Prophylaxis of primary cytomegalovirus disease in renal transplant recipients. A trial of ganciclovir vs immunoglobulin

Efficacy and safety of conventional antiviral agents in preventive strategies for cytomegalovirus infection after kidney transplantation: a systematic review and network meta-analysis

Cytomegalovirus (CMV) infection is common in kidney transplantation (KT). Antiviral-agents are used as universal prophylaxis. Our purpose aimed to compare and rank efficacy and safety. MEDLINE, Embase, SCOPUS, and CENTRAL were used from inception to September 2020 regardless language restriction. We included randomized clinical trials (RCTs) comparing the CMV infection/disease prophylaxis among antiviral-agents in adult KT recipients. Of 24 eligible RCTs, prophylactic valganciclovir (VGC) could significantly lower the overall CMV infection and disease risks than placebo with pooled risk differences (RDs) [95% confidence interval (CI)] of -0.36 (-0.54, -0.18) and -0.28 (-0.48, -0.08), respectively. Valacyclovir (VAC) and ganciclovir (GC) significantly decreased risks with the corresponding RDs of -0.25 (-0.32, -0.19) and -0.30 (-0.37, -0.22) for CMV infection and -0.26 (-0.40, -0.12) and -0.22 (-0.31, -0.12) for CMV disease. For subgroup analysis by seropositive-donor and seronegative-recipient (D+/R-), VGC and GC significantly lowered the risk of CMV infection/disease with RDs of -0.42 (-0.84, -0.01) and -0.35 (-0.60, -0.12). For pre-emptive strategies, GC lowered the incidence of CMV disease significantly with pooled RDs of -0.33 (-0.47, -0.19). VGC may be the best in prophylaxis of CMV infection/disease follow by GC. VAC might be an alternative where VGC and GC are not available.

Antiviral treatment approaches for cytomegalovirus prevention in kidney transplant recipients: A systematic review of randomized controlled trials

Various CMV anti-viral (AV) preventive strategies have been utilized in KTRs. We examined efficacy, safety and costs of CMV-AV prevention strategies in KTRs using a systematic literature review (SLR) of randomized controlled trials (RCTs) publications indexed in MEDLINE and Embase (from inception to November 2018). Thirty RCTs met inclusion criteria with 22 unique AV preventive strategies. Prophylaxis was associated with significantly lower rates of CMV infection/disease (CMVi/d) compared to no prophylaxis (pooled odds ratio, pOR with 95% confidence interval (CI): CMVi: 0.33; 0.19, 0.57; CMVd: 0.27; 0.19; 0.39). Preemptive therapy (PET) had lower rates of CMVd (0.29; 0.11, 0.77), and medical costs compared to no PET. Prophylaxis had significantly lower rates of early CMVi/d, and higher rates of late CMVi and hematological adverse events (leukopenia, 2.93; 1.22, 7.04), and similar overall medical costs compared to PET. Studies involving head-to-head comparison of different prophylaxis approaches showed mixed findings with respect to optimum dose, duration and route of administration on CMV outcomes. Although there was heterogeneity across populations and interventions, both prophylaxis and PET strategies reduced CMVi/d compared to no prophylaxis/PET and had differential safety profile in terms of hematological adverse events. For comprehensiveness we did not limit study inclusion based on date; the wide time-period may have contributed to the heterogeneity in prevention approaches which subsequently made pooling studies a challenge. Despite demonstrated efficacy of prophylaxis/PET, our findings highlight the potential need of a novel intervention with a better safety profile and perhaps improved outcomes.

Clinical outcomes of polyvalent immunoglobulin use in solid organ transplant recipients: A systematic review and meta-analysis

Polyvalent immunoglobulin is commonly used for desensitization and treatment of antibody-mediated rejection in kidney transplantation but its impact on other outcomes is not known. This systematic review investigated the impact of immunoglobulin prophylaxis on infection, rejection, graft loss, and death following kidney transplantation. A comprehensive literature search located 18 studies (n = 8 randomized controlled trials). None examined the effect of immunoglobulin prophylaxis in transplant recipients with hypogammaglobulinemia. Quality of included studies was variable with high to very high risk of bias. In the randomized trials, immunoglobulin use did not reduce cytomegalovirus infection (OR 0.68 [0.39, 1.21]; 6 studies, n = 295), rejection (OR 0.96 [0.50, 1.82]; 4 studies, n = 187), or graft loss (OR 1.03 [0.46, 2.30]; 6 studies, n = 265). In non-randomized studies, immunoglobulin did not reduce cytomegalovirus infection (OR 0.63 [0.20, 1.94]; 6 studies, n = 361) or death (OR 1.32 [0.05, 38.79]; 3 studies, n = 222) but reduce rejection (OR 0.47 [0.24, 0.94]; 4 studies, n = 268) and graft loss (OR 0.15 [0.05, 0.43]; 2 studies, n = 118). Data were scarce and sample size of current evidence was small. Adequately powered randomized trials are needed to determine if immunoglobulin is an effective intervention to reduce infection, rejection, graft loss, or death following kidney transplantation with and without hypogammaglobulinemia.

