Cytomegalovirus infection in liver transplant recipients: Updates on clinical management

A 13-Year Nationwide Analysis of Nocardia and Actinomyces Infection Outcomes in Liver Transplant Recipients

Liver transplant (LT) recipients have a profound susceptibility to infections. Although Nocardia and Actinomyces (NAs) are well-known bacteria that typically affect immunosuppressed patients, a scarcity of research exists on the effects of LT with NA infections. Our study aims to evaluate the outcomes associated with NA infections in patients with LT. Patients were selected from the National Inpatient Sample (NIS) from 2008 through 2020. International Classification of Disease revision 9 (ICD-9) and ICD revision 10 (ICD-10) codes. Patients admitted with a history of LT were subdivided into those who were and were not diagnosed with an NA infection. Records were weighted using the NIS algorithm. Primary outcomes were all-cause hospital mortality, acute kidney injury (AKI), acute myocardial infarction (AMI), shock, and a composite of these. Secondary outcomes were length of stay, total charges, cytomegalovirus (CMV), and transplant rejection. Demographics and comorbidities were compared between the groups with a weighted chi-square test. Outcomes were compared between the two groups, and adjusted odds ratios (ORs) and regression coefficients were calculated using weighted logistic or linear regression as appropriate. ORs were adjusted for age, gender, race, hospital characteristics, Charlson Comorbidity Index (CCI), median income based on zip code, weekend admission, and insurance. There were 469,141 patients with LT who were included in this study, 310 of them had NA infection (0.07%). Patients in each group were of similar age, race, and overall medical complexity (P > .05). Patients with NA infection were less likely to have a history of coronary artery disease (CAD; 4.84% vs 16.20%, P < .05), hypertension (14.53% vs 25.82%, P < .05), and obesity (1.61% vs 9.0%, P < .05) than the healthy controls. Patients with LT with NA infection were found to have higher odds of mortality (OR = 5.50, P < .001), AKI (OR = 1.9, P < .05), composite outcome (OR = 2.19, P < 0.01), and more likely to have CMV infection (OR = 6.38, P < .01). Patients with LT with NA infection stayed 13.11 days longer in the hospital (P < .01) with charges of $60,399 more (P < .01) than the healthy controls. Patients with LT who acquired an NA infection were at nearly six-fold higher odds of death and other negative outcomes. Based on previous research that has demonstrated organ transplant patients to be at high risk of infections, more vigilant care should be taken to protect patients with LT from such opportunistic infections.

Healthcare disparity and its associations with cytomegalovirus disease in pediatric liver transplant recipients in South Africa

BACKGROUND

Cytomegalovirus (CMV) infection and disease are preventable complications following pediatric liver transplantation (PLT), despite the use of prophylaxis to minimize the risk of CMV disease. We evaluated the incidence and complications of CMV disease in PLT recipients in South Africa (SA), with particular reference to potential differences in outcome between state and private sector patients.

METHODS

Medical records of patients younger than 16 years of age who received liver transplants between January 1, 2012, and August 31, 2018 were analyzed.

RESULTS

Records of all 150 PLT patients were retrieved. The median age at transplant was 29.2 months (95% confidence interval 15.6-58.4) and follow-up was 46.3 months (interquartile range 27.6-63.1). Sixty-six (44%) patients were high risk, 79 (52.7%) were intermediate risk, and five (3.3%) were low risk for CMV infection. Forty-three (28.9%) patients had CMV DNAemia following transplantation, and 30 (20.1%) developed CMV disease. Receipt of care in the private sector was consistently associated with a lower hazard of CMV disease (adjusted hazard ratio [aHR] ranging from 0.36 to 0.43) and a consistently lower hazard of death among recipients at high risk for CMV disease and/or those who developed CMV disease (aHR ranging from 0.28 to 0.33).

CONCLUSION

Receipt of care in the private health sector was associated with a consistently lower hazard of CMV disease and death in individuals with CMV disease and/or at high risk for CMV disease. Policies aimed at creating a more equitable healthcare system in SA may mitigate the differential burden of illness associated with CMV in PLT recipients.

Risk factors for high level cytomegalovirus viremia in liver transplant recipients and associated outcomes

PURPOSE

To evaluate epidemiology, risk-factors and outcomes of high-level cytomegalovirus (CMV) viremia in liver transplant recipients.

METHODS

Adult patients receiving a liver transplant between 1/1/2017-9/30/2020 were evaluated. Viral loads at UW Health Clinical Laboratories were required to allow for numerical comparison. Primary objective was incidence and outcomes of high-level (HL) CMV viremia (viral-load >100,000 IU/mL). Secondary objective was to elucidate risk factors to allow targeted interventions.

RESULTS

209 patients met inclusion criteria; 175 kept their graft for at least 240 days. Of these 9 patients developed HL CMV, 28 developed low-level (LL CMV, viral-load 250-100,000 IU/mL) and 138 did not develop CMV viremia. When comparing these 3 groups via classic statistical methods time from transplant to viremia was similar (HL 158 ± 77 days, LL 150 ± 76 days). Clinical factors were also similar with the exception of donor seropositivity (HL 87.5%, LL 70.4%, No CMV 49.6%, p = 0.025). HL CMV was significantly associated with graft loss (p < 0.0001) on Kaplan-Meier analysis; graft loss in the LL CMV group did not differ from the No CMV group (p = 0.96) To allow valid assessment of risk factors in the total study population (n = 209) models of time-varying covariates were used and Cox proportional hazards ratios were calculated. In this analysis HL CMV was associated with a significantly increased risk of graft loss (HR 5.6, p = 0.0016). When investigating risk factors associated with HL CMV, donor seropositivity significantly increased risk (HR 8.85, 95% CI 1.13-71.43, p = 0.038). Pre-transplant total bilirubin (HR 1.04, 95% CI 0.998-1.07, p = 0.06) trended towards significance. Recipient seronegativity, liver disease, clinical and allocation MELD, transplant surgery duration, age, sex, induction immunosuppression, and maintenance immunosuppression were not significantly associated with development of HL CMV.

