Cytomegalovirus Infection in Renal Transplantation

Cytomegalovirus Member of the herpes virus family (EBV, varicella-zoster, herpes simplex) Worldwide seroprevalence 30-100% Found in body fluids Blood, saliva, urine, breast milk

Types of CMV Infection Primary infection (asymptomatic to mononucleosis like syndrome in immune competent individuals) Latent infection (presence of viral genome in mononuclear leukocytes, endothelial cells, and organs in the absence of active replication of infectious virus) Reactivation Reinfection (new strain of CMV)

CMV and SOT CMV is the most common and single most important viral infection in solid organ transplant recipients. CMV infection usually develops during the first few months after transplantation Associated with clinical infectious disease (eg, fever, pneumonia, GI ulcers, hepatitis) and acute and/or chronic graft injury and dysfunction

CMV Infection and Transplantation Approximately 20% to 60% of all transplant recipients develop symptomatic CMV infection. The patient at highest risk for symptomatic disease is the CMV-seropositive donor/CMV-seronegative recipient (D+/R-) who develops a primary infection after transplantation. Such patients are at particular risk for severe manifestations of CMV infection, including tissue-invasive CMV and CMV recurrence Emovon OE et al, American Society of Nephrology 35th Annual Meeting, 2002

Primary and Secondary Infections Reactivation infection develops in the patient who becomes CMV-seropositive before transplantation via the traditional routes of transmission and exposure during hemodialysis and blood transfusion, and is more frequent than primary CMV infection. CMV-seropositive recipients are also at risk for superinfection by CMV from a CMV-seropositive donor, especially in the setting of intense immunosuppression (ie, OKT3 and antithymocyte globulin) Nancy et al Organ Transplant 2003 Avery RK. Medscape Transplantation. 2000. http://www.medscape.com/viewprogram/282

Direct Effects of CMV Infection in the Transplant Recipient CMV infection is a multifaceted phenomenon with a variety of direct and indirect effects in the organ transplant recipient. Symptomatology for clinical infectious disease fever, pneumonia, GI ulcers, hepatitis) ranges from the mild, subclinical case to life-threatening multi-organ disease. Symptomatic CMV infection can be characterized by a self-limiting syndrome of episodic fever spikes for a period of 3 to 4 weeks, arthralgias, fatigue, anorexia, abdominal pain, and diarrhea. CMV infection can disseminate to various organs and can cause death CMV retinitis can lead to retinal detachment and blindness. Nancy et al Organ Transplant 2003

CMV Infection: Indirect effects An increased risk for fungal and other opportunistic infections due to additional immunosuppression from CMV infection A "bidirectional" interaction between CMV infection and the host's immune system. The type, duration, and intensity of exogenous immunosuppressive therapy influence and enhance CMV infection. CMV is an immunomodulatory virus, and its effects on the host include enhanced susceptibility to opportunistic infections and, probably, chronic allograft dysfunction. Acute and/or chronic allograft injury and dysfunction. Rubin R. Infection in organ transplant recipients. In: Rubin RH, Young LS, (eds). Clinical Approach to Infection in the Compromised Host, 3rd ed., Nancy et al Organ Transplant 20

Sequence of Infections After Organ Transplant Fishman, J. A. et al. N Engl J Med 1998;338:1741-1751

CMV and Renal Allograft CMV causes renal allograft injury that may be indistinguishable from injury caused by rejection or other factors Results in decreased allograft survival Brennan D. XVIII International Congress of the Transplantation Society. Medscape Transplantation. 2002. Available at: http://www.medscape.com/viewarticle/419014

CMV and Renal Allograft It has been linked to acute rejection and chronic rejection in the form of bronchiolitis obliterans in lung transplant recipients, coronary atherosclerosis in heart transplant recipients, vanishing bile duct syndrome in liver transplant recipients, and a variety of additional histologic lesions in renal transplant recipients Brennan D. XVIII International Congress of the Transplantation Society. Medscape Transplantation. 2002. Available at: http://www.medscape.com/viewarticle/419014

Detection of CMV Infection Immune status: serology (IgG) Active infection (viremia) Histology Viral culture Shell vial culture Antigenemia assay CMV PCR (qualitative/quantitative)

Cytomegalovirus Which Diagnostic Test Should be Utilized and Why?

