GESITRA-SEIMC/REIPI recommendations for the management of cytomegalovirus infection in solid-organ transplant patients

CMV Infection Risk Factors and Viral Dynamics After Valganciclovir Prophylaxis: 10 Years of Experience in Lung Transplant Recipients

(1) The prevention of cytomegalovirus (CMV) in lung transplant recipients (LTx) is based on the administration of VGC for a period of 6-12 months, but there is little information on the premature discontinuation of the drug. Our objective was to evaluate the reasons for early cessation of VGC and the dynamics of CMV replication after discontinuation. (2) We carried out a retrospective study of LTx on VGC prophylaxis according to guidelines, with an outpatient follow-up period of >90 days. The detection of any level of CMV-DNA in the plasma (Cobas, Roche Diagnostics®) during a period of 18 months after the discontinuation of VGC was considered positive. (3) We included 312 patients (64% male, mean age 53.50 ± 12.27; 71% D+R+, 15% D-R+, and 14% D+R-) in our study. The prescribed prophylaxis was completed by 179 patients (57.05%). The mean duration of prophylaxis was 7.17 ± 1.08 months. The recorded reasons for VGC discontinuation in 133 patients (43%) were myelotoxicity (n = 55), impaired renal function (n = 32), and gastrointestinal disturbances (n = 11). The reason for discontinuation was not recorded for 29 patients. CMV-DNA was detected in 79% (n = 246) of cases, and D+R+ and D+R- recipients showed a high risk of detection (p < 0.001). The median times to onset of CMV-DNA detection were 35 days in D+R-, 73 days in D+R+, and 96 days in D-R+ (p < 0.001). (4) Adverse effects of VGC are frequent in LTx. CMV-DNA detection is very common after the discontinuation of VGC and is related to the CMV donor and recipient serostatus.

A Retrospective Review of Calcineurin Inhibitors’ Impact on Cytomegalovirus Infections in Lung Transplant Recipients

Immunosuppressive therapy reduces the risk for allograft rejection but leaves recipients susceptible to infections. Cytomegalovirus (CMV) is one of the most frequent causes for infection after transplantation and increases the risk for allograft rejection. As lung transplant recipients (LTRs) need to be under immunosuppression for life, they are a vulnerable group. To determine the potential association between the development of CMV infection and the calcineurin inhibitor (CNI) blood levels within previous 90 days, a retrospective review of LTRs was performed. Data from recipients who underwent a lung transplantation (LTx) at our center from January 2011 to December 2018 were collected. The studied recipients, after case/control matching, included 128 CMV-infection cases. The median time from the transplant to the first positive CMV viral load was 291.5 days. In our study, more patients were treated with tacrolimus (91.9%) than with cyclosporine (8.1%). Drug blood levels at selected timepoints showed no statistically significant difference between cases and controls. However, we found that CMV infection was more frequent in the donor-seropositive/recipient-seronegative group, interstitial lung disease (ILD) recipients, LTRs who underwent basiliximab induction, cyclosporine treated recipients, and LTRs with lymphopenia (at the time of CMV infection and 90 days before). In this review of LTRs, no association between the CNI blood level and CMV infection was seen, although other immunity-related factors were found to be influencing, i.e., basiliximab induction, cyclosporine treatment, and lymphopenia.

Donor Graft Cytomegalovirus Serostatus and the Risk of Arterial and Venous Thrombotic Events in Seronegative Recipients After Non-Thoracic Solid Organ Transplantation

BACKGROUND

Cytomegalovirus (CMV) is the most common opportunistic pathogen, following solid organ transplantation (SOT), that leads to direct and indirect effects. The aim of this study was to assess the impact of CMV exposure at transplantation on the rate of posttransplant thrombotic events (TEs).

METHODS

We conducted a retrospective cohort study of patients transplanted at the University of Alberta Hospital between July 2005 and January 2018. We included adult SOT CMV-seronegative recipients at transplantation who received an allograft from either a seropositive donor (D+/R-) or a seronegative donor (D-/R-).

RESULTS

A total of 392 SOT recipients were included: 151 (39%) liver, 188 (48%) kidney, 45 (11%) pancreas, and 8 (2%) other transplants. The mean age was 47 years, 297 (76%) were males, and 181 (46%) had a CMV D+/R- donor. Patients in the CMV D+/R- cohort were slightly older (51 years versus 48 years in the D-/R- cohort; P = .036), while other variables, including cardiovascular risk factors and pretransplant TEs, were not different between groups. Overall, TEs occurred in 35 (19%) patients in the CMV D+/R- group, versus 21 (10%) in the CMV D-/R- group, at 5 years of follow-up (P = .008); the incidence rates per 100 transplant months were 5.12 and 1.02 in the CMV D+/R- and CMV D-/R- groups, respectively (P = .003). After adjusting for potential confounders with a Cox regression model, a CMV D+/R- transplantation was independently associated with an increased risk of a TE over 5 years (adjusted hazard ratio, 3.027; 95% confidence interval, 1.669-5.488).

CONCLUSIONS

A CMV D+/R- transplantation is associated with an increased risk of a TE posttransplantation.

Twelve-month effects of everolimus on renal and lung function in lung transplantation: differences in chronic lung allograft dysfunction phenotypes

Background:

Chronic lung allograft dysfunction (CLAD), a complication affecting the survival of lung transplanted patients, includes two clinical phenotypes: bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS). Everolimus is used in CLAD because of its antiproliferative mechanism. In lung transplant patients treated with everolimus, the clinical course of renal and lung function has not yet been assessed systematically in CLAD, BOS and RAS patients for more than 6 months.

Methods:

We retrospectively evaluated the 12-month follow-up of renal and lung function of lung-transplanted patients switched to everolimus and evaluated the reduction in immunosuppressant dosage (ISD) and mortality. Subgroups were based on indication for everolimus treatment: CLAD and non-CLAD patients, BOS and RAS among CLAD patients.

