Clinical Features and Outcomes of Delayed-onset Primary Cytomegalovirus Disease in Cardiac Transplant Recipients

Evaluation of risk factors for cytomegalovirus DNAemia after end of regular prophylaxis after heart transplantation

BACKGROUND

Cytomegalovirus (CMV) infections after heart transplantation (HTx) can cause cardiac allograft vasculopathy. Consequently, monitoring and prophylaxis for cytomegalovirus deoxyribonucleic acid (CMV-DNAemia) within the first weeks after HTx is recommended.

METHODS

All patients who underwent HTx between September 2010 and 2021 surviving the first 90 days (n = 196) were retrospectively reviewed. The patients were divided on the prevalence of CMV-DNAemia during the first postoperative year after the end of the prophylaxis. A total of n = 35 (20.1%) developed CMV-DNAemia (CMV group) and were compared to patients without CMV-DNAemia (controls, n = 139). The remaining patients (n = 22) were excluded due to incomplete data.

RESULTS

Positive donors and negative recipients (D+/R-) and negative donors and positive recipients (D-/R+) serology was significantly increased and D-/R- decreased in the CMV group (p < .01). Furthermore, the mean age was 57.7 ± 8.7 years but only 53.6 ± 10.0 years for controls (p = .03). Additionally, the intensive care unit (p = .02) and total hospital stay (p = .03) after HTx were approximately 50% longer. Interestingly, the incidence of CMV-DNAemia during prophylaxis was only numerically increased in the CMV group (5.7%, respectively, 0.7%, p = .10), the same effect was also observed for postoperative infections. Multivariate analyses confirmed that D+/R- and D-/R+ CMV immunoglobulin G match were independent risk factors for postprophylaxis CMV-DNAemia.

CONCLUSION

Our data should raise awareness of CMV-DNAemia after the termination of regular prophylaxis, as this affects one in five HTx patients. Especially old recipients as well as D+/R- and D-/R+ serology share an elevated risk of late CMV-DNAemia. For these patients, prolongation, or repetition of CMV prophylaxis, including antiviral drugs and CMV immunoglobulins, may be considered.

Incidence and severity of cytomegalovirus infection in seropositive heart transplant recipients

BACKGROUND

The frequency and significance of cytomegalovirus (CMV) infection in seropositive (R+) heart transplant recipients (HTR) is unclear, with preventative recommendations mostly extrapolated from other groups. We evaluated the incidence and severity of CMV infection in R+ HTR, to identify risk factors and describe outcomes.

METHODS

R+ HTR from 2010 to 2019 were included. Antiviral prophylaxis was not routinely used, with clinically guided monitoring the local standard of care. The primary outcome was CMV infection within one-year post-transplant; secondary outcomes included other herpesvirus infections and mortality.

RESULTS

CMV infection occurred in 27/155 (17%) R+ HTR. Patients with CMV had a longer hospitalization (27 vs. 20 days, unadjusted HR 1.02, 95% CI 1.00-1.02, p = .01), higher rate of intensive care readmission (26% vs. 9%, unadjusted HR 3.46, 1.46-8.20, p = .005), and increased mortality (33% vs. 8%, unadjusted HR 10.60, 4.52-24.88, p < .001). The association between CMV and death persisted after adjusting for multiple confounders (HR 24.19, 95% CI 7.47-78.30, p < .001). Valganciclovir prophylaxis was used in 35/155 (23%) and was protective against CMV (infection rate 4% vs. 27%, adjusted HR .07, .01-.72, p = .025), even though those receiving it were more likely to have received thymoglobulin (adjusted OR 10.5, 95% CI 2.01-55.0, p = .005).

CONCLUSIONS

CMV infection is common in R+ HTR and is associated with a high burden of disease and increased mortality. Patients who received valganciclovir prophylaxis were less likely to develop CMV infection, despite being at higher risk. These findings support the routine use of antiviral prophylaxis following heart transplantation in all CMV R+ patients.

Cytomegalovirus-related Complications and Management in Facial Vascularized Composite Allotransplantation: An International Multicenter Retrospective Cohort Study

BACKGROUND

There is a paucity of data on the impact of cytomegalovirus (CMV) serostatus and CMV infection on outcomes in facial vascularized composite allotransplantation.

METHODS

This international, multicenter, retrospective cohort study presents data on CMV and basic transplant-related demographics, including pretransplant viral D/R serostatus, and duration of antiviral prophylaxis. CMV-related complications (viremia, disease), allograft-related complications (rejection episodes, loss), and mortality were analyzed.

RESULTS

We included 19 patients, 4 of whom received CMV high-risk transplants (D+/R-). CMV viremia was noted in 6 patients (all 4 D+/R- patients and 2 D-/R+), mostly within the first-year posttransplant, shortly after discontinuation of antiviral prophylaxis (median 2 mo). CMV disease occurred in 2 D+/R- patients. The high-risk group experienced relatively more rejection episodes per month follow-up. None of D+/R- patients suffered allograft loss due to rejection (longest follow-up: 121 mo).

CONCLUSIONS

D+/R- patients were at increased risk of CMV-related complications. Although a higher number of rejections was noted in this group, none of the D+/R- patients lost their allograft or died because of CMV or rejection. Thus, CMV D+/R- face transplantation can likely be safely performed with prophylaxis, active surveillance, and prompt treatment.