Cytomegalovirus post kidney transplantation: prophylaxis versus pre-emptive therapy?

Cytomegalovirus is the most important pathogen causing opportunistic infections in kidney allograft recipients. The occurrence of CMV disease is associated with higher morbidity, higher incidence of other opportunistic infections, allograft loss and death. Therefore, an efficient strategy to prevent CMV disease after kidney transplantation is required. Two options are currently available: pre-emptive therapy based on regular CMV PCR monitoring and generalized antiviral prophylaxis during a defined period. In this review, we describe those two approaches, highlight the distinct advantages and risks of each strategy and summarize the four randomized controlled trials performed in this field so far. Taken this evidence together, pre-emptive therapy and anti-CMV prophylaxis are both equally potent in preventing CMV-associated complications; however, the pre-emptive approach may have distinct advantages in allowing for development of long-term anti-CMV immunity. We propose a risk-adapted use of these approaches based on serostatus, immunosuppressive therapy and availability of resources at a particular transplant centre.

longitudinal analysis of levels of immunoglobulins against BK virus capsid proteins in kidney transplant recipients

This study sought to evaluate serology and PCR as tools for measuring BK virus (BKV) replication. Levels of immunoglobulin G (IgG), IgM, and IgA against BKV capsids were measured at five time points for 535 serial samples from 107 patients by using a virus-like particle-based enzyme-linked immunosorbent assay. Viral DNA in urine and plasma samples was quantitated. The seroconversion rate was 87.5% (14/16); 78.6% (11/14) and 14.3% (2/14) of patients who seroconverted developed viruria and viremia, respectively. Transient seroreversion was observed in 18.7% of patients at 17.4 +/- 11.9 weeks posttransplant and was not attributable to loss of antigenic stimulation, changes in immunosuppression, or antiviral treatment. Titers for anti-BK IgG, IgA, and IgM were higher in patients with BKV replication than in those without BKV replication. A rise in the optical density (OD) of anti-BK IgA (0.19), IgM (0.04), or IgG (0.38) had a sensitivity of 76.6 to 88.0% and a specificity of 71.7 to 76.1% for detection of viruria. An anti-BK IgG- and IgA-positive phenotype at week 1 was less frequent in patients who subsequently developed viremia (14.3%) than in those who subsequently developed viruria (42.2%) (P = 0.04). Anti-BK IgG OD at week 1 showed a weak negative correlation with peak urine viral load (r = -0.25; P = 0.05). In summary, serial measurements of anti-BKV immunoglobulin class (i) detect onset of viral replication, (ii) document episodes of seroreversion, and (iii) can potentially provide prognostic information.

WITHDRAWN: Cytomegalovirus prophylaxis with antiviral agents for solid organ transplantation

BACKGROUND

Cytomegalovirus (CMV) disease is a major cause of morbidity and mortality in solid organ transplantation. It is also associated with an increased risk of opportunistic infections, allograft injury and higher transplantation costs. CMV infection also seems to increase the risk of acute and chronic rejection of allografts via immune-mediated vascular injury. These serious consequences of CMV disease have lead to the development of effective strategies for the prevention, early diagnosis and treatment. However, there is no consensus on the necessity and the efficacy of CMV prophylaxis.

OBJECTIVES

To assess the efficacy of antiviral agents in solid organ transplant recipients in the prevention of cytomegalovirus infection and symptomatic disease and in the reduction of the incidence of acute rejection, graft loss and death.

SEARCH STRATEGY

A computerised search was conducted on Medline, Embase and Pascal. The reference lists of the current review articles and some congress proceedings were searched manually (Transplantation Proceedings, American Thoracic Society, European Society of Organ Transplantation).

SELECTION CRITERIA

Prospective, randomised studies in adults or paediatric recipients of a solid organ transplant, in which one arm received a prophylactic treatment with acyclovir and/or ganciclovir, started before cytomegalovirus infection, and the control arm received placebo or no treatment.

DATA COLLECTION AND ANALYSIS

Data were extracted from each trial and a letter sent to the authors to ask them to verify the data extracted, and to provide any data that was missing. For each outcome, several methods were used to calculate the chi-square for association and the estimate for the treatment effect with its 95% CI, with an additive model (rate difference), or a multiplicative model (odds ratio, relative risk). We considered the test of association to be significant when the p value was less than 0.01 and the homogeneity test to be significant when the p value was less than 0.1.

MAIN RESULTS

Prophylactic treatment was found to be associated with a significant decrease in cytomegalovirus disease compared with placebo or no treatment, using the logarithm of relative risk method (RR 0.51, 95% CI 0.41-0.64, p value for X(2) association < 0.001). Prophylactic treatment also decreased the rate of cytomegalovirus infection (RR 0.62, 95%CI 0.53-0.73, p < 0.001). Our analysis failed to show a significant decrease in graft loss, acute rejection or death in the prophylactic treatment group. Sub-group analysis based on the type of antiviral agent (acyclovir or ganciclovir) and on the type of organ (kidney or liver) gave comparable results.

