Reduced levels of liver kinase B1 in small extracellular vesicles as a predictor for chronic lung allograft dysfunction in cystic fibrosis lung transplant recipients.

Small extracellular vesicles (sEVs) isolated from plasma of lung transplant recipients (LTRs) with chronic lung allograft dysfunction (CLAD) contain increased levels of lung associated self-antigens, Kα1 tubulin and collagen V, and decreased expression of the tumor suppressor liver kinase B1 (LKB1). In this study, sEVs were isolated from plasma collected from LTRs with or without cystic fibrosis (CF) from multiple centers at the onset of CLAD and 6 and 12 months before clinical diagnosis of CLAD (n = 32) as well as from time-matched stable controls (n = 25). sEVs were analyzed for Kα1 tubulin, collagen V, and LKB1 by western blot.

Collagen-V and K-α-1 Tubulin Antibodies as Potential Markers of Unsuspected GERD-Related Lung Damage: Insights from a Cross-Sectional Analysis.

Purpose: Our group has proposed that aspiration of gastric contents leads to exposure of normally sequestered lung self-antigens (SAgs), specifically collagen-V (Col-V) and K-α-1-tubulin (Kα1T), which elicits an immune response characterized by increasing concentrations of self-antibodies (SAbs) anti-Col-V and anti-Kα1T. We sought to establish the point prevalence of abnormally elevated concentrations of SAbs among patients with pathological gastroesophageal reflux disease (GERD) and/or hiatal hernia undergoing antireflux surgery (ARS).

Methods: For this cross-sectional study, we retrieved a plasma aliquot from the Norton Thoracic Institute BioBank from blood samples that were taken preoperatively from patients who underwent ARS between November 2019 and August 2022.

Noninvasive biomarkers for the detection of GERD-induced pulmonary injury.

Background: The role of gastroesophageal reflux in progressive lung damage is increasingly recognized. We have proposed, based on our work with lung transplant recipients, a novel immune mechanism of pulmonary injury after aspiration of gastric contents, during which higher levels of normally sequestered lung self-antigens (SAgs) collagen V (Col-V) and K-alpha-1 tubulin (Kα1T) in circulating small extracellular vesicles (EVs) induce the production of self-antibodies (SAbs) anti-Col-V and anti-Kα1T. Thus, we aimed to determine whether levels of SAbs or SAgs increased in an animal model of aspiration-induced lung damage in a nontransplant setting.

Enhanced enrichment of extracellular vesicles for laboratory and clinical research from drop-sized blood samples.

In the realm of biomedical advancement, extracellular vesicles (EVs) are revolutionizing our capacity to diagnose, monitor, and predict disease progression. However, the comprehensive exploration and clinical application of EVs face significant limitations due to the current isolation techniques. The size exclusion chromatography, commercial precipitation reagents, and ultracentrifugation are frequently employed, necessitating skilled operators and entailing challenges related to consistency, reproducibility, quality, and yields.

Study of association between antibodies to non-HLA kidney self-antigens and progression to chronic immune injury after kidney transplantation.

Background: Immune response to several kidney self-antigens (KSAg) such as Collagen IV (Col-IV), Perlecan (PL), and Fibronectin (FN) have been associated with antibody-mediated damage and poor allograft survival. Thus, the aim of this study was to determine if humoral immune responses to KSAg correlates with progression of chronic immune injury (CII) changes at 1 year or 2 years.

Methods: Kidney transplant recipients who underwent 1- or 2-year biopsies, with chronic interstitial inflammation (ci > 1) and/or glomerular membrane double contouring (cg > 0) were analyzed with matched controls.

Extracellular Vesicles in Transplantation: Friend or Foe.

The long-term function of transplanted organs, even under immunosuppression, is hindered by rejection, especially chronic rejection. Chronic rejection occurs more frequently after lung transplantation, termed chronic lung allograft dysfunction (CLAD), than after transplantation of other solid organs. Pulmonary infection is a known risk factor for CLAD, as transplanted lungs are constantly exposed to the external environment; however, the mechanisms by which respiratory infections lead to CLAD are poorly understood.

Circulating exosomes from brain death and cardiac death donors have distinct molecular and immunologic properties: A pilot study.

Background And Aims: Comparison of donation after brain death (DBD) and donation after cardiac death (DCD) lung tissue before transplantation have demonstrated activation of pro-inflammatory cytokine pathway in DBD donors. The molecular and immunological properties of circulating exosomes from DBD and DCD donors were not previously described.

Methods: We collected plasma from 18 deceased donors (12 DBD and six DCD).

Loss of IGFBP2 mediates alveolar type 2 cell senescence and promotes lung fibrosis.

Accumulation of senescent cells contributes to age-related diseases including idiopathic pulmonary fibrosis (IPF). Insulin-like growth factor binding proteins (IGFBPs) regulate many biological processes; however, the functional contributions of IGFBP2 in lung fibrosis remain largely unclear. Here, we report that intranasal delivery of recombinant IGFBP2 protects aged mice from weight loss and demonstrated antifibrotic effects after bleomycin lung injury.

