Publications by authors named "Mark Robien"

Rationale: Chronic lung allograft dysfunction (CLAD) hinders lung transplant success. A 2019 consensus refined CLAD diagnosis, introducing probable or definite CLAD based on persistence of lung function decline. Outcomes and risks for probable CLAD remain uncertain.

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Article Synopsis
  • Poor agreement among lung transplant pathologists in assessing rejection has been noted, making inter-rater reliability crucial for effective patient care and clinical trial inclusion criteria.
  • A survey and diagnostic sessions with nine pathologists from eight centers evaluated their practices and scoring of high-risk histopathologic findings related to chronic lung allograft dysfunction (CLAD).
  • The results showed good inter-rater reliability for identifying high-risk findings after these alignment sessions, indicating that collaborative discussions improved consensus among pathologists.
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Unlabelled: Solid organ transplant recipients (SOTRs) suffer more frequent and more severe infections due to their compromised immune responses resulting from immunosuppressive treatments designed to prevent organ rejection. Pharmacological immunosuppression can adversely affect immune responses to vaccination. A cohort of kidney transplant recipients (KTRs) received their third dose of ancestral, monovalent COVID-19 vaccine in the context of a clinical trial and antibody responses to the vaccine strain, as well as to Omicron variants BA.

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Background: Kidney transplant recipients (KTRs) generate lower antibody responses to messenger RNA (mRNA)-based severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination, yet precise mechanisms for this poor response remain uncertain. One potential contributor is suboptimal spike antigen (sAg) translation and expression owing to transplant immunosuppression, which might lead to insufficient exposure to develop humoral and/or cellular immune responses.

Methods: Within a single-arm clinical trial, 65 KTRs underwent ultrasensitive plasma sAg testing before, and 3 and 14 days after, the third mRNA vaccine doses.

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Kidney transplant recipients (KTRs) develop decreased antibody titers to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination compared to healthy controls (HCs), but whether KTRs generate antibodies against key epitopes associated with neutralization is unknown. Plasma from 78 KTRs from a clinical trial of third doses of SARS-CoV-2 vaccines and 12 HCs underwent phage display immunoprecipitation and sequencing (PhIP-Seq) to map antibody responses against SARS-CoV-2. KTRs had lower antibody reactivity to SARS-CoV-2 than HCs, but KTRs and HCs recognized similar epitopes associated with neutralization.

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Introduction: In pancreatic islet transplantation, the exact contribution of human leukocyte antigen (HLA) matching to graft survival remains unclear. Islets may be exposed to allogenic rejection but also the recurrence of type 1 diabetes (T1D). We evaluated the HLA-DR matching, including the impact of diabetogenic HLA-DR3 or HLA-DR4 matches.

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Epstein-Barr virus (EBV)-positive posttransplant lymphoproliferative disorder (PTLD) results in significant morbidity and mortality in pediatric transplant recipients. Identifying individuals at an increased risk of EBV-positive PTLD could influence clinical management of immunosuppression and other therapies, improving posttransplant outcomes. A 7-center prospective, observational clinical trial of 872 pediatric transplant recipients evaluated the presence of mutations at positions 212 and 366 of EBV latent membrane protein 1 (LMP1) as an indicator of risk of EBV-positive PTLD (clinical trials: NCT02182986).

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Article Synopsis
  • PTLD (Post-transplant lymphoproliferative disorder) is a serious risk for organ transplant recipients and is linked to factors like EBV infection and weakened immune response due to immunosuppression.
  • Previous research revealed that EBV affects the microRNA expression in B cells, specifically suppressing miR-194 in EBV-positive PTLD, but studies on circulating miRs in PTLD patients were lacking.
  • The current study found significantly lower levels of several miRs (including miR-194, 17, 19, and 106a) in the plasma and extracellular vesicles of pediatric transplant recipients with EBV+ PTLD, indicating that these miRs
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We determined prognostic implications of acute lung injury (ALI) and organizing pneumonia (OP), including timing relative to transplantation, in a multicenter lung recipient cohort. We sought to understand clinical risks that contribute to development of ALI/OP. We analyzed prospective, histologic diagnoses of ALI and OP in 4786 lung biopsies from 803 adult lung recipients.

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Histopathologic lung allograft injuries are putative harbingers for chronic lung allograft dysfunction (CLAD). However, the mechanisms responsible are not well understood. CXCL9 and CXCL10 are potent chemoattractants of mononuclear cells and potential propagators of allograft injury.

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The histopathologic diagnosis of acute allograft injury is prognostically important in lung transplantation with evidence demonstrating a strong and consistent association between acute rejection (AR), acute lung injury (ALI), and the subsequent development of chronic lung allograft dysfunction (CLAD). The pathogenesis of these allograft injuries, however, remains poorly understood. CXCL9 and CXCL10 are CXC chemokines induced by interferon-γ and act as potent chemoattractants of mononuclear cells.

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Depletional induction using antithymocyte globulin (ATG) reduces rates of acute rejection in adult kidney transplant recipients, yet little is known about its effects in children. Using a longitudinal cohort of 103 patients in the Immune Development in Pediatric Transplant (IMPACT) study, we compared T cell phenotypes after ATG or non-ATG induction. We examined the effects of ATG on the early clinical outcomes of alloimmune events (development of de novo donor specific antibody and/or biopsy proven rejection) and infection events (viremia/viral infections).

