Herpes simplex virus infections in solid organ transplantation: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

Rejection in Liver Transplantation Recipients

Rejection following liver transplantation continues to impact transplant recipients although rates have decreased over time with advances in immunosuppression management. The diagnosis of rejection remains challenging with liver biopsy remaining the reference standard for diagnosis. Proper classification of rejection type and severity is imperative as this guides management and ultimately graft preservation. Future areas of promise include non-invasive testing for detection of rejection to reduce the morbidity associated with invasive testing and further advances in immunosuppression management to reduce toxicities associated with immunosuppression while minimizing rejection related morbidity.

A practical guide to real-world implementation of pre-emptive therapy for Cytomegalovirus disease prevention in high-risk seronegative liver transplant recipients with seropositive donors

The Comparison of Antiviral Preventative Strategies In Liver Transplant (CAPSIL) study showed pre-emptive therapy (PET) to be superior to antiviral prophylaxis for Cytomegalovirus (CMV) disease prevention in high-risk CMV seronegative liver transplant recipients (LTRs) with seropositive donors (D+R-). Despite the statistical superiority of PET over prophylaxis in research settings, PET is perceived as a logistically more complex strategy that requires careful coordination of weekly CMV PCR testing, prompt initiation of CMV antivirals upon viremia detection, and timely cessation of antivirals following viremia resolution. Transplant centers may be hesitant to use PET for CMV disease prevention in D+R- LTRs out of concern that PET coordination is not feasible in clinical practice. We recently described our experience using PET in CMV D+R- LTRs in a real-world setting, and found it to be as effective for CMV disease prevention as PET performed as part of a clinical trial. Here, we describe a systematic approach for PET implementation in real-world settings and provide practical tools to address anticipated challenges. This framework can support transplant programs in overcoming logistical barriers to PET and incorporating an evidence-based and cost-effective CMV prevention strategy into routine care for high-risk CMV D+R- LTRs.

Infections in lung transplanted patients: A review

Lung transplantation can improve the survival of patients with severe chronic pulmonary disorders. However, the short- and long-term risk of infections can increase morbidity and mortality rates. A non-systematic review was performed to provide the most updated information on pathogen, host, and environment-related factors associated with the occurrence of bacterial, fungal, and viral infections as well as the most appropriate therapeutic options. Bacterial infections account for about 50% of all infectious diseases in lung transplanted patients, while viruses represent the second cause of infection accounting for one third of all infections. Almost 10% of patients develop invasive fungal infections during the first year after lung transplant. Pre-transplantation comorbidities, disruption of physical barriers during the surgery, and exposure to nosocomial pathogens during the hospital stay are directly associated with the occurrence of life-threatening infections. Empiric antimicrobial treatment after the assessment of individual risk factors, local epidemiology of drug-resistant pathogens and possible drug-drug interactions can improve the clinical outcomes.

Management of oral herpes simplex virus infections: The problem of resistance. A narrative review

Herpes Simplex Virus (HSV) type 1 (HSV-1) and type 2 (HSV-2) are among the most common human viral pathogens, affecting several billion people worldwide. Although in healthy patients clinical signs and symptoms of HSV infection are usually mild and self-limiting, HSV-infections in immunocompromised patients are frequently more aggressive, persistent, and even life-threatening. Acyclovir and its derivatives are the gold standard antiviral drugs for the prevention and treatment of HSV infections. Although the development of acyclovir resistance is a rather uncommon condition, it may be associated with serious complications, especially in immunocompromised patients. In this review, we aim to address the problem of drug resistant HSV infection and discuss the available alternative therapeutic interventions. All relative studies concerning alternative treatment modalities of acyclovir resistant HSV infection published in PubMed between 1989 to 2022 were reviewed. Long-term treatment and prophylaxis with antiviral agents predisposes to drug resistance, especially in immunocompromised patients. Cidofovir and foscarnet could serve as alternative treatments in these cases. Although rare, acyclovir resistance may be associated with severe complications. Hopefully, in the future, novel antiviral drugs and vaccines will be available in order to avoid the existing drug resistance.

Skin and soft tissue infections in solid organ transplants

PURPOSE OF REVIEW

Skin and soft tissue infections (SSTI) in solid organ transplant (SOT) recipients may be a great challenge for clinicians caring for SOT due to the involvement of both common and opportunistic pathogens associated with a blunted immune response. The purpose of this review is to outline current literature and describe open issues on the management of SSTI in this special population.

RECENT FINDINGS

Clinical presentation in SOT recipients can manifest as isolated skin lesions after primary inoculation or be the sign of a disseminated infection. Tissue samples for microscopy and histopathology are crucial to making an accurate diagnosis given the nonspecific and heterogeneous appearance of skin lesions. Multidisciplinary teams are required for a comprehensive diagnosis and management.

SUMMARY

SSTI are frequent contributors to morbidity and mortality in SOT. Specific research focused on the clinical presentation, risk factors and management in this special population is needed.