Clinical Characteristics of Late-Onset Cytomegalovirus Infection After Kidney Transplantation

BACKGROUND

Late-onset cytomegalovirus (CMV) infection (LCI) has been emerging mong solid-organ transplant recipients. We explored clinical characteristics, risk factors, and outcomes of LCI in kidney transplantation (KT) recipients.

METHODS

A retrospective study of all adult KT recipients with LCIs (that occurred >6 months after transplant) from 2016 to 2018 was conducted. Clinical characteristics and outcomes were extracted. Risk factors of LCI were analyzed using Cox proportional hazards models.

RESULTS

A total of 518 KT recipients were included. Ninety-eight percent had donor CMV-seropositive and recipient CMV-seropositive status (D+/R+). Ten (2%) KT recipients developed LCI with a median onset of 14 (interquartile range, 8-15) months. Those included asymptomatic CMV infection (40%) and tissue-invasive disease (60%). CMV D+/R- serostatus and a prior episode of rejection within 6 months were associated with LCI (hazard ratio, 17.35; 95% confidence interval, 3.60-83.63; P < .001) and (hazard ratio, 38.15; 95% confidence interval, 6.15-236.72; P < .001), respectively. There was no difference in the rate of allograft failure and mortality in those with LCI compared with those with early-onset CMV infection.

CONCLUSION

LCI is uncommon after KT. Those with CMV seromismatch and a prior episode of rejection were more likely to develop LCI. Clinical and allograft outcomes were not different among each group.

Impact of late-onset cytomegalovirus infection in the development of cardiac allograft vasculopathy in heart transplant recipients

BACKGROUND

The impact of late-onset cytomegalovirus (CMV) infection (LOCI) on cardiac allograft vasculopathy (CAV) has yet to be established.

METHODS

A retrospective study was performed for patients who had undergone heart transplantation (HT) between January 1995 and October 2017 to analyze epidemiology of LOCI (any positive level of CMV pp65 antigenemia or DNAemia after 100 days, without previous CMV replication) and its association with CAV. Our main hypothesis was that LOCI causes less direct and indirect effects compared to early onset infection (EOCI).

RESULTS

Late-onset cytomegalovirus infection developed in 57 of 410 patients (13.9%) in a median time of 4.7 months post-transplant. CAV at 10 years was diagnosed in 31.6% of patients with LOCI, 34.6% with EOCI, and in 19.3% of CMV-uninfected patients. In the multivariate analysis, EOCI was an independent variable for developing CAV (HR 1.8, 95% CI 1.13-2.82, P = .01). Patients with LOCI showed a trend toward a higher risk of CAV, but the difference was not statistically significant (HR 1.7, 95% CI 0.95-3.08, P = .07). In the complementary log-log model, LOCI and EOCI had a similar CAV-free survival, and a higher probability of developing CAV than CMV-uninfected patients (P = .02).

CONCLUSIONS

Cytomegalovirus infection after HT may result in the same long-term events regardless of its onset, with a higher risk of developing CAV at 10 years than patients without CMV.

Impact of valganciclovir prophylaxis duration on cytomegalovirus disease in high-risk donor seropositive/recipient seronegative heart transplant recipients

BACKGROUND

Few data support use of 6 over 3 months of antiviral prophylaxis for cytomegalovirus (CMV) disease prevention in donor seropositive/recipient seronegative (D+R-) heart transplant recipients (HTR).

METHODS

We retrospectively assessed CMV disease and outcomes in 310 adult HTR between July 5, 2005, and December 30, 2016, at our center. Valganciclovir (VGCV) prophylaxis was given for 3-6 months in the D+R- group. Multivariable models evaluated risk factors for CMV disease in patients who received 3 vs 6 months (±1 month) of prophylaxis, with investigation of inverse probability weighting to correct for confounding variables.

RESULTS

The incidence of CMV disease among all patients and the D+R- group was 8.7% (27/310) and 26.5% (22/83), respectively, and included syndrome in 22.2% (6/27) and end-organ involvement in 77.8% (21/27). In a multivariable model, 6 vs 3 months of antiviral prophylaxis was not associated with reduced risk for CMV disease (OR 2.28 [95% CI 0.66, 7.91], P = .19). CMV disease in D+R- HTR was associated with higher rates of hospitalization (87.5% [14/16] vs 6.3% [1/16], P < .001) and for a longer duration than in matched D+R- controls without disease.

CONCLUSIONS

Cytomegalovirus disease remains a major cause of morbidity in D+R- HTR. In contrast to documented benefit in D+R- lung and kidney recipients, VGCV duration of 6 months was not associated with a lower incidence of CMV disease in D+R- HTR compared to 3-month duration and should be reconsidered in this patient population.

Incidence of cytomegalovirus in cardiac transplant recipients receiving induction immunosuppression with antithymocyte globulin

BACKGROUND

Cytomegalovirus (CMV) is a major cause of morbidity and mortality in cardiac transplant recipients. Use of induction immunosuppression in cardiac transplantation may have an impact on the incidence of CMV, but literature is limited.

METHODS

Single-center, retrospective cohort study comparing the risk of CMV infection and disease in cardiac transplant patients receiving antithymocyte globulin (ATG) induction therapy to those receiving no antibody induction.