CONCLUSION

HL CMV after liver transplant is uncommon but is associated with a significantly increased risk of graft loss that is not present in those patients who develop LL CMV or do not develop CMV viremia. Given these negative graft effects, CMV stewardship interventions targeting recipients of CMV seropositive allografts are warranted. Future larger scale studies evaluating the potential role of other factors in risk stratification are needed. This article is protected by copyright. All rights reserved.

Cytomegalovirus infection in liver-transplanted children

Cytomegalovirus (CMV) infection is a common complication of liver trans-plantation in children. The CMV serostatus of recipients and donors is the primary risk factor, and prophylaxis or pre-emptive strategies are recommended for high-risk patients. Graft rejection, coinfection and Epstein-Bar virus reactivation, which can lead to post-transplant lymphoproliferative disease, are indirect effects of CMV infection. Assessment of CMV infection viral load should be routinely performed upon clinical suspicion. However, tissue-invasive CMV disease is not associated with CMV viraemia and requires confirmation by tissue pathology. Oral valganciclovir and intravenous ganciclovir are equivalent treatments, and the duration of treatment depends on factors including CMV viral load, tissue pathology, and clinical response. Risk stratification by donor and recipient status prior to transplantation and post-transplantation antiviral prophylaxis or pre-emptive therapy are recommended. Adult guidelines have been established but additional study of the effectiveness of the preventive guidelines in children is needed. This review summarizes the burden, risk factors, clinical manifestations, laboratory evaluation, treatment, and prevention of CMV infection in children after liver transplantation.

Epidemiology and long-term outcomes of cytomegalovirus DNAemia and disease in pediatric solid organ transplant recipients

Despite prevention strategies, cytomegalovirus (CMV) remains a common infection in pediatric solid organ transplant recipients (SOTR). We sought to determine the frequency, associations with, and long-term outcomes of CMV DNAemia in pediatric SOTR. We performed a single-center retrospective cohort study, including 687 first time SOTR ≤21 years receiving universal prophylaxis from 2011 to 2018. Overall, 159 (23%) developed CMV DNAemia, the majority occurring after completing primary prophylaxis. CMV disease occurred in 33 (5%) SOTR, 25 (4%) with CMV syndrome and 10 (1%) with proven/probable tissue-invasive disease. CMV contributed to the death of three (0.4%) patients (all lung). High-risk (OR 6.86 [95% CI, 3.6-12.9]) and intermediate-risk (4.36 [2.3-8.2]) CMV status and lung transplantation (4.63 [2.33-9.2]) were associated with DNAemia on multivariable analysis. DNAemia was associated with rejection in liver transplant recipients (p < .01). DNAemia was not associated with an increase in graft failure, all-cause mortality, or other organ-specific poor outcomes. We report one of the lowest rates of CMV disease after SOTR, showing that universal prophylaxis is effective and should be continued. However, we observed CMV morbidity and mortality in a subset of patients, highlighting the need for research on optimal prevention strategies. This study was IRB approved.

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.

Comparison of Humoral and Cellular CMV Immunity in Patients Awaiting Kidney Transplantation

Chronic kidney disease may alter antiviral T cell immunity. In the current study, we assessed in 63 patients prior to kidney transplantation how humoral and cellular immunity against cytomegalovirus (CMV) correlated using an interferon (IFN)-γ ELISpot (T-Track^® CMV, Mikrogen, Neuried, Germany). The cohort comprised 24 patients with negative and 39 with positive CMV IgG. Whereas none of the patients with negative CMV IgG showed detectable responses to the T-Track^® CMV, 26 out of 39 patients with positive CMV IgG had positive ELISpot responses. The median response to CMV pp65 in the CMV seronegative group was 0 spot forming units (SFU) per 200,000 PBMC (range 0–1) and in the seropositive group 43 SFU (range 0–750). Thus, 13 out of 39 patients with positive CMV serostatus (33%) had undetectable T cell immunity and may be at an increased risk of CMV reactivation. CMV pp65-specific ELISpot responses were 29.3-fold higher in seropositive patients with vs. without dialysis and 5.6-fold higher in patients with vs. without immunosuppressive therapy, but patients with dialysis and immunosuppressive therapy showed, as expected, lower responses to phytohemagglutinin, the positive control. This finding may be caused by (subclinical) CMV-DNAemia and a “booster” of CMV-specific T cells.

Comparison of Three Cellular Assays to Predict the Course of CMV Infection in Liver Transplant Recipients

To estimate protection from cytomegalovirus (CMV) replication after solid organ transplantation, CMV serology has been considered insufficient and thus CMV immunity is increasingly assessed by cellular in vitro methods. We compared two commercially available IFN-γ ELISpot assays (T-Track CMV and T-SPOT.CMV) and an IFN-γ ELISA (QuantiFERON-CMV). Currently, there is no study comparing these three assays. The assays were performed in 56 liver transplant recipients at the end of antiviral prophylaxis and one month thereafter. In CMV high- or intermediate-risk patients the two ELISpot assays showed significant correlation (p < 0.0001, r > 0.6) but the correlation of the ELISpot assays with QuantiFERON-CMV was weaker. Results of both ELISpot assays were similarly predictive of protection from CMV-DNAemia ≥500 copies/mL [CMV pp65 T-SPOT.CMV at the end of prophylaxis: area under curve (AUC) = 0.744, cut-off 142 spot forming units (SFU), sensitivity set to 100%, specificity 46%; CMV IE-1 T-Track CMV at month 1: AUC = 0.762, cut-off 3.5 SFU, sensitivity set to 100%, specificity 59%]. The QuantiFERON-CMV assay was inferior, reaching a specificity of 23% when setting the sensitivity to 100%. In conclusion, both CMV-specific ELISpot assays appear suitable to assess protection from CMV infection/reactivation in liver transplant recipients.

