The next-generation cystic fibrosis transmembrane conductance regulator (CFTR) corrector VX-659, in triple combination with tezacaftor and ivacaftor (VX-659-tezacaftor-ivacaftor), was developed to ...restore the function of Phe508del CFTR protein in patients with cystic fibrosis.
We evaluated the effects of VX-659-tezacaftor-ivacaftor on the processing, trafficking, and function of Phe508del CFTR protein using human bronchial epithelial cells. A range of oral VX-659-tezacaftor-ivacaftor doses in triple combination were then evaluated in randomized, controlled, double-blind, multicenter trials involving patients with cystic fibrosis who were heterozygous for the Phe508del CFTR mutation and a minimal-function CFTR mutation (Phe508del-MF genotypes) or homozygous for the Phe508del CFTR mutation (Phe508del-Phe508del genotype). The primary end points were safety and the absolute change from baseline in the percentage of predicted forced expiratory volume in 1 second (FEV
).
VX-659-tezacaftor-ivacaftor significantly improved the processing and trafficking of Phe508del CFTR protein as well as chloride transport in vitro. In patients, VX-659-tezacaftor-ivacaftor had an acceptable safety and side-effect profile. Most adverse events were mild or moderate. VX-659-tezacaftor-ivacaftor resulted in significant mean increases in the percentage of predicted FEV
through day 29 (P<0.001) of up to 13.3 points in patients with Phe508del-MF genotypes; in patients with the Phe508del-Phe508del genotype already receiving tezacaftor-ivacaftor, adding VX-659 resulted in a further 9.7-point increase in the percentage of predicted FEV
. The sweat chloride concentrations and scores on the respiratory domain of the Cystic Fibrosis Questionnaire-Revised improved in both patient populations.
Robust in vitro activity of VX-659-tezacaftor-ivacaftor targeting Phe508del CFTR protein translated into improvements for patients with Phe508del-MF or Phe508del-Phe508del genotypes. VX-659 triple-combination regimens have the potential to treat the underlying cause of disease in approximately 90% of patients with cystic fibrosis. (Funded by Vertex Pharmaceuticals; VX16-659-101 and VX16-659-001 ClinicalTrials.gov numbers, NCT03224351 and NCT03029455 .).
Anesthetics are known to modulate host immune responses, but separating the variables of surgery from anesthesia when analyzing hospital acquired infections is often difficult. Here, the bacterial ...pathogen Listeria monocytogenes (Lm) was used to assess the impact of the common anesthetic propofol on host susceptibility to infection. Brief sedation of mice with physiologically relevant concentrations of propofol increased bacterial burdens in target organs by more than 10,000-fold relative to infected control animals. The adverse effects of propofol sedation on immune clearance of Lm persisted after recovery from sedation, as animals given the drug remained susceptible to infection for days following anesthesia. In contrast to propofol, sedation with alternative anesthetics such as ketamine/xylazine or pentobarbital did not increase susceptibility to systemic Lm infection. Propofol altered systemic cytokine and chemokine expression during infection, and prevented effective bacterial clearance by inhibiting the recruitment and/or activity of immune effector cells at sites of infection. Propofol exposure induced a marked reduction in marginal zone macrophages in the spleens of Lm infected mice, resulting in bacterial dissemination into deep tissue. Propofol also significantly increased mouse kidney abscess formation following infection with the common nosocomial pathogen Staphylococcus aureus. Taken together, these data indicate that even brief exposure to propofol severely compromises host resistance to microbial infection for days after recovery from sedation.