Clinical Suspicion for CMV CMV in the immunocompetent host -inapparent infection -mononucleosis-like syndrome Primary CMV infection in pregnancy -symptoms in neonate range from moderate hepatosplenomegaly with jaundice to fatal illness -sequelae include hearing loss, vision impairment, and varying degrees of mental retardation CMV in the immunocompromised host -commonly reactivation of latent infection -variable presentation: retinitis, esophagitis, colitis, interstitial pneumonia, hepatitis, meningoencephalitis

Diagnostic Tests for CMV Serology Cultures Early Antigen Detection CMV Antigenemia Assays Molecular Amplification

Serology Diagnosis of recent or acute CMV probable with: -detection of CMV-specific IgM antibodies -4 fold increase in IgG titers in paired samples at least 2 weeks apart Paired samples limit the tests utility in establishing a timely diagnosis Helpful in determining past exposure to CMV infection Helpful in determining risk of acquisition CMV Avidity assay measures IgG maturity effective at identifying primary infection

Cultures Isolated from blood, urine, throat washings, CSF, bronchial washings, and biopsy specimens Takes 1 to 6 weeks to show cytopathic effects on human fibroblast cultures. Detection of CMV in culture does not confirm active disease: CMV may be shed intermittently for several months after acute infection May be useful in determining drug resistance

Early Antigen Detection (Shell Vial Cultures) Allows identification of CMV antigens in culture before cytopathic effects are apparent Cells are exposed to monoclonal antibodies, binding indicative of early CMV replication in cells Results available within two to three days

CMV Antigenemia Assays Rapid detection (24 hours) of CMV proteins in PMNs Tagged monoclonal antibodies to p65 lower matrix protein of CMV Effective for identification of CMV in immunosuppressed Showed 90% sensitivity and 96% specificity in detecting primary infection in immunocompetent host

Molecular Amplification Fast and reliable COBAS Amplicor test: PCR assay that amplifies region of CMV polymerase gene Hybrid Capture System CMV DNA test (CMV Digene): RNA probe that targets 17% of CMV genome. RNA:DNA hybrid is detected with an antibody by signal amplification Nucleic acid sequence based system : detects early gene IE1 and late gene pp67 expression

CMV Pathology Diagnostic hallmarks of active CMV infection include: -cytomegaly -intranuclear and intracytoplasmic inclusions bodies -halo around the inclusion body Immunohistochemistry and in situ hybridization

Cytomegalovirus Definitions and Diagnosis CMV Infection – isolation of CMV virus, proteins or nucleic acid from any body fluid or tissue (culture, antigenemia, PCR) CMV Syndrome – CMV infection associated with systemic symptoms (fever, malaise, myalgia) and leukopenia +/- thrombocytopenia CMV Tissue Invasive Disease – CMV infection plus signs/symptoms of disease and consistent histology (pneumonitis, GI, hepatitis, CNS, nephritis,myocarditis, pancreatitis etc)

Cytomegalovirus Risk of CMV disease depends on: D/R serostatus D+/R-: high risk (primary infection) D-/R+ or D+/R+: intermediate (reactivation or superinfection) D-/R-: low risk Organ – K-P, lung/H-L, small bowel Net state immunosoppression – ALA therapy Rejection Other immunomodulatory viruses (HHV-6) Prophylaxis: risk decreased, not eliminated

Treatment of CMV Infection Prevention of CMV infection is the standard care The recent emphasis on prophylaxis has changed the temporal characteristics of CMV, once an early disease (occurring < 3 months after transplantation), to the current pattern of late disease (occurring > 3 months after transplantation) Razonable RR. 40th Annual Meeting of Infectious Diseases Society of America; October 24-27, 2002; Chicago, Illinois. Medscape Transplantation. 2002. Available at: http://www.medscape.com/viewarticle/443973

Prevention of CMV Disease RL28 Viral Infection in Organ Transplantation CME Review Version September 1, 2005 Prevention of CMV Disease Cytomegalovirus (CMV) infection, once acquired, is lifelong. Serologic testing is used to determine past exposures. Prevention is, therefore, related to prevention of exposure to seronegative transplant recipients (R-) and reduction of the risk for reactivation in either seropositive recipients (R+) or with grafts from seropositive donors (D+). Multiple complementary strategies may be used, of which the most important is probably the minimization of the intensity of immune suppression. Opelz G, Dohler B, Ruhenstroth A. Cytomegalovirus prophylaxis and graft outcome in solid organ transplantation: a collaborative transplant study report. Am J Transplant. 2004;4:928-936. Opelz G et al. Am J Transplant. 2004;4:928-936.

