Πέμπτη 20 Ιουνίου 2019

Transplantation

An interdisciplinary approach to the older transplant patient: strategies for improving clinical outcomes
Purpose of review Describe the latest investigations into the role of frailty and assessment of other aging-related issues in the solid organ transplant candidate and recipient. This information is relevant for all involved in the care of transplant patients, but is especially relevant in infectious diseases, given the increased burden of infection seen in older and frailer patients. Recent findings The Fried Frailty Phenotype (FFP) and Short Performance Physical Battery (SPPB) are well validated tools for measuring frailty in older adults. Recently, these frailty tools have also been used to predict a range of clinical outcomes in adults with endstage organ disease undergoing advanced therapies including mechanical circulatory device (MCSD) or transplantation including death on the waiting list, length of hospital stay, need for readmission, infection, and death. Frailty may also be estimated by chart review and comorbidity assessment. Other aging-related evaluations of interest are cognitive function, sarcopenia, and nutritional status. The strength of association for each tool varies by the type of end organ disease, although there are many findings in common across organ types. Summary As trends in the aging of the population continue to impact transplant and MCSD candidates and recipients, it is increasingly important for providers to be cognizant of the methods for assessment of aging-associated dysfunction including frailty and sarcopenia. Correspondence to Joanna Schaenman, Division of Infectious Diseases, Department of Medicine, David Geffen School of medicine at UCLA, CHS 37-121, Los Angeles, CA 90095, USA. Tel: +1 310 825 7225; e-mail: jschaenman@mednet.ucla.edu Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Kidney transplantation across minor ABO incompatibility: the use of A: 2: to B transplants
Purpose of review On 4 December 2014, the new kidney allocation system (KAS) went into effect. As part of this system, UNOS approved for the first time a national system with a specific mechanism affording priority to allocate kidneys across so-called 'minor ABO incompatibility' from blood group A2 donors into blood group B recipients. This significantly increased the number of such transplants done and the opportunities to learn about the specifics of such transplants. Recent findings A2 to B transplants have been demonstrated to be well tolerated, effective, and cost-effective ways of addressing disparities in the allocation system. Further data about the use of anti-A titers and the limits to successful transplant have better defined the bounds of who can benefit from such transplants. Summary The success thus far with A2 to B transplants should increase comfort and acceptance of the allocation policy changes and we should see further increases in centers willing to use such transplants to better address inequalities in the system. Correspondence to Alexander J. Gilbert, MD, 3800 Reservoir Road, NW, PHC Building, 2nd Floor, Washington DC 20007, USA. Tel: +1 202 444 0621; e-mail: Alexander.J.Gilbert@gunet.georgetown.edu Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Machine perfusion in kidney transplantation
Purpose of review The shortage of kidneys for transplantation has led to an urgent need to efficiently utilize the available cadaveric kidneys. Efficient use of machine perfusion may potentially lead to increased use of marginal kidneys by lowering the incidence of delayed graft function (DGF) and improving graft outcomes. Recent findings Machine perfusion has had a resurgence in the last 10–15 years over static cold storage (SCS). Hypothermic machine perfusion (HMP), the most commonly utilized type of machine perfusion reduces the rates of DGF when compared with SCS with a trend towards improving the overall graft survival. Summary Despite reduction in the rates of DGF by HMP, its effect on long-term renal and patient outcomes is not clearly known. There is limited clinical literature in the use of normothermic machine perfusion (NMP) but a few pilot studies have shown its potential to resuscitate commonly discarded kidneys. In addition to preservation, machine perfusion also allows for various diagnostic and therapeutic interventions during the preservation period to assess and optimize the viability of the procured kidney. Correspondence to Ashish Kataria, MD, Division of Nephrology, Department of Medicine, University at Buffalo, Buffalo, NY 14225, USA. Tel: +1 716 898 3337; e-mail: ashishka@buffalo.edu Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Community-acquired respiratory viruses