AUTHORS' CONCLUSIONS

The use of antiviral agents for the prevention of cytomegalovirus disease and cytomegalovirus infection in solid organ transplantation is supported by this meta-analysis.

Immunoglobulins, vaccines or interferon for preventing cytomegalovirus disease in solid organ transplant recipients

BACKGROUND

Cytomegalovirus (CMV) is the most common virus causing disease and death in solid organ transplant recipients during the first six months post-transplant. Previous systematic reviews have demonstrated the efficacy of antiviral medications used prophylactically or pre-emptively in preventing CMV disease. In this review the efficacy of older agents (immunoglobulins (IgG), anti CMV vaccines and interferon) are examined.

OBJECTIVES

To assess the benefits and harms of IgG, anti CMV vaccines or interferon for preventing symptomatic CMV disease in solid organ transplant recipients.

SEARCH STRATEGY

We searched the Cochrane Renal Group's Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL, in The Cochrane Library), MEDLINE, EMBASE, reference lists and abstracts from conference proceedings without language restriction. Date of last search: December 2005

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing IgG, anti CMV vaccine or interferon with placebo or no treatment, IgG alone or combined with antiviral medications with antiviral medications or IgG alone in recipients of any solid organ transplant.

DATA COLLECTION AND ANALYSIS

Two of four authors independently assessed trial quality and extracted data from each trial. Statistical analyses were performed using the random effects model and results expressed as relative risk (RR) for dichotomous outcomes with 95% confidence intervals (CI).

MAIN RESULTS

Thirty seven trials (2185 participants) were included in this review. There was no significant difference in the risk for CMV disease (16 trials, 770 patients: RR 0.80, 95% CI 0.61 to 1.05), CMV infection (14 trials, 775 patients: RR 0.94, 95% CI 0.80 to 1.10) or all-cause mortality (8 trials, 502 patients: RR 0.57, 95% CI 0.32 to 1.03) with IgG compared with placebo/no treatment. However IgG significantly reduced the risk of death from CMV disease (6 trials, 346 patients: RR 0.33, 95% CI 0.14 to 0.80). There was no difference in the risk for CMV disease (4 trials, 298 patients: RR 1.17, 95% CI 0.74 to 1.86), CMV infection (4 trials, 298 patients: RR 1.16, 95% CI 0.89 to 1.52) or all-cause mortality (2 trials, 217 patients: RR 0.92, 95% CI 0.37 to 2.29) between antiviral medication combined with IgG and antiviral medication alone. There was no significant difference in the risk of CMV disease with anti CMV vaccine or interferon compared with placebo or no treatment.

AUTHORS' CONCLUSIONS

Currently there are no indications for IgG in the prophylaxis of CMV disease in recipients of solid organ transplants.

Valganciclovir: what is the status in solid organ transplantation?

Prophylactic drug therapy for cytomegalovirus disease in solid organ transplant recipients is effective and simple to implement, but it is associated with patient nonadherence and viral resistance. Recent data show that the efficacy and safety of oral ganciclovir and oral valganciclovir are similar. However, three large daily doses of oral ganciclovir are required, which is inconvenient, and viral resistance can develop to the drug. The single daily dose and lack of viral resistance are advantages of valganciclovir. This has become the primary agent for the prevention of cytomegalovirus disease. Current trials are underway to determine its effectiveness for treatment of cytomegalovirus disease, the optimal length of prophylaxis, and the safety and efficacy of a syrup formulation in children.

Antibody-based therapies as anti-infective agents

Antibody-based therapies are effective against a wide variety of pathogens. Historically, antibody-based therapies were largely abandoned with the advent of antimicrobial chemotherapy, due to the toxicity associated with the administration of heterologous immune sera. As a class, antibody-based therapies have significant advantages and disadvantages relative to conventional antimicrobial chemotherapy. Advantages include versatility, specificity, and antimicrobial activities not available in antibiotic drugs, such as toxin and viral neutralisation, opsonisation, complement activation and the enhancement of host immune function. Disadvantages include expense, the necessity for early and accurate diagnosis prior to use, and the complex logistics necessary for therapeutic use. Advances in antibody technology have minimised some of the disadvantages associated with antibody therapy. In recent years, the therapy of infectious diseases has been complicated by the emergence of new pathogens, the spread of antibiotic-resistant strains and the relative inefficacy of antimicrobial chemotherapy in immunocompromised hosts. This has led to renewed interest in the utilisation of antibody-based therapies as anti-infectives. Many opportunities for developing antibody-based drugs now exist in areas where the available antimicrobial therapies are inadequate.