Results:

We included 26 patients, 17 with CLAD (10 BOS, seven RAS). After 1 year from the everolimus switch, we observed renal function improvement (serum creatinine −17%, estimated glomerular filtration rate +24%) and stable pulmonary function [forced expiratory volume in the first second (FEV₁) −0.5%, forced vital capacity (FVC) +0.05%]. RAS patients had progressive functional loss, whereas BOS patients had FEV₁ improvement and FVC stability. All-cause mortality was higher in the CLAD versus non-CLAD group (41% versus 11%), without differences between BOS and RAS patients (p > 0.05). All patients had significant and persistent ISD reduction.

Conclusion:

Lung transplant patients treated with everolimus had improvements in renal function and reduced ISD. We observed sustained improvements in lung function for CLAD related to BOS subgroup results, whereas RAS confirmed the 1-year worsening functional trend. Data seem to suggest one more piece of the puzzle in CLAD phenotyping.

Prevention and Management of CMV Infections after Liver Transplantation: Current Practice in German Transplant Centers

Human cytomegalovirus (CMV) remains a major cause of mortality and morbidity in human liver transplant recipients. Anti-CMV therapeutics can be used to prevent or treat CMV in liver transplant recipients, but their toxicity needs to be balanced against the benefits. The choice of prevention strategy (prophylaxis or preemptive treatment) depends on the donor/recipient sero-status but may vary between institutions. We conducted a series of consultations and roundtable discussions with German liver transplant center representatives. Based on 20 out of 22 centers, we herein summarize the current approaches to CMV prevention and treatment in the context of liver transplantation in Germany. In 90% of centers, transient prophylaxis with ganciclovir or valganciclovir was standard of care in high-risk (donor CMV positive, recipient CMV naive) settings, while preemptive therapy (based on CMV viremia detected during (bi) weekly PCR testing for circulating CMV-DNA) was preferred in moderate- and low-risk settings. Duration of prophylaxis or intense surveillance was 3-6 months. In the case of CMV infection, immunosuppression was adapted. In most centers, antiviral treatment was initiated based on PCR results (median threshold value of 1000 copies/mL) with or without symptoms. Therefore, German transplant centers report similar approaches to the prevention and management of CMV infection in liver transplantation.

Maribavir for Preemptive Treatment of Cytomegalovirus Reactivation

BACKGROUND

Maribavir is a benzimidazole riboside with activity against cytomegalovirus (CMV). The safety and efficacy of maribavir for preemptive treatment of CMV infection in transplant recipients is not known.

METHODS

In a phase 2, open-label, maribavir dose-blinded trial, recipients of hematopoietic-cell or solid-organ transplants (≥18 years of age, with CMV reactivation [1000 to 100,000 DNA copies per milliliter]) were randomly assigned to receive maribavir at a dose of 400, 800, or 1200 mg twice daily or the standard dose of valganciclovir for no more than 12 weeks. The primary efficacy end point was the percentage of patients with a response to treatment, defined as confirmed undetectable CMV DNA in plasma, within 3 weeks and 6 weeks after the start of treatment. The primary safety end point was the incidence of adverse events that occurred or worsened during treatment.

RESULTS

Of the 161 patients who underwent randomization, 159 received treatment, and 156 had postbaseline data available - 117 in the maribavir group and 39 in the valganciclovir group. The percentage of patients with postbaseline data available who had a response to treatment within 3 weeks was 62% among those who received maribavir and 56% among those who received valganciclovir. Within 6 weeks, 79% and 67% of patients, respectively, had a response (risk ratio, 1.20; 95% confidence interval, 0.95 to 1.51). The percentages of patients with a response to treatment were similar among the maribavir dose groups. Two patients who had a response to treatment had a recurrence of CMV infection within 6 weeks after starting maribavir at a dose of 800 mg twice daily; T409M resistance mutations in CMV UL97 protein kinase developed in both patients. The incidence of serious adverse events that occurred or worsened during treatment was higher in the maribavir group than in the valganciclovir group (52 of 119 patients [44%] vs. 13 of 40 [32%]). A greater percentage of patients in the maribavir group discontinued the trial medication because of an adverse event (27 of 119 [23%] vs. 5 of 40 [12%]). A higher incidence of gastrointestinal adverse events was reported with maribavir, and a higher incidence of neutropenia was reported with valganciclovir.

CONCLUSIONS

Maribavir at a dose of at least 400 mg twice daily had efficacy similar to that of valganciclovir for clearing CMV viremia among recipients of hematopoietic-cell or solid-organ transplants. A higher incidence of gastrointestinal adverse events - notably dysgeusia - and a lower incidence of neutropenia were found in the maribavir group. (Funded by ViroPharma/Shire Development; EudraCT number, 2010-024247-32.).

CMV gastric ulcer in a patient with pauci immune crescentic glomerulonephritis on rituximab - a rare combination

Cytomegalovirus (CMV) infections are asymptomatic in immunocompetent patients but in immunocompromised patients, CMV infections have varying manifestations depending on their location. Patient who are organ transplant recipients, taking immunosuppressive therapy for a long time are at increased risk of CMV infections. CMV-induced gastric ulcer is very rare but many cases have been reported in the literature. No case describing association between CMV-related gastric ulcer and glomerulonephritis has been reported in the literature so far. In this article, we describe a case of pauci immune crescentic glomerulonephritis in a patient who was on rituximab and long-term steroid therapy and found to have CMV-related gastric ulcer. The association of small vessel vasculitis and CMV-related gastrointestinal infection has not been studied in the literature. Pauci immune crescentic glomerulonephritis is a subtype of rapidly progressive glomerulonephritis manifested by continuous loss of renal functions with features of dysmorphic red blood cells and glomerular proteinuria. Treatment of such condition is a genetically engineered chimeric murine/human monoclonal IgG1 kappa antibody directed against the CD20 antigen known as Rituximab. We also discussed the pathogenesis of CMV- induced gastric ulcer after rituximab therapy. This case emphasizes the importance of opportunistic infections in glomerulonephritis patients and raises the awareness that glomerunephritis patients are at increased risk of opportunistic infections as well. Rituximab was considered to be a safer drug but over the years, the incidence if opportunistic infections in patients on rituximab has been increasing.