Primary sclerosing cholangitis as an independent risk factor for cytomegalovirus infection after liver transplant

BACKGROUND

Cytomegalovirus (CMV) infection is one of the most common infectious complications after solid organ transplant; it is associated with morbidity and mortality and with many direct and indirect effects. However, monitoring and therapeutic procedures are very heterogeneous across treatment centers. Additionally, factors that place patients at risk of CMV infection are poorly defined.

METHODS

Clinical and demographic data from 833 LT recipients and their donors were retrospectively analyzed. Univariate and multivariate analysis were applied. CMV infection was detected by quantitative nucleic acid testing with a lower limit of detection of 40 IU/mL.

RESULTS

In total, 192 of 833 patients (23%) experienced at least one episode of CMV infection after LT; CMV infection occurred to a large extent during the first year after transplant (70%). Multivariate analysis demonstrated that CMV donor-recipient risk constellation (OR 2.05, 95% CI) and primary sclerosing cholangitis (PSC) before LT (OR 3.76, 95% CI) are independent risk factors for CMV infection after LT.

CONCLUSION

Patients with high-risk serostatus, PSC, or both should be monitored more thoroughly and should receive prolonged prophylaxis against CMV infection.

Incidence, Predictors, and Impact on Survival of Long-term Cardiovascular Events After Liver Transplantation

BACKGROUND

Information on the risk factors, particularly kidney function, and impact of long-term cardiovascular events (CVE) after liver transplantation (LT) remains scarce.

METHODS

This is a retrospective, single-center study that included consecutive LT recipients between 2007 and 2017. The incidence of CVE, their risk factors, and their impact on patient survival were investigated.

RESULTS

We included 627 LT recipients. The incidence of CVE was 8% and 20% at 12 and 60 months after LT, respectively. The independent risk factors of long-term (beyond 12 mo) CVE were age at LT (hazard ratio [HR], 1.04; 95% confidence interval [CI], 1.01-1.07), male gender (HR, 2.48; 95% CI, 1.21-5.05), history of pre-LT cardiovascular disease (HR, 2.19; 95% CI, 1.2-3.98), and immunosuppression with cyclosporine A (HR, 1.93; 95% CI, 1.14-3.3). In patients with pre-LT cardiovascular disease, creatinine levels 12 months after LT significantly impacted the risk of long-term CVE. Long-term CVE (HR, 2.12; 95% CI, 1.24-3.61), hepatitis C as the etiology of liver disease (HR, 2.18; 95% CI, 1.29-3.67), cytomegalovirus infection (HR, 1.89; 95% CI, 1.08-3.3), and donor age (HR, 1.02; 95% CI, 1.01-1.04) were independent factors associated with post-LT patient death.

CONCLUSIONS

Age, male gender, cardiovascular disease before LT, and cyclosporine A were associated with the risk of long-term CVE. The impact of serum creatinine was restricted to patients with pre-LT cardiovascular disease. In these patients, preservation of kidney function early after LT may lessen the incidence of CVE, which are an independent predictor of post-LT death.

Prevention and Management of CMV Infections after Liver Transplantation: Current Practice in German Transplant Centers

Human cytomegalovirus (CMV) remains a major cause of mortality and morbidity in human liver transplant recipients. Anti-CMV therapeutics can be used to prevent or treat CMV in liver transplant recipients, but their toxicity needs to be balanced against the benefits. The choice of prevention strategy (prophylaxis or preemptive treatment) depends on the donor/recipient sero-status but may vary between institutions. We conducted a series of consultations and roundtable discussions with German liver transplant center representatives. Based on 20 out of 22 centers, we herein summarize the current approaches to CMV prevention and treatment in the context of liver transplantation in Germany. In 90% of centers, transient prophylaxis with ganciclovir or valganciclovir was standard of care in high-risk (donor CMV positive, recipient CMV naive) settings, while preemptive therapy (based on CMV viremia detected during (bi) weekly PCR testing for circulating CMV-DNA) was preferred in moderate- and low-risk settings. Duration of prophylaxis or intense surveillance was 3-6 months. In the case of CMV infection, immunosuppression was adapted. In most centers, antiviral treatment was initiated based on PCR results (median threshold value of 1000 copies/mL) with or without symptoms. Therefore, German transplant centers report similar approaches to the prevention and management of CMV infection in liver transplantation.

Epstein-Barr Virus and Cytomegalovirus Infections of the Liver

Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infections are common and are associated with a variety of liver manifestations. EBV and CMV infections, in immunocompetent hosts, commonly manifest as acute hepatitis, with severity varying from asymptomatic, self-limited icteric hepatitis to acute liver failure. Atypical manifestations, such as cholestasis, chronic hepatitis, precipitation of acute-on-chronic liver failure, and autoimmune hepatitis, are reported with EBV infection, whereas cholestasis, portal vein thrombosis, and Budd-Chiari syndrome are reported with CMV infection. In the setting of liver transplantation, CMV is the most common infectious complication and carries significant morbidity; EBV is the major cause of post-transplant lymphoproliferative disorders.

Earlier and higher rates of cytomegalovirus infection in pediatric liver transplant recipients as compared to adults: An observational study

AIM:

To study and compare the incidence and time of occurrence of cytomegalovirus (CMV) infection in the posttransplant period in adult and pediatric liver transplant recipients.

