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Assay Sheet

Test ID

5500 Cytomegalovirus (CMV) Real-time qPCR

CPT Code

87497   

Clinical Utility

CMV is an important pathogen in the transplant setting causing pneumonitis, colitis, hepatitis, CNS disease, neutropenia, and disseminated disease. Prior to the availability of rapid and sensitive DNA PCR, CMV was a leading cause of morbidity and mortality in the transplant population. Quantitative CMV DNA PCR can be used for early detection of CMV reactivation, primary infections, and monitoring response to treatment.

Procedure

Extraction of CMV DNA from plasma, CSF, urine, other biological fluids, or tissues followed by amplification and detection using real-time, quantitative PCR. An internal control is added to ensure the extraction was performed correctly and the PCR reaction was not inhibited. ViraCor’s assay design includes multiple targets to account for viral mutations, which exponentially reduces the chance of false negative results.

Specimen type & specimen handling

Whole Blood: 4-5 mls collected in EDTA (lavender top) tube. Do not freeze; ship ambient. Testing will be performed on plasma separated from the submitted whole blood specimen. Whole blood specimens are accepted as a matter of convenience for the originating laboratory. Special arrangements for testing of whole blood may be made by calling ViraCor prior to specimen shipment. 

Plasma: Collect 4-5 mls whole blood in EDTA or ACD tube, centrifuge and transfer 2 mls plasma to sterile, screw top tube. Ship at ambient temperature Monday thru Friday. Specimen must be received within 96 hrs of collection.

Amniotic Fluid: 2 mls collected in a sterile, screw top tube. Ship at ambient temperature Monday thru Friday. Specimen must be received within 96 hrs of collection.

Bone Marrow: 2 mls collected in EDTA tube. Ship at ambient temperature Monday thru Friday. Do not centrifuge or freeze. Specimen must be received within 96 hrs of collection.

Bronchial Lavage/Bronchial Wash: 2 mls collected in a sterile, screw top tube. Ship at ambient temperature Monday thru Friday. Specimen must be received within 96 hrs of collection.

Conjunctival Swab:  Sterile swab placed in 2 ml sterile saline, M4, or viral transport media in a sterile, screw top tube.  Do not use calcium alginate swab or wood shafted swab.  Ship at ambient temperature Monday thru Friday.  Specimen must be received within 96 hrs of collection.

CSF: 2 mls, collected in a sterile, screw top tube. Freeze and ship on dry ice Monday thru Friday.  Specimen must be received within 96 hrs of collection.

Pleural Fluid: 2 mls collected in a sterile, screw top tube. Ship at ambient temperature Monday thru Friday. Specimen must be received within 96 hrs of collection.

Sputum: 2 mls collected in a sterile container, then transferred to sterile, screw top tube for shipment. Ship at ambient temperature Monday thru Friday. Specimen must be received within 96 hrs of collection. 

Throat Gargle:  Instruct patient to gargle with 2 to 3ml sterile saline.  Expectorate into sterile cup, then transfer contents to sterile, screw-cap tube for shipment; ship ambient.

Tissue: Place in sterile, screw top container; add small amount of sterile saline to keep moist. Paraffin embedded tissue is acceptable.  Ship at ambient temperature Monday thru Friday.  Fresh tissue must arrive within 96 hrs of collection.

Upper respiratory aspirate (NP aspirate, nasal aspirate/wash, tracheal aspirate, etc.): 2 mls collected in a sterile, screw top tube. Ship at ambient temperature Monday thru Friday. Specimen must be received within 96 hrs of collection.

Upper respiratory swab (NP swab, throat swab): Sterile swab placed in 2 ml sterile saline, M4, or viral transport media in a sterile, screw top tube.  Do not use calcium alginate swab or wood shafted swab.  Ship at ambient temperature Monday thru Friday.  Specimen must be received within 96 hrs of collection.

Urine: 2 mls sample collected in a sterile urinalysis container then transferred to sterile, screw top tube for shipment.  Ship at ambient temperature Monday thru Friday. Specimen must be received within 96 hrs of collection.

Vitreous Fluid: Small volumes are acceptable. Transfer collected amount to sterile, screw top tube for shipment. Do not ship specimen in syringe.  Ship at ambient temperature Monday thru Friday. Specimen must be received within 96 hrs of collection.