[Immunoprophylaxis of respiratory infections]

Anti-infective antibody-based immunotherapy has gained renewed interest since the crisis of antibiotic resistance and because there is no therapy against various viral infections. The immunoprophylaxis of respiratory infections aims to utilize the ability of local antibodies to neutralize inhaled micro-organisms and their cytopathic products. Immunoglobulins for intravenous use (i.v.i.g.) have a wide spectrum of specificities. Hyperimmune i.v.i.g. containing high titers of specific antibodies have demonstrated efficacy in clinical trials, notably against the respiratory syncytial virus. Monoclonal antibodies have the advantage to be homogenous and specific for one selected epitope and several studies have demonstrated their efficacy to neutralize several infectious agents. Moreover, antibodies can be administered topically and are effective at lower doses than those needed for systemic administration. The mechanism of action could be the agglutination of bacteria or viruses at the epithelial surfaces of the respiratory tract inhibiting the early steps of the infectious process. Thanks to new technologies of humanized monoclonal antibodies, immunotherapy offers real promising perspectives for prophylactic and therapeutic therapies against a variety of current or emerging infectious diseases.

Back to the future: antibody-based strategies for the treatment of infectious diseases

Before antibiotics, sera from immune animals and humans were used to treat a variety of infectious diseases, often with successful results. After the discovery of antimicrobial agents, serum therapy for bacterial infections was rapidly forsaken. In the last two decades, problems with treatment of newly emerged, re-emerged, or persistent infectious diseases necessitated researchers to develop new and/or improved antibody-based therapeutic approaches. This article reviews some information on the use of antibodies for the treatment of infectious diseases, with special reference to the most seminal discoveries and current advances as well as available treatment approaches in this field.

Long-term oral ganciclovir prophylaxis for prevention of cytomegalovirus infection and disease in cytomegalovirus high-risk renal transplant recipients

BACKGROUND

Although specific therapy is available with ganciclovir, cytomegalovirus (CMV) disease remains a major problem after renal transplantation especially in CMV seronegative recipients of organs of seropositive donors (D+R-).

METHODS

In an open-labeled prospective controlled trial we evaluated the effect of long-term oral ganciclovir prophylaxis (3 g/day for 3 months posttransplantation) in a cohort of 31 CMV-high risk (D+R-) renal transplant recipients (GC) compared with a cohort of 28 high-risk patients with targeted CMV prophylaxis (CO) receiving i.v. ganciclovir during antirejection therapy. Primary end-points were CMV infection, diagnosed by pp65 antigenemia assay or serologic method, and CMV disease. Additionally severity of CMV disease quantified by a scoring system was evaluated.

RESULTS

CMV prophylaxis significantly reduced the incidence of CMV infection (CO: 75%, GC: 45%; P<.05) and CMV disease (CO: 60%, GC: 29%; P<.05) without relevant side effects and without any clinical suspicion of ganciclovir resistance. Severity of CMV disease as quantified by a scoring system was reduced from 8.3+/-6.7 points in controls to 3.3+/-2.6 points in ganciclovir-treated patients (P<.05). Mortality did not differ significantly between the two groups (CO: n=3, GC: n=1; NS). However, there was one lethal CMV disease and a second death possibly attributable to CMV disease in the control group, whereas in ganciclovir-treated patients there was no CMV-associated fatal outcome.

CONCLUSION

Long-term oral ganciclovir prophylaxis is effective and safe in CMV high-risk renal transplant recipients.

Cost-effectiveness model of cytomegalovirus management strategies in renal transplantation. Comparing valaciclovir prophylaxis with current practice

BACKGROUND

Cytomegalovirus (CMV) disease may occur following renal transplantation and has been shown to have health and cost consequences in this setting.

OBJECTIVE

To compare the cost effectiveness of different CMV management strategies for renal transplant patients: prophylaxis with (i) oral valaciclovir or (ii) intravenous ganciclovir; viral testing for CMV followed by (iii) pre-emptive therapy with intravenous ganciclovir or (iv) adjustment of immunosuppression and intensive monitoring; or (v) waiting to treat when CMV disease develops.

METHODS

A decision-tree model was constructed that included the different management strategies for the donor seropositive/recipient seronegative (D+R-) population. Clinical outcomes for the D+R- population came from clinical trials. Treatment algorithms and costs for CMV syndrome and tissue invasive disease were developed from published literature and UK physician interviews. One- and 2-way sensitivity analyses were performed.

STUDY PERSPECTIVE

UK National Health Service.

RESULTS

Prophylaxis with either oral valaciclovir or intravenous ganciclovir dominated (lower costs and fewer cases of CMV disease) the pre-emptive treatment and wait-and-treat strategies. The cost per patient was from 157 Pounds to 438 Pounds higher with oral valaciclovir prophylaxis compared with intravenous ganciclovir prophylaxis and the incremental cost per case of CMV disease avoided with valaciclovir prophylaxis ranged from 2243 Pounds to 8111 Pounds (1996 values). These results are sensitive to the efficacy of intravenous ganciclovir prophylaxis and CMV management costs.

CONCLUSIONS

For D+R- renal transplant patients, prophylaxis is the dominant (more effective and less costly) management strategy compared with pre-emptive and wait-and-treat strategies. The cost per patient with oral valaciclovir prophylaxis compared with intravenous ganciclovir prophylaxis is slightly higher in our base case scenario, but may be lower under reasonable alternative assumptions.