MATERIALS AND METHODS:

Consecutive live donor liver transplant recipients not on CMV prophylaxis, were prospectively enrolled from March 2012 to September 2015 and followed up for 1 year post transplant to look for CMV infection. For analysis, patients were divided into pediatric (up to 18 years) and adult (>18 years) age groups.

RESULTS:

The study population of 146 patients consisted of 132 adult and 14 pediatric patients. Overall CMV infection posttransplant was seen in 54/146 (36.98%) patients, and 16/54 (29.6%) patients developed CMV disease. Post-transplant CMV infection rate was significantly higher in pediatric patients(10/14 [71.4%]) as compared to adults (44/132 [33.4%]) (P = 0.004). Among adults, CMV infection was seen in 22 (50%) patients in the 1^st month, 13 (29.5%) patients in the 2^nd month, 5 (11.4%) patients in the 3^rd month, 2 (4.5%) patients in the 4^th month, and 1 (2.3%) patient each in the 5^th and 6^th month. However, in pediatric patients, all the patients having CMV infection had it in the 1^st-month posttransplant (P = 0.003). The median time of occurrence of CMV infection was 11.5 (7.75–19.00) days in pediatric patients versus 30 (18.5–54.5) days in adult patients (P = 0.001).

CONCLUSIONS:

The results of this study show a clear difference in the incidence and timeline of posttransplant CMV infection in pediatric patients as compared to adults.

Infectious Lung Disease

Infectious diseases are one of the main causes of morbidity and mortality worldwide. With new pathogens continuously emerging, known infectious diseases reemerging, increasing microbial resistance to antimicrobial agents, global environmental change, ease of world travel, and an increasing immunosuppressed population, recognition of infectious diseases plays an ever-important role in surgical pathology. This becomes particularly significant in cases where infectious disease is not suspected clinically and the initial diagnostic workup fails to include samples for culture. As such, it is not uncommon that a lung biopsy becomes the only material available in the diagnostic process of an infectious disease. Once the infectious nature of the pathological process is established, careful search for the causative agent is advised. This can often be achieved by examination of the hematoxylin and eosin-stained sections alone as many organisms or their cytopathic effects are visible on routine staining. However, ancillary studies such as histochemical stains, immunohistochemistry, in situ hybridization, or molecular techniques may be needed to identify the organism in tissue sections or for further characterization, such as speciation.

Postoperative hyperglycemia may negatively impact cytomegalovirus infection in seropositive liver transplant recipients: a retrospective cohort study

The aim of the study was to evaluate the association between postoperative hyperglycemia and CMV infection. We analyzed 741 CMV seropositive recipients, of livers from seropositive living donors, who underwent preemptive CMV treatment without CMV prophylaxis. The primary outcome was early CMV infection within 1 month after surgery. Hyperglycemia was defined when mean postoperative blood glucose concentration was >180 mg/dl based on previous research and guidelines. Survival analysis was performed using the Fine and Gray model by accounting for the competing risk of CMV infection-unrelated death. Of the 741 recipients (hyperglycemic group, n = 287; nonhyperglycemic group, n = 454), 372 (50.2%) recipients developed cytomegalovirus (CMV) infection within 1 month after surgery. CMV infection risk was significantly higher in hyperglycemic group than in nonhyperglycemic group in univariable analysis [hazard ratio (HR) 1.34, 95% confidence interval (CI), 1.08-1.66; P = 0.007] and in multivariable analysis (HR 1.25, 95% CI 1.0-1.54; P = 0.038). CMV infection risk was also significantly associated with recipient age, graft ischemia time, model for end-stage liver disease score, and preoperative neutrophil-to-lymphocyte ratio (P < 0.05). In conclusion, preventing postoperative hyperglycemia appears to be an important factor decreasing the risk of CMV infection in seropositive liver transplant recipients undergoing preemptive CMV treatment.

Diagnostic Utility of Cytomegalovirus Nucleic Acid Testing during Antigenemia-Guided Cytomegalovirus Monitoring after Hematopoietic Stem Cell Transplantation or Liver Transplantation

Cytomegalovirus (CMV) is an opportunistic pathogen, and careful monitoring of CMV is important for immunocompromised patients. Antigenemia-based CMV monitoring is a standard test used for managing CMV infection in transplant recipients; however, in Japan, there are no reports of CMV monitoring using the standardized test. The utility of a standardized CMV nucleic acid test (NAT) was evaluated during antigenemia-based CMV monitoring after hematopoietic stem cell transplantation (HSCT) or liver transplantation. Blood collection for CMV monitoring was performed under the physician's instructions depending on the condition of the patient, and CMV NAT and antigenemia was evaluated. For HSCT recipients, blood collection only for NAT was additionally performed during the pre-engraftment phase. The results of the NAT were blinded to those evaluating the results. A total of 34 patients were enrolled (11 HSCT recipients and 23 liver transplant recipients). NAT detected the first CMV episode no later than antigenemia in 2 (18.2%) HSCT recipients and 3 (13.0%) liver transplant recipients, earlier than antigenemia in 3 (27.3%) HSCT recipients and 7 (30.4%) liver transplant recipients, and later than antigenemia in 1 (9.1%) HSCT recipient and 1 (4.3%) liver transplant recipient. In 5 HSCT recipients, NAT was positive during the pre-engraftment phase. Among the 468 blood samples which were evaluated by both NAT and antigenemia, 124 (26.7%) were positive in NAT and 51 (10.9%) were positive in antigenemia. The standardized CMV NAT is useful for accurately diagnosing CMV infection and determining appropriate therapeutic interventions for HSCT recipients and liver transplant recipients.