Causes for rejection

Whole blood frozen

Call ViraCor at 800-305-5198 if specimen is greater than 96 hrs old

Specimen types other than those listed above that were sent without prior authorization

Specificity

The primers and probes used in this assay are specific for known CMV strains based on similarity search algorithms. Additionally, no cross reactivity was detected when tested against adenoviruses, BKV, EBV, HSV-1, HSV-2, HHV-6 variant A, HHV-6 variant B, HHV-7, HHV-8, JCV, parvovirus B19, SV-40, and VZV.

Cytomegalovirus Assay Range

100 copies/ml to 1 x 10¹⁰ copies/ml

Tissue specimen results will be normalized  to copies/1,000 cells

Fecal specimen results will be in copies

Turnaround Time

Same day (within 8 to 12 hours of receiving specimen), Monday through Saturday

Shipping

The CPT codes provided are based on ViraCor’s interpretation of the American Medical Association’s Current Procedural Terminology (CPT) codes and are provided for informational purposes only. CPT coding is the sole responsibility of the billing party. Questions regarding coding should be addressed to your local Medicare carrier. ViraCor assumes no responsibility for billing errors due to reliance on the CPT codes illustrated in this material. PCR tests are performed pursuant to a license agreement with Roche Molecular Systems, Inc. This assay was developed and the performance characteristics were determined at ViraCor Laboratories. This test is performed in a CLIA certified laboratory. FDA approval is not required for the performance of this test.

AS05-0808

Pathogen Overview

ABOUT CYTOMEGALOVIRUS

Cytomegalovirus (CMV) is a linear, double-stranded DNA virus with an icosahedral capsid and is a member of the Herpesviridae family, which infects humans along with HSV-1, HSV-2, VZV, EBV, HHV-6, HHV-7, and HHV-8. CMV is also known as HHV-5. CMV, HHV-6, and HHV-7 are all members of the Betaherpesvirinae subfamily. The replication cycle of CMV is slow and produces large, multinucleated cells (cytomegalia). Once the virus has infected an individual, it establishes latency in lymphoreticular tissue, secretory glands, kidneys, and other tissues. Human cytomegalovirus (HCMV) infects only humans and will grow in the laboratory only in cell lines of human origin.

CYTOMEGALOVIRUS CLINICAL MANIFESTATIONS

HCMV is ubiquitous throughout the world. When the virus is acquired at a young age, it rarely causes any noticeable illness. However, in developed Western countries, infection is often delayed, thus more likely to cause significant illness. The prevalence of antibodies among adults in the U.S. is between 40 and 100%, depending largely upon socioeconomic conditions. The infection rate gradually increases throughout childhood. Once infected, the individual carries the virus for the rest of his/her life. It is estimated that at any given time up to 10% of the population is secreting CMV from various sources, such as urine, saliva, semen, and breast milk. The virus is transmitted easily through any of these sources. Children, as well as daycare workers, are at high risk for contracting CMV since it is shed frequently in urine. In adults, primary CMV infection is typically acquired through blood transfusions, contact with an infected cervix or semen, or transplanted organ tissues. In young adults and CMV seronegative recipients of CMV positive blood transfusions, a syndrome resembling mild EBV mononucleosis is not uncommon. The patient will often present with prolonged fever, splenomegaly, abnormal liver function, and atypical lymphocytes. The positive heterophile antibody test does not occur in CMV mononucleosis as in EBV mononucleosis.

Currently, transplacental infection with CMV is the most common viral cause of prenatal damage to fetuses. Approximately 1% of fetuses are infected with CMV in-utero; however, the majority of maternal infections are reactivations and rarely cause congenital CMV syndrome. Primary infection during the first trimester of pregnancy puts the fetus at higher risk for congenital CMV syndrome. Primary infection carries a 30 to 40% risk of fetal infection with a 10 to 15% risk of clinical abnormalities. A smaller percentage of those infants will suffer severe CMV syndrome, which can include microcephaly, thrombocytopenia, hepatosplenomegaly, petechial hemorrhages, jaundice, encephalitis, mental retardation, and hearing impairment. Neonates can also acquire the virus during passage through the birth canal or contact with infected saliva and breast milk.

The immunocompromised population, including transplant patients, HIV patients, and cancer patients (though to a lesser extent), are those at highest risk for developing the significant disease syndromes caused by CMV, including interstitial pneumonia, gastrointestinal infection, CNS disease, hepatitis, retinitis, and encephalitis.