Viral meningoencephalitis in pediatric solid organ or hematopoietic cell transplant recipients: a diagnostic and therapeutic approach

Neurologic complications, both infectious and non-infectious, are frequent among hematopoietic cell transplant (HCT) and solid organ transplant (SOT) recipients. Up to 46% of HCT and 50% of SOT recipients experience a neurological complication, including cerebrovascular accidents, drug toxicities, as well as infections. Defects in innate, adaptive, and humoral immune function among transplant recipients predispose to opportunistic infections, including central nervous system (CNS) disease. CNS infections remain uncommon overall amongst HCT and SOT recipients, compromising approximately 1% of total cases among adult patients. Given the relatively lower number of pediatric transplant recipients, the incidence of CNS disease amongst in this population remains unknown. Although infections comprise a small percentage of the neurological complications that occur post-transplant, the associated morbidity and mortality in an immunosuppressed state makes it imperative to promptly evaluate and aggressively treat a pediatric transplant patient with suspicion for viral meningoencephalitis. This manuscript guides the reader through a broad infectious and non-infectious diagnostic differential in a transplant recipient presenting with altered mentation and fever and thereafter, elaborates on diagnostics and management of viral meningoencephalitis. Hypothetical SOT and HCT patient cases have also been constructed to illustrate the diagnostic and management process in select viral etiologies. Given the unique risk for various opportunistic viral infections resulting in CNS disease among transplant recipients, the manuscript will provide a contemporary review of the epidemiology, risk factors, diagnosis, and management of viral meningoencephalitis in these patients.

Controlling infections in hospitalized pretransplant candidates

PURPOSE OF REVIEW

Infections in hospitalized patients awaiting solid organ transplantation can pose complicated diagnostic and therapeutic challenges. Goals of management include stabilizing the patient, treating or controlling infections, and decreasing the risk of reactivation of infection after transplant.

RECENT FINDINGS

Groups such as The Organ Procurement and Transplantation Network, American Society of Transplantation Infectious Diseases Community of Practice and the European Society of Clinical Microbiology and Infectious Diseases have updated their guidelines on screening and treatment of infection in transplant candidates. There are also recent developments in therapeutic options for tuberculosis, COVID-19, Clostridioides difficile colitis, bloodstream infections, and other common infections.

SUMMARY

Ideally, antimicrobial therapy should be complete prior to transplantation. In situations in which completion of therapy prior to transplant is not feasible, therapy may need to be prolonged or modified. In most situations, infections can be managed similarly to the general population, although some infections, particularly fungal and mycobacterial, require a different management approach. We review disease- and organ-specific management.

Risk of herpes simplex virus infection in solid organ transplant recipients: A population-based cross-sectional study

BACKGROUND

Herpes simplex virus (HSV) is an opportunistic infection antigen in solid organ transplant (SOT) recipients. However, this phenomenon has received limited attention from epidemiologists. Our study aims to determine the HSV infection risk in SOT recipients.

METHODS

This was a nationwide population-based cross-sectional study based on the National Health Insurance Research Database from 2002 to 2015. We used propensity score matching to avoid selection bias and analyzed the association between HSV infection and SOT recipients with multiple logistic regression analysis.

RESULTS

At a 3-year follow-up, SOT recipients had a higher risk of developing HSV, with an adjusted odds ratio (aOR) of 3.28 (95% confidence interval (CI), 2.51-4.29). Moreover, at 6-month, 1-year, and 2-year follow-ups, SOT recipients also had an increased risk of HSV than general patients with aORs of 3.85 (95% CI, 2.29-6.49), 4.27 (95% CI, 2.86-6.36), and 3.73 (95% CI, 2.74-5.08), respectively. In the subgroup analysis, lung transplant recipients (aOR = 8.01; 95% CI, 2.39-26.88) exhibited a significantly higher chance of HSV among SOT recipients, followed by kidney transplant recipients (aOR = 3.33; 95% CI, 2.11-5.25) and liver transplant recipients (aOR = 3.15; 95% CI, 2.28-4.34).

CONCLUSION

HSV can develop at any time after organ transplantation. SOT recipients had a higher risk of HSV infection than the general population at 6 months, 1 year, 2 years, and 3 years after transplantation, with the highest chance at 1 year after. In addition, the patients who underwent lung transplantion were at higher risk for HSV infection than liver or kidney transplant recipients.

Mycophenolate Mofetil-Induced Aphthous Stomatitis After Kidney Transplant: A Clinical Case Report

Aphthous stomatitis, with frequent and painful aphthous ulcers (also called canker sores or simply oral ulcers) on the non-keratinized oral mucous membranes, is often a cutaneous complication in kidney transplant recipients. Mycophenolate mofetil is a drug that is part of an immunosuppressive regimen in kidney transplant recipients, along with corticosteroids and calcineurin inhibitors. Mycophenolate mofetil, the triggering agent for mouth ulcers in kidney transplant recipients, has been communicated in scientific literature. Herein, we report a case of multiple painful oral ulcerations secondary to mycophenolate mofetil in a 23-year-old female kidney transplant recipient. The oral ulcers resolved immediately after discontinuation of the mycophenolate mofetil. Withdrawal of mycophenolate mofetil or switching to other medicine must be considered when a patient with a kidney transplant history complains of oral ulcers and a negative workup for other etiologies.

Hematopoietic stem cell transplantation and the noncytomegalovirus herpesviruses

Although hematopoietic stem cell transplantation (HSCT) and other cellular therapies have significantly improved outcomes in the management of multiple hematological and nonhematological malignancies, the resulting impairment in humoral and cellular response increases the risk for opportunistic infection as an undesirable side effect. With their ability to establish latent infection and reactivate when the host immune system is at its weakest point, the Herpesviridae family constitutes a significant proportion of these opportunistic pathogens. Despite recent advancements in preventing and managing herpesvirus infections, they continue to be a common cause of significant morbidity and mortality in transplanted patients. Herein, we aim to provide and update on herpesvirus other than cytomegalovirus (CMV) affecting recipients of HSCT and other cellular therapies.