Donor-derived Viral Infections in Liver Transplantation

Donor-derived infections are defined as any infection present in the donor that is transmitted to 1 or more recipients. Donor-derived infections can be categorized into 2 groups: "expected" and "unexpected" infections. Expected transmissions occur when the donor is known to have an infection, such as positive serology for cytomegalovirus, Epstein Barr virus, or hepatitis B core antibody, at the time of donation. Unexpected transmissions occur when a donor has no known infection before donation, but 1 or more transplant recipients develop an infection derived from the common donor. Unexpected infections are estimated to occur in far less than 1% of solid organ transplant recipients. We will review the epidemiology, risk factors, and approaches to prevention and management of donor-derived viral infectious disease transmission in liver transplantation.

Infections in Liver Transplantation

Liver transplantation has become an important treatment modality for patients with end-stage liver disease/cirrhosis, acute liver failure, and hepatocellular carcinoma. Although surgical techniques and immunosuppressive regimens for liver transplantation have improved significantly over the past 20 years, infectious complications continue to contribute to the morbidity and mortality in this patient population. The use of standardized screening protocols for both donors and recipients, coupled with targeted prophylaxis against specific pathogens, has helped to mitigate the risk of infection in liver transplant recipients. Patients with chronic liver disease and cirrhosis have immunological deficits that place them at increased risk for infection while awaiting liver transplantation. The patient undergoing liver transplantation is prone to develop healthcare-acquired infections due to multidrug-resistant organisms that could potentially affect patient outcomes after transplantation. The complex nature of liver transplant surgery that involves multiple vascular and hepatobiliary anastomoses further increases the risk of infection after liver transplantation. During the early post-transplantation period, healthcare-acquired bacterial and fungal infections are the most common types of infection encountered in liver transplant recipients. The period of maximal immunosuppression that occurs at 1–6 months after transplantation can be complicated by opportunistic infections due to both primary infection and reactivation of latent infection. Severe community-acquired infections can complicate the course of liver transplantation beyond 12 months after transplant surgery. This chapter provides an overview of liver transplantation including indications, donor-recipient selection criteria, surgical procedures, and immunosuppressive therapies. A focus on infections in patients with chronic liver disease/cirrhosis and an overview of the specific infectious complications in liver transplant recipients are presented.

New therapies for human cytomegalovirus infections

The recent approval of letermovir marks a new era of therapy for human cytomegalovirus (HCMV) infections, particularly for the prevention of HCMV disease in hematopoietic stem cell transplant recipients. For almost 30 years ganciclovir has been the therapy of choice for these infections and by today's standards this drug exhibits only modest antiviral activity that is often insufficient to completely suppress viral replication, and drives the selection of drug-resistant variants that continue to replicate and contribute to disease. While ganciclovir remains the therapy of choice, additional drugs that inhibit novel molecular targets, such as letermovir, will be required as highly effective combination therapies are developed not only for the treatment of immunocompromised hosts, but also for congenitally infected infants. Sustained efforts, largely in the biotech industry and academia, have identified additional highly active lead compounds that have progressed into clinical studies with varying levels of success and at least two have the potential to be approved in the near future. Some of the new drugs in the pipeline inhibit new molecular targets, remain effective against isolates that have developed resistance to existing therapies, and promise to augment existing therapeutic regimens. Here, we will describe some of the unique features of HCMV biology and discuss their effect on therapeutic needs. Existing drugs will also be discussed and some of the more promising candidates will be reviewed with an emphasis on those progressing through clinical studies. The in vitro and in vivo antiviral activity, spectrum of antiviral activity, and mechanism of action of new compounds will be reviewed to provide an update on potential new therapies for HCMV infections that have progressed significantly in recent years.

Acute allograft rejection in liver transplant recipients: Incidence, risk factors, treatment success, and impact on graft failure

Objective This study was performed to identify risk factors for acute cellular rejection after liver transplantation (LT). Methods Consecutive LT recipients who underwent surgery in our institution from 2002 to 2015 were retrospectively evaluated. Results In total, 176 patients were eligible for statistical analysis. During a mean observation period of 61.1 ± 36.3 months, 43 episodes of acute rejection were evident. Of these, 34 (79.0%) were responsive to methylprednisolone, 3 (7.0%) were treated by adjusting the dosage of immunosuppressive agents, and 6 (14.0%) were methylprednisolone-resistant and treated using anti-thymocyte globulin. Biliary complications (odds ratio [OR] = 4.89, 95% confidence interval [CI] = 2.00-11.98); donor-negative, recipient-positive CMV mismatch (OR = 9.88, 95% CI = 1.18-82.36); sex mismatch (OR = 3.16, 95% CI = 1.31-8.10); and sex mismatch with a female donor (OR = 3.00, 95% CI = 1.10-7.58) were identified as significant risk factors for acute graft rejection after LT. Conclusion In patients who develop acute cellular rejection after LT, biliary complications should be evaluated as a potential cause. Most acute rejections after LT respond to bolus corticosteroid therapy.

In vitro evaluation of current and novel antivirals in combination against human cytomegalovirus

Human cytomegalovirus (HCMV) can cause severe disease in patients with compromised or immature immune systems. Currently approved pharmacotherapies for the treatment of systemic HCMV infections [ganciclovir (GCV), cidofovir (CDV), foscarnet] are limited by a high incidence of adverse effects and/or the development of drug resistance. Given that many of these drugs have the same viral target (HCMV-encoded DNA polymerase), cross-resistance is relatively common. The primary means to combat drug resistance is combination pharmacotherapy using therapeutics with different molecular mechanisms of action with the expectation that those combinations result in an additive or synergistic enhancement of effect; combinations that result in antagonism can, in many cases, be detrimental to the outcome of the patient. We therefore tested select combinations of approved (GCV, CDV, letermovir (LMV)) and experimental (brincidofovir (BCV), cyclopropavir (CPV), maribavir (MBV), BDCRB) drugs with the hypothesis that combinations of drugs with different and distinct molecular mechanisms of action will produce an additive and/or synergistic enhancement of antiviral effect against HCMV in vitro. Using MacSynergy II (a statistical package that measures enhancement or lessening of effect relative to zero/additive), select drug combination studies demonstrated combination indices ranging from 160 to 372 with 95% confidence intervals greater than zero indicating that these combinations elicit a synergistic enhancement of effect against HCMV in vitro. These data suggest that administration of a viral DNA polymerase inhibitor, MBV, and/or a viral terminase inhibitor in combination has the potential to address the resistance/cross-resistance problems associated with currently available therapeutics.