RESULTS

A total of 75 patients were included in our analysis, 50 who received ATG induction and 25 who did not. CMV infection occurred in 10 (20%) and 5 (20%) patients in the ATG and No ATG groups, respectively (P > 0.99). CMV disease occurred in 10 (20%) and 4 (16%) patients in the ATG and No ATG groups, respectively (P = 0.763). The median time from transplant to CMV infection was 200.0 [142.5, 364.5] days in the ATG group vs 221.0 [192.0, 299.0] days in the No ATG group (P = 0.723). The median time from end of CMV prophylaxis to CMV infection was 94.5 [66.5, 151.0] days in the ATG group vs 53.0 [41.0,149.5] days in the No ATG group (P = 0.202). Freedom from CMV infection was highest in the D+/R+ group and lowest in the D+/R- group.

CONCLUSION

In cardiac transplant recipients, ATG induction was not associated with an increased incidence of CMV infection or disease in the setting of valganciclovir prophylaxis and an initial maintenance immunosuppression regimen of primarily steroids, mycophenolate mofetil, and tacrolimus.

Cytomegalovirus infection in heart transplantation: A single center experience

BACKGROUND

Cytomegalovirus (CMV) infection remains a major complication after heart transplantation with varying prophylaxis strategies employed. We sought to determine the impact of valganciclovir (VGC) duration on the epidemiology of CMV infections after heart transplantation.

METHODS

We performed a prospective cohort study of CMV donor (D) or recipient (R) seropositive heart transplant recipients from 2005 to 2012 who completed VGC prophylaxis, ranging from 3 to 12 months according to serostatus and induction immunosuppression. Univariate and multivariate logistic regression was performed.

RESULTS

Among 159 heart transplant recipients during the study period, 130 (82%) were eligible for VGC prophylaxis. CMV D/R serostatus was as follows: 24% D+/R-, 30% D+/R+, and 29% D-/R+. 65% and 21% received basiliximab and thymoglobulin induction, respectively, followed by maintenance tacrolimus, mycophenolate mofetil, and prednisone. Twenty-one (16%) recipients suffered CMV infection. There was no association with comorbidities including diabetes mellitus, chronic kidney disease, or mechanical assist devices, nor were there associations with rejection, treatments of rejection, or mortality. When VGC prophylaxis duration was stratified by ≤6 vs ≥12 months, time from heart transplantation to CMV infection was delayed (median 247 vs 452 days, P = .002) but there was no difference in days from VGC discontinuation to onset of CMV infection (median 72 vs 83 days, P = .31). CMV infection occurred most frequently within 6-16 weeks of VGC cessation, and 95% of infections occurred during the 6 months post-prophylaxis period.

CONCLUSIONS

Relative to ≤6 months, ≥12 months of VGC did not reduce incidence of CMV infection and only delayed time to onset. 95% of CMV infection occurs within 6 months after cessation of VGC.

Burden of cytomegalovirus disease in solid organ transplant recipients: a national matched cohort study in an inpatient setting

BACKGROUND

We investigated the impact of early- (E-CMV) and late onset (L-CMV) cytomegalovirus disease on the probability of graft rejection, graft failure, mortality, and healthcare resource use, following solid organ transplantation (SOT) in France.

METHODS

A retrospective analysis of data from the French 'Programme de Médicalisation des Systèmes d'Information' database (2007-2011) was conducted to identify SOT recipients who developed CMV disease in an inpatient setting. Recipients were stratified by time to CMV disease onset: E-CMV (≤3 months), L-CMV-3M (>3-24 months), and L-CMV-6M (>6-24 months). Data were analyzed by comparing recipients with CMV disease or without (controls) in a 1:2 ratio, matched according to age, gender, target organ, and previous/simultaneous occurrence of graft rejection. Graft failure, graft rejection, all-cause in-hospital mortality, and resource utilization (including hospitalization costs) were assessed over 12 months following CMV disease diagnosis.

RESULTS

Among 20 473 SOT recipients, 2430 (11.86%) were reported to have CMV disease within 24 months after transplantation. CMV disease was significantly associated with an increased risk of graft rejection and mortality, as indicated by logistic regression analysis. Odd ratios (ORs) for the risk of graft rejection were E-CMV=1.43, L-CMV-3M=1.50, and L-CMV-6M=1.61 (all P<.05), while ORs for mortality were E-CMV=2.85, L-CMV-3M=4.22, and L-CMV-6M=4.77 (all P<.0001). Only L-CMV was significantly correlated with a higher risk of graft failure: E-CMV=1.18 (P=.1906), L-CMV-3M=1.77 (P=.0013), and L-CMV-6M=3.12 (P<.0001). Hospitalization costs increased by €7078 (range €6270-€22 111), €6523 (range €5328-€10 295), and €6311 (range €5295-€9184) in recipients with E-CMV, L-CMV-3M, and L-CMV-6-M, respectively.

CONCLUSION

This study, based on French national data, demonstrates the considerable burden of CMV disease in SOT recipients and highlights the importance of developing new strategies to prevent and manage CMV disease and improve clinical outcomes for SOT patients.