NKG2C Natural Killer Cells in Bronchoalveolar Lavage Are Associated With Cytomegalovirus Viremia and Poor Outcomes in Lung Allograft Recipients

BACKGROUND

Cytomegalovirus (CMV) infection is a risk factor for chronic lung allograft dysfunction (CLAD), which limits survival in lung allograft recipients. Natural killer (NK) cells that express the NKG2C receptor mediate CMV-specific immune responses. We hypothesized that NKG2C NK cells responding to CMV in the lung allograft would reduce CMV-related inflammation and would improve CLAD-free survival.

METHODS

We prospectively followed 130 subjects who underwent lung transplantation from 2012 to 2016. Bronchoalveolar lavage (BAL) NK cells were immunophenotyped for NKG2C, maturation, and proliferation markers. CMV viral load, serologies, serial spirometry, and mortality were recorded from medical records. Natural killer cell subset association with CMV endpoints were made using generalized estimating equation-adjusted linear models. BAL NKG2C NK cell association with CLAD-free survival was assessed by Cox proportional hazards modeling.

RESULTS

NKG2C NK cells were more mature and proliferative than NKG2C NK cells and represented a median of 7.8% of BAL NK cells. The NKG2C NK cell proportion increased prior to the first detection of viremia and was nearly tripled in subjects with high level viremia (>1000 copies/mL) compared with no detected viremia. Subjects with increased BAL NKG2C NK cells, relative to the median, had a significantly increased risk for CLAD or death (hazard ratio, 4.2; 95% confidence interval, 1.2-13.3).

CONCLUSIONS

The BAL NKG2C NK cell proportion may be a relevant biomarker for assessing risk of CMV viremia and quantifying potential CMV-related graft injury that can lead to CLAD or death.

Critical Appraisal of International Clinical Practice Guidelines in Kidney Transplantation Using the Appraisal of Guidelines for Research and Education II Tool: A Systematic Review

BACKGROUND

Although clinical practice guidelines (CPGs) are used for the development of local protocols in kidney transplantation (Ktx), the quality of their methodology is variable. This systematic review aimed to critically appraise international CPGs in all aspects of Ktx using the Appraisal of Guidelines for Research and Evaluation II tool.

METHODS

Clinical Practice Guidelines in Ktx and donation published between 2010 and 2017 were identified from MEDLINE, Embase, National Guideline Clearinghouse, National Health Service and National Institute for Health and Care Excellence Evidence Searches, and the websites of transplant societies. Using Appraisal of Guidelines for Research and Evaluation II, 3 appraisers assessed the quality of CPGs. Interrater reliability was measured using the intraclass correlation coefficient (ICC).

RESULTS

Searches identified 3168 records, and 115 CPGs were included. The highest scoring Appraisal of Guidelines for Research and Evaluation II domain was "scope and purpose" (80%; range, 30%-100%), followed by "clarity of presentation" (77%; range, 43%-98%), "editorial independence" (52%; range, 0%-94%), "rigor of development" (47%; range 6%-97%) and "stakeholder involvement" (41%; range, 11%-85%). The poorest scoring domain was "applicability" (31%; range, 3%-74%). Most CPGs were recommended for future use either with (63%) or without (18%) modifications. A small number (14%) were not recommended for future use or reviewers (5%) did not agree on recommending the CPG. The overall mean CPG quality score was 4 of 7 (range, 2-7). The mean ICC of 0.74 indicated substantial agreement between reviewers.

CONCLUSIONS

The quality of international CPGs in Ktx was variable, and most CPGs lacked key aspects of methodological robustness and transparency. Improvements in methodology, patient involvement, and strategies for implementation are required.

Hepatitis C viremia as a risk factor for opportunistic infections in kidney transplant recipients

The aim of the present study was to determine the clinical characteristics, frequency of opportunistic infections (OI) in HCV-positive kidney recipients, and to evaluate HCV replication as a risk factor for developing an OI. We conducted a retrospective study of all kidney recipients from 2003 to 2014. A total of 1203 kidney transplants were performed during the study period. Opportunistic infections were recorded in 251 patients (21%) and nucleic acid amplification testing (NAAT) positivity in 75 (6%). Patients who are HCV NAAT positive were more likely to present an OI than those who are HCV NAAT negative (45% vs 20%, P < 0.001). Multivariate analysis showed the factors that were independently associated with the development of OI to be acute rejection, graft loss, post-transplantation hemodialysis, and HCV replication. Liver cirrhosis after transplantation could not be considered a risk factor to develop OI. To conclude, a high index of suspicion of OI must be maintained in the case of kidney recipients with HCV replication. Active surveillance of cytomegalovirus infection and other prophylactic strategies against OI should be considered after 6 month post-transplantation. Prompt initiation of DAA therapies may be a useful option aiming to decrease the incidence of OI after transplantation.

Cyclosporine Versus Tacrolimus: Which Calcineurin Inhibitor Has Influence on Cytomegalovirus Infection in Cardiac Transplantation?

INTRODUCTION

Cytomegalovirus (CMV) infection is a relevant cause of morbidity and mortality in transplantation patients. Its major incidence is in the first year and viral replication is related to acute rejection, survival reduction, and graft vascular disease.

OBJECTIVE

This study aims to evaluate retrospectively whether a high dose of calcineurin inhibitors correlates with CMV-positive polymerase chain reaction (PCR), need for treatment, and death in cardiac transplantation patients.