Strategies for Prevention of CMV Disease RL28 Viral Infection in Organ Transplantation CME Review Version September 1, 2005 Strategies for Prevention of CMV Disease Screening of blood and organ donors Reduction of risk with leukocyte-filtered whole blood Active immunization—not yet Passive immunization Immunoglobulin (Ig)—non-selected polyclonal IgG CMV hyperimmune polyclonal globulin (pooled antibody) Monoclonal antibody to CMV Prophylaxis with antiviral agents Reduction in the use of anti-lymphocyte sera and in the overall intensity of immune suppression Transmission of CMV in seronegative individuals may be the result of transplantation, transfusion, or sexual contacts. Primary infection in the immunocompromised host may be severe and usually merits antiviral therapy. CMV immune globulin (CMVIg) has been used successfully in the prevention of CMV infection, particularly in combination with antiviral agents. Many centers reserve CMVIg as a component of therapy for symptomatic infection or in prophylaxis for individuals with antiviral-resistant or slow-to-respond infections. Opelz G et al. Am J Transplant. 2004;4:928-936.

Prophylaxis: How to Best Prevent Disease? RL28 Viral Infection in Organ Transplantation CME Review Version September 1, 2005 Prophylaxis: How to Best Prevent Disease? Universal prophylaxis: administration of antiviral agents to all individuals at risk for a fixed duration May increase cost, toxicity, risk of resistance Preemptive therapy: administration of antiviral therapy in response to a positive microbiologic assay (eg, viral load measurements) or clinical scenarios (eg, use of lymphocyte-depleting antibodies or treatment of graft rejection) Requires careful monitoring, close patient contact, and use of highly sensitive, quantitative assay A decision must be made as to the most effective approach to prevention of viral infection based on the resources and preferences of each center and for each patient. In general, pre-emptive therapy is more labor-intensive (patient monitoring and nursing time) and has more risk for asymptomatic infection. Universal prophylaxis has higher costs for drugs, more toxicity, and may contribute to the development of antiviral resistance. Hart GD, Paya CV. Prophylaxis for CMV should now replace pre-emptive therapy in solid organ transplantation. Rev Med Virol. 2001;11:73-81. Emery VC. Prophylaxis for CMV should not now replace pre-emptive therapy in solid organ transplantation. Rev Med Virol. 2001;11:83-86. Hart GD, Paya CV. Rev Med Virol. 2001;11:73-81. Emery VC. Rev Med Virol. 2001;11:83-86.

RL28 Viral Infection in Organ Transplantation CME Review Version September 1, 2005 Preemptive Therapy: CMV Viral Load Testing in Predicting CMV Disease in D+/R- Solid OrganTransplant Recipients Plasma viral load measurements determined in 364 D+/R- organ transplant recipients receiving oral prophylaxis: CMV disease in 64 (17.6%) patients by 12 months Using a positive cutoff of >400 copies/mL, sensitivity was 38%, specificity was 60%, positive predictive value was 17%, and negative predictive value was 82% for prediction of CMV disease Routine monitoring would have predicted disease in only 24 of 64 (38%) patients The strategy selected for the prevention of CMV disease is based on many factors including cost, assay availability, clinical support staff, and, most importantly, the risk for disease in an individual patient or group of patients. Humar A, Paya C, Pescovitz MD, et al. Clinical utility of cytomegalovirus viral load testing for predicting CMV disease in D+/R- solid organ transplant recipients. Am J Transplant. 2004;4:644-649. Humar A et al. Am J Transplant. 2004;4:644-649.