Cytomegalovirus Immunoglobulin After Thoracic Transplantation: An Overview

Cytomegalovirus (CMV) is a highly complex pathogen which, despite modern prophylactic regimens, continues to affect a high proportion of thoracic organ transplant recipients. The symptomatic manifestations of CMV infection are compounded by adverse indirect effects induced by the multiple immunomodulatory actions of CMV. These include a higher risk of acute rejection, cardiac allograft vasculopathy after heart transplantation, and potentially bronchiolitis obliterans syndrome in lung transplant recipients, with a greater propensity for opportunistic secondary infections. Prophylaxis for CMV using antiviral agents (typically oral valganciclovir or intravenous ganciclovir) is now almost universal, at least in high-risk transplants (D+/R-). Even with extended prophylactic regimens, however, challenges remain. The CMV events can still occur despite antiviral prophylaxis, including late-onset infection or recurrent disease, and patients with ganciclovir-resistant CMV infection or who are intolerant to antiviral therapy require alternative strategies. The CMV immunoglobulin (CMVIG) and antiviral agents have complementary modes of action. High-titer CMVIG preparations provide passive CMV-specific immunity but also exert complex immunomodulatory properties which augment the antiviral effect of antiviral agents and offer the potential to suppress the indirect effects of CMV infection. This supplement discusses the available data concerning the immunological and clinical effects of CMVIG after heart or lung transplantation.

CMV Immunoglobulins for the Treatment of CMV Infections in Thoracic Transplant Recipients

Intravenous ganciclovir and, increasingly, oral valganciclovir are now considered the mainstay of treatment for cytomegalovirus (CMV) infection or CMV disease. Under certain circumstances, CMV immunoglobulin (CMVIG) may be an appropriate addition or, indeed, alternative. Data on monotherapy with CMVIG are limited, but encouraging, for example in cases of ganciclovir intolerance. In cases of recurrent CMV in thoracic transplant patients after a disease- and drug-free period, adjunctive CMVIG can be considered in patients with hypogammaglobulinemia. Antiviral-resistant CMV, which is more common among thoracic organ recipients than in other types of transplant, can be an indication for introduction of CMVIG, particularly in view of the toxicity associated with other options, such as foscarnet. Due to a lack of controlled trials, decision-making is based on clinical experience. In the absence of a robust evidence base, it seems reasonable to consider the use of CMVIG to treat CMV in adult or pediatric thoracic transplant patients with ganciclovir-resistant infection, or in serious or complicated cases. The latter can potentially include (i) treatment of severe clinical manifestations, such as pneumonitis or eye complications; (ii) patients with a positive biopsy in end organs, such as the lung or stomach; (iii) symptomatic cases with rising polymerase chain reaction values (for example, higher than 5.0 log₁₀) despite antiviral treatment; (iv) CMV disease or CMV infection or risk factors, such as CMV-IgG–negative serostatus; (vi) ganciclovir intolerance; (vii) patients with hypogammaglobulinemia.

Low-Dose Valacyclovir for Cytomegalovirus Infection Prophylaxis After a Heart Transplant

OBJECTIVES

Cytomegalovirus infection is a major cause of morbidity and mortality in solid-organ transplant. Low doses of valacyclovir have been administered as cytomegalovirus prophylaxis in our institution for years. To the best of our knowledge, there is no published study of a low-dose regimen for cytomegalovirus prophylaxis in heart transplant patients. Therefore, our aim was to determine the results of low doses of valacyclovir in heart transplant.

MATERIALS AND METHODS

Between September 2006 and December 2014, sixty-eight patients underwent orthotopic heart transplants. All of the patients received triple immunosuppressive therapy after surgery. During the next 6 months, sulfamethoxazole/trimethoprim was administered for Pneumocystis jiroveci pneumonia, and toxoplasmosis. Additionally all patients received valacyclovir hydrochloride (1000 mg/d, oral) for cytomegalovirus prophylaxis and nystatin oral rinse for prophylaxis of fungal infections.

RESULTS

There was only 1 cytomegalovirus infection at follow-up. The patient had cytomegalovirus pneumonia at 17-month follow-up. In response to treatment with 1-week intravenous ganciclovir, the patient was discharged with a further 6-month oral valacyclovir therapy (1000 mg/d).

CONCLUSIONS

In this study, we hypothesized that daily use of low-dose valacyclovir (1000 mg/d) is not only sufficient for cytomegalovirus prophylaxis but also beneficial in terms of cost.

A Prospective Monitoring Study of Cytomegalovirus Infection in Non-Immunosuppressed Critical Heart Surgery Patients

Background

Reactivation of cytomegalovirus (CMV) has been reported occasionally in immnunocompetent patients in the intensive care unit (ICU). The epidemiology and association of CMV infection with adverse outcome is not well defined in this population. Patients undergoing major heart surgery (MHS) are at a particularly high risk of infection. CMV infection has not been systematically monitored in MSH-ICU patients.

Methods

We assessed CMV plasma viremia weekly using a quantitative polymerase chain reaction assay in a prospective cohort of immunocompetent adults admitted to the MHS-ICU for at least 72 hours between October 2012 and May 2013. Risk factors for CMV infection and its potential association with continued hospitalization or death by day 30 (composited endpoint) were assessed using univariate and multivariate logistic regression analyses.

Results

CMV viremia at any level was recorded in 16.5% of patients at a median of 17 days (range, 3-54 days) after admission to the MHS-ICU. Diabetes (adjusted OR, 5.6; 95% CI, 1.8-17.4; p=0.003) and transfusion requirement (>10 units) (adjusted OR, 13.7; 95% CI, 3.9-47.8; p<0.001) were independent risk factors associated with CMV reactivation. Reactivation of CMV at any level was independently associated with the composite endpoint (adjusted OR, 12.1; 95% CI, 2.3-64; p=0.003).

Conclusion

Reactivation of CMV is relatively frequent in immunocompetent patients undergoing MHS and is associated with prolonged hospitalization or death.