Purpose of review Community-acquired respiratory viruses (CARV) have been historically linked to upper respiratory tract infections; however, new data has emerged in recent years that has provided new insight into their role as causative pathogens for lower respiratory tract infections. We aim to discuss the importance of recognition of viruses both epidemiologically and clinically as causes of lower respiratory tract infection. Recent findings With advances of molecular testing it is now possible to identify viruses from clinical specimens which have many implications that range from therapeutics to antibiotic stewardship. Recent studies suggest that most of the cases of community-acquired pneumonia are caused by viruses, which corresponds to a paradigm shift for most clinicians. Summary As community-acquired lower respiratory infections are the most common cause of ICU admission in the USA, it is important for medical providers to be aware of the association with viruses, especially in patients with immunosuppression because of solid organ transplant and hematologic malignancies when sometimes diagnosis can be challenging and patients can be exposed to unnecessary antibiotics. Correspondence to Emily Blodget, MD, MPH, Division of Infectious Diseases, University of Southern California, Keck School of Medicine, 2020 Zonal Avenue, IRD Room 436, Los Angeles, CA 90033, USA. Tel.: +1 323 409 4444;. fax: +1 323 226 7726; e-mail: eblodget@med.usc.edu Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Innovations in kidney paired donation transplantation
Purpose of review To analyze the innovations that have increased the reliability, convenience, and outcomes of kidney paired donation (KPD) that has led to thousands of living donor kidney transplants across the United States. Recent findings Over the past 10 years, KPD has grown over 200% on an annual basis. Though concerns had existed over cold ischemia time, research has shown that there is no correlation between travel time of a shipped kidney and the transplant outcome. The voucher program has started to continue to expand how to overcome obstacles to donation by solving the issue of a pair chronological incompatibility. Summary KPD is a relatively new field and the innovations it has spawned should continue to improve availability of high-quality living donor organs. The introduction of the family voucher should continue this trend. Correspondence to Thomas D'Alessandro, National Kidney Registry, 42 Fire Island Avenue, Babylon, NY 11702, USA. Tel: +1 631 560 7887; fax: +1 800 401 8919; e-mail: TDAlessandro@kidneyregistry.org Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Coccidioidomycosis in solid organ transplant recipients
Purpose of review The purpose of the review is an update of diagnosis and treatment of coccidioidomycosis infection in solid organ transplant (SOT) patients. Endemic fungal infections continue to be a cause of serious morbidity and mortality in transplant recipients. Recent findings In transplant patients there are recommendations regarding screening in areas that are endemic for coccidioidomycosis. This screening involves serologic testing and chest imaging. In endemic areas pretransplant seropositivity varies from 1.4 to 5.6%. In immunocompromised patients with elevated complement fixation titers, evaluation of cerebrospinal fluid is recommended even in the absence of symptoms. Although coccidioidomycosis can be a self-limited disease in immunocompotent patients, all SOT patients should be treated regardless of severity. This may include intravenous amphotericin B in severe cases and fluconazole therapy in milder episodes. In those SOT recipients with evidence of prior coccidioidomycosis, lifelong secondary prophylaxis with fluconazole given risk of recurrent disease. Summary Coccidioidomycosis continues to be a cause of serious morbidity and mortality in transplant recipients but with proper screening and treatment can be successfully managed. Correspondence to Emily Blodget, MD, Division of Infectious Disease, Keck School of Medicine of University of Southern California, 2020 Zonal Avenue, Room 436, Los Angeles, CA 90033, USA. Tel: +1 323 409 4444; e-mail: eblodget@med.usc.edu Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Carbapenemase-producing organisms in solid organ transplantation
Purpose of review Carbapenem-resistant enterobacteriaceae (CRE) are a critical healthcare threat. Infections caused by CRE disproportionately affect transplant patients. Retrospective case studies suggest that up to 10% of transplant recipients develop a CRE infection. The current literature is reviewed with a particular focus on transplant-specific implications. Recent findings There are specific risks inherent to transplant recipients that result in an elevated risk for CRE carriage and subsequent infection. Additionally, the manifestations of these infections are dependent on the specific transplant type. The optimal treatment of CRE infections in transplant recipients has not been defined. Summary A reduction in the regional community CRE burden can lead to a secondary reduction in their occurrence within vulnerable transplant populations. Therefore, core principles of antibiotic stewardship and infection control within all levels of the healthcare system remains the most effective strategy for addressing the current health crisis. Simultaneously, an integrated approach to risk stratification and an approach to treatment is postulated for management of CRE infection within the solid-organ transplant population. Correspondence to Darren Wong, MD, Division of Infectious Diseases, Keck School of Medicine at the University of Southern California (USC), Los Angeles, California, USA. Tel: +1 323 409 4397; e-mail: darrenww@med.usc.edu Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Current state of organ transplant tolerance