CMV is the most common and most important infectious agent among transplant recipients, both solid organ and hematopoietic stem cell transplant (HSCT) patients. Reactivation can occur in any individual who is latently infected; however, no transplant patient is safe from CMV since he/she can also acquire the virus from the transplanted organ or the virus can be community-acquired following transplantation. This is of particular concern in pediatric transplant patients. In transplant recipients, the factor which influences the degree of morbidity and mortality is the type and extent of immunosuppression. Morbidity and mortality from CMV are lowest among kidney transplant patients and highest among bone marrow transplant patients, since they are the most profoundly immunocompromised.

CYTOMEGALOVIRUS LABORATORY DIAGNOSIS

A diagnosis of CMV cannot be made on solely clinical grounds; laboratory confirmation is required. Culture has been the traditional method to diagnose CMV infection, however, culture has several significant limitations: CMV can take up to 6 weeks to grow, the virus is temperature labile and may die before it reaches the laboratory; culture is not quantitative so viral load cannot be tracked, and most significantly, the amount of virus needed to cause disease in a transplant patient is far less than the amount of virus needed to grow in culture.

Another popular diagnostic method is the CMV antigenemia assay. A major step forward from culture, antigenemia is more sensitive, semi-quantitative and the assay can be performed in one day. However, the blood specimen must be less than 6 hours old to be tested, and the assay is quite labor intensive and technically demanding. In this assay, the patient’s white cells are removed from the whole blood specimen and attached to a glass slide. The cells are then stained with CMV-specific monoclonal antibodies that are conjugated to a fluorescent molecule. The laboratory scientist then visualizes the patient’s white cells under a fluorescent microscope and looks for cells containing CMV inclusions, which indicate that CMV is replicating in that cell. While this method is generally acceptable, there are several notable limitations. First, if the patient has a very low cell count, the specimen could be rejected. Secondly, there are reports in the literature of organ-specific CMV disease occurring while the CMV antigenemia assay remains negative. This could be due to a mutation of the virus leading to a false negative result on the antigenemia assay. Alternatively, the CMV could be replicating only in the involved organ and not in the circulating white blood cells.

The need for a rapid, sensitive, specific, and quantitative CMV detection system that overcomes the limitations of previous platforms has been acute. The advent of quantitative, real-time polymerase chain reaction (PCR) has dramatically improved CMV detection, thereby positively impacting transplant patient survival. Quantitative, real-time PCR can be used to monitor the patient’s response to antiviral drug treatment. Of further advantage, it can be performed on a wide variety of specimen sources including blood, CSF, urine, bronchial washes, eye swabs, tissue biopsies, and bone marrow biopsies, among others. Of note, it is important to choose the appropriate blood compartment for testing. Due to the highly sensitive nature of molecular testing, utilizing a cell based assay can yield positive results due to latent CMV in white blood cells. To avoid latent CMV, plasma can be used for testing, which will yield positive results only if actively replicating virus is present. A cell based CMV molecular assay can also encounter the same issues mentioned above in the CMV antigenemia discussion.

If CMV is replicating in white blood cells or a specific organ, there will be free virus circulating in the bloodstream, which can easily be detected when plasma is tested. For these reasons, ViraCor routinely utilizes plasma for testing of blood specimens.

CYTOMEGALOVIRUS TREATMENT

Treatment of a chronic viral infection, such as CMV, in an immunocompromised patient presents a special challenge. Antiviral medications may have limited effectiveness in these patients, or may stop suppressing replication of the virus once they are discontinued. Resistance to these agents is also an issue. Transplant programs typically take 1 of 2 approaches in an attempt to prevent and treat CMV disease: prophylactic treatment regimens or pre-emptive treatment regimens. In institutions that treat pre-emptively, an in-house protocol is usually followed as to when treatment with gancyclovir will be initiated, which is generally based on the results of a molecular based detection method or CMV antigenemia testing. Foscarnet is generally used in patients resistant to ganciclovir, because it is not as well tolerated.

Selected References

Ho M. Cytomegalovirus. In: Mandell GL, Bennett JE, Dolin, eds. Mandell, Douglas and Bennett’s Principles and Practice of Infectious Diseases. Vol 2. 4th ed. New York, NY: Churchill Livingstone; 1995:1351-1364.

