Cytomegalovirus immunoglobulin decreases the risk of cytomegalovirus infection but not disease after pediatric lung transplantation

Evaluation of Two Different CMV-Immunoglobulin Regimens for Combined CMV Prophylaxis in High-Risk Patients following Lung Transplant

BACKGROUND

The clinical benefits of the common off-label use of cytomegalovirus (CMV)-specific immunoglobulin (CMV-Ig) combined with antivirals in organ transplantation have not been previously assessed. The objective was to compare the risk of CMV infection and other post-transplantation outcomes between two CMV-Ig prophylaxis regimens in lung transplant recipients; Methods: Retrospective study of 124 donor CMV positive/recipient negative (D+/R-) patients receiving preventive ganciclovir/valganciclovir for 12 months, of whom 62 received adjunctive CMV-Ig as per label indication (short regimen [SR-Ig]; i.e., 7 doses over 2.5 months) and were compared to 62 who received an extended off-label regimen (ER-Ig) consisting of 17 doses over one year after transplantation.

RESULTS

The incidence of CMV infection or disease, acute rejection, chronic lung allograft dysfunction, and survival did not differ between the two CMV-Ig schedules. Although the time to the first CMV infection after transplantation was shorter in the ER-Ig than in the SR-Ig adjunctive group (log-rank: p = 0.002), the risk was independently predicted by antiviral cessation (odds ratio = 3.74; 95% confidence interval = 1.04-13.51; p = 0.030), whereas the CMV-Ig schedule had no effect.

CONCLUSIONS

Extending the adjunctive CMV-Ig prophylaxis beyond the manufacturer's recommendations up to one year does not confer additional clinical benefits regarding lung post-transplantation outcomes.

Cytomegalovirus in the transplant setting: Where are we now and what happens next? A report from the International CMV Symposium 2021

The CMV Symposium in September 2021 was an international conference dedicated to cytomegalovirus (CMV) infection after solid organ or hematopoietic stem cell transplantation. This review provides an overview of the presentations given by the expert faculty, supplemented with educational clinical cases. Topics discussed include CMV epidemiology and diagnosis, the burden of CMV infection and disease, CMV-specific immunity and management of CMV in transplant settings. Major advances in the prevention and treatment of CMV in the past decade and increased understanding of CMV immunity have led to improved patient outcomes. In the future, management algorithms may be individualized based on the transplant recipient's immune profile, which will mark the start of a new era for patients with CMV.

Effectiveness of Prophylactic Human Cytomegalovirus Hyperimmunoglobulin in Preventing Cytomegalovirus Infection following Transplantation: A Systematic Review and Meta-Analysis

Cytomegalovirus (CMV) is a common infection occurring in patients undergoing solid organ transplantation (SOT) or hematopoietic stem cell transplantation (HSCT). CMV-specific hyperimmunoglobulin (CMVIG) has been used for the past four decades and is typically administered either prophylactically or pre-emptively. The present meta-analysis evaluated CMV infection rates in SOT patients who received prophylactic CMVIG. PubMed and the Cochrane Library were searched for studies published up to October 2021. The primary endpoint was CMV infection rate. Thirty-two SOT studies were identified (n = 1521 CMVIG-treated and n = 1196 controls). Prophylactic CMVIG treatment was often associated with a lower risk of CMV infection in transplant recipients. The average CMV infection rate was 35.8% (95% confidence interval [CI]: 33.4−38.2%) in patients treated prophylactically with CMVIG and 41.4% (95% CI: 38.6−44.2%) in the control group not receiving CMVIG (p = 0.003). Similar results were observed in analyses limited to publications evaluating currently available CMVIG products (Cytotect CP and Cytogam; p < 0.001). In combination with the established safety profile for CMVIG, these results suggest that prophylactic CMVIG treatment in patients undergoing solid organ transplantation may be beneficial, particularly in those at high risk of CMV infection or disease.