METHODS

This is a case-control study including patients who underwent transplantation between 2014 and 2016. They were separated into two groups (positive or negative PCR) and evaluated for dosage serum levels of cyclosporine and tacrolimus. Patients were classified with adequate dose of immunosuppressant or high dose, and was analyzed that there was any association with those and positive CMV-PCR, need for treatment for CMV, and deaths. For statistical analysis, the Student t test was used for the quantitative variables and the Fisher's Exact Test for qualitative variables. To show CMV-free survival, the Kaplan-Meier curve was used. The level of significance was set at 5%.

RESULTS

CMV-positive PCR in the sample was 72% for a total of 50 individuals. Positive PCR correlated with a high dose of calcineurin inhibitors in a statistically significant way (P = .002), as did a high dose of cyclosporine (P = .004); however, a high dose of tacrolimus had no such association (P = .17). When a high dose was assessed with a need for treatment, the chance of needing treatment increased more than eight times (P = .024; odds ratio = 8.25; 95% CI = 1.33 to 51.26), which was different from results found with high-dose tacrolimus (P = 1.0). However, no significant association was found in relation to deaths.

CONCLUSIONS

Tacrolimus serum levels showed no association with CMV-PCR, which was different from serum cyclosporine, which showed association with CMV-PCR positivity, increasing the need for treatment approximately 8-fold, without association with death.

Levels of anti-CMV antibodies are modulated by the frequency and intensity of virus reactivations in kidney transplant patients

Anti-CMV (cytomegalovirus) antibody titers are related to immune alterations and increased risk of mortality. To test whether they represent a marker of infection history, we analyzed the effect of viral reactivations on the production of specific antibodies in kidney transplant patients. We quantified CMV-DNAemia and antibody titers in 58 kidney transplant patients before transplantation and during a follow-up of 315 days (standard deviation, SD: 134.5 days). In order to calculate the intensity of the infection, we plotted the follow-up time of the infection on the x-axis and the number of DNA-CMV copies on the y-axis and calculated the area under the curve (CMV-AUC). The degree of T-lymphocyte differentiation was analyzed with flow cytometry, the cells were labelled with different monoclonal antibodies in order to distinguish their differentiation state, from naive T-cells to senescent T-cells. Peak viremia was significantly higher in patients experiencing a primary infection (VI) compared to patients experiencing viral reactivation (VR). Our data indicate that the overall CMV viral load over the course of a primary infection is significantly higher than in a reactivation of a previously established infection. Whereas patients who experienced an episode of CMV reactivation during the course of our observation showed increased levels of CMV-specific antibodies, patients who did not experience CMV reactivation (WVR) showed a drop in CMV antibody levels that corresponds to an overall drop in antibody levels, probably due to the continuing immunosuppression after the renal transplant. We found a positive correlation between the CMV viremia over the course of the infection or reactivation and the CMV-specific antibody titers in the examined patients. We also observed a positive correlation between anti-CMV titers and T-cell differentiation. In conclusion, our data show that anti-CMV antibody titers are related to the course of CMV infection in kidney transplant patients.

Cytomegalovirus reactivation in liver transplant recipients due to hepatitis C cirrhosis is associated with higher cardiovascular risk - an observational, retrospective study

The association between cytomegalovirus (CMV) reactivation and cardiovascular risk has been reported in solid organ transplant populations; however, it has yet to be assessed in liver transplantation (LT). We aim to evaluate whether CMV reactivation is associated with cardiovascular events (CVE) in HCV-LT patients. LT patients (2010 and 2014) due to HCV cirrhosis were included. Clinically significant CMV (CS-CMV) was defined as viral load (VL) >5000 copies/ml, need of therapy or CMV disease. Baseline variables and endpoint measures (CVE, survival, severe recurrent hepatitis C, de novo tumors, and diabetes) were collected. One hundred and forty patients were included. At LT, a history of AHT was present in 23%, diabetes 22%, tobacco use 45%, obesity 20%, and renal impairment (eGFR < 60 ml/min) in 26.5%. CS-CMV reactivation occurred in 25% of patients. Twenty-six patients (18.5%) developed a CVE. Cox regression analysis revealed two factors significantly associated with CVE: Pre-LT DM [HR = 4.6 95% CI (1.6, 13), P = 0.004] and CS-CMV [HR = 4.7 95% CI (1.8, 12.5), P = 0.002]. CS-CMV was not independently associated with the remaining endpoints except for survival (P = 0.03). In our series, CS-CMV reactivation was associated with a greater risk of developing CVE, thus confirming data from other solid organ transplant populations and emphasizing the need for adequate CMV control.

Severe Hepatitis C Recurrence as a Risk Factor for Opportunistic Infections in Liver Transplant Recipients

OBJECTIVE

The aim of the study was to determine the clinical characteristics, frequency of opportunistic infections (OI), and the outcomes for liver transplant recipients with severe hepatitis C virus (HCV) recurrence. In addition, the objective was to evaluate HCV recurrence as a risk factor for developing an OI.

METHODS

We conducted a retrospective observational study recording all liver transplant recipients from July 1, 2003, to December 31, 2012. Patients with liver disease due to HCV were selected. Active surveillance of infections was conducted periodically, and patients were classified according to presence of severe HCV recurrence.

RESULTS

Three hundred seventy patients underwent liver transplantation because of chronic HCV. One hundred forty-seven patients presented severe recurrence (SR) (49%) and 50 (17%) of them had post-liver transplant cholestatic hepatitis C. Patients with SR presented OI, especially cytomegalovirus (CMV) infections and invasive fungal infections, more frequently than patients without SR (33% vs 13%; P < .001). From the diagnosis of SR to the presentation of OI, the median number of days was 169 (6-2083). Acute allograft rejection (OR 1.8 95% confidence interval [CI] 1.1-3.3) donor age ≥60 years (OR 2.9 95% CI 1.3-6.8), and SR (OR 2.8, 95% CI 1.6-5.1) were independently associated with the development of OI in liver transplant recipients.