Failure of ganciclovir prophylaxis to completely eradicate CMV disease in renal transplant recipients treated with intense anti-rejection immunotherapy

Ganciclovir prophylactic regimens have been shown to be effective in renal transplant recipients at risk for primary (donor seropositive/recipient seronegative) and secondary (recipient seropositive) cytomegalovirus (CMV) disease. However, in addition to serologic factors, the type and intensity of the administered immunosuppression is a strong risk factor for CMV disease. Since January 1995, we have utilized a potent immunosuppressive protocol selectively in recipients at high risk for immunologic graft loss, defined as retransplant recipients, recipients with delayed graft function, non-Caucasian recipients, and recipients suffering from acute rejection. Between January 1995 and December 1996, 110 consecutive renal transplants were performed in recipients who were either CMV seropositive or received an allograft from a CMV-seropositive donor. All recipients received ganciclovir prophylactic therapy for 3 months post-transplant. Group I (N = 43) consisted of recipients at high-immunologic risk for graft loss as defined above. These recipients were treated with an intense anti-rejection immunotherapeutic regimen consisting of Cellcept, Neoral, and prednisone, with the frequent addition of antilymphocyte antibody therapies and intravenous methylprednisolone. The remaining 67 recipients (group II) were treated with a less intense immunotherapeutic regimen consisting of azathioprine, Neoral, and prednisone. The incidence and severity of CMV disease and the patient and allograft survival were compared. The incidence of CMV syndrome was greater in group I (28%) compared with group II (7%), and was statistically significant (p < 0.05). The 1-yr patient and graft survival were similar, 95 and 91%, respectively, for group I compared with 97 and 97%, respectively, for group II. These data suggest that 3 months of ganciclovir prophylactic therapy is significantly less effective for the prevention of CMV disease in renal transplant recipients at high risk for acute rejection treated with an intense immunotherapeutic regimen. These data suggest that more effective prevention of CMV disease in these high-risk recipients will require the addition of other anti-viral agents, such as immunoglobulin preparation to the prophylactic regimen.

Aspects of Pulmonary Infections After Solid Organ Transplantation

The increasing number of solid organ transplant (SOT) recipients have high rates of pulmonary infections due to bacterial, fungal, and viral pathogens. These patients have unique sets of factors predisposing to infection. Lung and heart-lung transplants are associated with particularly high infection rates. The prominence of cytomegalovirus (CMV) as a pathogen in all subsets of SOT patients has led to new strategies for prophylaxis, detection, and treatment of CMV pneumonitis. Progress is similarly being made in managing fungal and bacterial infections. Advances in liver, kidney, heart, and lung transplantation are being discussed, with further attention to specific pathogens (ie, CMV, Aspergillus, Pneumocystis carinii, and Mycobacterium tuberculosis).

Influence of anti-rejection therapy on the timing of cytomegalovirus disease and other infections in renal transplant recipients

Infections are an important cause of mortality and morbidity in renal transplant recipients. To study the impact of anti-rejection therapy on the timing of infections, the records of 599 consecutive renal transplants, performed prior to 31 December 1996 at the Royal Melbourne Hospital, were reviewed. Patients were grouped according to acute rejection (AR) episode and treatment during the first 6 months after transplantation. Group 1 [n = 168 (35%)] patients did not experience any episode of AR. Group 2 [n = 169 (35%)] patients had one or more episodes of AR and received high doses of steroids. Group 3 [n = 141 (30%)] patients had more than one episode of AR and received anti-lymphocyte antibodies in addition to high doses of steroids. Infections were more common in Groups 2 and 3 but only cytomegalovirus (CMV) disease occurred earlier in patients treated with lympholytics. Given the high incidence and early onset of CMV disease in patients receiving lympholytics and considering that an effective prophylactic protocol remains undetermined, pre-emptive treatment with ganciclovir in this high risk group appears justified.

New strategies for prevention and therapy of cytomegalovirus infection and disease in solid-organ transplant recipients

In the past three decades since the inception of human organ transplantation, cytomegalovirus (CMV) has gained increasing clinical import because it is a common pathogen in the immunocompromised transplant recipient. Patients may suffer from severe manifestations of this infection along with the threat of potential fatality. Additionally, the dynamic evolution of immunosuppressive and antiviral agents has brought forth changes in the natural history of CMV infection and disease. Transplant physicians now face the daunting task of recognizing and managing the changing spectrum of CMV infection and its consequences in the organ recipient. For the microbiology laboratory, the emphasis has been geared toward the development of more sophisticated detection assays, including methods to detect emerging antiviral resistance. The discovery of novel antiviral chemotherapy is an important theme of clinical research. Investigations have also focused on preventative measures for CMV disease in the solid-organ transplant population. In all, while much has been achieved in the overall management of CMV infection, the current understanding of CMV pathogenesis and therapy still leaves much to be learned before success can be claimed.

Cytomegalovirus prophylaxis with antiviral agents for solid organ transplantation

OBJECTIVES

To assess the efficacy of antiviral agents in solid organ transplant recipients in the prevention of cytomegalovirus infection and symptomatic disease and in the reduction of the incidence of acute rejection, graft loss and death.