Knipe D, Howley P. Fields Virology. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2006. Lowance D, Neumayer HH, Legendre CM, Squifflet JP, Kovarik J, et al. Valcyclovir for the prevention of cytomegalovirus disease after renal transplantation. N Engl J Med. 1999;(340):1462-1470.

Patel R, Snydman DR, Rubin RH, Ho M, Pescovitz M, et al. Cytomegalovirus prophylaxis in solid organ transplant recipients. Transplantation. 1996;(61):1279-1289.

PAO-03-0707 PCR tests are performed pursuant to a license agreement with Roche Molecular Systems, Inc.

Abstracts & Publications

Bauer CC, Jaksch P, Aberle SW, et al. Relationship between cytomegalovirus DNA load in epithelial lining fluid and plasma of lung transplant recipients and analysis of coinfection with Epstein-Barr virus and human herpesvirus 6 in the lung compartment. J Clin Microbiol. 2007;45(2):324-328.

Cytomegalovirus (CMV) is a significant cause of morbidity and mortality in lung transplant recipients (LTRs). The aim of the present study was to elucidate the relationship between the CMV DNA load in the lung compartment and that in plasma. For CMV load determination, the level of CMV DNA in plasma and bronchoalveolar lavage (BAL) samples was measured in a total of 97 paired BAL and plasma samples obtained from 25 LTRs. The original virus concentration in the epithelial lining fluid (ELF) was calculated from the BAL samples by correcting for dilution using the urea dilution method. In addition, the load of Epstein-Barr virus (EBV) and that of human herpesvirus 6 (HHV-6) DNA also were determined in BAL samples, recalculated for their concentrations in the ELF, and compared with the CMV DNA load. CMV DNA was found more frequently and at significantly higher levels in the lung compartment than in plasma (P < 0.001, Wilcoxon test), and the CMV load in the ELF was associated with symptomatic CMV disease. EBV and HHV-6 were detected in 43.6% and 21.7% of the ELF samples, respectively. A statistically significant association was found between the CMV and EBV DNA loads in the ELF (P < 0.001; Spearman's rho = 0.651). Thus, in LTRs, determination of the CMV DNA load in the lung compartment may be advantageous compared to monitoring only viremia. The significant relationship between EBV and CMV DNA loads in the ELF of LTRs and its clinical impact require further investigation.

Boeckh M, Huang ML, Ferrenberg J, et al. Optimization of quantitative detection of cytomegalovirus DNA in plasma by real-time PCR. J Clin Microbiol. 2004;42(3):1142-1148.

Previous studies have shown that detection of cytomegalovirus (CMV) DNA in plasma is less sensitive than the antigenemia assay for CMV surveillance in blood. In 1,983 blood samples, plasma PCR assays with three different primer sets (UL125 alone, UL126 alone, and UL55/UL123-exon 4) were compared to the pp65 antigenemia assay and blood cultures. Plasma PCR detected CMV more frequently in blood specimens than either the antigenemia assay or cultures, but of the three PCR assays, the double-primer assay (UL55/UL123-exon 4) performed best with regard to sensitivity, specificity, and predictive values compared to antigenemia: 122 of 151 antigenemia-positive samples were detected (sensitivity, 80.1%), and there were 122 samples that were PCR positive-antigenemia negative (specificity, 93%). Samples with discrepant results had a low viral load (median, 0.5 cells per slide; 1,150 copies per ml) and were often obtained from patients receiving antiviral therapy. CMV could be detected by other methods in 15 of 29 antigenemia positive-PCR negative samples compared to 121 of 122 PCR positive-antigenemia negative samples (P < 0.001). On a per-subject basis, 21 of 25 patients (antigenemia positive-PCR negative) and all 57 (PCR positive-antigenemia negative) could be confirmed at different time points during follow-up. The higher sensitivity of the double-primer assay resulted in earlier detection compared to antigenemia in a time-to-event analysis of 42 CMV-seropositive stem cell transplant recipients, and two of three patients with CMV disease who were antigenemia negative were detected by plasma PCR prior to the onset of disease. Interassay variability was low, and the dynamic range was >5 log10. Automated DNA extraction resulted in high reproducibility, accurate CMV quantitation (R = 0.87, P < 0.001), improved sensitivity, and increased speed of sample processing. Thus, primer optimization and improved DNA extraction techniques resulted in a plasma-based PCR assay that is significantly more sensitive than pp65 antigenemia and blood cultures for detection of CMV in blood specimens.