CONCLUSION

A high index of suspicion of opportunistic infections must be maintained when faced with severe HCV recurrence in liver transplant recipients. Moreover, active surveillance against CMV infection and other prophylactic strategies against opportunistic infections should be considered.

Herpes zoster in kidney transplant recipients: protective effect of anti-cytomegalovirus prophylaxis and natural killer cell count. A single-center cohort study

Despite its impact on quality of life and potential for complications, specific risk and protective factors for herpes zoster (HZ) after kidney transplantation (KT) remain to be clarified. We included 444 patients undergoing KT between November 2008 and March 2013. Peripheral blood lymphocyte subpopulations were measured at baseline and months 1 and 6. The risk factors for early (first post-transplant year) and late HZ (years 1-5) were separately assessed. We observed 35 episodes of post-transplant HZ after a median follow-up of 48.3 months (incidence rate: 0.057 per 1000 transplant-days). Median interval from transplantation was 18.3 months. Six patients (17.1%) developed disseminated infection. Postherpetic neuralgia occurred in 10 cases (28.6%). The receipt of anti-cytomegalovirus (CMV) prophylaxis with (val)ganciclovir decreased the risk of early HZ [adjusted hazard ratio (aHR): 0.08; 95% CI: 0.01-1.13; P-value = 0.062], whereas the natural killer (NK) cell at month 6 was protective for the occurrence of late HZ [aHR (per 10-cells/μl increase): 0.94; 95% CI: 0.88-1.00; P-value = 0.054]. In conclusion, two easily ascertainable factors (whether the patient is receiving anti-CMV prophylaxis and the NK cell count at month 6) might be potentially useful to tailor preventive strategies according to individual susceptibility to post-transplant HZ.

Risk factors, survival, and impact of prophylaxis length in cytomegalovirus-seropositive lung transplant recipients: A prospective, observational, multicenter study

BACKGROUND

The optimal length of cytomegalovirus (CMV) prophylaxis in lung transplantation according to CMV serostatus is not well established.

METHODS

We have performed a prospective, observational, multicenter study to determine the incidence of CMV infection and disease in 92 CMV-seropositive lung transplant recipients (LTR), their related outcomes and risk factors, and the impact of prophylaxis length.

RESULTS

At 18 months post transplantation, 37 patients (40%) developed CMV infection (23 [25%]) or disease (14 [15.2%]). Overall mortality was higher in patients with CMV disease (64.3% vs 10.2%; P<.001), but only one patient died from CMV disease. In the multivariate analysis, CMV disease was an independent death risk factor (odds ratio [OR] 18.214, 95% confidence interval [CI] 4.120-80.527; P<.001). CMV disease incidence was higher in patients with 90-day prophylaxis than in those with 180-day prophylaxis (31.3% vs 11.8%; P=.049). Prophylaxis length was an independent risk factor for CMV disease (OR 4.974, 95% CI 1.231-20.094; P=.024). Sixteen patients withdrew from prophylaxis because of adverse events.

CONCLUSION

CMV infection and disease in CMV-seropositive LTR remain frequent despite current prophylaxis. CMV disease increases mortality, whereas 180-day prophylaxis reduces the incidence of CMV disease.

Serum sCD30: A promising biomarker for predicting the risk of bacterial infection after kidney transplantation

BACKGROUND

The transmembrane glycoprotein CD30 contributes to regulate the balance between Th₁ and Th₂ responses. Previous studies have reported conflicting results on the utility of its soluble form (sCD30) to predict post-transplant infection.

METHODS

Serum sCD30 was measured by a commercial ELISA assay at baseline and post-transplant months 1, 3, and 6 in 100 kidney transplant (KT) recipients (279 monitoring points). The impact of sCD30 levels on the incidence of overall, bacterial and opportunistic infection during the first 12 months after transplantation was assessed by Cox regression.

RESULTS

There were no differences in serum sCD30 according to the occurrence of overall or opportunistic infection. However, sCD30 levels were higher in patients with bacterial infection compared to those without at baseline (P=.038) and months 1 (P<.0001), 3 (P=.043), and 6 after transplantation (P=.006). Patients with baseline sCD30 levels ≥13.5 ng/mL had lower 12-month bacterial infection-free survival (35.0% vs 80.0%; P<.0001). After adjusting for potential confounders, baseline sCD30 levels ≥13.5 ng/mL remained as an independent risk factor for bacterial infection (adjusted hazard ratio [aHR]: 4.65; 95% confidence interval [CI]: 2.05-10.53; <.001). Analogously, sCD30 levels ≥6.0 ng/mL at month 1 acted as a risk factor for subsequent bacterial infection (aHR: 5.29; 95% CI: 1.11-25.14; P=.036).

CONCLUSION

Higher serum sCD30 levels were associated with an increased risk of bacterial infection after KT. We hypothesize that this biomarker reflects a Th₂ -polarized T-cell response, which exerts a detrimental effect on the immunity against bacterial pathogens.

[What the family doctor must know about lung transplant (Part 1)]

Lung transplant is a therapeutic, medical-surgical procedure indicated for pulmonary diseases (except lung cancer), that are terminal and irreversible with current medical treatment. More than 3,500 lung transplants have been performed in Spain, with a rate of over 6 per million and increasing. In this review, an analysis is made of the types of transplants, their indications and contraindications, the procedures, immunosuppressive treatments, their side effects and medical interactions, current prophylaxis. A list of easily accessible literature references is also include, the majority being by national authors.