Incidence, risk factors, and outcomes of delayed-onset cytomegalovirus disease in a large, retrospective cohort of heart transplant recipients

BACKGROUND

Delayed-onset cytomegalovirus (CMV) disease can occur among heart transplant recipients after stopping anti-CMV prophylaxis. We evaluated a large, retrospective cohort of heart transplant recipients in the United States through the use of billing data from 3 Healthcare Cost and Utilization Project (HCUP) State Inpatient Databases (SID) to determine the epidemiology of delayed-onset CMV disease coded during hospital readmission.

METHODS

We identified 2280 adult heart transplant recipients from 2004 to 2010 through the use of the California, Florida, and New York SID. Demographics, comorbidities, heart failure etiology, CMV disease, and inpatient death were identified. CMV disease was classified as early-onset (≤100 days) or delayed-onset (>100 days after transplant). Possible tissue invasion by CMV was determined through the use of codes for CMV pneumonitis, hepatitis, and gastrointestinal endoscopy. Multivariate analysis was performed with the use of Cox proportional hazards models.

RESULTS

Delayed-onset CMV disease occurred in 7.5% (170/2280) and early-onset CMV disease occurred in 2.0% (45/2280) of heart transplant recipients. Risk factors for delayed-onset CMV disease included residence in a non-metropolitan locale (aHR. 1.8; 95% confidence interval [CI], 1.0-3.3) and ischemic cardiomyopathy as heart failure etiology (aHR, 1.8; 95% CI, 1.3-2.5). Inpatient death >100 days after transplant was associated with delayed-onset CMV disease with possible tissue invasion (aHR, 2.0; 95% CI, 1.1-3.8), transplant failure or rejection (aHR, 4.0; 95% CI, 2.7-5.8), and renal failure (aHR, 1.5; 95% CI, 1.1-2.0).

CONCLUSIONS

Delayed-onset CMV disease is more common than early-onset CMV disease among heart transplant recipients. These results suggest that delayed-onset tissue-invasive CMV disease may be associated with an increased risk of death.

[Prophylaxis of cytomegalovirus infection in heart transplantation]

Cytomegalovirus (CMV) is a common complication after heart transplantation, affecting almost half of all recipients. The clinical spectrum of this infection includes, in order of greater to lesser severity, latent infection, asymptomatic viremia, CMV syndrome and CMV disease. CMV is associated with rejection and vascular graft disease and is a major cause of morbidity and mortality. The factors most frequently involved in susceptibility to this infection and its severity are donor and recipient CMV serological status, the intensity of immunosuppression and the type of immunosuppressive agents used. The management strategies of this infection include universal or targeted prophylaxis, preemptive therapy and treatment of established disease. The use of preventive measures significantly reduces the incidence of symtomatic infection or CMV disease, which has been reported to be less than 3% in some recent series.

Update on cytomegalovirus infections of the gastrointestinal system in solid organ transplant recipients

Cytomegalovirus (CMV) infection of the gastrointestinal tract is the most common manifestation of tissue-invasive CMV disease, and is a significant cause of morbidity and mortality in the solid organ transplantation (SOT) recipient. In addition to the direct effects of the infection, its indirect effects on allograft function, risk for other opportunistic infections, and mortality are significant in this population. The most common clinical syndromes are esophagitis, colitis, and hepatitis; however, infection can occur anywhere in the gastrointestinal tract. Diagnosis is usually by histopathology or viral culture of tissue specimens; molecular assays also often have a role. Antivirals are the cornerstone of therapy for gastrointestinal tract CMV disease and complications such as recurrent infection and antiviral resistance are not uncommon. Prevention with antiviral prophylaxis or preemptive therapy is important. This review summarizes recent data regarding the clinical manifestations, diagnosis, treatment, and prevention of gastrointestinal tract CMV infection in the SOT population.

Management of viral infections in solid organ transplant recipients

Management of viral infections after transplantation involves antiviral drug therapy (if available) and reduction in immunosuppression, which allows for development of pathogen-specific immunity to the offending virus. Prevention of viral infections is of the utmost importance, and this may be accomplished through vaccination, antiviral strategies and infection control measures. This article discusses the current management of selected viral pathogens that cause clinical illness in solid organ transplant recipients. The benefits and toxicities of antiviral therapies are discussed in the context of prevention and treatment of various viral diseases. The emerging issue of antiviral resistance is emphasized for cytomegalovirus, recurrent hepatitis B and influenza, while the importance of immunominimization is discussed in the management of BK nephropathy and virus-associated malignancies.

Strategies for managing cytomegalovirus in transplant recipients

IMPORTANCE OF THE FIELD

Cytomegalovirus (CMV) is the most important pathogen that affects transplant recipients, by directly causing clinical disease and by indirectly reducing patient and allograft survival.

AREAS COVERED IN THIS REVIEW

This review provides a brief overview of the direct and indirect effects of CMV disease and the traditional and newly described factors that increase the risk of disease after transplantation. Newly acquired data in the diagnostics, prevention and treatment of CMV infection are discussed, with emphasis on guidelines for management as recently endorsed by the American Society of Transplantation and the Transplantation Society.

WHAT THE READER WILL GAIN

The reader will gain up-to-date insights into the contemporary management of CMV after solid organ transplantation. Practical aspects of its diagnosis, prevention and treatment are discussed. Emerging concerns of late-onset CMV disease and antiviral resistance are also highlighted to emphasize the need to optimize CMV-prevention strategies.