Direct Correlation of Soluble HLA and HLA-Containing Exosomes and Inverse Correlation of Tolerance Marker-Containing Exosomes With Antibody-Mediated Rejection After Simultaneous Liver-Kidney Transplantation: A Case Study.

There is a lower incidence of antibody-mediated rejection (AMR) after simultaneous liver-kidney transplantation (SLKT) than after kidney-only transplantation. It has been suggested that soluble human leukocyte antigen (sHLA) produced by the liver protects the kidney from AMR. However, this hypothesis has not been tested after SLKT.

Role for exosomes with self-antigens and immune regulatory molecules in allo- and auto-immunity leading to chronic immune injury following murine kidney transplantation.

Objective: Antibodies against donor human leukocyte antigen are a risk factor for chronic immune injury (CII) following renal transplantation; however, it is often not detectable. The main goal of this study is to gain new insights into the kinetics of exosome release and content in sensitized vs non-sensitized recipients. Towards this, we investigated the role for circulating exosomes with allo and self-antigens as well as immunoregulatory molecules in the development of CII and acute rejection.

Low-dose IL-2 prevents murine chronic cardiac allograft rejection: Role for IL-2-induced T regulatory cells and exosomes with PD-L1 and CD73.

To determine the effects and immunological mechanisms of low-dose interleukin-2 (IL-2) in a murine model of chronic cardiac allograft rejection (BALB/c to C57BL/6) after costimulatory blockade consisting of MR1 (250 μg/ip day 0) and CTLA4-Ig (200 μg/ip day 2), we administered low-dose IL-2 (2000 IU/day) starting on posttransplant day 14 for 3 weeks. T regulatory (Treg) cell infiltration of the grafts was determined by immunohistochemistry; circulating exosomes by western blot and aldehyde bead flow cytometry; antibodies to donor MHC by immunofluorescent staining of donor cells; and antibodies to cardiac self-antigens (myosin, vimentin) by ELISA. We demonstrated that costimulation blockade after allogeneic heart transplantation induced circulating exosomes containing cardiac self-antigens and antibodies to both donor MHC and self-antigens, leading to chronic rejection by day 45.

Extracellular Vesicles Mediate Immune Responses to Tissue-Associated Self-Antigens: Role in Solid Organ Transplantations.

Transplantation is a treatment option for patients diagnosed with end-stage organ diseases; however, long-term graft survival is affected by rejection of the transplanted organ by immune and nonimmune responses. Several studies have demonstrated that both acute and chronic rejection can occur after transplantation of kidney, heart, and lungs. A strong correlation has been reported between synthesis of donor-specific antibodies (HLA-DSAs) and development of both acute and chronic rejection; however, some transplant recipients with chronic rejection do not have detectable HLA-DSAs.

Lung Transplant Candidates With Pretransplant Gastroesophageal Reflux and Antibodies to Lung Self-antigens Have Shorter CLAD-free Survival After Transplant.

Unlabelled: Pre-lung transplant (LTx) gastroesophageal reflux (GER) and circulating antibodies against the lung self-antigens (SAbs) collagen V and K-alpha-1 tubulin may predispose recipients to chronic lung allograft dysfunction (CLAD). We aimed to study the association of pre-LTx GER or pre-LTx SAbs with CLAD.

Methods: In this retrospective analysis of patients who underwent LTx between 2015 and 2019, pre-LTx GER and SAbs were dichotomously defined as present or absent.

Association Between Antibodies Against Lung Self-Antigens and Gastroesophageal Reflux in Lung Transplant Candidates.

Gastroesophageal reflux (GER) and pretransplant antibodies against lung self-antigens (SAbs) collagen-V and/or k-alpha 1 tubulin are both independently associated with allograft dysfunction after lung transplantation (LTx). The role of GER in inducing lung injury and SAbs is unknown. We aimed to study the association between pre-LTx GER and SAbs.

Novel role for tumor suppressor gene, liver kinase B1, in epithelial-mesenchymal transition leading to chronic lung allograft dysfunction.

Epithelial-mesenchymal transition (EMT) has been implicated to play a role in chronic lung allograft dysfunction (CLAD). Liver kinase B1 (LKB1), a tumor suppressor gene, can regulate EMT. However, its role in CLAD development following lung transplantation remains unknown.

A decline in club cell secretory proteins in lung transplantation is associated with release of natural killer cells exosomes leading to chronic rejection.

Background: In human lung transplant recipients, a decline in club cell secretory protein (CCSP) in bronchoalveolar lavage fluid has been associated with chronic lung allograft dysfunction (CLAD) as well as the induction of exosomes and immune responses that lead to CLAD. However, the mechanisms by which CCSP decline contributes to CLAD remain unknown.