A quick algorithmic review on management of viral infectious diseases in pediatric solid organ transplant recipients

Pediatric solid organ transplant is a life-saving procedure for children with end-stage organ failure. Viral infections are a common complication following pediatric solid organ transplantation (SOT), which can lead to increased morbidity and mortality. Pediatric solid organ transplant recipients are at an increased risk of viral infections due to their immunosuppressed state. The most commonly encountered viruses include cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus (HSV), varicella-zoster virus (VZV), adenoviruses, and BK polyomavirus. Prevention strategies include vaccination prior to transplantation, post-transplant prophylaxis with antiviral agents, and preemptive therapy. Treatment options vary depending on the virus and may include antiviral therapy and sometimes immunosuppression modification. This review provides a Quick Algorithmic overview of prevention and treatment strategies for viral infectious diseases in pediatric solid organ transplant recipient.

Risk factors for infection in patients with a failed kidney allograft on immunosuppressive medications

Patients with a failing kidney allograft are often continued on immunosuppression (IS) to preserve residual kidney function and prevent allosensitization. It has been previously accepted that maintaining patients on immunosuppressive therapy results in an increased risk of infection, hospitalization, and mortality. However, as the management of IS in patients with a failed kidney allograft continues to evolve, it is important to review the data regarding associations between infection and specific immunosuppression regimens. We present a review of the literature of failed kidney allograft management and infection risk, and discuss practices for infection prevention. Fifteen studies, published from 1995 to 2022, which investigated the experience of patients with failed allograft and infection, were identified. Infection was most commonly documented as a general event, but when specified, included infections caused by Candida, Mycobacterium tuberculosis, and Aspergillus. In addition, the definition of reduced "IS" varied from decreased doses of a triple drug regimen to monotherapy, whereas others did not specify which medications patients were receiving. Despite attempts at lowering net immunosuppression, patients with failed allografts remain at risk of acquiring opportunistic and non-opportunistic infections. Although opportunistic infections secondary to IS are expected, somewhat surprisingly, it appears that the greatest risk of infection may be related to complications of dialysis. Therefore, mitigating strategies, such as planning for an arteriovenous (AV) fistula over a hemodialysis catheter placement, may reduce infection risk. Additional studies are needed to provide more information regarding the types and timing of infection in the setting of a failed kidney allograft. In addition, more data are needed regarding specific medications, doses, and timing of taper of IS to guide future patient management and inform strategies for infection surveillance and prophylaxis.

Donor-derived fulminant herpes simplex virus hepatitis after liver transplantation: Two cases and review of literature

BACKGROUND

Fulminant herpetic hepatitis due to herpes simplex virus (HSV), serotype 1 or 2, is a rare but often fatal complication after solid organ transplantation (SOT). HSV hepatitis in SOT recipients can occur either due to primary infection acquired post transplantation, viral reactivation in a seropositive patient, or as donor-derived infection. Cases of fatal hepatitis have been reported in the liver as well as in other SOT recipients. The fatal outcome is mostly due to delayed diagnosis and treatment, which is explained by the lack of clinical specificity of HSV hepatitis.

METHODS

We report two cases of fatal donor-derived HSV hepatitis in liver-transplanted recipients. We reviewed all published cases of donor-derived HSV infections after SOT with an evaluation of the presence of prophylaxis and outcome.

RESULTS

In both liver recipients, the retrospective determination of HSV serostatus was negative, and both cases occurred in the absence of cytomegalovirus or HSV prophylaxis. A review of the literature showed a significant series of cases of severe hepatitis, mostly fatal, as well as the absence of specific preventive therapy guidelines in cases of HSV serology mismatch.

CONCLUSIONS

The occurrence of two fatal donor-derived hepatitis made the Swiss Transplant Infectious Diseases working group modify its national recommendations regarding pretransplant serostatus determination and HSV prophylaxis after liver transplantation. Further studies are needed to assess this approach.

Current Perspectives on the Management of Herpesvirus Infections in Solid Organ Transplant Recipients

Solid organ transplant recipients (SOTRs) are at high risk of human herpesvirus (HHV)-related morbidity and mortality due to the use of immunosuppressive therapy. We aim to increase awareness and understanding of HHV disease burden in SOTRs by providing an overview of current prevention and management strategies as described in the literature and guidelines. We discuss challenges in both prevention and treatment as well as future perspectives.

Prediction of herpes virus infections after solid organ transplantation: a prospective study of immune function

Introduction

Herpes virus infections are a major concern after solid organ transplantation and linked to the immune function of the recipient. We aimed to determine the incidence of positive herpes virus (cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus type 1/2 (HSV-1/2), and varicella zoster virus (VZV)) PCR tests during the first year post-transplantation and assess whether a model including immune function pre-transplantation and three months post-transplantation could predict a subsequent positive herpes virus PCR.