Obliterative bronchiolitis (OB), characterized by fibrous obliteration of the small airways, is a major impediment to long-term survival in lung allograft recipients. We found previously that IL-17A ...is produced primarily by CD4
T cells and γδ T cells after lung transplant in a mouse model of orthotopic lung transplant. The absence of either subset of T cells was compensated for by expansion of the other subset, which suggested that systemic blockade of IL-17A was necessary. To determine the specific role of IL-17A in the development of OB, we treated lung allograft recipients with an IL-17A antagonistic antibody. After IL-17A blockade, the incidence of OB was significantly reduced in lung allografts. IL-17A blockade also significantly attenuated the severity of acute rejection and overall lung fibrosis. The decreased OB incidence was associated with reduced lymphocyte recruitment, particularly CD8
T cells and other IFN-γ-producing lymphocytes, to the lung allograft. Interestingly, IL-17A blockade led to an increase in the frequency of IL-17A-producing T-helper cell type 17 cells and γδ T cells in lung allografts, suggesting that IL-17A is a negative regulator of these T cells. Our data suggest that blocking IL-17A after lung transplant reduces the overall IFN-γ-mediated lymphocyte response and decreases the development of OB.
In the past decade, advances in immunology have led to the recognition that T cell differentiation is not simply Th1 or Th2 but involves differentiation to other subsets, such as T regulatory cells, ...T follicular helper cells, and Th17 cells. Th17 cells, characterized by production of IL-17, IL-22, and IL-21, have been implicated in the pathogenesis of autoimmune diseases, like rheumatoid arthritis and multiple sclerosis, but also play an important role in host defense and mucosal immunity. IL-17, with its pleiotropic effects on stromal cells, as well as hematopoietic cells, has long been recognized as a possible mediator of rejection after lung transplantation. Recent data have implicated IL-17 and Th17 cells in the development of autoimmunity and chronic rejection after lung transplantation in both animal models and humans. In this review, we will discuss the current data on Th17 and the prospects for the future for lung transplantation.
Lung transplant survival is limited by obliterative bronchiolitis (OB), but the mechanisms of OB development are unknown. Previous studies in a mouse model of orthotopic lung transplantation ...suggested a requirement for IL‐17. We have used this orthotopic mouse model to investigate the source of IL‐17A and the requirement for T cells producing IL‐17A. The major sources of IL‐17A were CD4+ T cells and γδ T cells. Depletion of CD4+ T cells led to a significantly decreased frequency and number of IL‐17A+ lymphocytes and was sufficient to prevent acute rejection and OB. However, mice with STAT3‐deficient T cells, which are unable to differentiate into Th17 cells, rejected lung allografts and developed OB similar to control mice. The frequency of IL‐17A+ cells was not decreased in mice with STAT3‐deficient T cells due mainly to the presence of IL‐17A+ γδ T cells. Deficiency of γδ T cells also did not affect the development of airway fibrosis. Our data suggest that CD4+ T cells are required for OB development and expansion of IL‐17A responses in the lung, while Th17 and γδ T cells are not absolutely required and may compensate for each other.
This study finds that CD4+ T cell deficiency attenuates the IL‐17 immune response and prevents lung transplant obliterative bronchiolitis in a mouse model, but the absence of either major source of IL‐17, Th17 cells or yδ T cells, is not sufficient to prevent allograft rejection and airway fibrosis.
γδ T cells producing interleukin-17A (γδT17) are thought to develop spontaneously in the thymus and to be maintained in the periphery. Previous studies suggested a role for T-helper 17 (Th17) cells ...in the maintenance of γδT17 via the expression of transforming growth factor-β1 (TGFβ1). However, we have previously found that Th17 cells were not required for expansion of γδT17 cells after lung transplant in a mouse model. Using mice deficient in signal transducer and activator of transcription 3 (STAT3) in CD4
T cells, which are unable to develop Th17 cells, we investigated the requirement for Th17 cells and TGFβ1 to maintain γδT17 cells in the lung and lymphoid tissues. At steady state, we found no defect in γδT17 cells in the thymus or periphery of these mice. Further, STAT3-deficient CD4
T cells produced significantly higher levels of TGFβ1 than wild-type CD4
T cells under Th17 differentiation conditions in vitro. To determine whether STAT3-deficient CD4
T cells could expand γδT17 cells in vivo, we used TCRβ
mice, which are known to have a defect in γδT17 cells that can be rescued by Th17 cells. However, adoptive transfer of wild-type Th17 cells or bulk CD4
T cells did not expand γδT17 cells in TCRβ
mice. In contrast, interferon-γ
γδ T cells preferentially expanded, particularly in the lungs. Interestingly, we found in vivo and in vitro that TGFβ1 may negatively regulate the pool of γδT17 cells. Our data suggest that Th17 cells and TGFβ1 are not required for the maintenance of γδT17 cells.