Recent Approaches and Strategies in the Generation of Anti-human Cytomegalovirus Vaccines

Human cytomegalovirus is the largest human herpesvirus and shares many core features of other herpesviruses such as tightly regulated gene expression during genome replication and latency as well as the establishment of lifelong persistence following infection. In contrast to stereotypic clinical syndromes associated with alpha-herpesvirus infections, almost all primary HCMV infections are asymptomatic and acquired early in life in most populations in the world. Although asymptomatic in most individuals, HCMV is a major cause of disease in hosts with deficits in adaptive and innate immunity such as infants who are infected in utero and allograft recipients following transplantation. Congenital HCMV is a commonly acquired infection in the developing fetus that can result in a number of neurodevelopmental abnormalities. Similarly, HCMV is a major cause of disease in allograft recipients in the immediate and late posttransplant period and is thought to be a major contributor to chronic allograft rejection. Even though HCMV induces robust innate and adaptive immune responses, it also encodes a vast array of immune evasion functions that are thought aid in its persistence. Immune correlates of protective immunity that prevent or modify intrauterine HCMV infection remain incompletely defined but are thought to consist primarily of adaptive responses in the pregnant mother, thus making congenital HCMV a potentially vaccine modifiable disease. Similarly, HCMV infection in allograft recipients is often more severe in recipients without preexisting adaptive immunity to HCMV. Thus, there has been a considerable effort to modify HCMV specific immunity in transplant recipient either through active immunization or passive transfer of adaptive effector functions. Although efforts to develop an efficacious vaccine and/or passive immunotherapy to limit HCMV disease have been underway for nearly six decades, most have met with limited success at best. In contrast to previous efforts, current HCMV vaccine development has relied on observations of unique properties of HCMV in hopes of reproducing immune responses that at a minimum will be similar to that following natural infection. However, more recent findings have suggested that immunity following naturally acquired HCMV infection may have limited protective activity and almost certainly, is not sterilizing. Such observations suggest that either the induction of natural immunity must be specifically tailored to generate protective activity or alternatively, that providing targeted passive immunity to susceptible populations could be prove to be more efficacious.

The Third International Consensus Guidelines on the Management of Cytomegalovirus in Solid-organ Transplantation

Despite recent advances, cytomegalovirus (CMV) infections remain one of the most common complications affecting solid organ transplant recipients, conveying higher risks of complications, graft loss, morbidity, and mortality. Research in the field and development of prior consensus guidelines supported by The Transplantation Society has allowed a more standardized approach to CMV management. An international multidisciplinary panel of experts was convened to expand and revise evidence and expert opinion-based consensus guidelines on CMV management including prevention, treatment, diagnostics, immunology, drug resistance, and pediatric issues. Highlights include advances in molecular and immunologic diagnostics, improved understanding of diagnostic thresholds, optimized methods of prevention, advances in the use of novel antiviral therapies and certain immunosuppressive agents, and more savvy approaches to treatment resistant/refractory disease. The following report summarizes the updated recommendations.

An Update in Antimicrobial Therapies and Infection Prevention in Pediatric Lung Transplant Recipients

Lung transplantation can offer life-prolonging therapy to children with otherwise terminal end-stage lung disease. However, infectious complications, like those experienced by their adult counterparts, are a significant cause of morbidity and mortality. These include bacteria, viruses, and fungi that infect the patient pretransplant and those that may be acquired from the donor or by the recipient in the months to years posttransplant. An understanding of the approach to the management of each potential infecting organism is required to ensure optimal outcomes. In particular, emphasis on aggressive preoperative management of infections in pediatric patients with cystic fibrosis is important. These include multidrug-resistant Gram-negative bacteria, fungi, and Mycobacterium abscessus, the posttransplant outcome of which depends on optimal pretransplant management, including vaccination and other preventive, antibiotic-sparing strategies. Similarly, increasing the transplant donor pool to meet rising transplant demands is an issue of critical importance. Expanded-criteria donors-those at increased risk of blood-borne viruses in particular-are increasingly being considered and transplants undertaken to meet the rising demand. There is growing evidence in the adult pool that these transplants are safe and associated with comparable outcomes. Pediatric transplanters are therefore likely to be presented with increased-risk donors for their patients. Finally, numerous novel antibiotic-sparing therapeutic approaches are on the horizon to help combat infections that currently compromise transplant outcomes.