Methods

All participants were preemptively screened for CMV, and EBV IgG-negative participants were screened for EBV during the first year post-transplantation. Herpes virus PCR tests for all included herpes viruses (CMV, EBV, HSV-1/2, and VZV) were retrieved from the Danish Microbiology database containing nationwide PCR results from both hospitals and outpatient clinics. Immune function was assessed by whole blood stimulation with A) LPS, B) R848, C) Poly I:C, and D) a blank control. Cytokine concentrations (TNF-α, IL-1β, IL-6, IL-8, IL-10, IL-12p40, IL-17A, IFN-α, and IFN-γ) were measured using Luminex.

Results

We included 123 liver (54%), kidney (26%), and lung (20%) transplant recipients. The cumulative incidence of positive herpes virus PCR tests was 36.6% (95% CI: 28.1-45.1) during the first year post-transplantation. The final prediction model included recipient age, type of transplantation, CMV serostatus, and change in Poly I:C-induced IL-12p40 from pre-transplantation to three months post-transplantation. The prediction model had an AUC of 77% (95% CI: 61-92). Risk scores were extracted from the prediction model, and the participants were divided into three risk groups. Participants with a risk score <5 (28% of the cohort), 5-10 (45% of the cohort), and >10 (27% of the cohort) had a cumulative incidence of having a positive herpes virus PCR test at 5.8%, 25%, and 73%, respectively (p < 0.001).

Conclusion

In conclusion, the incidence of positive herpes virus PCR tests was high, and a risk model including immune function allowed the prediction of positive herpes virus PCR and may be used to identify recipients at higher risk.

Fatal HSV-2 primary infection most likely acquired by kidney transplantation: A case report

Herpes simplex virus 2 (HSV-2) rarely causes severe disease, even in solid organ transplant recipients. This paper describes a fatal case of HSV-2 infection, probably transmitted from a donor to a kidney transplant recipient. The donor was seropositive for HSV-2 but not for HSV-1, whereas the recipient was seronegative for both viruses before transplantation, suggesting that the graft was the source of infection. The recipient received valganciclovir prophylaxis due to cytomegalovirus seropositivity. Three months after transplantation, the recipient presented with rapidly disseminated cutaneous HSV-2 infection with meningoencephalitis. The HSV-2 strain was resistant to acyclovir, probably acquired under valganciclovir prophylaxis. Despite early initiation of acyclovir therapy, the patient died. This fatal case of HSV-2 infection, probably transmitted by the kidney graft with acyclovir-resistant HSV-2 from the onset, is uncommon.

Herpesvirus-Related Lesions of the Oral Mucosa

The human herpesvirus (HHV) family is a group of enveloped DNA viruses containing 8 members known to produce oral mucosal lesions. Following initial exposure, which may result in symptomatic primary infection, the viruses establish latency within specific cells/tissues. After reactivation, herpesviruses can cause localized symptomatic or asymptomatic recurrent (secondary) infections or diseases. HHV may have a significant role in the cause of oral mucosal infectious diseases in immunocompromised patients. This article discusses the role of those herpesviruses that can induce oral mucosal lesions, with focus on the clinical features and treatment/management.

Clinical application of immune repertoire sequencing in solid organ transplant

Background

Measurement of T cell receptor (TCR) or B cell receptor (BCR) gene utilization may be valuable in monitoring the dynamic changes in donor-reactive clonal populations following transplantation and enabling adjustment in therapy to avoid the consequences of excess immune suppression or to prevent rejection with contingent graft damage and to indicate the development of tolerance.

Objective

We performed a review of current literature to examine research in immune repertoire sequencing in organ transplantation and to assess the feasibility of this technology for clinical application in immune monitoring.

Methods

We searched MEDLINE and PubMed Central for English-language studies published between 2010 and 2021 that examined T cell/B cell repertoire dynamics upon immune activation. Manual filtering of the search results was performed based on relevancy and predefined inclusion criteria. Data were extracted based on study and methodology characteristics.

Results

Our initial search yielded 1933 articles of which 37 met the inclusion criteria; 16 of these were kidney transplant studies (43%) and 21 were other or general transplantation studies (57%). The predominant method for repertoire characterization was sequencing the CDR3 region of the TCR β chain. Repertoires of transplant recipients were found to have decreased diversity in both rejectors and non-rejectors when compared to healthy controls. Rejectors and those with opportunistic infections were more likely to have clonal expansion in T or B cell populations. Mixed lymphocyte culture followed by TCR sequencing was used in 6 studies to define an alloreactive repertoire and in specialized transplant settings to track tolerance.

Conclusion

Methodological approaches to immune repertoire sequencing are becoming established and offer considerable potential as a novel clinical tool for pre- and post-transplant immune monitoring.

Herpes simplex virus hepatitis in a renal transplant recipient seronegative pre-transplant

BACKGROUND: Herpes simplex virus (HSV) is a rare cause of acute viral hepatitis but has high mortality rates and primarily affects immunocompromised hosts. We report a case of HSV hepatitis in a 20-year-old female kidney transplant recipient who had 1000-fold elevations in transaminases on post-transplant day 14, and the strategies employed for diagnoses and treatment. METHODS: Routine laboratory, serological, and molecular viral testing was completed, and she underwent a bone marrow biopsy given initial suspicion of hemophagocytic lymphohistiocytosis (HLH). HSV serologic results and high transaminases triggered a liver biopsy. RESULTS: The patient presented with elevated transaminases (ALT 1731 U/L and AST 1400) and ferritin (1431 μg/L). Transaminases and ferritin peaked with an ALT of 6609 U/L, AST of 6525 U/L, and ferritin >50000 μg/L. Bone marrow biopsy revealed no definitive HLH. HSV-DNA PCR of blood was positive, and she was empirically started on intravenous acyclovir 10 mg/kg 3 times per day. Liver biopsy confirmed the histological diagnosis of HSV hepatitis. CONCLUSIONS: Given the high mortality rates associated with HSV hepatitis, it is crucial to determine pre-transplant HSV status, initiate appropriate antiviral prophylaxis, and to have a low threshold for investigating for HSV hepatitis and initiating treatment in patients with a suspected diagnosis.