[What the family doctor must know about lung transplantation. Complications, health promotion, and outcomes (Part 2)]

The lung transplantation is a therapeutic procedure indicated for lung diseases that are terminal and irreversible (except lung cancer) despite the best medical current treatment. It is an emergent procedure in medical care. In this review, an analyse is made of the most frequent complications of lung transplant related to the graft (rejection and chronic graft dysfunction), immunosuppression (infections, arterial hypertension, renal dysfunction, and diabetes), as well as others such as gastrointestinal complications, osteoporosis. The most advisable therapeutic options are also included. Specific mention is made of the reviews and follow-up for monitoring the graft and the patients, as well as the lifestyle recommended to improve the prognosis and quality of life. An analysis is also made on the outcomes in the Spanish and international registries, their historical evolution and the most frequent causes of death, in order to objectively analyse the usefulness of the transplant.

Targeted preemptive therapy according to perceived risk of CMV infection after kidney transplantation

Background

Methods

Results

Conclusion

Clinical significance of the single nucleotide polymorphism TLR2 R753Q in heart transplant recipients at risk for cytomegalovirus disease

BACKGROUND

The toll-like receptor 2 (TLR2) is a significant component of innate immunity against cytomegalovirus (CMV) infection but information on the clinical significance of the single nucleotide polymorphism (SNP) (R753Q) is conflicting.

OBJECTIVES

The inconsistent observations of the immunological and clinical significance of the TLR2 R753Q polymorphism for CMV infection indicates the influence of confounders.

STUDY DESIGN

The presence of the TLR2 polymorphism was determined by a genotyping assay of 175 HTX patients and 281 healthy blood donors and evaluated in relation to selected virological and clinical parameters.

RESULTS

Relative frequency of TLR2 polymorphism was similar in HTX patients and blood donors (homozygous wild-type, 94.3% vs. 94.0%; heterozygous, 5.1% vs. 5.7%; homozygous mutated, <1%). CMV viremia was detectable in 108 (61.7%) of HTX patients. The TLR2 polymorphism was neither associated with occurrence or level of CMV infection nor with survival, graft failure or rejection, or CMV serostatus of patient before transplantation. Nevertheless, CMV viremia occurred in 83.1% of R+/D+, 77.1% of R+/D-, and 64.3% of R-/D+ patients. Time of first CMV viremia was in R-/D+ patients later than in CMV-seropositive patients (median, 182days versus 23 days; P<0.001) corresponding to the duration of antiviral prophylaxis in R-/D+ patients.

CONCLUSIONS

The TLR2 R753Q polymorphism is extremely rare in the general population and HTX patients. Screening for this risk factor of CMV disease may not be cost-effective in contrast to testing for CMV viremia.

Monitoring of intracellular adenosine triphosphate in CD4(+) T cells to predict the occurrence of cytomegalovirus disease in kidney transplant recipients

The measurement of intracellular concentrations of adenosine triphosphate (iATP) in phytohemagglutinin-stimulated CD4(+) T cells constitutes a surrogate marker for post-transplant cell-mediated immunity (CMI). This assay has shown suboptimal accuracy for predicting infection after kidney transplantation (KT). We hypothesize that its predictive capacity depends on the specific contribution of the CMI to host-pathogen interactions. We assessed iATP levels in 100 KT recipients at baseline and months 1, 3, and 6 (363 measurements). No association was found between iATP at month 1 and the risk for overall or bacterial infection, although such association was evident for cytomegalovirus (CMV) disease (multivariate-adjusted hazard ratio [per 50-unit increment]: 0.83; P-value = 0.048). There were no significant differences in mean iATP between stable patients (319.4 ng/ml) and those developing overall (304.1 ng/ml) or bacterial infection (346.9 ng/ml) over the 45 days following monitoring. However, iATP was significantly lower in patients who developed CMV disease (223.5 ng/ml; P-values <0.002). The optimal cutoff (265 ng/ml) for predicting CMV disease in patients not receiving antiviral prophylaxis yielded sensitivity, specificity, positive, and negative predictive values of 85.7%, 68.3%, 15.2%, and 98.6%, respectively. In conclusion, a non-pathogen-specific monitoring of CMI by means of iATP informs the risk of CMV disease in KT recipients.

Prevention strategies differentially modulate the impact of cytomegalovirus replication on CD8(+) T-cell differentiation in high-risk solid organ transplant patients

The present study aimed to determine whether antiviral prevention strategies against cytomegalovirus (CMV) infection used in high-risk D+R- solid organ transplanted patients can modulate the impact of CMV replication on CD8(+) T-cell differentiation. The different CD8(+) T-cell subpopulations were measured at a single point when at least one year had elapsed since transplantation. A total of 68 D+R- patients were included, of which 33 underwent pre-emptive therapy and 35 received prophylaxis. Multivariate analysis showed that CMV replication was associated with the expansion of CD28־ EMRA CD8(+) T cells in patients managed pre-emptively but not in patients under prophylaxis (21.4% vs. 3.6%). This finding is likely related to the higher frequency of CMV recurrence observed in patients under pre-emptive therapy compared to those under prophylaxis (75% vs. 14.3%; p < 0.001). In fact, multivariate analysis showed that having more than one replication episode was associated with a 17.2% increase (p = 0.001) in the percentage of CD28־ EMRA CD8(+) T cells compared to "no episode" and with a 10.9% increase with respect to "single episodes" (p = 0.025). Additionally, patients with IFNγ response to CMV (QuantiFERON-CMV Reactive) had a higher percentage of late-differentiated CD8(+) T cells than patients lacking this response. In summary, recurrent CMV replication in D+R- patients under pre-emptive therapy was associated with the expansion of CD28־ EMRA CD8(+) T cells, which might have a short-term beneficial effect related to the high functionality of this T-cell subpopulation. Nevertheless, we cannot rule out that this accumulation might have a long-term detrimental effect related to immunosenescence and inflammation.

