morbidity and mortality after lung transplantation. The major identified risk factors for BOS are acute rejection and human cytomegalovirus (HCMV) infection, the latter despite the use of relatively insensitive and nonspecific measures such as HCMV pneumonitis and HCMV serostatus, respectively. We hypothesized that a more accurate prospective analysis of HCMV reactivation in lung transplant recipients (LTRs) would improve our understanding of the association between HCMV and BOS development. Methods. In 26 LTRs, HCMV DNAaemia was measured using quantitative polymerase chain reaction at monthly intervals during the initial 6 months posttransplantation. BOS was defined as a sustained irreversible 20% decrease in FEV1 compared with the best baseline FEV1 posttransplantation in the absence of any other cause. Results. Of the 26 LTRs, 23 were assessable with regard to the BOS outcome variable. At a median follow-up of 37 months, 10 patients had developed BOS. During the first 6-month monitoring period, HCMV DNAaemia was detected in 15 of the 23 patients on at least one occasion, and there were 12 episodes of HCMV pneumonitis in eight patients. Episodes of grade A3 or greater acute rejection occurred in eight LTRs, six of whom had been HCMV DNAaemia positive at least once and four of whom also demonstrated HCMV pneumonitis. Our results revealed a strong association between BOS and early HCMV DNAaemia detection (univariate analysis [P =0.002] and freedom from BOS analysis [P =0.006]). Conclusion. Early HCMV DNAaemia in LTRs is associated with the development of BOS despite routine ganciclovir prophylaxis.

C3d and C4d Deposition Early After Lung Transplantation

BACKGROUND Complement staining as a predictor of antibody-mediated rejection (AMR) after lung transplantation continues to be debated. METHODS In a cohort of 33 lung transplant recipients (LTRs) we assessed early post-transplant (<or=3 months) graft deposition of the complement factors C3d and C4d and correlated staining with clinical outcome. A retrospective analysis of allograft C3d and C4d deposition was performed by an experienced histopathologist blinded to clinical outcomes. Biopsies were graded 0 to 3 based on extent of septal capillary complement staining. RESULTS Significant C3d and C4d staining (i.e., Grade >or=2 on more than one occasion) was observed in 20 and 11 LTRs, respectively. Complement staining was increased in LTRs with severe primary graft dysfunction or airway infection, but was not associated with acute cellular or chronic rejection, or with morphologic features of AMR. In a sub-group analysis we identified 9 LTRs who developed early bronchiolitis obliterans syndrome (BOS) in the absence of acute cellular rejection or cytomegalovirus reactivation, but they had significant lung allograft C3d/C4d deposition along with corroborative light-microscopic features suggestive of AMR. CONCLUSIONS Complement activation, as judged by lung allograft deposition of C3d/C4d, is common early post-lung transplant and may be triggered by primary graft dysfunction and/or airway infection, and may play a role in the development of early BOS.

Acute Fibrinoid Organizing Pneumonia after Lung Transplantation

RATIONALE The barrier to long-term success after lung transplantation is the development of chronic lung allograft dysfunction. As the experience with lung transplantation accrues, it has become increasingly apparent that not all chronic allograft dysfunction is consistent with the traditionally recognized small-airway histological process of obliterative bronchiolitis (OB). OBJECTIVES To identify and describe chronic allograft dysfunction that is not consistent with the well-described bronchiolitis obliterans syndrome and to further characterize a novel histopathological process, acute fibrinoid organizing pneumonia (AFOP), that has led invariably to respiratory decline and death after lung transplantation. METHODS We evaluated 194 bilateral lung transplant recipients, identifying 87 individuals who developed chronic allograft dysfunction. They were then classified according to features on spirometry, chest imaging, and histopathological specimens. MEASUREMENTS AND MAIN RESULTS Two main phenotypes of chronic allograft dysfunction were identified; 39 (45%) recipients were categorized as having developed OB and 22 (25%) as having AFOP. Survival in those who developed AFOP was significantly worse than in those who developed OB (median time to death 101 vs. 294 d; P = 0.02), with all exhibiting a rapid decline in respiratory function leading to death. CONCLUSIONS AFOP is a novel form of chronic allograft dysfunction exhibiting spirometric, radiological, and histopathological characteristics that differentiate it from OB. The further characterization of chronic allograft dysfunction and its heterogeneous manifestations will allow the targeting of clinical and experimental efforts to prevent and treat chronic allograft dysfunction.

Lung Transplantation in Pulmonary Fibrosis: Challenging Early Outcomes Counterbalanced by Surprisingly Good Outcomes Beyond 15 Years

Interstitial lung disease (ILD) has been reported to have a poor outcome following lung transplantation due to difficulties getting ill recipients to transplantation and challenging early postoperative outcomes. To assess long-term outcomes for this cohort, we performed a retrospective 18-year chart review of all ILD lung transplant recipients. ILD single (SLT) and bilateral sequential lung transplantations (BSLT) were compared with all other lung transplant patients and International Society for Heart and Lung Transplantation (ISHLT) Registry data over the same time period. Of 585 lung transplantations, 90 (15%) were ILD (53 SLT, 37 BSLT); 67 (74%) were idiopathic pulmonary fibrosis (IPF), 9 (10%) were sarcoidosis, 9 (10%) were lymphangioleiomyomatosis, and 5 (6%) had other indications. Mean age was 52 years (range, 34-69 years). Actuarial survival at 1, 5, 10, 15, and 18 years compared favorably to all other lung transplantations performed (77% vs 83%, 51% vs 50%, 42% vs 26%, 28% vs 17%, and 28% vs 8%, respectively). IPF actuarial survival at 1, 5, and 10 years appeared superior to ISHLT Registry data (76% vs 72%, 50% vs 44%, and 34% vs 20%, respectively). There was equivocal survival between SLT and BSLT at 1, 5, and 10 years (78% vs 68%, 49% vs 50%, and 29% vs 50%, respectively). Our ILD figures compared favorably to lung transplantation for other diseases and international standards, while survival from SLT was as successful as BSLT both in the short and the longer term. Consideration should be given to utilizing SLT to maximize the allocation of donor lungs and to decrease waiting list mortality associated with IPF.

Immunosuppression for lung transplantation: evidence to date.

With the introduction of ciclosporin (cyclosporine) into routine clinical practice 20 years ago, lung transplantation has become an established treatment for patients with advanced lung disease. Most lung transplant recipients routinely continue to receive a triple-drug maintenance immunosuppressive regimen consisting of a calcineurin inhibitor, an antimetabolite and corticosteroids. The use of antibody-based induction therapy remains common, although there has been a shift away from T cell-depleting agents, such as antithymocyte globulin, towards anti-interleukin-2 receptor monoclonal antibodies. Recent years have seen the introduction of sirolimus and everolimus, immunosuppressive drugs that act by blocking growth factor-driven cell proliferation. While the newer immunosuppressive drugs have been rigorously evaluated in large randomised trials in kidney, liver and cardiac transplantation, such studies are lacking in lung transplantation. Despite a shift towards more potent immunosuppressive regimens that incorporate tacrolimus and mycophenolate mofetil, the development of chronic allograft rejection, as manifested by the bronchiolitis obliterans syndrome continues to negatively impact on the long-term survival of lung transplant recipients. This article reviews the evidence for the immunosuppressive regimens used during induction and maintenance of patients undergoing lung transplantation, and discusses current strategies in the management of chronic rejection.