Assessing and restoring adaptive immunity to HSV, VZV, and HHV-6 in solid organ and hematopoietic cell transplant recipients

BACKGROUND

Herpes simplex virus (HSV) 1 and 2, varicella zoster virus (VZV), and human herpesvirus 6 (HHV-6) cause severe infections in immunocompromised hosts. Interventions to optimize virus-specific adaptive immunity may have advantages over antivirals in the prophylaxis and treatment of these infections.

OBJECTIVES

We sought to review adaptive immune responses and methods for assessing and replenishing cellular and humoral immunity to HSV, VZV, and HHV-6 in solid organ transplant and hematopoietic cell transplant recipients.

SOURCES

We searched PubMed for relevant studies on immune responses to HSV, VZV, and HHV-6 as well as studies describing methods for evaluating and restoring cell-mediated immunity to other double-stranded DNA viruses in transplant recipients. Recent studies, randomized controlled trials, and investigations highlighting key concepts in clinical virology were prioritized for inclusion.

CONTENT

We describe the mechanisms of adaptive immunity to HSV, VZV, and HHV-6 and limitations of antivirals as prophylaxis and treatment for these infections in solid organ transplant and hematopoietic cell transplant recipients. We review methods for measuring and restoring cellular immunity to double-stranded DNA viruses; their potential applications to management of HSV, VZV, and HHV-6 in immunocompromised hosts; and barriers to clinical use. Vaccination and virus-specific T cell therapies are discussed in detail.

IMPLICATIONS

The growing repertoire of diagnostic and therapeutic techniques focused on virus-specific adaptive immunity provides a novel approach to management of viral infections in transplant recipients. Investigations to optimize such interventions specifically in HSV, VZV, and HHV-6 are needed.

Infectious Complications in Lung Transplant Recipients

Infection remains a common cause of death throughout the lifespan of a lung transplant recipient. The increased susceptibility of lung transplant recipients is multifactorial including exposure of the graft to the external environment, impaired mucociliary clearance, and high levels of immunosuppression. Long-term outcomes in lung transplant recipients remain poor compared with other solid organ transplants largely due to deaths from infections and chronic allograft dysfunction. Antibacterial, antifungal, and antiviral prophylaxis may be used after lung transplantation to target a number of different opportunistic infections for varying durations of time. The first-month posttransplant is most commonly characterized by nosocomial infections and donor-derived infections. Following the first month to the first 6 months after transplant-a period of intense immunosuppression-is associated with opportunistic infections. While immunosuppression is reduced after the first year posttransplant, infection remains a risk with community-acquired and rarer infectious agents. Clinicians should be vigilant for infection at all time points after transplant. The use of patient-tailored prophylaxis and treatments help ensure graft and patient survival.

40 Years after the Registration of Acyclovir: Do We Need New Anti-Herpetic Drugs?

Herpes simplex virus types 1 and 2 HSV1 and 2, namely varicella-zoster VZV and cytomegalovirus CMV, are among the most common pathogens worldwide. They remain in the host body for life. The course of infection with these viruses is often asymptomatic or mild and self-limiting, but in immunocompromised patients, such as solid organ or bone marrow transplant recipients, the course can be very severe or even life-threatening. Unfortunately, in the latter group, the highest percentage of infections with strains resistant to routinely used drugs is observed. On the other hand, frequent recurrences of genital herpes can be a problem even in people with normal immunity. Genital herpes also increases the risk of acquiring sexually transmitted diseases, including HIV infection and, if present in pregnant women, poses a risk to the fetus and newborn. Even more frequently than herpes simplex, congenital infections can be caused by cytomegalovirus. We present the most important anti-herpesviral agents, the mechanisms of resistance to these drugs, and the associated mutations in the viral genome. Special emphasis was placed on newly introduced drugs such as maribavir and brincidofovir. We also briefly discuss the most promising substances in preclinical testing as well as immunotherapy options and vaccines currently in use and under investigation.

Bacterial and Viral Infection and Sepsis in Kidney Transplanted Patients

Kidney transplanted patients are a unique population with intrinsic susceptibility to viral and bacterial infections, mainly (but not exclusively) due to continuous immunosuppression. In this setting, infectious episodes remain among the most important causes of death, with different risks according to the degree of immunosuppression, time after transplantation, type of infection, and patient conditions. Prevention, early diagnosis, and appropriate therapy are the goals of infective management, taking into account that some specific characteristics of transplanted patients may cause a delay (the absence of fever or inflammatory symptoms, the negativity of serological tests commonly adopted for the general population, or the atypical anatomical presentation depending on the surgical site and graft implantation). This review considers the recent available findings of the most common viral and bacterial infection in kidney transplanted patients and explores risk factors and outcomes in septic evolution.