Immunomodulation by hyperimmunoglobulins after solid organ transplantation: Beyond prevention of viral infection

Hyperimmunoglobulins are pharmaceutical formulations of human IgG which contain high titers of antibodies against specific viruses. They have been successfully used in solid organ transplantation (SOT) to prevent Cytomegalovirus (CMV) and Hepatitis B Virus (HBV) infection. The introduction of effective and cheaper antiviral drugs has resulted in decreasing usage of hyperimmunoglobulins in SOT. However, it may still be attractive to combine antiviral drug therapy with hyperimmunoglobulins after SOT, as there is some evidence that hyperimmunoglobulins, similar to high doses of intravenous immunoglobulins (IVIgs), might exert anti-inflammatory activity and thereby prevent immunological graft damage and improve graft and patient survival. In this review we discuss the existing clinical evidence for beneficial anti-inflammatory effects of hyperimmunoglobulins after cardiac, lung, kidney, and liver transplantation. Only a limited number of studies have addressed this issue, and these studies often included small patient cohorts and showed considerable variations in the type, intensity and duration of treatment regimens. Due to these limitations, it is difficult to draw firm conclusions. Retrospective studies consistently demonstrated that addition of CMV hyperimmunoglobulin (CMV-Ig) to antiviral drug prophylaxis after lung transplantation is associated with reduced rates of CMV disease and bronchiolitis obliterans syndrome (BOS), and improved patient survival. The doses of CMV-Ig administered after SOT are much lower than the minimal effective dose of IVIg used for anti-inflammatory therapy in auto-immune diseases. Therefore, it is questionable whether the reduced incidence of BOS is the result of 'direct' anti-inflammatory effects of CMV-Ig or is caused by a reduction of CMV infection, which is a risk factor for BOS. No or very limited evidence for better prevention of immunological graft damage by anti-CMV combination therapy is available for heart, kidney and liver transplant patients. In liver transplantation published evidence suggests that the high-doses of Hepatitis B virus hyperimmunoglobulin (HBIg) administered to prevent HBV-infection may reduce the risk of acute rejection, while combination therapy of HBIg and antiviral drugs in HBV-infected patients is consistently associated with better graft and patient survival compared to antiviral monotherapy. Well-designed prospective randomized studies with larger patient cohorts are needed to substantiate the current limited evidence for anti-inflammatory benefits of hyperimmunoglobulins besides prevention of CMV and HBV infection after SOT.

Cytomegalovirus Infection and Treatment in Allogeneic Hematopoietic Stem Cell Transplantation: A Retrospective Study from a Single Institution in an Endemic Area

Objective:

Although Cytomegalovirus (CMV) infection is a major complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT), the risk factors for CMV reactivation and treatment failure in CMV endemic areas have remained unclear. This study investigated the risk factors for CMV reactivation among allo-HSCT recipients in an area where CMV is highly endemic.

Materials and Methods:

Medical records of 82 allo-HSCT recipients from a CMV endemic area were retrospectively reviewed. The patients were stratified into two groups: those with CMV reactivation (n=32) and those without CMV reactivation (n=50). We investigated possible variables associated with CMV reactivation and treatment failure.

Results:

Univariate analyses showed that non-remission disease status [hazard ratio (HR): 2.15; p=0.032] and ≥grade III acute graft-versus-host disease (GVHD) (HR: 3.07; p=0.002) were associated with CMV reactivation. Multivariate analysis further demonstrated that older age (HR: 1.03; p=0.029) and ≥grade III acute GVHD (HR: 2.98; p=0.012) were associated with CMV reactivation. Overall survival time seemed lower among patients with CMV reactivation than among patients without CMV reactivation, although the difference was not statistically significant (p=0.165). The absence of ≥grade III acute GVHD was associated with successful CMV treatment in the current study (odds ratio: 4.40; p=0.008).

Conclusion:

Prophylactic anti-CMV therapy might need to be considered for allo-HSCT recipients who have ≥grade III GVHD.

Microbial Cryptotopes are Prominent Targets of B-cell Immunity

B-cell recognition of microbial antigens may be limited by masking of epitopes within three-dimensional structures (cryptotopes). Here we report that unmasking of cryptotopes by unfolding whole cytomegalovirus (CMV) antigen preparations with the chaotropic reagent Urea and probing with immune sera from healthy individuals (n = 109) increased ELISA signals by 36% in comparison to folded CMV antigens (P < 0.001). ELISA signals increased also significantly upon unfolding of S. aureus or E. coli antigens, whereas unfolded influenza H1N1 or respiratory syncitial virus antigens yielded reduced or unchanged reactivity in comparison to folded ones, respectively. Blocking of CMV cryptotope-specific Abs by incubation of an immunoglobuline preparation and three sera with unfolded CMV antigens enhanced clearly the neutralizing capacity of this immunoglobuline preparation against CMV infection. Thus, B-cell immunity frequently targets cryptotopes on CMV but these Abs are non-neutralizing, may reduce the neutralizing effectiveness of pathogen-specific Abs, and increase during immune maturation following primary CMV infection. The observation of functional consequences of Abs specific for cryptotopes may open whole new avenues to a better understanding of the humoral immune response to CMV and development of more effective vaccines and immunoglobuline preparations.