Purpose of review Immunological tolerance has long been considered the 'holy grail' of organ transplantation. Although tolerance has been an active area of research for 70 years, its clinical application has only been possible in the last two decades and widespread use remains an, as yet, unattained goal. Recent advances in the understanding of immune regulation have identified many new approaches to tolerance induction and several clinical trials are currently aimed at bringing this treatment to more patients. Recent findings Mixed chimerism remains the most successful approach to tolerance induction. However, many treatments, including adoptive transfer of regulatory T cells, regulatory B cells, and immune suppressive dendritic cells and myeloid derived suppressor cells have shown great promise in preclinical models. Recent clinical studies have found that both kidney and liver operational tolerance are achievable in the appropriate settings. Furthermore, combining multiple tolerance approaches has shown potential to produce durable and safer tolerance. Summary Tolerance to protect kidney and liver allografts has become a valuable therapy in the correct circumstances. Through further clinical trials and an improved understanding of immune regulatory components, tolerance is poised to have a significant impact on transplantation in the years to come. Correspondence to James F. Markmann, MD, PhD, Massachusetts General Hospital, 55 Fruit Street – White 507, Boston, MA 02114, USA. Tel: +1 617 643 4533; fax: +1 617 643 4579; e-mail: jmarkmann@partners.org Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Updates on antiviral drugs for cytomegalovirus prevention and treatment
Purpose of review Cytomegalovirus (CMV) is the most common infection after organ transplant. In addition to causing a viral syndrome and infection, it also increases the risk for complications in the organ transplant, along with higher overall morbidity and mortality. Prevention and ideal treatment of CMV is paramount for optimal outcomes, both for individuals as well as for transplant programs. New guidelines and novel therapies are changing the way we manage disease. Recent findings Several new antiviral agents have emerged in recent times, including letermovir, maribavir, and brincidofovir, enhancing our ability to prevent and treat CMV. Recent data on novel agents will be reviewed, with an emphasis on recent guidelines and best practices. Summary Optimal treatment, influenced by recent advances in the field, including management of resistant virus, results in better outcomes with this significant and virulent virus. Correspondence to Camille N. Kotton, Transplant and Immunocompromised Host Infectious Diseases, Infectious Diseases Division, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Cox 5th floor, Boston, MA 02114, USA. Tel: +1 617 724 0082 (Karen Manning, Administrative Assistant); fax: +1 617 726 7653; e-mail: ckotton@partners.org Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

The past, present, and future of costimulation blockade in organ transplantation
Purpose of review Manipulating costimulatory signals has been shown to alter T cell responses and prolong graft survival in solid organ transplantation. Our understanding of and ability to target various costimulation pathways continues to evolve. Recent findings Since the approval of belatacept in kidney transplantation, many additional biologics have been developed targeting clinically relevant costimulation signaling axes including CD40-CD40L, inducible costimulator-inducible costimulator ligand (ICOS-ICOSL), and OX40-OX40L. Currently, the effects of costimulation blockade on posttransplant humoral responses, tolerance induction, and xenotransplantation are under active investigation. Here, we will discuss these pathways as well as preclinical and clinical outcomes of biologics targeting these pathways in organ transplantation. Summary Targeting costimultion is a promising approach for not only controlling T cell but also B cell responses. Consequently, costimulation blockade shows considerable potential for improving outcomes in antibody-mediated rejection and xenotransplantation. Correspondence to Stuart J. Knechtle, MD, 330 Trent Drive, DUMC Box 3512, Durham, NC 27710, USA. Tel: +1 919 613 9687; fax: +1 919 684 8716; e-mail: stuart.knechtle@dm.duke.edu Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Alexandros Sfakianakis
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