Cytomegalovirus infection of liver transplant recipients: comparison of antigenemia and molecular biology assays

Cytomegalovirus viremia in solid organ transplantation: does the initial viral load correlate with risk factors and outcomes?

Consistent data for using CMV quantitative PCR (QnPCR) on initial presentation to predict outcomes after solid organ transplantation (SOT) are lacking. Recipients with measurable CMV QnPCR and either CMV-V (asymptomatic viremia) or CMV-D (symptomatic CMV infection) were analyzed over 24 months. Risk factors and outcomes were evaluated in relation to initial QnPCR by regression analysis and time-to-event curves. Twenty-eight recipients were identified: five CMV-V, 23 CMV-D. Patients with CMV-D had a higher median initial QnPCR (230 000 copies/mL) compared with CMV-V (2500 copies/mL; p < 0.05). No patients with CMV-V had an initial QnPCR > 10 000 copies/mL compared with 83% of the CMV-D (p = 0.004). The initial QnPCR was higher (250 000 copies/mL) in patients who did not clear CMV PCR than those who cleared (8000 copies/mL) after 14 d of treatment (p = 0.03). Risk factors and indirect CMV effects were not associated with initial QnPCR. Our results highlight the importance of the initial CMV QnPCR in relation to the development of symptomatic CMV and a slower response to therapy. Alternatively, late asymptomatic viremia and recurrent CMV are associated with lower PCR levels and a low likelihood to progress and result in clinical disease.

Pre-transplant risk factors predicting post-transplant cytomegalovirus infection in liver transplant recipients

Cytomegalovirus (CMV) infection causes significant morbidity and mortality among transplant recipients. Although it is still not clear if a preemptive strategy is superior to a prophylactic strategy, many transplant programs elect for preemptive treatment for post-transplant CMV infection. In order to improve the preemptive strategy, we analyzed a series of liver recipients by means of quantitative real-time polymerase chain reaction (PCR). Ninety-one liver transplant recipients were monitored by real-time PCR for CMV, and the results were analyzed in terms of preoperative conditions. Multivariate analysis revealed fulminant hepatic failure as an underlying disease (odds ratio, 6.8; 95% CI, 1.2-39.2), while an ABO-incompatible graft (odds ratio, 5.0; 95% CI, 1.3-19.1), and a serological combination of the donor (D) being positive with the recipient (R) being negative for CMV (D+/R-) (odds ratio, 5.8; 95% CI, 1.3-26.0) were independently associated with the development of significant CMV infection. Patients with risk factors had higher peak CMV DNA concentrations than those without, and developed CMV infections faster (P = 0.0002). Screening of recipients according to risk factors and PCR monitoring may result in an optimization of the preemptive strategy.

Analysis of a quantitative PCR assay for CMV infection in liver transplant recipients: an intent to find the optimal cut-off value

BACKGROUND

Preemptive therapy required highly predictive tests for CMV disease. CMV antigenemia assay (pp65 Ag) has been commonly used for rapid diagnosis of CMV infection. Amplification methods for early detection of CMV DNA are under analysis.

OBJECTIVES

To compare two diagnostic methods for CMV infection and disease in this population: quantitative PCR (qPCR) performed in two different samples, plasma and leukocytes (PMNs) and using a commercial diagnostic test (COBAS Amplicor Monitor Test) versus pp65 Ag.

STUDY DESIGN

Prospective study conducted in liver transplant recipients from February 2000 to February 2001.

RESULTS

Analyses were performed on 164 samples collected weekly during early post-transplant period from 33 patients. Agreements higher than 78% were observed between the three assays. Optimal qPCR cut-off values were calculated using ROC curves for two specific antigenemia values. For antigenemia >or=10 positive cells, the optimal cut-off value for qPCR in plasma was 1330 copies/ml, with a sensitivity (S) of 58% and a specificity (E) of 98% and the optimal cut-off value for qPCR-cells was 713 copies/5x10(6) cells (S:91.7% and E:86%). Using a threshold of antigenemia >or=20 positive cells, the optimal cut-off values were 1330 copies/ml for qPCR-plasma (S 87%; E 98%) and 4755 copies/5x10(6) cells for qPCR-cells (S 87.5%; E 98%). Prediction values for the three assays were calculated in patients with CMV disease (9 pts; 27%). Considering the assays in a qualitative way, the most sensitive was CMV PCR in cells (S: 100%, E: 54%, PPV: 40%; NPV: 100%). Using specific cut-off values for disease detection the sensitivity, specificity, PPV and NPV for antigenemia >or=10 positive cells were: 89%; 83%; 67%; 95%, respectively. For qPCR-cells >or=713 copies/5x10(6) cells: 100%; 54%; 33% and 100% and for plasma-qPCR>or=1330 copies/ml: 78%, 77%, 47%, 89% respectively.

CONCLUSIONS

Optimal cut-off for viral load performed in plasma and cells can be obtained for the breakpoint antigenemia value recommended for initiating preemptive therapy with high specificities and sensitivities. Diagnostic assays like CMV pp65 Ag and quantitative PCR for CMV have similar efficiency and could be recommended as methods of choice for diagnosis and monitoring of active CMV infection after transplantation.

Treatment of opportunistic mycoses: how long is long enough?

For most opportunistic mycoses no optimum duration of antifungal therapy has been defined. Although a long course of therapy is prudent, especially for mycelial fungal infections, excessively and unnecessarily extended courses of treatment incur a risk of toxicity and the expense of the therapeutic regimen. On the basis of existing reports on the pathogenesis and the effect of duration of therapy and other variables on outcome and response rate in fungal infections, this review proposes guidelines that may facilitate a rational approach to decision-making about the duration of antifungal therapy.

Gastrointestinal Infections Caused by Cytomegalovirus

Cytomegalovirus (CMV) is an important human pathogen, causing a variety of syndromes ranging from asymptomatic infections to life-threatening end-organ disease. Infections of the gastrointestinal tract are an especially common form of disease caused by CMV and are usually manifest as luminal infections, such as esophagitis or colitis. Solid organ disease caused by CMV is also known to occur, with hepatitis being the most common syndrome. The large majority of cases of tissue-invasive disease caused by CMV have been reported to occur in immunocompromised hosts. Patients at highest risk for serious CMV-mediated disease are commonly HIV infected, recipients of transplants, or are receiving potent immunosuppressive medications. Intriguingly, several recent reports have discussed the previously underappreciated role of serious forms of CMV-mediated disease occurring in immunocompetent patients. This paper reviews several recent reports addressing important aspects related to the diagnosis, treatment, and management of CMV infections of the gastrointestinal tract.