PRIMARY HERPES SIMPLEX VIRUS TYPE 1 INFECTION WITH ACUTE LIVER FAILURE IN SOLID ORGAN TRANSPLANTATION: REPORT OF THREE CASES AND REVIEW

Herpes virus infections is not uncommon in solid organ transplantation patients. We report 3 cases with primary Herpes simplex virus type-1 (HSV1) infection with acute liver failure (ALF). This is a rare and potentially fatal entity that could be a donor-derived infection. Although the initial clinical presentation is non-specific, it should be considered as a differential diagnosis in HSV-negative serology patients with liver failure and empirical treatment must be started in combination with a drastic reduction of immunosuppression. A strategy of HSV prophylaxis for pre-transplant HSV seronegative patients must be stablished in order to reduce the risk of clinical disease.

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HSV hepatitis is a rare and fatal entity that can be a donor-derived infection.

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It should be suspected in highly immunosuppressed transplant patients who develop acute liver failure.

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The treatment delay is associated with higher fatality.

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In transplant patients with negative HSV serology, prophylaxis is recommended if they are not with prophylaxis for CMV.

Newer developments in viral hepatitis: Looking beyond hepatotropic viruses

Viral hepatitis in the entirety of its clinical spectrum is vast and most discussion are often restricted to hepatotropic viral infections, including hepatitis virus (A to E). With the advent of more advanced diagnostic techniques, it has now become possible to diagnose patients with non-hepatotropic viral infection in patients with hepatitis. Majority of these viruses belong to the Herpes family, with characteristic feature of latency. With the increase in the rate of liver transplantation globally, especially for the indication of acute hepatitis, it becomes even more relevant to identify non hepatotropic viral infection as the primary hepatic insult. Immunosuppression post-transplant is an established cause of reactivation of a number of viral infections that could then indirectly cause hepatic injury. Antiviral agents may be utilized for treatment of most of these infections, although data supporting their role is derived primarily from case reports. There are no current guidelines to manage patients suspected to have viral hepatitis secondary to non-hepatotropic viral infection, a gap that needs to be addressed. In this review article, the authors analyze the common non hepatotropic viral infections contributing to viral hepatitis, with emphasis on recent advances on diagnosis, management and role of liver transplantation.

Prevention of viral infections in solid organ transplant recipients in the era of COVID-19: a narrative review

INTRODUCTION

In solid organ transplant (SOT) recipients, viral infections are associated with direct morbidity and mortality and may influence long-term allograft outcomes. Prevention of viral infections by vaccination, antiviral prophylaxis, and behavioral measures is therefore of paramount importance.

AREAS COVERED

We searched Pubmed to select publications to review current preventive strategies against the most important viral infections in SOT recipients, including SARS-CoV-2, influenza, CMV, and other herpesvirus, viral hepatitis, measles, mumps, rubella, and BK virus.

EXPERT OPINION

The clinical significance of the reduced humoral response following mRNA SARS-CoV-2 vaccines in SOT recipients still needs to be better clarified, in particular with regard to the vaccines' efficacy in preventing severe disease. Although a third dose improves immunogenicity and is already integrated into routine practice in several countries, further research is still needed to explore additional interventions. In the upcoming years, further data are expected to better delineate the role of virus-specific cell mediated immune monitoring for the prevention of CMV and potentially other viral diseases, and the role of the letermovir in the prevention of CMV in SOT recipients. Future studies including clinical endpoints will hopefully facilitate the integration of successful new influenza vaccination strategies into clinical practice.

Evaluation of low dose famciclovir as herpes simplex virus and varicella zoster virus prophylaxis in cytomegalovirus low-risk solid organ transplant recipients

OBJECTIVE

Famciclovir is a recommended option for herpes simplex virus (HSV) and varicella-zoster virus (VZV) prophylaxis in cytomegalovirus (CMV) low-risk solid organ transplant (SOT) recipients in current guidelines; however there is currently no data evaluating its use in SOT recipients. We conducted a multicenter provider survey on antiviral prophylaxis in CMV low-risk SOT recipients and evaluated the efficacy and safety of once daily famciclovir antiviral prophylaxis.

METHODS

Two-part analysis consisting of a national provider survey and a retrospective chart review of 78 kidney transplant recipients at a single institution.

RESULTS

Providers from 45 transplant centers within the United States responded to the survey. Across all organs, acyclovir 400 mg twice daily was utilized by the majority of respondents (70.4%), with most using prophylaxis for a duration of 3 months (68.8%). No respondents reported use of famciclovir at their institution. In the retrospective review there were no documented cases of HSV/VZV/CMV infection during the 3 months of famciclovir prophylaxis, and only one patient (1.3%) later developed VZV infection at 12 months post-transplant. One patient (1.3%) required premature discontinuation of famciclovir due to concern for acute interstitial nephritis.

CONCLUSION

Nationwide, the most common antiviral prophylaxis used in CMV low-risk SOT recipients is acyclovir 400 mg twice daily. Among patients receiving once daily famciclovir for CMV low-risk antiviral prophylaxis, there was no HSV/VZV/CMV infection while on prophylaxis. Once daily famciclovir may provide an effective and convenient once daily dosing regimen for antiviral prophylaxis in CMV low-risk SOT recipients.