Acute Viral Hepatitis: Beyond A, B, and C

From the standpoint of the surgical pathologist "hepatitis" is defined as the set of histologic patterns of lesions found in livers infected by hepatotropic viruses, by non-hepatotrophic viruses leading to liver inflammation in the context of systemic infection, or due to an autoimmune disease, drug, or toxin involving the liver. This article is centered on the histologic patterns of injury in acute viral hepatitis, encompassing the hepatotropic viruses A, B, C, D, and E and the "icteric hemorrhagic fevers" (dengue, hantavirus, yellow fever). A brief mention of viruses causing hepatitis in immunosuppressed patients also is presented.

Cytomegalovirus Disease After Liver Transplant-A Description of a Treatment-Resistant Case: A Case Report and Literature Review

Cytomegalovirus (CMV) infection is a common complication in solid organ transplant recipients. In patients receiving immunosuppressive treatment, CMV may lead to life-threatening organ complications or graft loss. We describe a case of 31-year-old CMV-seronegative patient who underwent liver transplant from a CMV-seropositive donor with an early acute resistant rejection of the transplanted organ followed by primary CMV infection, despite prophylaxis, and its severe organ complications. Routine treatment of acute allograft rejection through increasing the base immunosuppression and then administering methylprednisolone infusions did not yield significant therapeutic effect. This resulted in anti-thymocyte globulin and ultimately proteasome inhibitor introduction. The cholestasis remitted and liver parameters improved. But 4 weeks later the patient was admitted again due to incorrect liver function tests. Blood tests revealed high CMV viral load, and primary CMV infection was diagnosed. On diagnosis the patient was treated with ganciclovir (GCV) intravenously. As GCV resistance was suspected based on clinical premises, foscarnet (FOS) and leflunomide (LFM) were implemented with concomitant cautious immunosuppression reduction due to the history of recent graft rejection. Despite aggressive treatment introduction, viral clearance was not obtained. Ultimately the patient died due to respiratory distress resulting from lung fibrosis, most probably owing to CMV diseases with Pneumocystis jiroveci coinfection. The presented case proves the importance of strictly following the rules of prophylaxis, especially in patients with a high risk factor of CMV infection development. A quick diagnosis, implementation of appropriate treatment, and fast reaction to the lack of satisfying therapeutic effect can be the key to a successful treatment.

Early Use of Etanercept for Graft-Versus-Host Disease After Liver Transplant: the Importance of Broad Spectrum Infective Prophylaxis

Graft-versus-host-disease after orthotopic liver transplant is a rare and life-threatening complication. The diagnosis is challenging and usually confirmed by chimerism and skin biopsies. The most common cause of death is sepsis (60%), and broad-spectrum antibiotics and antifungal prophylaxis are strongly recommended. We present a case of a 61-year-old man with hepatocellular carcinoma and a previous history of metabolic and alcoholic cirrhosis who underwent orthotopic liver transplant. The immunosuppression regimen consisted of corticosteroids, calcineurin inhibitor, and mammalian target of rapamycin complex 1 inhibitor. Nine days after surgery, the patient developed leukopenia and skin rash. After confirmation of graft-versus-host disease by chimerism and skin biopsy, etanercept, a novel anti-tumor necrosis factor-alpha drug used for patients with hematologic and rheumatologic disease, was administrated. Unfortunately, no clinical improvements or bone marrow recovery were noted, and the patient had subsequent fatal sepsis due to Enterococcus faecium, Aspergillus fumigatus, and viral superinfection. There are no US Food and Drug Administration-approved treatments for graft-versus-host disease after orthotopic liver transplant. The main risk factors are recipients > 50 years old, patients with glucose intolerance, patients transplanted due to hepatocellular carcinoma, donor-recipient age difference of > 20 years, and any HLA-class I match. In accordance with the literature, we suggest early use of broad-spectrum antibiotics and antifungal drugs during etanercept treatment. In addition, because of substantially higher risk for severe sepsis, we strongly recommend adding an antiviral prophylaxis to prevent Cytomegalovirus reactivation or unexpected superinfection.

Single-cycle adenovirus vectors in the current vaccine landscape

INTRODUCTION

Traditional inactivated and protein vaccines generate strong antibodies, but struggle to generate T cell responses. Attenuated pathogen vaccines generate both, but risk causing the disease they aim to prevent. Newer gene-based vaccines drive both responses and avoid the risk of infection. While these replication-defective (RD) vaccines work well in small animals, they can be weak in humans because they do not replicate antigen genes like more potent replication-competent (RC) vaccines. RC vaccines generate substantially stronger immune responses, but also risk causing their own infections. To circumvent these problems, we developed single-cycle adenovirus (SC-Ad) vectors that amplify vaccine genes, but that avoid the risk of infection. This review will discuss these vectors and their prospects for use as vaccines.

AREAS COVERED

This review provides a background of different types of vaccines. The benefits of gene-based vaccines and their ability to replicate antigen genes are described. Adenovirus vectors are discussed and compared to other vaccine types. Replication-defective, single-cycle, and replication-competent Ad vaccines are compared.

EXPERT COMMENTARY

The potential utility of these vaccines are discussed when used against infectious diseases and as cancer vaccines. We propose a move away from replication-defective vaccines towards more robust replication-competent or single-cycle vaccines.