Cicogna C, Polsky B. Cytomegalovirus infection in bone marrow transplant patients. Infect Med. 1994;11(258):256-262.

Cytomegalovirus (CMV) infection remains a major cause of morbidity and mortality among patients receiving allogeneic bone marrow transplantation. Pneumonia is the most serious manifestation, with an incidence of 15% to 30%. Although the use of ganciclovir with intravenous immunoglobulin has improved survival, CMV pneumonia is often fatal, underscoring the need for effective prophylaxis.

Griffiths PD. Tomorrow's challenges for herpesvirus management: potential applications of valacyclovir. J Infect Dis. 2002;186(suppl 1):S131-S137.

Controlled trials suggest that acyclovir/valacyclovir can provide significant clinical benefits when used for prophylaxis in the immunocompromised host. These findings implicate herpesvirus(es) in the pathogenesis of complex medical conditions, including graft rejection and death. However, it is not known which of the 8 herpesviruses are important under particular circumstances. Prime candidates for triggering adverse outcomes are cytomegalovirus (CMV) in solid organ transplant recipients (causing rejection), CMV and human herpesvirus type 6 (HHV-6) in bone marrow transplant patients (causing marrow suppression), and herpes simplex virus, HHV-6, and CMV in AIDS patients (accelerating the rate of human immunodeficiency virus disease progression and death). Other diseases that may have a herpesvirus component or trigger susceptible antiviral agents include atherosclerosis and multiple sclerosis. In the future, clinicians should be alert to novel findings of randomized trials that may provide insight into the pathogenesis of these diseases and the contributions made by clinically silent herpesvirus infections.

Griffiths PD, Clark DA, Emery VC. ß-herpesviruses in transplant recipients. J Antimicrob Chemother. 2000;(45):29-43.

The three betaherpesviruses known to infect humans are cytomegalovirus (CMV) and human herpesviruses 6 and 7 (HHV-6 and -7). All three viruses can infect opportunistically after organ transplantation. CMV causes a variety of end-organ diseases, including pneumonitis, hepatitis and gastrointestinal ulceration. Patients who develop overt CMV diseases have significantly higher CMV viral loads than infected patients without evidence of clinical disease. A high CMV viral load largely explains the previously described risk factors for the development of CMV disease, which include donor/recipient serostatus before transplant and viremia after transplant. CMV also causes some cases of allograft rejection, which can be prevented by antiviral prophylaxis. Application of similar quantitative methods for the study of HHV-6 and -7 have shown that HHV-6 and CMV are significantly and independently associated with biopsy-proven graft rejection after liver transplantation. The full clinicopathological significance of the betaherpesviruses may, thus, be greater than is currently appreciated.

Guiver M, Fox AJ, Mutton K, Mogulkoc N, Egan J. Evaluation of CMV viral load using TaqMan™ CMV quantitative PCR and comparison with CMV antigenemia in heart and lung transplant recipients. Transplantation. 2001;71(11):1609-1615.

BACKGROUND: Quantitative assessment of cytomegalovirus (CMV) infection using the antigenemia test has been used to monitor CMV infection in heart and lung transplant patients enabling a preemptive treatment strategy. However, the method is labour intensive, samples have to be processed within a few hours and requires skilled interpretation. A comparative prospective evaluation of a real-time TaqMan CMV quantitative PCR (QPCR) with the CMV antigenemia was undertaken.
METHODS: A real-time quantitative TaqMan CMV PCR from EDTA bloods was developed. In this study 25 heart transplant and single-lung transplant patients were monitored posttransplantation by antigenemia and TaqMan CMV QPCR. CMV DNA extracted from EDTA blood was amplified by TaqMan QPCR using primers and probe designed from the CMV glycoprotein B (gB) gene. Quantification of the genome copies is extrapolated from a standard curve generated from amplification of quantified standards.
RESULTS: Antigenaemia levels and TaqMan CMV QPCR genome copies showed a linear correlation between the two assays (R=0.843, P=0.001). A clinically significant threshold of 50 CMV pp65 antigen positive polymorphonuclear leucocytes (PMNLs) per 200 000 cells previously reported was used to extrapolate an equivalent value of 40 000 (log 4.6) genome copies per ml of blood for the TaqMan CMV QPCR.
CONCLUSIONS: The TaqMan system enables a rapid high-throughput of samples. The TaqMan CMV QPCR can be used as an accurate and robust alternative to the antigenemia test to predict CMV disease and to monitor effectiveness of treatment.