Hepatic Manifestations of Nonhepatotropic Infectious Agents Including Severe Acute Respiratory Syndrome Coronavirus-2, Adenovirus, Herpes Simplex Virus, and Coxiella burnetii

Nonhepatotropic viruses such as adenovirus, herpes simplex virus, flaviviruses, filoviruses, and human herpes virus, and bacteria such as Coxiella burnetii, can cause liver injury mimicking acute hepatitis. Most of these organisms cause a self-limited infection. However, in immunocompromised patients, they can cause severe hepatitis or in some cases fulminant hepatic failure requiring an urgent liver transplant. Hepatic dysfunction is also commonly seen in patients with severe acute respiratory syndrome coronavirus-2 infection. Patients with preexisting liver diseases are likely at risk for severe coronavirus disease 2019 (COVID-19) and may be associated with poor outcomes.

Survey of Viral Reactivations in Elite Athletes: A Case-Control Study

Exercise-induced immune perturbations have been proposed to increase susceptibility to viral infections. We investigated the replication of persisting viruses as indicators of immune function in elite cross-country skiers after ten months of sustained high-performance exercise. The viruses evaluated, nine human herpesviruses (HHVs) and torque teno virus (TTV), are typically restrained in health but replicate actively in immunosuppressed individuals. We collected sera from 27 Finnish elite cross-country skiers at the end of the competition's season and 27 matched controls who perform moderate exercise. We quantified all the HHVs and-TTV via highly sensitive qPCRs. To verify equal past exposures between the groups, we assessed the IgG antibody prevalences toward HHV-4 (Epstein-Barr virus, EBV) and HHV-5 (human cytomegalovirus, HCMV). We found equal TTV DNA prevalences in athletes (63%) and controls (63%) and loads with respective geometric means of 1.7 × 103 and 1.2 × 103 copies/mL of serum. Overall, the copy numbers were low and consistent with those of healthy individuals. Neither of the groups presented with herpesvirus viremia despite similar past exposures to HHVs (seroprevalences of EBV 70% vs. 78% and HCMV 52% vs. 44% in athletes and controls, respectively). We found no evidence of increased replication of persistent viruses in elite athletes, arguing against impaired viral immunity due to high-performance exercise.

Routine testing for herpes simplex virus in bronchoalveolar lavage specimens is unwarranted

Herpes simplex virus (HSV) infections of the lung are rare, but HSV is occasionally detected in bronchoalveolar lavage (BAL) specimens. We assessed whether routinely performing HSV PCR tests in BAL specimens is warranted. HSV was detected in 7% (52/722) of BALs. In 47% of HSV-positive patients a typical respiratory virus or pathologic microorganism was identified. Oral HSV reactivation was identified in 27%; however, anti-HSV therapy was initiated in just three patients following the positive HSV test. Patients undergoing BAL for transplant surveillance received anti-HSV prophylaxis more often than those with acute respiratory failure, but both groups did not differ significantly in terms of patient outcome or co-infections. No patient was diagnosed with HSV pneumonia. These findings suggest that positive HSV PCR results in BAL specimens most commonly represents contamination from oral HSV reactivation, and that HSV PCR should be ordered selectively, rather than routinely, as part of a test panel.

Assessing and mitigating risk of infection in patients with multiple sclerosis on disease modifying treatment

Introduction: The important development that the multiple sclerosis (MS) treatment field has experienced in the last years comes along with the need of dealing with new adverse events such as the increase risk of infections. In the shared therapeutic decision-making process, the MS expert neurologist should also balance the risks of specific infections under each particular treatment and be familiar with new mitigation strategies.Areas covered: In this review, the authors provide an up-to-date review of the infection risk associated with MS treatments with a specific focus on risk mitigating strategies. The search was conducted using Pubmed® database (2000 - present) to identify publications that reported infection rates and infection complications for each treatment (interferon beta, glatiramer acetate, teriflunomide, dimethyl fumarate, fingolimod, cladribine, natalizumab, alemtuzumab, rituximab, and ocrelizumab).Expert opinion: Since the emergence of the first natalizumab-related PML case, the arrival of new MS therapies has come hand in hand with new infectious complications. MS-specialist neurologist has to face new challenges regarding the management of immunosuppression-related infectious complications. The implementation of patient-centered management focus on preventive and mitigating strategies with a multidisciplinary approach should be seen in the future as a marker of excellence of MS management.

Donor-derived herpes simplex virus hepatitis in a kidney transplant recipient and review of the literature

Donor-derived (DD) herpes simplex virus (HSV) hepatitis in solid organ transplant (SOT) recipients is extremely uncommon but carries a high mortality rate. The diagnosis is challenging due to the non-specific presentation and lack of clinical suspicion. We report a case of DDHSV hepatitis in a HSV2 pre-transplant seronegative kidney recipient who received the organ from a HSV2 seropositive donor. The case is highlighted by a few unusual features, namely severe thrombocytopenia and the development of cutaneous, oral and esophageal HSV lesions several weeks after symptom onset while recovering on appropriate treatment. A review of nine proven and probable DDHSV hepatitis cases (including eight previously published ones) showed that fever is a common presenting feature while gastrointestinal symptoms and cutaneous manifestations are uncommon. The symptoms almost always occurred within 2 weeks of transplant. Six out of the nine DDHSV hepatitis patients, including five patients who were on appropriate treatment, died within a month after transplant.