Methods: To define the mechanisms leading to CCSP decline and chronic rejection, we employed two mouse models: 1) chronic rejection after orthotopic single lung transplantation and 2) anti-major histocompatibility complex (MHC) class I-induced obliterative airway disease.

CTOTC-08: A multicenter randomized controlled trial of rituximab induction to reduce antibody development and improve outcomes in pediatric lung transplant recipients.

We conducted a randomized, placebo-controlled, double-blind study of pediatric lung transplant recipients, hypothesizing that rituximab plus rabbit anti-thymocyte globulin induction would reduce de novo donor-specific human leukocyte antigen antibodies (DSA) development and improve outcomes. We serially obtained clinical data, blood, and respiratory samples for at least one year posttransplant. We analyzed peripheral blood lymphocytes by flow cytometry, serum for antibody development, and respiratory samples for viral infections using multiplex PCR.

Distinct molecular and immunological properties of circulating exosomes isolated from pediatric lung transplant recipients with bronchiolitis obliterans syndrome - a retrospective study.

Long-term success following human lung transplantation is poor due to chronic rejection. We demonstrated circulating exosomes of lung origin during acute and chronic lung allograft rejection. We analyzed plasma from pediatric lung transplant recipients (LTxRs) enrolled in the CTOT-C-03 to determine whether circulating exosomes are released into circulation during bronchiolitis obliterans syndrome (BOS).

Donor-derived regulatory dendritic cell infusion results in host cell cross-dressing and T cell subset changes in prospective living donor liver transplant recipients.

Regulatory dendritic cells (DCreg) promote transplant tolerance following their adoptive transfer in experimental animals. We investigated the feasibility, safety, fate, and impact on host T cells of donor monocyte-derived DCreg infused into prospective, living donor liver transplant patients, 7 days before transplantation. The DCreg expressed a tolerogenic gene transcriptional profile, high cell surface programed death ligand-1 (PD-L1):CD86 ratios, high IL-10/no IL-12 productivity and poor ability to stimulate allogeneic T cell proliferation.

Decline in Club Cell Secretory Proteins, Exosomes Induction and Immune Responses to Lung Self-antigens, Kα1 Tubulin and Collagen V, Leading to Chronic Rejection After Human Lung Transplantation.

Background: Chronic lung allograft dysfunction (CLAD), is a major hurdle for long-term lung allograft survival after lung transplant and roughly 50% of lung transplant recipients (LTxRs) develop CLAD within 5 years. The mechanisms of CLAD development remain unknown. Donor-specific immune responses to HLA and lung self-antigens (SAgs) are vital to the pathogenesis of CLAD.

Circulating exosomes with lung self-antigens as a biomarker for chronic lung allograft dysfunction: A retrospective analysis.

Background: Exosomes isolated from plasma of lung transplant recipients (LTxRs) with bronchiolitis obliterans syndrome (BOS) contain human leukocyte antigens and lung self-antigens (SAgs), K-alpha 1 tubulin (Kα1T) and collagen type V (Col-V). The aim was to determine the use of circulating exosomes with lung SAgs as a biomarker for BOS.

Methods: Circulating exosomes were isolated retrospectively from plasma from LTxRs at diagnosis of BOS and at 6 and 12 months before the diagnosis (n = 41) and from stable time-matched controls (n = 30) at 2 transplant centers by ultracentrifugation.

Respiratory viral infection in lung transplantation induces exosomes that trigger chronic rejection.

Background: Respiratory viral infections can increase the risk of chronic lung allograft dysfunction after lung transplantation, but the mechanisms are unknown. In this study, we determined whether symptomatic respiratory viral infections after lung transplantation induce circulating exosomes that contain lung-associated self-antigens and assessed whether these exosomes activate immune responses to self-antigens.

Methods: Serum samples were collected from lung transplant recipients with symptomatic lower- and upper-tract respiratory viral infections and from non-symptomatic stable recipients.

A novel mechanism for immune regulation after human lung transplantation.

Objective: Lung transplantation is therapeutic for end-stage lung disease, but survival is limited due to bronchiolitis obliterans syndrome and restrictive chronic lung allograft dysfunction. We sought a common denominator in lung transplant recipients, analyzing risk factors that trigger immune responses that lead to bronchiolitis obliterans syndrome.

Methods: We collected blood from patients who underwent lung transplant at our institution.

The role of donor-derived exosomes in lung allograft rejection.

Lung transplant recipients (LTxRs) with acute or chronic rejection release circulating exosomes that mostly originate from donor lung tissue and express mismatched human leucocyte antigens (HLA) and lung-associated self-antigens (SAgs), Collagen-V and K alpha 1 Tubulin. During lung transplant (LTx), donor lungs often undergo injuries that increase the antigenicity of the transplanted organ. 30% of LTxRs also have pre-transplant antibodies (Abs) to HLA and lung SAgs, which may induce conditions that increase the risk of chronic lung allograft dysfunction (CLAD).