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.

The presence of preexisting (memory) or de novo donor-specific HLA antibodies (DSAs) is a known barrier to successful long-term organ transplantation. Yet, despite the fact that laboratory tools and our understanding of histocompatibility have advanced significantly in recent years, the criteria to define presence of a DSA and assign a level of risk for a given DSA vary markedly between centers. A collaborative effort between the American Society for Histocompatibility and Immunogenetics and the American Society of Transplantation provided the logistical support for generating a dedicated multidisciplinary working group, which included experts in histocompatibility as well as kidney, liver, heart, and lung transplantation. The goals were to perform a critical review of biologically driven, state-of-the-art, clinical diagnostics literature and to provide clinical practice recommendations based on expert assessment of quality and strength of evidence. The results of the Sensitization in Transplantation: Assessment of Risk (STAR) meeting are summarized here, providing recommendations on the definition and utilization of HLA diagnostic testing, and a framework for clinical assessment of risk for a memory or a primary alloimmune response. The definitions, recommendations, risk framework, and highlighted gaps in knowledge are intended to spur research that will inform the next STAR Working Group meeting in 2019.

Lung transplantation is the only intervention that prolongs survival in idiopathic pulmonary fibrosis (IPF). Telomerase mutations are the most common identifiable genetic cause of IPF, and at times, the telomere defect manifests in extrapulmonary disease such as bone marrow failure. The relevance of this genetic diagnosis for lung transplant management has not been examined.We gathered an international series of telomerase mutation carriers who underwent lung transplant in the USA, Australia and Sweden.The median age at transplant was 52 years. Seven recipients are alive with a median follow-up of 1.9 years (range 6 months to 9 years); one died at 10 months. The most common complications were haematological, with recipients requiring platelet transfusion support (88%) and adjustment of immunosuppressives (100%). Four recipients (50%) required dialysis for tubular injury and calcineurin inhibitor toxicity. These complications occurred at significantly higher rates relative to historic series (p<0.0001).Our observations support the feasibility of lung transplantation in telomerase mutation carriers; however, severe post-transplant complications reflecting the syndromic nature of their disease appear to occur at higher rates. While these findings need to be expanded to other cohorts, caution should be exercised when approaching the transplant evaluation and management of this subset of pulmonary fibrosis patients.

Approximately one-third of lung transplant recipients have detectable HLA antibodies, which are associated with a worse prognosis regarding graft function and patient survival.

Aspergillus colonization after lung transplantation may increase the risk for bronchiolitis obliterans syndrome (BOS), a disease of small airways. We hypothesized that colonization with small conidia Aspergillus species would be associated with a greater risk of BOS, based upon an increased likelihood of deposition in small airways. We studied adult primary lung recipients from two large centers; 298 recipients at University of California, Los Angeles and 482 recipients at Duke University Medical Center. We grouped Aspergillus species by conidia diameter ≤3.5μm. We assessed the relationship of colonization with outcomes in Cox models. Pre-BOS colonization with small conidia Aspergillus species, but not large, was a risk factor for BOS (P = 0.002, HR 1.44, 95% CI 1.14–1.82), along with acute rejection, single lung, and Pseudomonas. Colonization with small conidia species also associated with risk of death (P = 0.03, HR 1.30, 95% CI 1.03–1.64). Although other virulence traits besides conidia size may be important, we have demonstrated in two large independent cohorts that colonization with small conidia Aspergillus species increases the risk of BOS and death. Prospective evaluation of strategies to prevent Aspergillus colonization of small airways is warranted, with the goal of preserving lung allograft function as long as possible.

Rationale: Cytomegalovirus pneumonitis is one of the most prevalent opportunistic infections after lung transplantation. Early studies reported that cytomegalovirus pneumonitis was a risk factor for chronic allograft dysfunction. More recently, in the era of routine prophylaxis and ganciclovir treatment, the adverse impact of treated cytomegalovirus pneumonitis on bronchiolitis obliterans syndrome has been challenged. Objectives: We hypothesized that cytomegalovirus pneumonitis contributes to adverse outcomes in the current antiviral era. We sought to define the impact of treated cytomegalovirus pneumonitis on bronchiolitis obliterans syndrome and survival in a large singlecenter cohort (n 5 231) of consecutive patients undergoing lung transplantation from 2000 to 2004, all receiving short-course ganciclovir prophylaxis. Methods: Transbronchial biopsies were performed at defined intervals with prospective cytomegalovirus immunostaining on every biopsy (n 5 1,887). Cox proportional hazards models were used to assess the relationship between treated cytomegalovirus pneumonitis and clinical outcomes. Measurements and Main Results: Forty-nine (21%) recipients developed cytomegalovirus pneumonitis a median of 106 days after transplantation. Treated cytomegalovirus pneumonitis within the first 6 months after transplantation significantly increased the risk for bronchiolitis obliterans syndrome (P 5 0.001; hazard ratio, 2.19; 95% confidence interval, 1.36-3.51) and post-transplantation death (P 5 0.02; hazard ratio, 1.89; 95% confidence interval, 1.11-3.23). This risk persisted when cytomegalovirus pneumonitis was considered as a time-dependent predictor as well as in multivariable models controlling for other risk factors. Conclusions: Cytomegalovirus pneumonitis affects more than 20% of lung transplant recipients. Despite treatment, it increases the risk for bronchiolitis obliterans syndrome and death. More effective preventive strategies for cytomegalovirus pneumonitis are needed to improve long-term outcomes after lung transplantation.

ClinicalTrials.gov; No.: NCT01766817; URL: www.clinicaltrials.gov.

The proteomic analysis of bronchoalveolar lavage fluid (BALF) can give insight into pulmonary disease pathology and response to therapy. Here, we describe the first gel-free quantitative analysis of BALF in idiopathic pulmonary fibrosis (IPF), a chronic and fatal scarring lung disease. We utilized two-dimensional reversed-phase liquid chromatography and ion-mobility-assisted data-independent acquisition (HDMSE) for quantitation of >1000 proteins in immunodepleted BALF from the right middle and lower lobes of normal controls and patients with IPF. Among the analytes that were increased in IPF were well-described mediators of pulmonary fibrosis (osteopontin, MMP7, CXCL7, CCL18), eosinophil- and neutrophil-derived proteins, and proteins associated with fibroblast foci. For additional discovery and targeted validation, BALF was also screened by multiple reaction monitoring (MRM), using the JPT Cytokine SpikeMix library of >400 stable isotope-labeled peptides. A refined MRM assay confirmed the robust expression of osteopontin, and demonstrated, for the first time, upregulation of the pro-fibrotic cytokine, CCL24, in BALF in IPF. These results show the utility of BALF proteomics for the molecular profiling of fibrotic lung diseases and the targeted quantitation of soluble markers of IPF. More generally, this study addresses critical quality control measures that should be widely applicable to BALF profiling in pulmonary disease.