Ho M. Cytomegalovirus. In Mandell GL, Bennett JE, Dolin, eds. Mandell, Douglas and Bennett's Principles and Practice of Infectious Diseases. Vol 2. 4th ed. New York, NY: Churchill Livingstone; 1995:1351-1364.

This chapter appears in the 2nd volume of the definite textbook on infectious diseases. Chapter 117 of the text describes the CMV pathogen, epidemiology of CMV infections, modes of transmission, clinical manifestations, treatment, and prevention of CMV infections.

Limaye AP, Huang ML, Leisenring W, Stensland L, Corey L, Boeckh M. Cytomegalovirus (CMV) DNA load in plasma for the diagnosis of CMV disease before engraftment in hematopoietic stem-cell transplant recipients. J Infect Dis. 2001;(183):377-382.

Among hematopoietic stem-cell transplant (HSCT) recipients, cytomegalovirus (CMV) disease before engraftment is rare but often fatal, and cell-based diagnostic tests have low sensitivity in this clinical setting. We used the quantitative real-time polymerase chain reaction (PCR) assay to test for CMV DNA in plasma samples from 15 HSCT recipients who developed CMV disease before engraftment and from 33 matched control patients. CMV DNA was detected in plasma in 14 (93.3%) of the 15 patients who had CMV disease before engraftment, compared with 5 (15.2%) of 33 control patients (P<.001). CMV DNA was detected a median of 13 days before the onset of CMV disease (range, 0-35 days). The maximum CMV virus load in plasma was >1 log[10] higher among case patients than among control patients (median, 1700 [range, 50 to 5.5 × 10[7]] vs. <50 [range, <50-350] CMV DNA copieslmL plasma, respectively; P<.001). Quantitative PCR for CMV DNA in plasma appears to be useful for the identification of HSCT recipients at risk for CMV disease before engraftment.

Ljungman P. ß-Herpesvirus challenges in the transplant recipient. J Infect Dis. 2002;186(suppl 1):S99-S109.

Cytomegalovirus (CMV) has major consequences after allogeneic stem cell and solid organ transplantation. CMV may cause significant morbidity and mortality, and monitoring to detect reactivation to reduce disease or management of end organ disease is associated with increased resource utilization. Two other members of the B-herpesvirus family, human herpesvirus (HHV) type 6 and HHV-7, are increasingly recognized as important pathogens in transplant recipients, either by direct infection (e.g., encephalitis, hepatitis, or pneumonitis) or via interaction with CMV. In addition to direct effects of CMV infection, such indirect effects as an increased risk for bacterial and fungal infections or impaired graft acceptance and function are important research topics. Diagnosis and treatment of CMV infection is currently more advanced than for HHV-6 and HHV-7.

Ljungman P, Griffiths P, Paya C. Definitions of cytomegalovirus infection and disease in transplant recipients. Clin Infect Dis. 2002;(34):1094-1097.

Cytomegalovirus (CMV) infection and disease are important causes of morbidity and mortality among transplant recipients. For the purpose of developing consistent reporting of CMV in clinical trials, definitions of CMV infection and disease were developed and published. This study seeks to update the definitions of CMV on the basis of recent developments in diagnostic techniques, as well as to add to these definitions the concept of indirect effects caused by CMV.

Lowance D, Neumayer HH, Legendre CM, et al. Valacyclovir for the prevention of cytomegalovirus disease after renal transplantation. N Engl J Med. 1999;(340):1462-1470.