RL28 Viral Infection in Organ Transplantation CME Review Version September 1, 2005 Valacyclovir for the Prevention of CMV Disease After Renal Transplantation 208 seronegative recipients of seropositive kidneys; 408 seropositive recipients Valacyclovir po 8 to 12 g/day vs placebo for 90 days Reduced incidence of HSV, CMV viruria and viremia, CMV disease Reduced incidence of graft rejection in both groups (D+/R-, D+/R+) 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. Lowance D et al. N Engl J Med. 1999;340:1462-1470.

RL28 Viral Infection in Organ Transplantation CME Review Version September 1, 2005 Prophylaxis of CMV Disease With Oral Ganciclovir in High-Risk (D+/R-) Transplant Recipients Renal Transplant Recipients Placebo Valacyclovir Prophylaxis (3 mo) 45% 3% Postprophylaxis (6 mo) 45% 16% Hepatic Transplant Recipients Placebo Ganciclovir (po) Prophylaxis (3 mo) 44% 5% Postprophylaxis (6 mo) 44% 15% Multiple studies have demonstrated the ability to reduce the incidence of CMV disease using antiviral prophylaxis with CMV immune globulin, (high dose) acyclovir, valacyclovir, ganciclovir, or valganciclovir. The efficacy of such therapies is increased by reducing the intensity of immune suppression over the posttransplant period. Decisions as to the best regimen must be based on drug bioavailability, toxicity, availability, and cost. Disease after the period of prophylaxis may relate to the intensity of immune suppression and/or to the development of antiviral immunity in the host. 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. Gane E, Saliba F, Valdecasas GJ, et al. Randomized trial of efficacy and safety of oral ganciclovir in the prevention of cytomegalovirus disease in liver-transplant recipients. Lancet. 1997;350:1729-1733. Razonable RR, Rivero A, Rodriguez A, et al. Allograft rejection predicts the occurrence of late-onset cytomegalovirus (CMV) disease among CMV-mismatched solid organ transplant patients receiving prophylaxis with oral ganciclovir. J Infect Dis. 2001;184:1461-1464. Paya C, Humar A, Dominguez E, et al, for the Valganciclovir Solid Organ Transplant Study Group. Efficacy and safety of valganciclovir vs. oral ganciclovir for prevention of cytomegalovirus disease in solid organ transplant recipients. Am J Transplant. 2004;4:611-620. Lowance D et al. N Engl J Med. 1999;340:1462-1470., Gane E et al. Lancet. 1997;350:1729-1733. Razonable RR et al. J Infect Dis. 2001;184:1461-1464. Paya C et al. Am J Transplant. 2004;4:611-620.

Valganciclovir for Prophylaxis in Solid Organ Transplantation RL28 Viral Infection in Organ Transplantation CME Review Version September 1, 2005 Valganciclovir for Prophylaxis in Solid Organ Transplantation 364 CMV D+/R- patients received valganciclovir 900 mg qd or oral ganciclovir 1000 mg tid through 100 days CMV disease developed in 12.1% of valganciclovir- and 15.2% of ganciclovir-treated patients by 6 months (some difference in the relative efficacy of agents between organs) and 17.2% and 18.4%, respectively, by 12 months CMV rate viremia during prophylaxis was lower with valganciclovir (2.9% vs 10.4% for ganciclovir; P=.001) and comparable by 12 months (48.5%, valganciclovir, vs 48.8%, ganciclovir) The optimal dosing of valganciclovir was not studied in this cohort. The main side effect of therapy was reversible leukopenia. Measurement of renal function may be a useful guide for adjusting valganciclovir dosage. However, individuals may have more or less leukopenia with the same level of renal function. The effect of asymptomatic viremia on patient and graft survival is not known. Efficacy of prophylaxis in the liver transplant cohort was not demonstrated in this study. Paya C, Humar A, Dominguez E, et al, for the Valganciclovir Solid Organ Transplant Study Group. Efficacy and safety of valganciclovir vs. oral ganciclovir for prevention of cytomegalovirus disease in solid organ transplant recipients. Am J Transplant. 2004;4:611-620. Paya C et al. Am J Transplant. 2004;4:611-620.