Lung transplantation remains the hope for many incurable pulmonary diseases, such as cystic fibrosis, pulmonary fibrosis, and chronic obstructive pulmonary disease. Remarkable progress has been made ...in improving outcomes, although the incidence of acute rejection remains more than 50% in the 1st year, and the 5-year graft survival is still less than 50% primarily because of the development of chronic rejection and graft dysfunction. Chronic rejection is characterized by the development of obliterative bronchiolitis in allografts and manifests as bronchiolitis obliterans syndrome in humans with no effective treatment. Previous studies support a role for alloreactive T cells in the development of bronchiolitis obliterans syndrome, but the specific mechanisms are unknown. One major stumbling block to research in the field of lung transplantation has been the lack of physiologic models to study the disease in the laboratory. We will review the current understanding of the immunology of the pathogenesis of obliterative bronchiolitis and will discuss exciting new advances from the laboratory as well as the implications for future research in lung transplantation.
Lung transplantation, a cure for a number of end-stage lung diseases, continues to have the worst long-term outcomes when compared with other solid organ transplants. Preclinical modeling of the most ...common and serious lung transplantation complications are essential to better understand and mitigate the pathophysiological processes that lead to these complications. Various animal and in vitro models of lung transplant complications now exist and each of these models has unique strengths. However, significant issues, such as the required technical expertise as well as the robustness and clinical usefulness of these models, remain to be overcome or clarified. The National Heart, Lung, and Blood Institute (NHLBI) convened a workshop in March 2016 to review the state of preclinical science addressing the three most important complications of lung transplantation: primary graft dysfunction (PGD), acute rejection (AR), and chronic lung allograft dysfunction (CLAD). In addition, the participants of the workshop were tasked to make consensus recommendations on the best use of these complimentary models to close our knowledge gaps in PGD, AR, and CLAD. Their reviews and recommendations are summarized in this report. Furthermore, the participants outlined opportunities to collaborate and directions to accelerate research using these preclinical models.
Memory CD4 T cells play a vital role in protection against re-infection by pathogens as diverse as helminthes or influenza viruses. Inducible costimulator (ICOS) is highly expressed on memory CD4 T ...cells and has been shown to augment proliferation and survival of activated CD4 T cells. However, the role of ICOS costimulation on the development and maintenance of memory CD4 T cells remains controversial. Herein, we describe a significant defect in the number of effector memory (EM) phenotype cells in ICOS(-/-) and ICOSL(-/-) mice that becomes progressively more dramatic as the mice age. This decrease was not due to a defect in the homeostatic proliferation of EM phenotype CD4 T cells in ICOS(-/-) or ICOSL(-/-) mice. To determine whether ICOS regulated the development or survival of EM CD4 T cells, we utilized an adoptive transfer model. We found no defect in development of EM CD4 T cells, but long-term survival of ICOS(-/-) EM CD4 T cells was significantly compromised compared to wild-type cells. The defect in survival was specific to EM cells as the central memory (CM) ICOS(-/-) CD4 T cells persisted as well as wild type cells. To determine the physiological consequences of a specific defect in EM CD4 T cells, wild-type and ICOS(-/-) mice were infected with influenza virus. ICOS(-/-) mice developed significantly fewer influenza-specific EM CD4 T cells and were more susceptible to re-infection than wild-type mice. Collectively, our findings demonstrate a role for ICOS costimulation in the maintenance of EM but not CM CD4 T cells.
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