Binding and neutralizing anti-cytomegalovirus activities in immune globulin products

Congenital infection as well as infection of immunocompromised individuals by cytomegalovirus (CMV) can be associated with significant morbidity, mortality, and long-term adverse health outcomes. Assessment of anti-viral activity using appropriate assays is essential for ensuring safe and efficacious use of therapeutic CMV immune globulin (IG) products. In this study, we used commercial ELISA kits to compare anti-CMV antibody binding activity and avidity for lots of CMV-specific and normal IG products available in the US market. Additionally, neutralizing activity of IG products was measured against CMV strains (AD169^wt131 or TB40E-GFP) in MRC-5 human fibroblasts and ARPE-19 human epithelial cells. Our data revealed that, regardless of the method, anti-CMV activity was higher in CMV IG lots we tested compared with normal IG lots; CMV binding activity was at least 4-fold higher, and neutralizing activity at least 2- and 3-fold higher for epithelial and fibroblast cells, respectively, in CMV IG lots compared with normal IG lots. Furthermore, anti-CMV activity values from all three methods (ELISA, neutralization in MRC-5 cells, and neutralization in ARPE-19 cells) were highly correlated, whereas avidity, although higher in CMV IG lots, did not correlate well with either binding or neutralizing activities.

High-Dose Acyclovir for Cytomegalovirus Prophylaxis in Seropositive Abdominal Transplant Recipients

Background: Following abdominal solid organ transplant (aSOT), valganciclovir (VGC) is recommended for cytomegalovirus (CMV) prophylaxis. This agent is associated with efficacy concerns, toxicity, and emergence of ganciclovir resistance. Objective: To evaluate the incidence of high-dose acyclovir (HD-A) prophylaxis failure in seropositive aSOT recipients (R+). Methods: This was a retrospective, single-center study of R+ transplanted without lymphocyte-depleting induction between January 1, 2000, and June 30, 2013, discharged with 3 months of HD-A prophylaxis (800 mg 4 times daily). The primary outcome was incidence of prophylaxis failure. Secondary outcomes were incidence of biopsy-proven tissue-invasive disease and prophylaxis failure for each allograft subgroup. Results: A total of 1525 patients met inclusion criteria: 944 renal (RTX), 108 simultaneous pancreas-kidneys (SPK), 462 liver (LTX), and 11 pancreas (PTX) transplant recipients. The composite rate of HD-A prophylaxis failure was 7%; incidence of tissue-invasive disease was 0.4%. Failure rates were 4.5%, 6.1%, 11%, and 20% in the RTX, SPK, LTX, and PTX populations, respectively; tissue-invasive disease rates were 0.2%, 0%, 0.7%, and 10%. Failure occurred more frequently in the LTX and PTX populations ( P < 0.0001, HR = 2.6; P = 0.04 HR = 4.4). Incidence of tissue-invasive disease was minimal and not different in the RTX, LTX and SPK populations ( P = 0.34). When evaluating recipients of seronegative allografts (D−), the composite failure rate was 3.4% with no significant difference between allograft subgroups ( P = 0.45). Conclusion: HD-A may be a reasonable prophylaxis alternative for D−/R+ recipients, in the absence of lymphocyte-depleting induction, if low incidence viremia is tolerable. Future studies are needed to determine the long-term impact of CMV viremia in the setting of this prophylaxis approach.

Effectiveness of Preemptive Therapy for Cytomegalovirus Disease in Pediatric Liver Transplantation

BACKGROUND

Most pediatric liver transplantation (LT) centers administer long courses of prophylaxis against cytomegalovirus (CMV) without evidence of benefit and with significant drug exposure and costs. We aimed at evaluating overall outcomes, direct and putative indirect effects of CMV, possible impact of viremia and risk factors for CMV infection in pediatric LT recipients managed with ganciclovir-based preemptive therapy (PET).

METHODS

The records of all the children who underwent LT between 2008 and 2014 were retrospectively analyzed.

RESULTS

One hundred children were included. Three children had CMV disease; no CMV-related death or graft loss was recorded. The only identified risk factor for CMV infection was the donor/recipient serostatus (odds ratio, 17.23; 95% confidence interval, 1.88-157.87; P = 0.012), while viremia per se did not worsen LT outcomes, such as the incidence of acute rejection, Epstein-Barr virus infection, sepsis, biliary and vascular complications, nor graft dysfunction/loss or death at 3 and 5 years after LT. When compared with a historical cohort of children receiving ganciclovir prophylaxis, PET did not differ from prophylaxis for any of the selected outcomes, but was rather associated with lower antiviral drug exposure (6.4 ± 13 days vs 38.6 ± 14 days, P < 0.0001) and cost per patient (2.2 ± 3.9 k&OV0556; vs 6.6 ± 8.2 k&OV0556;, P = 0.001).

CONCLUSIONS

PET is effective in controlling CMV in children receiving LT, with lower costs and lower exposure to antivirals.

Practical Recommendations for Long-term Management of Modifiable Risks in Kidney and Liver Transplant Recipients: A Guidance Report and Clinical Checklist by the Consensus on Managing Modifiable Risk in Transplantation (COMMIT) Group

Short-term patient and graft outcomes continue to improve after kidney and liver transplantation, with 1-year survival rates over 80%; however, improving longer-term outcomes remains a challenge. Improving the function of grafts and health of recipients would not only enhance quality and length of life, but would also reduce the need for retransplantation, and thus increase the number of organs available for transplant. The clinical transplant community needs to identify and manage those patient modifiable factors, to decrease the risk of graft failure, and improve longer-term outcomes.COMMIT was formed in 2015 and is composed of 20 leading kidney and liver transplant specialists from 9 countries across Europe. The group's remit is to provide expert guidance for the long-term management of kidney and liver transplant patients, with the aim of improving outcomes by minimizing modifiable risks associated with poor graft and patient survival posttransplant.The objective of this supplement is to provide specific, practical recommendations, through the discussion of current evidence and best practice, for the management of modifiable risks in those kidney and liver transplant patients who have survived the first postoperative year. In addition, the provision of a checklist increases the clinical utility and accessibility of these recommendations, by offering a systematic and efficient way to implement screening and monitoring of modifiable risks in the clinical setting.