RL28 Viral Infection in Organ Transplantation CME Review Version September 1, 2005 Effects of Antiviral Agents on Allograft Injury: Prevention of Indirect Effects? Valacyclovir in kidney recipients  50%  in rejection Oral ganciclovir in heart, liver, kidney recipients   trend in rejection Unfortunately, we do not know much about the effect of antivirals at this point. Valacyclovir, the valine ester of acyclovir, is more effective than placebo in terms of prophylaxis, and it has been shown to reduce rejection rates among kidney recipients. Ganciclovir is an extremely potent anti-cytomegalovirus drug. When administered for 1 month to heart transplant recipients, IV ganciclovir provided a long-term benefit as evidenced by a decrease in vasculopathy in seropositive recipients. To date, a trend toward a decrease in rejection has been seen with oral ganciclovir. Lowance D, Neumeyer HH, Legendre CM, et al, for the International Valacyclovir Cytomegalovirus Prophylaxis Transplantation Study Group. Valacyclovir for the prevention of cytomegalovirus disease after renal transplantation. N Engl J Med. 1999;340:1462-1470. Valantine HA, Gao SZ, Menon SG, et al. Impact of prophylactic immediate posttransplant ganciclovir on development of transplant atherosclerosis: a post hoc analysis of a randomized, placebo-controlled study. Circulation. 1999;100:61-66. Ahsan N, Holman MJ, Yang HC. Efficacy of oral ganciclovir in prevention of cytomegalovirus infection in post-kidney transplant patients. Clin Transplant. 1997;11:633-639. Lowance D et al. N Engl J Med. 1999;340:1462-1470. Valantine HA et al. Circulation. 1999;100:61-66. Ahsan N et al. Clin Transplant. 1997;11:633-639.

Valganciclovir for Prophylaxis in Solid Organ Transplantation RL28 Viral Infection in Organ Transplantation CME Review Version September 1, 2005 Valganciclovir for Prophylaxis in Solid Organ Transplantation Times to onset of CMV disease and to viremia were delayed with valganciclovir; rates of acute allograft rejection were generally lower with valganciclovir Higher incidence of neutropenia with valganciclovir than with ganciclovir (8.2% vs 3.2%, respectively) “Once-daily oral valganciclovir was as clinically effective and well tolerated as oral ganciclovir tid for CMV prevention in high-risk SOT recipients.” The bioavailability of valganciclovir is approximately 60% whereas that of ganciclovir is 4% to 6%. Paya C, Humar A, Dominguez E, et al, for the Valganciclovir Solid Organ Transplant Study Group. Efficacy and safety of valganciclovir vs. oral ganciclovir for prevention of cytomegalovirus disease in solid organ transplant recipients. Am J Transplant. 2004;4:611-620. . Paya C et al. Am J Transplant. 2004;4:611-620.

Possible Prophylaxis for CMV RL28 Viral Infection in Organ Transplantation CME Review Version September 1, 2005 Possible Prophylaxis for CMV D+/R-: IV ganciclovir in hospital, po valganciclovir x 3 months (6 months with anti-lymphocyte-antibody induction) Repeat prophylaxis for ALS or antirejection therapy D-/R-: acyclovir or similar x 3 months (herpes simplex, VZV) D-/R+ : IV ganciclovir in hospital, po valganciclovir x 3 months (6 months with anti-lymphocyte-antibody induction) IV ganciclovir for ALS or graft rejection May substitute routine quantitative monitoring after 3 months Active disease: treat until assay is negative, then 1 to 2 weeks beyond; prophylaxis with po x 3 months minimum Multiple regimens have been used for prophylaxis. The main risk of “low-dose” prophylaxis is emergence of CMV with resistance to antiviral agents. Thus, it is generally preferable to use full-dose therapy with inherent toxicities, or monitoring without therapy. Support for white blood cell count with granulocyte colony-stimulating factor may be needed. It might be noted that reduction of the dose of anti-Pneumocystis prophylaxis with trimethoprim-sulfamethoxazole runs the risk of inadequate dosing to prevent other opportunistic infections, including susceptible strains of Nocardia, Listeria, or other bacterial pathogens. (This strategy is that used at Massachusetts General Hospital with modifications for individual patients based on unique risk factors.) CMV, cytomegalovirus; IV, intravenous; ALS, antilymphocyte serum; VZV, varicella-zoster virus.