SEARCH STRATEGY

A computerised search was conducted on Medline, Embase and Pascal. The reference lists of the current review articles and some congress proceedings were searched manually (Transplantation Proceedings, American Thoracic Society, European Society of Organ Transplantation).

SELECTION CRITERIA

Prospective, randomised studies in adults or paediatric recipients of a solid organ transplant, in which one arm received a prophylactic treatment with acyclovir and/or ganciclovir, started before cytomegalovirus infection, and the control arm received placebo or no treatment.

DATA COLLECTION AND ANALYSIS

Data were extracted from each trial and a letter sent to the authors to ask them to verify the data extracted, and to provide any data that was missing. For each outcome, several methods were used to calculate the chi-square for association and the estimate for the treatment effect with its 95% confidence interval, with an additive model (rate difference), or a multiplicative model (odds ratio, relative risk). We considered the test of association to be significant when the p value was less than 0.01 and the homogeneity test to be significant when the p value was less than 0.1.

MAIN RESULTS

Prophylactic treatment was found to be associated with a significant decrease in cytomegalovirus disease compared with placebo or no treatment, using the logarithm of relative risk method (relative risk 0.51, 95% confidence interval 0. 41-0.64, p value for X(2) association < 0.001). Prophylactic treatment also decreased the rate of cytomegalovirus infection (RR 0. 62, 95%CI 0.53-0.73, p < 0.001). Our analysis failed to show a significant decrease in graft loss, acute rejection or death in the prophylactic treatment group. Sub-group analysis based on the type of antiviral agent (acyclovir or ganciclovir) and on the type of organ (kidney or liver) gave comparable results.

REVIEWER'S CONCLUSIONS

The use of antiviral agents for the prevention of cytomegalovirus disease and cytomegalovirus infection in solid organ transplantation is supported by this meta-analysis.

Prevention and treatment of cytomegalovirus infection in organ transplant recipients

Cytomegalovirus (CMV) is the most common viral pathogen in organ transplant recipients. The patients at highest risk of developing CMV disease are seronegative recipients of seropositive donors, and seropositive recipients who receive antilymphocyte agents such as OKT3 and antithymocyte globulin (ATG) for induction or for rejection. There have been many trials of CMV prevention, but they are difficult to compare with one another because of variability in definitions and end points. Two modalities that have been used to prevent CMV disease are prophylaxis and preemptive therapy. In prophylaxis all patients are given an antiviral agent in order to prevent CMV disease, while in preemptive therapy (also called targeted prophylaxis) only patients who are identified as 'high risk' are selected for treatment. Selected trials of prophylaxis and preemptive therapy in solid-organ recipients are reviewed. The factors to be considered in using one modality or the other are side effects from antivirals, cost of monitoring and antivirals, efficacy of the two modalities, and potential emergence of drug resistance. Sensitive tests that have been used for early diagnosis and monitoring of CMV are antigenemia and the polymerase chain reaction (PCR). Antigen pp65 is a lower matrix protein and can be detected in peripheral blood leukocytes. The sensitivity and specificity are high and vary from 89% to 100% and 92% to 96%, respectively. Currently, many authors believe that the antigenemia test is more useful than the PCR test. The antigenemia test is useful for viral monitoring as a guide for preemptive therapy after organ transplantation. Persistence of high counts of antigenemia may indicate inadequate antiviral therapy or emergence of resistance. Recurrence of positive antigenemia after treatment of CMV disease can be a sign of relapse. Transplant patients who develop resistance to antiviral drugs are usually seronegative recipients who receive an organ from a seropositive donor and have several courses of antivirals for CMV disease. Ganciclovir is the most frequent antiviral agent used in transplant recipients and is usually well tolerated. Resistance to ganciclovir may occur and is usually secondary to virus mutation in the UL97 gene. The availability of sensitive diagnostic tests such as pp65 antigenemia has made the early diagnosis of CMV possible in organ transplant recipients. CMV is being treated much earlier now, and progression to disseminated disease is uncommon. Prudent use of antiviral drugs will hopefully limit the problem of drug resistance.

Cytomegalovirus infection in kidney transplant patients: clinical manifestations and diagnosis

Cytomegalovirus (CMV) infection is an important cause of morbidity and mortality after solid organ transplantation. CMV infection after kidney transplantation was confirmed in 19 (54.3%) out of 35 patients. 16 of these (84.2%) developed CMV disease. CMV infection was diagnosed based on a fourfold or greater increase of anti-CMV IgG antibody titre, detection of CMV-IgM antibodies and/or virus isolation. Primary infection was observed in 3 patients, reactivation in 9 and an undefined type of infection in 7. In most patients (63%), infection was diagnosed in the first 2 months, and in 3 patients, after 3, 5 and 9 years following kidney transplantation. The most frequent symptoms of CMV disease were fever (58%), pneumonitis (26.3%) and enterocolitis (15.8%). In 53% of the patients, CMV infection co-occurred with other pathogens such as Candida albicans. Cryptococcus neoformans, bacteria or viruses (HBV, HCV, HSV). Treatment with polyvalent globulin (Sandoglobin) or hyperimmune globulin (Cytotect), in combination with ganciclovir in 7 patients, resulted in a regression of CMV disease.