Contribution of Population Pharmacokinetics to Dose Optimization of Ganciclovir-Valganciclovir in Solid-Organ Transplant Patients

Treatment of solid-organ transplant (SOT) patients with ganciclovir (GCV)-valganciclovir (VGCV) according to the manufacturer's recommendations may result in over- or underexposure. Bayesian prediction based on a population pharmacokinetics model may optimize GCV-VGCV dosing, achieving the area under the curve (AUC) therapeutic target. We conducted a two-arm, randomized, open-label, 40% superiority trial in adult SOT patients receiving GCV-VGCV as prophylaxis or treatment of cytomegalovirus infection. Group A was treated according to the manufacturer's recommendations. For group B, the dosing was adjusted based on target exposures using a Bayesian prediction model (NONMEM). Fifty-three patients were recruited (27 in group A and 26 in group B). About 88.6% of patients in group B and 22.2% in group A reached target AUC, achieving the 40% superiority margin (P< 0.001; 95% confidence interval [CI] difference, 47 to 86%). The time to reach target AUC was significantly longer in group A than in group B (55.9 ± 8.2 versus 15.8 ± 2.3 days,P< 0.001). A shorter time to viral clearance was observed in group B than in group A (12.5 versus 17.6 days;P= 0.125). The incidences of relapse (group A, 66.67%, and group B, 9.01%) and late-onset infection (group A, 36.7%, and group B, 7.7%) were higher in group A. Neutropenia and anemia were related to GCV overexposure. GCV-VCGV dose adjustment based on a population pharmacokinetics Bayesian prediction model optimizes GCV-VGCV exposure. (This study has been registered at ClinicalTrials.gov under registration no. NCT01446445.).

Use of antibodies neutralizing epithelial cell infection to diagnose patients at risk for CMV Disease after transplantation

OBJECTIVES

Although a CMV-specific T-cell response is associated with reduced risk for infection after transplantation, some patients still develop CMV disease. Thus, the characterization of additional parameters of the CMV-specific immune response that correlate with the control of CMV infection and disease and their use in defining thresholds that can be applied to clinical practice is of interest.

METHODS

In a cohort of high risk solid organ transplant recipients we characterized CMV-specific T-cell responses using intracellular cytokine staining upon stimulation with pp65 and IE-1 peptides, and levels of CMV-specific antibodies neutralizing infection in fibroblast (MRC-5) and epithelial (ARPE-19) cells using microneutralization assays.

RESULTS

Although patients with a positive (≥0.25%CD8(+)CD69(+)IFN-γ+) T-cell response were 6.4 fold more protected (OR 6.4, 95% CI 1.6-25.3; p < 0.001) from CMV infection than patients without a response, 2 (4.2%) patients developed disease. We defined a cut-off titer for epithelial cell neutralizing antibodies of ≥480 that correlated with disease protection. Thus, patients with a CMV-specific T-cell response and titers ≥480 were 14.2 fold more protected from CMV infection (OR 14.2, 95% CI 5-40.2; p < 0.001) and had no episodes of CMV disease.

CONCLUSIONS

Our results indicate that antibodies neutralizing epithelial cell infection may have an important role in long-term protection. Quantification of antibodies neutralizing epithelial cells, in addition to the T-cell response, may be useful for identifying patients with lower risk for CMV disease.

Reduced Incidence of Cytomegalovirus Infection in Kidney Transplant Recipients Receiving Everolimus and Reduced Tacrolimus Doses

This study compared the incidence of CMV infection/disease in de novo kidney transplant recipients receiving everolimus or mycophenolate and no CMV pharmacological prophylaxis. We randomized 288 patients to receive a single 3 mg/kg dose of antithymocyte globulin, tacrolimus, everolimus, and prednisone (r-ATG/EVR, n = 85); basiliximab, tacrolimus, everolimus, and prednisone (BAS/EVR, n = 102); or basiliximab, tacrolimus, mycophenolate, and prednisone (BAS/MPS, n = 101). The primary end-point was the incidence of first CMV infection/disease in the intention-to-treat population at 12 months. Patients treated with r-ATG/EVR showed a 90% proportional reduction (4.7% vs. 37.6%, HR 0.10, 95% CI 0.037-0.29; p < 0.001), while those treated with BAS/EVR showed a 75% proportional reduction (10.8% vs. 37.6%, HR 0.25, 95% CI 0.13-0.48; p < 0.001) in the incidence of CMV infection/disease compared to BAS/MPS. There were no differences in the incidence of acute rejection (9.4 vs. 18.6 vs. 15.8%, p = 0.403), wound-healing complications, delayed graft function, and proteinuria. Mean estimated glomerular filtration rate was lower in BAS/EVR (65.7 ± 21.8 vs. 60.6 ± 20.9 vs. 69.5 ± 21.5 ml/min, p = 0.021). In de novo kidney transplant recipients receiving no pharmacological CMV prophylaxis, reduced-dose tacrolimus and everolimus was associated with a significant reduction in the incidence of CMV infection/disease compared to standard tacrolimus dose and mycophenolate (ClinicalTrials.gov NCT01354301).

Effect of long-term prophylaxis in the development of cytomegalovirus-specific T-cell immunity in D+/R- solid organ transplant recipients

BACKGROUND

This study aimed to characterize the dynamics of acquisition of cytomegalovirus (CMV)-specific cell-mediated immunity (CMI) in CMV donor positive/recipient negative solid organ transplant (SOT) patients receiving long-term antiviral prophylaxis, and to determine whether development of CMI confers protection against CMV disease.

METHODS

A prospective multicenter study was conducted in Spain from September 2009 to September 2012. Whole blood specimens were prospectively collected at 30, 90, 120, 200, and 365 days after SOT, and CMI was determined by enumeration of CMV pp65 and IE-1-specific CD69(+) /interferon-γ-producing CD8(+) and CD4(+) T cells by flow cytometry for intracellular cytokine staining. As part of a simultaneous clinical trial, patients received either early prophylaxis (in the first 3 days after transplantation) in the first period of the study or delayed prophylaxis (initiated at day 14) during the second period of the study. The impact of the dynamics of acquisition of CMV-specific CMI on the incidence of CMV disease was evaluated by Kaplan-Meier survival analysis.