TAKE HOME MESSAGE

Prevention of CMV disease is an important goal in the management of solid organ transplant recipients. The efficacy of CMV prevention should be measured not only by the significant reduction in CMV incidence but, as importantly, by the improvement in long-term allograft and patient survival.

Immune-based therapies for cytomegalovirus infection

Immune fitness is critical in the pathogenesis and outcome of cytomegalovirus (CMV) infection. CMV disease is seen almost exclusively among individuals with an immature or defective immune system, such as patients with AIDS, transplant recipients and the developing fetus. These observations have generated interest in immune-based strategies for the management of CMV disease. Among the immune-based therapies that have been investigated in experimental and clinical settings are: passive immunotherapy with immunoglobulin; CMV vaccination; adoptive CMV-specific T-cell immunotherapy; and immune reconstitution strategies (HAART in AIDS patients, and a reduction in pharmacologic immunosuppression among transplant recipients). However, except for immune reconstitution strategies, there is no widely accepted immune-based strategy that is proven to be highly effective for CMV disease management. The benefits of immunoglobulins remain debated in an era when antiviral therapy is widely available. CMV vaccination and adoptive immunotherapy, on the other hand, remain experimental, but have had encouraging preliminary results.

Primary CMV infections are common in kidney transplant recipients after 6 months valganciclovir prophylaxis

Prolonging cytomegalovirus (CMV) prophylaxis in CMV seronegative recipients of a kidney from CMV seropositive donor (D+/R-) may reduce the incidence of late infections. We analyzed late-onset primary CMV infections after 6 months valganciclovir prophylaxis. Data from all CMV D+/R- kidney transplant recipients between January 2004 and December 2008 at our center were analyzed. Patients with a functioning graft at 6 months after transplantation who received 6 months of valganciclovir prophylaxis 900 mg once daily were included (N = 127). CMV was diagnosed with quantitative PCR. Prophylaxis was completed in 119 patients. Prophylaxis was stopped at 3-5 months due to leukopenia or gastrointestinal side effects in eight patients. Late-onset primary CMV infection developed in 47/127 (37%) patients median 244 days after transplantation (range 150-655) and median 67 days after the cessation of prophylaxis (range 1-475). Four infections were asymptomatic. In others, symptoms included fever (N = 28), gastrointestinal symptoms (nausea, vomiting, diarrhea) (N = 24), respiratory tract symptoms (N = 12), and hepatopathy (N = 6). Median peak viral load was 13500 copies/mL (range 400-2,831,000). Recurrent CMV infection developed in 9/47 (19%) patients. No significant risk factors for CMV infection were identified. Symptomatic primary CMV infections were commonly detected also after prolonged valganciclovir prophylaxis.

New developments in the management of cytomegalovirus infection after solid organ transplantation

Despite remarkable advances in the diagnostic and therapeutic modalities for its management, cytomegalovirus (CMV) remains one of the most important pathogens impacting on the outcome of transplantation. Not only does CMV directly cause morbidity and occasional mortality, it also influences many short-term and long-term indirect effects that collectively contribute to reduced allograft and patient survival. Prevention of CMV infection and disease is therefore key in ensuring the successful outcome of solid organ transplantation (SOT). In this regard, antiviral prophylaxis and pre-emptive therapy are similarly effective in preventing CMV disease after transplantation. However, current guidelines prefer antiviral prophylaxis over pre-emptive therapy in preventing CMV disease in high-risk SOT recipients, such as CMV-seronegative recipients of organs from CMV-seropositive donors (CMV D+/R-), and lung, intestinal and pancreas transplant recipients. Antiviral prophylaxis has the benefits of reducing not only the incidence of CMV disease, but also the indirect effects of CMV on allograft and patient survival. The major drawback of antiviral prophylaxis is delayed-onset CMV disease, which occurs in 15-38% of CMV D+/R- SOT recipients who received 3 months of prophylaxis. Allograft rejection, over-immunosuppression and lack of CMV-specific immunity are factors that predispose patients to delayed-onset CMV disease. A recent randomized trial in CMV D+/R- kidney recipients demonstrates a significant reduction in the incidence of CMV disease when valganciclovir prophylaxis is extended to 200 days (compared with the standard 100 days) after transplantation; however, the safety and cost of this prolonged approach has yet to be assessed. In some studies, delayed-onset CMV disease has been significantly associated with allograft loss and mortality. In the vast majority of patients, CMV disease responds to treatment with intravenous ganciclovir. Recently, oral valganciclovir was demonstrated to have an efficacy that is comparable to intravenous ganciclovir in treating mild to moderate cases of CMV disease in SOT recipients. Reduction in the degree of immunosuppression should complement antiviral treatment of CMV disease. Although it remains rare, ganciclovir-resistant CMV disease is increasingly seen in clinical practice, potentially fostered by the prolonged use of antivirals in high-risk over-immunosuppressed transplant recipients. Treatment of drug-resistant CMV is currently non-standardized and may include foscarnet, cidofovir, CMV hyperimmune globulins or leflunomide. The investigational drug marivabir had the potential to treat ganciclovir-resistant CMV disease as it acts through a different mechanism. However, the recent phase III clinical trial in allogeneic bone marrow transplant recipients showed that maribavir was not significantly better than placebo for the prevention of CMV disease. Similarly, the preliminary data in a liver transplant population suggests that maribavir was inferior to oral ganciclovir for the prevention of CMV disease. This article reviews the recent data and other developments in the management of CMV infection after SOT.