Cytomegalovirus viremia in lung transplant recipients receiving ganciclovir and immune globulin

BACKGROUND

Cytomegalovirus (CMV) disease is an important cause of organ transplant-related morbidity and mortality. During the last 5 years at our institution, prophylactic ganciclovir and hyperimmune globulin have been routinely administered to lung transplant recipients whenever the donor or the recipient was CMV antibody-positive. We sought to assess the efficacy of prophylaxis on viremia, CMV disease, and bronchiolitis obliterans syndrome (BOS).

METHODS

A retrospective chart review of 61 consecutive lung transplants performed between recipients between January 1993 and August 1995 was performed. Fifty-six patients who survived at least 1 month were analyzed. Patients were considered at risk for CMV disease whenever pretransplant donor or recipient serology was positive.

RESULTS

Fourteen of the 39 patients at risk (36%) had viremia while on prophylaxis. The rate of CMV disease was 13% during the first 6 months following transplantation. A donor whose CMV serology was positive appeared to increase the risk of BOS in a Cox regression model (relative risk=2.4; 95% confidence interval=0.86-6.74; p=0.0957). Neither age, CMV infection (viremia or a positive specimen from BAL), recipient's serology at the time of transplantation, or CMV disease was associated with BOS. None of these variables was associated with mortality on Cox regression analysis or univariate analysis.

CONCLUSIONS

Administration of combination ganciclovir and hyperimmune globulin prophylactic therapy to lung transplant recipients at risk for CMV infection and disease is associated with a relatively low incidence of disease, which appears only after prophylaxis treatment with ganciclovir is completed. Ganciclovir prophylaxis does not prevent CMV viremia; however, viremia while on prophylaxis is not predictive of disease.

Eradication of cytomegalovirus reactivation disease using high-dose acyclovir and targeted intravenous ganciclovir in kidney and kidney/pancreas transplantation

BACKGROUND

The attack rate of cytomegalovirus (CMV) is over 50% in solid organ transplant recipients at risk for primary CMV infection and in those receiving antilymphocyte antibody therapy. Various CMV prophylaxis regimens over the last few years have reduced the attack rate to around 20% overall.

METHODS

We report our results using high-dose acyclovir for 3 months after transplant, with targeted intravenous ganciclovir for the duration of any antilymphocyte antibody therapy, in our kidney and simultaneous pancreas/kidney transplant recipients. Records of 109 consecutive patients over a 2-year period were reviewed.

RESULTS

Six cases of CMV disease were identified. Five cases occurred in 21 patients at risk for primary CMV disease (24%), whereas only one case occurred in 73 patients at risk for CMV reactivation (1.4%).

CONCLUSION

We conclude that high-dose acyclovir and targeted ganciclovir is excellent prophylaxis against CMV reactivation in kidney and simultaneous pancreas/kidney transplantation.

Infections in solid-organ transplant recipients

Solid-organ transplantation is a therapeutic option for many human diseases. Infections are a major complication of solid-organ transplantation. All candidates should undergo a thorough infectious-disease screening prior to transplantation. There are three time frames, influenced by surgical factors, the level of immunosuppression, and environmental exposures, during which infections of specific types most frequently occur posttransplantation. Most infections during the first month are related to surgical complications. Opportunistic infections typically occur from the second to the sixth month. During the late posttransplant period (beyond 6 months), transplantation recipients suffer from the same infections seen in the general community. Opportunistic bacterial infections seen in transplant recipients include those caused by Legionella spp., Nocardia spp., Salmonella spp., and Listeria monocytogenes. Cytomegalovirus is the most common cause of viral infections. Herpes simplex virus, varicella-zoster virus, Epstein-Barr virus and others are also significant pathogens. Fungal infections, caused by both yeasts and mycelial fungi, are associated with the highest mortality rates. Mycobacterial, pneumocystis, and parasitic diseases may also occur.

Summary of the International Consensus Symposium on Advances in the Diagnosis, Treatment and Prophylaxis and Cytomegalovirus Infection