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Background: Transplant recipients with HIV may have worse outcomes with coronavirus disease 2019 (COVID-19) due to impaired T-cell function coupled with immunosuppressive drugs. Alternatively, immunosuppression might reduce inflammatory complications and/or antiretrovirals could be protective.

Methods: Prospective reporting of all cases of SARS-CoV-2 infection was required within the HOPE in Action Multicenter Consortium, a cohort of kidney and liver transplant recipients with HIV who have received organs from donors with and without HIV at 32 transplant centers in the United States.

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Immunosuppression devoid of corticosteroids has been investigated to avoid long-term comorbidities. Likewise, alternatives to calcineurin inhibitors have been investigated as a strategy to improve long-term kidney function following transplanion. Costimulatory blockade strategies that include corticosteroids have recently shown promise, despite their higher rates of early acute rejection.

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Acute rejection, manifesting as lymphocytic inflammation in a perivascular (acute perivascular rejection [AR]) or peribronchiolar (lymphocytic bronchiolitis [LB]) distribution, is common in lung transplant recipients and increases the risk for chronic graft dysfunction. To evaluate clinical factors associated with biopsy-proven acute rejection during the first post-transplant year in a present-day, five-center lung transplant cohort. We analyzed prospective diagnoses of AR and LB from over 2,000 lung biopsies in 400 newly transplanted adult lung recipients.

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In a phase 2 multicenter open-label randomized trial sponsored by the National Institutes of Health, simultaneous pancreas-kidney (SPK) recipients were randomized to a calcineurin inhibitor (CNI)-based immunosuppressive regimen (tacrolimus) (n = 21), or an investigational arm using low-dose CNI plus costimulation blockade (belatacept) with intended CNI withdrawal (n = 22). Both arms included induction therapy with rabbit ATG, mycophenolate sodium, or mycophenolate mofetil and rapid withdrawal of steroids. Enrollment and CNI withdrawal were stopped after 43/60 planned subjects had been enrolled.

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Objective: Impaired awareness of hypoglycemia (IAH) and severe hypoglycemic events (SHEs) cause substantial morbidity and mortality in patients with type 1 diabetes (T1D). Current therapies are effective in preventing SHEs in 50-80% of patients with IAH and SHEs, leaving a substantial number of patients at risk. We evaluated the effectiveness and safety of a standardized human pancreatic islet product in subjects in whom IAH and SHEs persisted despite medical treatment.

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Background: In long-standing type 1 diabetes (T1D), loss of endogenous insulin secretion and glucose dysregulation can lead to severe hypoglycemia and associated complications. Here, we report the serial consistency and the correlation between different scores that characterize glucose dysregulation using self-monitoring of blood glucose (SMBG), in a cohort of T1D individuals being evaluated for transplant eligibility in Clinical Islet Transplantation Consortium trials.

Subjects And Methods: In total, 152 C-peptide-negative T1D subjects with at least one severe hypoglycemia episode in the prior year documented SMBG at enrollment and every 6 months until deemed ineligible or transplanted.

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Major national surveys do not collect the influenza vaccination status of all household members, thus limiting current understanding of household influenza vaccination patterns. In an early 2009 telephone survey of 800 households in the metropolitan Minneapolis-St Paul area, household respondents reported the age, gender, and 2008-2009 seasonal influenza vaccination status of all household members. After poststratification to adjust for nonresponse, the full household influenza vaccination rate for multiperson households is 35.

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The Structural Genomics of Pathogenic Protozoa (SGPP) Consortium aimed to determine crystal structures of proteins from trypanosomatid and malaria parasites in a high throughput manner. The pipeline of target selection, protein production, crystallization, and structure determination, is sketched. Special emphasis is given to a number of technology developments including domain prediction, the use of "co-crystallants," and capillary crystallization.

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The crystal structure of D-glyceraldehyde-3-phosphate dehydrogenase (PfGAPDH) from the major malaria parasite Plasmodium falciparum is solved at 2.25 A resolution. The structure of PfGAPDH is of interest due to the dependence of the malaria parasite in infected human erythrocytes on the glycolytic pathway for its energy generation.

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Purine metabolism in the parasite Plasmodium has been identified as a promising target for antimalarial therapies. Purine nucleoside phosphorylase (PNP) is part of a salvage pathway for the biosynthesis of purines, which are essential for parasite survival. Two crystal structures of PNP from Plasmodium falciparum (PfPNP) in two space groups, each with a single subunit in the asymmetric unit, are described here.

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Structural biology studies on cholera toxin and the closely related heat-labile enterotoxin from enterotoxigenic Escherichia coli over the past decade have shed light on the mechanism of toxin action at molecular and atomic levels. Also, components of the extracellular protein secretion apparatus that translocate the toxins across the outer membrane are being investigated. At the same time, structure-based design has led to various classes of compounds targeting different toxin sites, including highly potent multivalent inhibitors that block the toxin receptor-binding process.

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Article Synopsis
  • An altered version of peptide deformylase from Plasmodium falciparum has been successfully cocrystallized with a synthesized inhibitor, revealing a strong binding affinity.
  • The new crystal structure is determined at 2.2 A resolution, which is an improvement over the previous 2.8 A resolution of the unliganded PfPDF, thanks to modifications made to the protein construct.
  • This study presents the first-ever structure of a eukaryotic PDF protein in complex with a ligand, highlighting its potential as a drug target for malaria treatment.
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