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-).

Cytomegalovirus Hyper Immunoglobulin for CMV Prophylaxis in Thoracic Transplantation

Cytomegalovirus (CMV) infection negatively influences both short- and long-term outcomes after cardiothoracic transplantation. In heart transplantation, registry analyses have shown that CMV immunoglobulin (CMVIG) with or without virostatic prophylaxis is associated with a significant reduction in mortality and graft loss versus no prophylaxis, particularly in high-risk donor (D)+/recipient (R)- transplants. Randomized comparative trials are lacking but retrospective data suggest that addition of CMVIG to antiviral prophylaxis may reduce rates of CMV-related events after heart transplantation, including the incidence of acute rejection or chronic allograft vasculopathy. However, available data consistently indicate that when CMVIG is used, it should be administered with concomitant antiviral therapy, and that evidence concerning preemptive management with CMVIG is limited, but promising. In lung transplantation, CMVIG should again only be used with concomitant antiviral therapy. Retrospective studies have shown convincing evidence that addition of CMVIG to antiviral prophylaxis lowers CMV endpoints and mortality. The current balance of evidence suggests that CMVIG prophylaxis reduces the risk of bronchiolitis obliterans syndrome, but a controlled trial is awaited. Overall, the relatively limited current data set suggests that prophylaxis with CMVIG in combination with antiviral therapy appears effective in D+/R- heart transplant patients, whereas in lung transplantation, addition of CMVIG in recipients of a CMV-positive graft may offer an advantage in terms of CMV infection and disease.

Updated international consensus guidelines on the management of cytomegalovirus in solid-organ transplantation

Cytomegalovirus (CMV) continues to be one of the most common infections after solid-organ transplantation, resulting in significant morbidity, graft loss, and adverse outcomes. Management of CMV varies considerably among transplant centers but has been become more standardized by publication of consensus guidelines by the Infectious Diseases Section of The Transplantation Society. An international panel of experts was reconvened in October 2012 to revise and expand evidence and expert opinion-based consensus guidelines on CMV management, including diagnostics, immunology, prevention, treatment, drug resistance, and pediatric issues. The following report summarizes the recommendations.

The Role of Infections in BOS

Background: Infectious agents, particularly cytomegalovirus (CMV), have long been considered to be potential triggers for BOS, although the exact magnitude of the role of infections and the mechanisms thereof remain an area of active research. Methods: This chapter will review previous literature and newer results concerning the possible roles of CMV, other herpesviruses, community-acquired respiratory viruses, bacteria (including Pseudomonas, other gram-negative, gram-positive, and atypical organisms), and fungi, including colonization as well as invasive infection. Results: The text reviews and evaluates the body of literature supporting a role for these infectious agents as risk factors for BOS and time to BOS. Changing patterns of infection over time are taken into account, and studies that have shown an association between BOS (or lack thereof) and CMV are reviewed. Strategies for prevention or early treatment of infections are discussed as potential means of preserving allograft function long term. Immunizations, stringent infection-control practices, and antimicrobial treatment including newer therapies will be discussed. Conclusion: In addition to the classic literature that has focused on CMV, an expanding spectrum of infectious organisms has been implicated as possible risk factors for BOS. Increasing knowledge of the impact of long-term antiviral suppression, prophylaxis, and outcomes of early therapy will help guide future recipient management.

Cytomegalovirus risk, prevention, and management in pediatric solid organ transplantation

Cytomegalovirus (CMV) is an important cause of morbidity and mortality in children who have received organ transplants. Patients have been reported to be at differential risk for CMV disease based on the serostatus of the donor and recipient with highest risk reported for CMV seronegative recipients who receive an organ from a CMV seropositive donor. Prophylaxis with ganciclovir and/or oral valganciclovir is reasonable to attempt to prevent CMV infections. A hybrid strategy bridging prophylaxis and pre-emptive therapy appears to be emerging as an additional method to prevent CMV disease. However, there is no agreement on the optimal schedule of testing, duration and dosing of antiviral medications or the role of immunoglobulin therapy. This manuscript will review the most recent literature and recommendations for the prophylaxis and treatment of CMV infections and disease in pediatric transplant recipients. Multicenter, randomized, clinical studies involving several pediatric transplant centers are needed to determine the best strategies to prevent and treat CMV infections in these patients.