CMV infection and CMV disease can be difficult to differentiate and the diagnosis is usually based on a compatible clinical picture and the results of a diagnostic test for CMV. The only exception to this rule is in HIV-infected patients where fundoscopy is sufficient to diagnose CMV retinitis. Of the current diagnostic tests, qualitative and quantitative PCR, branched DNA and Hybrid Capture, are the most promising. The pp65 antigenemia assay has the disadvantage of being more labor-intensive than the DNA based tests. Preliminary data show that a positive qualitative PCR in a HIV-infected patient has a predictive value for the development of CMV retinitis. However, of the patients positive by qualitative PCR, those with high viral loads in quantitative PCR were at the greatest risk of CMV disease. This might make it possible to identify with great certainty the patients who will go on to develop CMV retinitis, thereby decreasing the number of patients eligible for preemptive or prophylactic therapy and increasing the cost-benefit of this therapeutic measure. Quantitative test might also be useful in monitoring response to therapy, but randomized trials comparing the test are needed. Prophylactic antiviral agents should not be used in seronegative transplant recipients receiving organs from seronegative donors. In high-risk transplant recipients, ganciclovir should be used. CMV vaccines are useful for the protection of babies from CMV seronegative mothers against congenital CMV disease. It also may be useful in seronegative transplant recipients receiving a seropositive donor organ, although the benefit of chemo prophylaxis may surpass that of vaccine. HIV-infected patients with CMV retinitis who relapse under either ganciclovir or foscarnet benefit from subsequent combination therapy, rather than switching to the other drug. However, the cost is high in terms of quality of life. Intravitreal therapy for CMV retinitis is very efficacious, suggesting that drug delivery is a problem in systemic therapy. However, intravitreal therapy does not protect against the development of CMV retinitis in the contralateral eye or from CMV disease elsewhere. Therefore, systemic therapy should be added. CMV disease of the CNS should be diagnosed early and treated agressively, possible with combination therapy. A diagnosis of CMV disease should be based on a compatible clinical picture and the demonstration of CMV in CSF by DNA or antigen assays which are more sensitive than culture.

Cytomegalovirus infection and colonic perforation in renal transplant patients

Cytomegalovirus (CMV) infection in immunocompromised patients is a major cause of morbidity and mortality. A well-documented manifestation of gastrointestinal CMV infection is gastrointestinal haemorrhage. In contrast, CMV-associated intestinal perforation has rarely been reported after transplantation, although it is well documented in AIDS patients. Three patients are reported who received their first cadaveric renal transplant in 1994 and subsequently developed CMV disease. During the course of their CMV illness, which was treated with ganciclovir, each presented with clinical suspicion of peritonitis and proceeded to laparotomy. All three were found to have sigmoid colon perforations with histological evidence of CMV infection. Following bowel resection and defunctioning, two patients made an uneventful recovery and have had the continuity of their bowel restored, but one died of overwhelming sepsis within hours of surgery. The explanation for the apparent clustering of this rare condition in transplant patients is uncertain.

Cytomegalovirus antibody status and renal transplantation: 1987-1994

We examined graft and patient survival rates of 47,146 patients in the United Network for Organ Sharing registry following transplants between donors and recipients who were cytomegalovirus (CMV) antibody negative and positive. CMV positivity increased with age to about 80% in patients over 60. Seropositivity was seen in 80% of Asians, 71% of African Americans, and 56% of Caucasians. In all age groups, females had a slightly higher incidence of positivity than males. Transplants involving CMV-positive donors resulted in lower graft survival rates than those with CMV-negative donors. This occurred regardless of whether the recipient was CMV negative or positive. The greatest effect was on patient survival rate, which, in turn, adversely affected graft survival rate. The CMV-positive-donor effect was primarily noted in (1) Caucasian recipients, (2) patients with HLA-A,B,DR mismatches, and (3) patients older than 15 years of age. In contrast, CMV-positive donors were not a risk factor for African American and Hispanic patients, CMV-positive Asian patients, patients younger than 16 years of age, and patients with no HLA-A,B,DR antigen mismatches. In conclusion, a kidney from a CMV-positive donor is a risk factor for certain patients and currently yields about a 4% overall lower graft survival rate at 3 years than a kidney from a CMV-negative donor.

Cytomegalovirus infection and colonic perforation in renal transplant patients

Cytomegalovirus (CMV) infection in immunocompromised patients is a major cause of morbidity and mortality. A well-documented manifestation of gastrointestinal CMV infection is gastrointestinal haemorrhage. In contrast, CMV-associated intestinal perforation has rarely been reported after transplantation, although it is well documented in AIDS patients. Three patients are reported who received their first cadaveric renal transplant in 1994 and subsequently developed CMV disease. During the course of their CMV illness, which was treated with ganciclovir, each presented with clinical suspicion of peritonitis and proceeded to laparotomy. All three were found to have sigmoid colon perforations with histological evidence of CMV infection. Following bowel resection and defunctioning, two patients made an uneventful recovery and have had the continuity of their bowel restored, but one died of overwhelming sepsis within hours of surgery. The explanation for the apparent clustering of this rare condition in transplant patients is uncertain.

Antibody-based therapies for emerging infectious diseases

In the 19th century, it was discovered that immune sera were useful in treating infectious diseases. Serum therapy was largely abandoned in the 1940s because of the toxicity associated with the administration of heterologous sera and the introduction of effective antimicrobial chemotherapy. Recent advances in the technology of monoclonal antibody production provide the means to generate human antibody reagents and reintroduce antibody therapies, while avoiding the toxicities associated with serum therapy. Because of the versatility of antibodies, antibody-based therapies could, in theory, be developed against any existing pathogen. The advantages of antibody-based therapies include versatility, low toxicity, pathogen specificity, enhancement of immune function, and favorable pharmacokinetics; the disadvantages include high cost, limited usefulness against mixed infections, and the need for early and precise microbiologic diagnosis. The potential of antibodies as antiinfective agents has not been fully tapped. Antibody-based therapies constitute a potentially useful option against newly emergent pathogens.