Distribution and effects of amino acid changes in drug-resistant α and β herpesviruses DNA polymerase

Emergence of drug-resistance to all FDA-approved antiherpesvirus agents is an increasing concern in immunocompromised patients. Herpesvirus DNA polymerase (DNApol) is currently the target of nucleos(t)ide analogue-based therapy. Mutations in DNApol that confer resistance arose in immunocompromised patients infected with herpes simplex virus 1 (HSV-1) and human cytomegalovirus (HCMV), and to lesser extent in herpes simplex virus 2 (HSV-2), varicella zoster virus (VZV) and human herpesvirus 6 (HHV-6). In this review, we present distinct drug-resistant mutational profiles of herpesvirus DNApol. The impact of specific DNApol amino acid changes on drug-resistance is discussed. The pattern of genetic variability related to drug-resistance differs among the herpesviruses. Two mutational profiles appeared: one favoring amino acid changes in the Palm and Finger domains of DNApol (in α-herpesviruses HSV-1, HSV-2 and VZV), and another with mutations preferentially in the 3′-5′ exonuclease domain (in β-herpesvirus HCMV and HHV-6). The mutational profile was also related to the class of compound to which drug-resistance emerged.

Cytomegalovirus Infection After Intestinal/Multivisceral Transplantation: A Single-Center Experience With 210 Cases

BACKGROUND

Cytomegalovirus (CMV) infection is the most prevalent infectious complication after solid organ transplantation, and recipients of isolated intestinal transplantation (IIT)/multivisceral transplantation (MVT) are among those at the highest risk. Limited clinical data exist regarding CMV infection after IIT/MVT. The aim of this study is to analyze risk factors for posttransplant CMV infection and to assess the efficacy and validity of our prophylaxis and treatment regimens in intestinal transplantation.

METHODS

Medical records of 210 IIT/MVT patients were retrospectively reviewed. Posttransplant CMV prophylaxis regimen consisted of ganciclovir followed by 1 year of valganciclovir. The addition of CMV immunoglobulin (CMVIG) was decided according to donor/recipient CMV serostatus (D/R). All results of CMV PCR and/or pp65 antigenemia, and pathological reports were reviewed. Time to the incidence of CMV infection (viremia and/or tissue invasive disease) and risk factors for CMV infection were investigated.

RESULTS

CMV infection was observed in 34 of 210 (16%) with a median onset of 347 days. Rejection was significantly associated with CMV infection (P = 0.01, odds ratio = 2.61). In the high-risk serostatus group (D+/R-), prophylactic CMVIG and induction with high-dose rabbit antithymocyte globulin (>10 mg/kg) were associated with a lower CMV infection rate on univariate analysis. The CMVIG remained to be an independent factor on multivariate analysis (P = 0.04, hazard ratio = 0.93/dose). Mortality associated with CMV infection occurred in 4, and CMV infection adversely affected patient survival (P = 0.001, hazard ratio = 2.71).

CONCLUSIONS

Prophylaxis with CMVIG and appropriate induction with rabbit antithymocyte globulin may be important to reduce CMV infection in high-risk serostatus group (D+/R-).

Virus-specific T-cell therapy in solid organ transplantation

This article reviews the current state of T-cell therapy as therapeutic option for virus-associated diseases against the background of the most common viral complications and their standard treatment regimens after SOT. The available data of clinical T-cell trials in SOT are summarized. References to the hematopoietic stem cell transplantation are made if applicable data in SOT are not available and their content was considered likewise valid for cell therapy in SOT. Moreover, aspects of different manufacturing approaches including beneficial product characteristics and the importance of GMP compliance are addressed.

Oral Valganciclovir as a Preemptive Treatment for Cytomegalovirus (CMV) Infection in CMV-Seropositive Liver Transplant Recipients

Objectives

Cytomegalovirus (CMV) infections in liver transplant recipients are common and result in significant morbidity and mortality. Intravenous ganciclovir or oral valganciclovir are the standard treatment for CMV infection. The present study investigates the efficacy of oral valganciclovir in CMV infection as a preemptive treatment after liver transplantation.

Methods

Between 2012 and 2013, 161 patients underwent liver transplantation at Samsung Medical Center. All patients received tacrolimus, steroids, and mycophenolate mofetil. Patients with CMV infection were administered oral valganciclovir (VGCV) 900mg/day daily or intravenous ganciclovir (GCV) 5mg/kg twice daily as preemptive treatment. Stable liver transplant recipients received VGCV.

Results

Eighty-three patients (51.6%) received antiviral therapy as a preemptive treatment because of CMV infection. The model for end-stage liver disease (MELD) score and the proportions of Child-Pugh class C, hepatorenal syndrome, and deceased donor liver transplantation in the CMV infection group were higher than in the no CMV infection group. Sixty-one patients received GCV and 22 patients received VGCV. The MELD scores in the GCV group were higher than in the VGCV group, but there were no statistical differences in the pretransplant variables between the two groups. AST, ALT, and total bilirubin levels in the GCV group were higher than in the VGCV group when CMV infection occurred. The incidences of recurrent CMV infection in the GCV and VGCV groups were 14.8% and 4.5%, respectively (P=0.277).

Conclusion

Oral valganciclovir is feasible as a preemptive treatment for CMV infection in liver transplant recipients with stable graft function.