BACKGROUND: Cytomegalovirus (CMV) disease is a major complication of organ transplantation. We hypothesized that prophylactic treatment with valacyclovir would reduce the risk of CMV disease.
METHODS: A total of 208 CMV-negative recipients of a kidney from a seropositive donor and 408 CMV-positive recipients were randomly assigned to receive either 2 g of valacyclovir or placebo orally four times daily for 90 days after transplantation, with the dose adjusted according to renal function. The primary end point was laboratory-confirmed CMV disease in the first six months after transplantation.
RESULTS: Treatment with valacyclovir reduced the incidence or delayed the onset of CMV disease in both the seronegative patients (P<0.001) and the seropositive patients (P=0.03). Among the seronegative patients, the incidence of CMV disease 90 days after transplantation was 45 percent among placebo recipients and 3 percent among valacyclovir recipients. Among the seropositive patients, the respective values were 6 percent and 0 percent. At six months, the incidence of CMV disease was 45 percent among seronegative recipients of valacyclovir; it was 6 percent among seropositive placebo recipients and 1 percent among seropositive valacyclovir recipients. At six months, the rate of biopsy-confirmed acute graft rejection in the seronegative group was 52 percent among placebo recipients and 26 percent among valacyclovir recipients (P=0.001). Treatment with valacyclovir also decreased the rates of CMV viremia and viruria, herpes simplex virus disease, and the use of inpatient medical resources. Hallucinations and confusion were more common with valacyclovir treatment, but these events were not severe or treatment limiting. The rates of other adverse events were similar among the groups.
CONCLUSIONS: Prophylactic treatment with valacyclovir is a safe and effective way to prevent CNV disease after renal transplantation.

Mendez JC, Dockrell DH, Espy MJ, et al. Human beta-herpesvirus interactions in solid organ transplant recipients. J Infect Dis. 2001;(183):179-184.

The replication of B-herpesviruses-cytomegalovirus (CMV), human herpesvirus (HHV)-6 and HHV-7-and their association with CMV disease and response to antiviral therapy were prospectively investigated in 33 liver transplant recipients not given antiviral prophylaxis. CMV, HHV-6, and HHV-7 DNA were detected within 8 weeks after transplantation in 70%, 33%, and 42% of the patients, respectively. The univariate association between CMV disease and the 3 ?-herpesviruses was more significant by virus load quantification than by qualitative detection of DNA. This association with high levels of CMV, HHV-6, and HHV-7 (P<.001, .022, and .001, respectively) occurred mainly in CMV-seronegative recipients of transplants from CMV-seropositive donors. Antiviral therapy with ganciclovir (Gcv) reduced the load of CMV and HHV-6 and HHV-7. These results suggest that CMV disease in transplant recipients is related to the unique interaction of the B-herpesviruses and is ultimately reduced after intravenous Gcv treatment.

Patel R, Snydman DR, Rubin RH, et al. Cytomegalovirus prophylaxis in solid organ transplant recipients. Transplantation. 1996;(61):1279-1289.

An overview article. Symptomatic cytomegalovirus (CMV) infection occurs in 8%, 29%, and 39% of kidney, liver, heart, and heart-lung transplant recipients, respectively. CMV is transmitted to transplant recipients mainly by the donor organ and to a lesser degree by blood products. In the solid organ transplant recipient, CMV is related to: (1) infectious diseases syndromes and organ involvement (lung, liver, gastrointestinal, retinitis, among others); (2) increased Immunosuppression (hence its frequent association with other opportunistic infections, e.g., fungal and Pneumocystis); (3) and, although controversial, acute and chronic allograft injury.

Puchhammer-Stöckl E, Görzer I. Cytomegalovirus and Epstein-Barr virus subtypes-the search for clinical significance. J Clin Virol. 2006;(36):239-248.

Cytomegalovirus (CMV) as well as Epstein Barr virus (EBV) genomes include regions which show in part substantial polymorphisms. Characterization of several polymorphic regions led to the identification of various CMV and EBV subtypes. Within the last years there have been undertaken numerous efforts to find out whether the diverse subtypes differentially contribute to clinical manifestations. However, although some associations have been described so far between a certain virus subtype and the development of individual diseases these analyses were greatly complicated by the huge genomic background of CMV and EBV, by the large variety of individual host-virus relations and by differences in the geographic or demographic subtype distribution. In addition, it was shown meanwhile that a substantial proportion of virus infections is due to mixed infections with different subtypes. In this review we will give an overview of the current knowledge concerning the clinical significance of individual CMV and EBV subtypes, defined by characterization of selected polymorphisms. In addition, we also focus on recent analyses which show that infection with mixed virus subtype populations may be disadvantageous compared to single virus subtype infections.

Razonable RR, Emery VC. Management of CMV infection and disease in transplant patients. Herpes. 2004;11(3):77-86.