Clinical predictors of relapse after treatment of primary gastrointestinal cytomegalovirus disease in solid organ transplant recipients

Primary gastrointestinal cytomegalovirus (CMV) disease after solid organ transplantation (SOT) is difficult to treat and may relapse. Herein, we reviewed the clinical records of CMV D+/R- SOT recipients with biopsy-proven gastrointestinal CMV disease to determine predictors of relapse. The population consisted of 26 kidney (13 [50%]), liver (10 [38%]) and heart (3 [12%]) transplant recipients who developed gastrointestinal CMV disease at a median of 54 (interquartile range [IQR]: 40-70) days after stopping antiviral prophylaxis. Except for one patient, all received induction intravenous ganciclovir (mean+/-SD, 33.8+/-19.3 days) followed by valganciclovir (27.5+/-13.3 days) in 18 patients. Ten patients further received valganciclovir maintenance therapy (41.6+/-28.6 days). The median times to CMV PCR negativity in blood was 22.5 days (IQR: 16.5-30.7) and to normal endoscopic findings was 27.0 days (IQR: 21.0-33.5). CMV relapse, which occurred in seven (27%) patients, was significantly associated with extensive disease (p=0.03). CMV seroconversion, viral load, treatment duration, maintenance therapy and endoscopic findings at the end of therapy were not significantly associated with CMV relapse. In conclusion, an extensive involvement of the gastrointestinal tract was significantly associated with CMV relapse. However, endoscopic evidence of resolution of gastrointestinal disease did not necessarily translate into a lower risk of CMV relapse.

Incidence rate and outcome of Gram-negative bloodstream infection in solid organ transplant recipients

Bacterial infections are common complications of solid organ transplantation (SOT). In this study, we defined the incidence, mortality and in vitro antimicrobial resistance rates of Gram-negative bloodstream infection (BSI) in SOT recipients. We identified 223 patients who developed Gram-negative BSI among a cohort of 3367 SOT recipients who were prospectively followed at the Mayo Clinic (Rochester, MN) from January 1, 1996 to December 31, 2007. The highest incidence rate (IR) of Gram-negative BSI was observed within the first month following SOT (210.3/1000 person-years [95% confidence interval (CI): 159.3-268.3]), with a sharp decline to 25.7 (95% CI: 20.1-32.1) and 8.2 (95% CI: 6.7-10.0) per 1000 person-years between 2 and 12 months and more than 12 months following SOT, respectively. Kidney recipients were more likely to develop Gram-negative BSI after 12 months following transplantation than were liver recipients (10.3 [95% CI: 7.9-13.1] vs. 5.2 [95% CI: 3.1-7.8] per 1000 person-years). The overall unadjusted 28-day all-cause mortality of Gram-negative BSI was 4.9% and was lower in kidney than in liver recipients (1.6% vs. 13.2%, p < 0.001). We observed a linear trend of increasing resistance among Escherichia coli isolates to fluoroquinolone antibiotics from 0% to 44% (p = 0.002) throughout the study period. This increase in antimicrobial resistance may influence the choice of empiric therapy.

Management of human cytomegalovirus infection in transplant recipients by the pre-emptive therapy approach

Human cytomegalovirus (HCMV) infections are still a major infectious complication in the post-transplant period of both solid organ transplant recipients (SOTRs) and hematopoietic stem cell transplant recipients (HSCTRs). For many years, the major diagnostic assay has been antigenemia, allowing semi-quantification of HCMV load in blood from transplanted patients with disseminated HCMV infection. More recently, the real-time PCR assay has replaced antigenemia for HCMV DNAemia quantification. Prevention of HCMV disease is based on either prophylaxis or pre-emptive therapy with antiviral drugs. The latter approach has been in use in our department for the last 15 years. A cut-off of 300,000 DNA copies/ml whole blood in SOTRs with either primary or reactivated infection, and a cut-off of 10,000 DNA copies/ml blood in HSCTRs proved to be safe and effective in prospective randomized, controlled trials. With this approach, HCMV disease is consistently prevented, except for a limited number of cases of organ localization in the absence of virus in blood. In these cases, HCMV infection/disease must be diagnosed by local biopsy samples.

Immune monitoring of anti cytomegalovirus antibodies and risk of cytomegalovirus disease in heart transplantation

We sought to determine whether quantitative assessment of anti-cytomegalovirus (CMV) antibodies could be useful to identify patients at risk of cytomegalovirus (CMV) disease after heart transplantation (HT). 75 patients who underwent HT at a single health care center were prospectively studied. Induction therapy included 2 doses of daclizumab and maintenance tacrolimus (n=42) or cyclosporine (n=29), mycophenolate mofetil and prednisone. All patients received prophylaxis with gancyclovir or valganciclovir. Anti-CMV intravenous immunoglobulin (CMV-IG) was added in high risk patients (CMV D+/R- serostatus). Serial determinations of anti-CMV antibodies, immunoglobulins (IgG, IgA, IgM) and IgG-subclasses were analysed. CMV infection was based on detection of the virus by antigenemia. CMV disease consisted of detection of signs or symptoms attributable to this microorganism. Ten patients (13.3%) developed CMV disease. Mean time of development of CMV disease was 3.4+/-1.6 months. In Cox regression analysis, patients with low baseline anti-CMV titers (<4.26 natural logarithm of titer, RH: 8.1, 95%CI: 1.93-34.1, p=0.004) and recipients with 1-month post-HT IgG hypogammaglobulinemia (IgG<500 mg/dl, RH: 4.49, 95%CI: 1.26-15.94, p=0.02) were at higher risk of having CMV disease. Despite use of prophylactic CMV-IG, D+/R- patients showed significantly lower titers of anti-CMV antibodies at 7 d, 30 d and 90 d post HT as compared with HT recipients without infections. Four out of 6 of these patients developed late CMV disease. Monitoring of specific anti-CMV antibodies on the bedside warrants further evaluation as a potential tool to identify heart transplant recipients at higher risk of CMV disease.