Considerations and controversies of pharmacologic management of the pediatric kidney transplant recipient

Pediatric kidney transplantation has experienced considerable growth and improvement in patient and allograft outcomes over the past 20 years, in part due to advancements in immunosuppressive regimens and management. Despite this progress, care for this unique population can be challenging due to limited pediatric transplant data and trials, intricacies related to differences in children and adolescents compared with their adult counterparts, and limitations to long-term survival facing all solid organ transplant populations. Immunosuppression and infection prevention practices vary from one pediatric transplant center to another and clinical controversies exist surrounding treatment and dosing. This review aims to summarize key aspects of pharmacologic management in this population and present pertinent data that describe the influence of practice to serve as a resource for practitioners caring for this unique specialty patient population. Additionally, this review highlights select controversies that exist within pediatric kidney transplantation.

Tocilizumab for the Treatment of COVID-19 Among Hospitalized Patients: A Matched Retrospective Cohort Analysis

Background

There is currently no single treatment that mitigates all harms caused by severe acute respiratory syndrome coronavirus 2 infection. Tocilizumab, an interleukin-6 antagonist, may have a role as an adjunctive immune-modulating therapy.

Methods

This was an observational retrospective study of hospitalized adult patients with confirmed coronavirus disease 2019 (COVID-19). The intervention group comprised patients who received tocilizumab; the comparator arm was drawn from patients who did not receive tocilizumab. The primary outcome was all-cause mortality censored at 28 days; secondary outcomes were all-cause mortality at discharge, time to clinical improvement, and rates of secondary infections. Marginal structural Cox models via inverse probability treatment weights were applied to estimate the effect of tocilizumab. A time-dependent propensity score-matching method was used to generate a 1:1 match for tocilizumab recipients; infectious diseases experts then manually reviewed these matched charts to identify secondary infections.

Results

This analysis included 90 tocilizumab recipients and 1669 controls. Under the marginal structural Cox model, tocilizumab was associated with a 62% reduced hazard of death (adjusted hazard ratio [aHR], 0.38; 95% CI, 0.21 to 0.70) and no change in time to clinical improvement (aHR, 1.13; 95% CI, 0.68 to 1.87). The 1:1 matched data set also showed a lower mortality rate (27.8% vs 34.4%) and reduced hazards of death (aHR, 0.47; 95% CI, 0.25 to 0.88). Elevated inflammatory markers were associated with reduced hazards of death among tocilizumab recipients compared with controls. Secondary infection rates were similar between the 2 groups.

Conclusions

Tocilizumab may provide benefit in a subgroup of patients hospitalized with COVID-19 who have elevated biomarkers of hyperinflammation, without increasing the risk of secondary infection.

Skin and Soft Tissue Infections in Non-Human Immunodeficiency Virus Immunocompromised Hosts

Skin and soft tissue infections among the non-human immunodeficiency virus infected immunosuppressed population are a serious and growing concern. Many pathogens can cause cutaneous infections in these patients owing to the highly varied and profound immune deficits. Although patients can be infected by typical organisms, the diversity and antimicrobial-resistant nature of the organisms causing these infections result in significant morbidity and mortality. The diagnostic approach to these infections in immunocompromised hosts can differ dramatically depending on the potential causative organisms. An understanding of new immunosuppressive treatments and evolving antimicrobial resistance patterns are required to optimally manage these difficult cases.

Infectious Complications in Lung Transplant Recipients

Lung transplantation is a lifesaving intervention for patients with advanced lung disease. Due to a combination of immunosuppression, continuous exposure of the lungs to the environment, and complications at the anastomotic sites, lung transplant recipients are at high risk for infectious complications. The aim of this review is to summarize recent developments in the field of infectious diseases as it pertains to lung transplant recipients.

Diagnosis and management of oral ulcerations associated with mycophenolate mofetil in kidney transplantation

AIMS

The final diagnosis of oral mucosal ulcerations in solid organ transplant recipients represents a challenge. We describe a unique case of oral ulceration related to mycophenolate mofetil (MMF) toxicity, 11 years after kidney transplantation, whose dose reduction was sufficient to resolve it.

METHODS AND RESULTS

A 54-year-old female patient, who underwent kidney transplantation 11 years ago, presents multiple ulcers on the buccal mucosa bilaterally, soft palate and tongue dorsum, for 8 months, with moderate pain. The diagnosis of oral ulcerations associated with MMF therapy was assumed by excluding infection and malignancy diagnosis. After MMF dose reduction, the oral ulcers healed utterly.

CONCLUSIONS

MMF toxicity manifested as oral ulcers. Reduction or discontinuation of MMF therapy should be considered in a patient with refractory oral ulcers and a negative workup for other causes.

Direct T-cell Inhibition and Agents Targeting T-cell Migration and Chemotaxis

Lymphocyte depletion and blockade of T-cell activation and trafficking serve as therapeutic strategies for an enlarging number of immune-mediated diseases and malignancies. This review summarizes the infection risks associated to monoclonal antibodies that bind to the α chain of the interleukin-2 receptor, the cell surface glycoprotein CD52, and members of α4- and β2-integrin families acting as cell-adhesion molecules. An outline of the mechanisms of action, approved indications and off-label uses, expected impact on the host immune response, and available clinical evidence is provided for each of these agents.