The International Herpes Management Forum (IHMF) has published guidelines for the diagnosis and management of cytomegalovirus (CMV) infection and disease in solid organ (SOT) and haematopoietic stem cell transplant (HSCT) recipients. These recommendations have been updated to include, among others: (1) use of whole blood for the polymerase chain reaction (PCR) diagnosis of CMV infection; (2) CMV load measurements for prognostication and for monitoring response to anti-CMV therapy; (3) valganciclovir prophylaxis in CMV donor-positive/recipientnegative (D+/R-) SOT patients for prevention of CMV disease; (4) oral ganciclovir prophylaxis, in preference to aciclovir, to reduce incidence of CMV disease in SOT patients; (5) pre-emptive therapy with oral ganciclovir to reduce incidence of CMV disease and viraemia in liver transplant patients; (6) valaciclovir prophylaxis, in preference to high-dose oral aciclovir, to prevent CMV infection in allogeneic HSCT patients; and (7) foscarnet as an alternative to intravenous ganciclovir for pre-emptive treatment of CMV infection in allogeneic HSCT patients. New developments in the field requiring further research were highlighted, including: optimal frequency of CMV monitoring in CMV D+/R- SOT patients; optimal duration of prophylaxis for the prevention of late CMV disease; need for an acceptable viral threshold for initiation of pre-emptive therapy; and assessment of the clinical efficacy of valganciclovir for the treatment of CMV disease and as pre-emptive therapy in SOT and HSCT patients. This article presents supporting evidence for these recommendations and statements.

Razonable RR, Fanning C, Brown RA, et al. Selective reactivation of human herpesvirus 6 variant A occurs in critically ill immunocompetent hosts. J Infect Dis. 2002;(185):110-113.

Reactivation of human B-herpesvirus (cytomegalovirus [CMV], human herpesvirus [HHV]-6, and HHV-7) in nonimmunocompromised hosts is rare. Because these viruses are susceptible to reactivation by cytokines and stress-related mechanisms, the incidence of their reactivation was investigated among 120 patients during stress related to critical illness and compared with findings among 50 healthy volunteers. Human B-herpesvirus DNA was found in 65% of critically ill patients (60% men; mean age, 63 years) who required admission to an intensive care unit for medical (40%) or surgical (53%) indications or trauma (7%). HHV-6 reactivation was higher in critically ill patients than in healthy volunteers (54/101 vs. 0/50; P=.001). All patients except 1 were confirmed as HHV-6 variant A (mean virus load 5066 copies/106 peripheral blood leukocytes). The reactivation of HHV-6A did not affect disease severity and outcome. No significant reactivation of HHV-7 or CMV was demonstrated among the critically ill patients. These findings contribute to the less-defined epidemiology of HHV-6A infection.

Verkruyse LA, Storch GA, Devine SM, DiPersio JF, Vij R. Once daily ganciclovir as initial pre-emptive therapy delayed until threshold CMV load ≥ 10000 copies/ml: a safe and effective strategy for allogeneic stem cell transplant patients. BMT. 2006;(37):51-56.

Quantitative polymerase chain reaction (QPCR) for cytomegalovirus (CMV) is emerging as the preferred screening method for detection of CMV viremia in patients following allogeneic bone marrow and peripheral blood stem cell transplant. However, there are currently no universally accepted QPCR treatment thresholds at which to start pre-emptive therapy. We report here results of a pre-emptive therapy strategy using ganciclovir (GCV) 5 mg/kg initiated once daily (ODG) delayed till a threshold CMV load of > or =10 000 copies/ml whole blood in clinically stable patients. Sixty-nine at risk patients underwent allogeneic stem cell transplant. 48/69 (70%) patients had an initial episode of CMV viremia. 5/48 (10%) cleared viremia without requiring treatment. 28/43 (65%) patients requiring treatment initiated treatment with ODG. 17/28 (61%) patients successfully cleared CMV viremia on ODG, 10/28 (36%) patients required dose escalation to twice daily GCV for increasing viral loads. There were two cases of CMV disease (colitis) and no deaths due to CMV disease in patients initiating treatment with ODG. We conclude delaying pre-emptive therapy with ODG until whole blood QPCR> or =10 000 copies/ml is a safe and effective strategy for CMV viremia after allogeneic stem cell transplant in clinically stable patients.