Prevention of posttransplant cytomegalovirus disease and related outcomes with valganciclovir: a systematic review

The precise impact of valganciclovir as preventive therapy for cytomegalovirus (CMV) in solid organ transplant (SOT) recipients is not fully defined. Data from studies using valganciclovir as preemptive therapy or prophylaxis for CMV in SOT recipients were synthesized for descriptive analysis. CMV disease occurred in 2.6% and 9.9% of the patients receiving valganciclovir as preemptive therapy and prophylaxis, respectively. Although the incidence of early-onset (<or=90 days posttransplant) CMV disease was only 0.8% and 1.2% in all patients and R-/D+ patients receiving valganciclovir prophylaxis, the incidence of late-onset (>90 days posttransplant) CMV disease rose up to 8.9% and 17.7% in the prophylactic group, respectively. On the contrary, no patients developed late-onset CMV disease in preemptive group. Both approaches with valganciclovir have successfully decreased CMV disease in SOT recipients. Late-onset CMV disease is a complication observed uniquely with valganciclovir prophylaxis, particularly in R-/D+ patients, but not with preemptive therapy.

Deficiency of cytomegalovirus (CMV)-specific CD8+ T cells in patients presenting with late-onset CMV disease several years after transplantation

Cytomegalovirus (CMV) is a major cause of morbidity and mortality among transplant recipients. The routine use of anti-CMV prophylaxis has modified the epidemiology of post-transplant CMV infection by delaying the onset of clinical disease. While the majority of delayed-onset CMV disease still occurs during the first year after transplant, reports of late-onset CMV disease presenting many years after transplantation are increasing. Here, we describe 2 CMV-seropositive transplant recipients who presented with late-onset CMV disease at 8 and 11 years after transplantation. To determine whether CMV disease occurring at a very late period after transplantation is related to immune competence, we assessed global and CMV-specific cellular immunity by evaluating the activation capability of CD8+ T cells to a mitogenic stimulus and by quantitative and functional analysis (as assessed by intracellular cytokine production and degranulation) of CMV-specific CD8+ T cells. In both patients, we demonstrated the absence or marked deficiency of CMV-specific T-cell immunity despite CMV seropositivity, and in one patient, a partial defect in the immune response to phorbol myristate acetate and ionomycin suggesting impaired global immune competence. Hence, our data suggest that late-onset CMV disease occurring many years after transplantation remains related to defects in the immune competence of patients. Measurement of CMV-specific cellular immune competence may therefore provide an additional tool to screen for patients at high risk of developing late-onset CMV disease. The clinical utility of this assay, however, will need to be evaluated in larger prospective studies.

Gastrointestinal cytomegalovirus disease in the immunocompromised patient

Cytomegalovirus (CMV) has emerged as a significant opportunistic pathogen in the era of immunosuppression. CMV was a common cause of gastrointestinal disease in AIDS patients, but the introduction of highly active antiretroviral therapy has led to a dramatic decline in AIDS-related disease. Among patients with solid organ transplants, CMV has become an increasingly important cause of gastrointestinal disease as more routine use of early CMV prophylaxis has increased delayed-onset disease, which is often tissue invasive at presentation. The role of CMV in inflammatory bowel disease is controversial; treatment may be indicated in selected cases of steroid-refractory disease with evidence of CMV. Diagnosis of gastrointestinal CMV disease generally requires endoscopic biopsy with histologic confirmation. CMV culture of biopsy material may be falsely positive because of contamination from latently infected cells. The standard induction treatment of gastrointestinal CMV disease uses intravenous ganciclovir, though the use of oral valganciclovir is increasing, especially for long-term maintenance or suppression therapy.

Bench-to-bedside review: rare and common viral infections in the intensive care unit--linking pathophysiology to clinical presentation

Viral infections are common causes of respiratory tract disease in the outpatient setting but much less common in the intensive care unit. However, a finite number of viral agents cause respiratory tract disease in the intensive care unit. Some viruses, such as influenza, respiratory syncytial virus (RSV), cytomegalovirus (CMV), and varicella-zoster virus (VZV), are relatively common. Others, such as adenovirus, severe acute respiratory syndrome (SARS)-coronavirus, Hantavirus, and the viral hemorrhagic fevers (VHFs), are rare but have an immense public health impact. Recognizing these viral etiologies becomes paramount in treatment, infection control, and public health measures. Therefore, a basic understanding of the pathogenesis of viral entry, replication, and host response is important for clinical diagnosis and initiating therapeutic options. This review discusses the basic pathophysiology leading to clinical presentations in a few common and rare, but important, viruses found in the intensive care unit: influenza, RSV, SARS, VZV, adenovirus, CMV, VHF, and Hantavirus.