Implications for human leukocyte antigen antibodies after lung transplantation: a 10-year experience in 441 patients

Impact of forced vital capacity loss on survival after the onset of chronic lung allograft dysfunction

RATIONALE

Emerging evidence suggests a restrictive phenotype of chronic lung allograft dysfunction (CLAD) exists; however, the optimal approach to its diagnosis and clinical significance is uncertain.

OBJECTIVES

To evaluate the hypothesis that spirometric indices more suggestive of a restrictive ventilatory defect, such as loss of FVC, identify patients with distinct clinical, radiographic, and pathologic features, including worse survival.

METHODS

Retrospective, single-center analysis of 566 consecutive first bilateral lung recipients transplanted over a 12-year period. A total of 216 patients developed CLAD during follow-up. CLAD was categorized at its onset into discrete physiologic groups based on spirometric criteria. Imaging and histologic studies were reviewed when available. Survival after CLAD diagnosis was assessed using Kaplan-Meier and Cox proportional hazards models.

MEASUREMENTS AND MAIN RESULTS

Among patients with CLAD, 30% demonstrated an FVC decrement at its onset. These patients were more likely to be female, have radiographic alveolar or interstitial changes, and histologic findings of interstitial fibrosis. Patients with FVC decline at CLAD onset had significantly worse survival after CLAD when compared with those with preserved FVC (P < 0.0001; 3-yr survival estimates 9% vs. 48%, respectively). The deleterious impact of CLAD accompanied by FVC loss on post-CLAD survival persisted in a multivariable model including baseline demographic and clinical factors (P < 0.0001; adjusted hazard ratio, 2.73; 95% confidence interval, 1.86-4.04).

CONCLUSIONS

At CLAD onset, a subset of patients demonstrating physiology more suggestive of restriction experience worse clinical outcomes. Further study of the biologic mechanisms underlying CLAD phenotypes is critical to improving long-term survival after lung transplantation.

Vessel rejection secondary to human leucocyte antigen antibodies directed against the arterial conduit following pancreas transplantation from a separate donor

Whole-organ pancreas transplantation is typically carried out using a Y-graft derived from the donor iliac vessels. We describe a case in which a 31-year-old male underwent a simultaneous pancreas-kidney transplant, but in which vessels from a different donor were used for the arterial anastomosis of the pancreas graft. Although initially there was good function, 18 months post-transplant the patient was admitted with diabetic ketoacidosis secondary to pancreas graft failure. Radiological investigations revealed complete occlusion of the vascular Y-graft, and laboratory investigations demonstrated donor-specific human leucocyte antigen (HLA) antibodies directed against HLA mismatches of the vessel donor. This case highlights the risks of using allogeneic vascular material for surgical anastomoses.

Banff 2013 meeting report: inclusion of c4d-negative antibody-mediated rejection and antibody-associated arterial lesions

The 12th Banff Conference on Allograft Pathology was held in Comandatuba, Brazil, from August 19-23, 2013, and was preceded by a 2-day Latin American Symposium on Transplant Immunobiology and Immunopathology. The meeting was highlighted by the presentation of the findings of several working groups formed at the 2009 and 2011 Banff meetings to: (1) establish consensus criteria for diagnosing antibody-mediated rejection (ABMR) in the presence and absence of detectable C4d deposition; (2) develop consensus definitions and thresholds for glomerulitis (g score) and chronic glomerulopathy (cg score), associated with improved inter-observer agreement and correlation with clinical, molecular and serological data; (3) determine whether isolated lesions of intimal arteritis ("isolated v") represent acute rejection similar to intimal arteritis in the presence of tubulointerstitial inflammation; (4) compare different methodologies for evaluating interstitial fibrosis and for performing/evaluating implantation biopsies of renal allografts with regard to reproducibility and prediction of subsequent graft function; and (5) define clinically and prognostically significant morphologic criteria for subclassifying polyoma virus nephropathy. The key outcome of the 2013 conference is defining criteria for diagnosis of C4d-negative ABMR and respective modification of the Banff classification. In addition, three new Banff Working Groups were initiated.

[Lung transplantation]

Lung transplantation is a therapeutic option for patients with end-stage lung diseases. Selection of candidates requires careful consideration of the disease-specific indications and contraindications for transplantation. Advances have been made in candidate selection via the ability to prognosticate outcomes of various lung diseases and through the implementation of the lung allocation score (LAS) with specific consideration of the degree of urgency and good postoperative survival rate, after neglecting the waiting time. This system has resulted in decreased mortality on the waiting list for lung transplantation. The availability of donor organs can possibly be increased by implementation of ex vivo lung perfusion as an alternative to conventional organ preservation. Risk factors for poor outcomes post-lung transplantation have been identified and understanding of the physiological, cellular and molecular mechanisms responsible for lung and airway damage has been extensively expanded. Primary graft dysfunction, infectious diseases, acute rejection, antibody-mediated rejection, lymphocytic bronchiolitis, obliterative bronchiolitis, restrictive allograft syndrome, and chronic lung allograft dysfunction are well defined complications and continue to be common causes of morbidity and mortality. This article provides a comprehensive update on these topics for the non-transplantation clinician.

CXCR3 ligands are associated with the continuum of diffuse alveolar damage to chronic lung allograft dysfunction

RATIONALE

After lung transplantation, insults to the allograft generally result in one of four histopathologic patterns of injury: (1) acute rejection, (2) lymphocytic bronchiolitis, (3) organizing pneumonia, and (4) diffuse alveolar damage (DAD). We hypothesized that DAD, the most severe form of acute lung injury, would lead to the highest risk of chronic lung allograft dysfunction (CLAD) and that a type I immune response would mediate this process.

OBJECTIVES

Determine whether DAD is associated with CLAD and explore the potential role of CXCR3/ligand biology.

METHODS

Transbronchial biopsies from all lung transplant recipients were reviewed. The association between the four injury patterns and subsequent outcomes were evaluated using proportional hazards models with time-dependent covariates. Bronchoalveolar lavage (BAL) concentrations of the CXCR3 ligands (CXCL9/MIG, CXCL10/IP10, and CXCL11/ITAC) were compared between allograft injury patterns and "healthy" biopsies using linear mixed-effects models. The effect of these chemokine alterations on CLAD risk was assessed using Cox models with serial BAL measurements as time-dependent covariates.

MEASUREMENTS AND MAIN RESULTS

There were 1,585 biopsies from 441 recipients with 62 episodes of DAD. An episode of DAD was associated with increased risk of CLAD (hazard ratio, 3.0; 95% confidence interval, 1.9-4.7) and death (hazard ratio, 2.3; 95% confidence interval, 1.7-3.0). There were marked elevations in BAL CXCR3 ligand concentrations during DAD. Furthermore, prolonged elevation of these chemokines in serial BAL fluid measurements predicted the development of CLAD.

CONCLUSIONS

DAD is associated with marked increases in the risk of CLAD and death after lung transplantation. This association may be mediated in part by an aberrant type I immune response involving CXCR3/ligands.

Transplantation: Autoantibodies-epiphenomena or biological clues

The potential roles for autoantibodies in renal transplantation are increasing, as illustrated by a recent report of polyreactive autoantibodies produced by B-cell clones from a kidney transplant recipient that can bind apoptotic cells and activate complement. Such autoantibodies have the potential to amplify microcirculation injury caused by alloantibody in antibody-mediated transplant rejection.