RESULTS

A total of 95 SOT recipients were recruited. CMV infection and disease occurred in 38 (40%) and 26 (27.4%) patients, respectively. The proportion of patients achieving any detectable CMV-specific CMI response at each of the different monitoring points was higher in liver transplant recipients, as compared to kidney or heart transplant recipients. The presence of any detectable response at day 120 or 200 was protective against the development of CMV disease (positive predictive values 92% and 93%, respectively).

CONCLUSIONS

The rate of acquisition of CMV-specific CMI in SOT recipients undergoing antiviral prophylaxis differed significantly between different SOT populations. Patients developing any detectable CMI response were protected against the occurrence of CMV disease.

Effect of delaying prophylaxis against CMV in D+/R- solid organ transplant recipients in the development of CMV-specific cellular immunity and occurrence of late CMV disease

OBJECTIVES

Evaluate the protective effect against late CMV disease of delaying antiviral prophylaxis initiation in D+/R- patients receiving solid organ transplant (SOT).

METHODS

Prospective multicenter study in D+/R- SOT recipients in Spain (Sept/09-Sept/12). Whole blood specimens were prospectively collected after Tx for CMV-specific cell-mediated immunity (CMI) determination. Two prophylaxis strategies were compared: early prophylaxis (EP; starting within the first 3 days after Tx) and delayed prophylaxis (DP; starting 14 days after Tx). Risk factors for the occurrence of CMV disease were determined by survival analysis and proportional risk Cox regression models.

RESULTS

We included 95 patients (50 EP V 45 DP). Twenty six patients (27.4%) developed CMV disease: 32.7% EP vs. 20% DP; (p = 0.2). No cases of CMV disease were reported previously to beginning delayed prophylaxis. The percentage of individuals with detectable CMI response was higher in patients with DP although differences did not reach statistic significance (42% vs 29.6% at day 200 after Tx; p = 0.4). There was a clear trend towards less end-organ CMV disease in patients receiving DP (18.2% EP vs 5% DP; p = 0.09) and DP was the only protective factor in the multivariate analysis (HR: 0.26; CI: 0.05-1.2; p = 0.09).

CONCLUSIONS

A 14-day delay in CMV prophylaxis in D+/R- SOT recipients is safe and may reduce the incidence of late CMV end-organ disease although correlation of this effect with CMI responses was not complete.

Cytomegalovirus infection in transplant recipients

Cytomegalovirus infection is a frequent complication after transplantation. This infection occurs due to transmission from the transplanted organ, due to reactivation of latent infection, or after a primary infection in seronegative patients and can be defined as follows: latent infection, active infection, viral syndrome or invasive disease. This condition occurs mainly between 30 and 90 days after transplantation. In hematopoietic stem cell transplantation in particular, infection usually occurs within the first 30 days after transplantation and in the presence of graft-versus-host disease. The major risk factors are when the recipient is cytomegalovirus seronegative and the donor is seropositive as well as when lymphocyte-depleting antibodies are used. There are two methods for the diagnosis of cytomegalovirus infection: the pp65 antigenemia assay and polymerase chain reaction. Serology has no value for the diagnosis of active disease, whereas histology of the affected tissue and bronchoalveolar lavage analysis are useful in the diagnosis of invasive disease. Cytomegalovirus disease can be prevented by prophylaxis (the administration of antiviral drugs to all or to a subgroup of patients who are at higher risk of viral replication) or by preemptive therapy (the early diagnosis of viral replication before development of the disease and prescription of antiviral treatment to prevent the appearance of clinical disease). The drug used is intravenous or oral ganciclovir; oral valganciclovir; or, less frequently, valacyclovir. Prophylaxis should continue for 90 to 180 days. Treatment is always indicated in cytomegalovirus disease, and the gold-standard drug is intravenous ganciclovir. Treatment should be given for 2 to 3 weeks and should be continued for an additional 7 days after the first negative result for viremia.

The impact of donor viral replication at transplant on recipient infections posttransplant: a prospective study

BACKGROUND

Organ donors are often implicated as the source of posttransplant recipient infection. We prospectively studied kidney and liver donor-recipient pairs to determine if donor viral replication of cytomegalovirus (CMV), Epstein-Barr virus (EBV), and BK polyomavirus (BKV) at transplant was a risk factor for posttransplant recipient infection and disease.

METHODS

Donors and recipients were studied for antibodies against CMV and EBV and for quantitative viral replication of CMV, EBV, and BKV in oral washes, urine, and whole blood pretransplant. Recipient testing continued every 3 months after transplantation. Demographic and clinical data on infections and graft and subject outcomes were obtained.

RESULTS

The 98 donor-recipient pairs included 15 liver and 83 kidney transplants (18 of whom were children). No donor had detectable CMV replication; therefore, its impact on recipient CMV replication could not be analyzed. Donor EBV replication occurred in 22%, mostly in the oral wash and showed no impact on posttransplant recipient EBV replication (P=0.9) or EBV viremia (P=0.6) in kidney or liver recipients. Donor BKV replication occurred in 17%, mostly in the urine and although not associated with posttransplant recipient urinary BKV replication in recipients, it was associated with BKV viremia (P=0.02), and a significantly shorter time to BKV viremia (P=0.01) in kidney recipients.

CONCLUSION

Donor replication of CMV or EBV did not impact posttransplant recipient viral replication in kidney or liver transplants. Donor urinary BKV replication is associated with recipient BKV viremia in kidney transplants.

Association between individual and combined SNPs in genes related to innate immunity and incidence of CMV infection in seropositive kidney transplant recipients

In this study, we assessed the association between single-nucleotide polymorphisms (SNPs) in seven candidate genes involved in orchestrating the immune response against cytomegalovirus (CMV) and the 12-month incidence of CMV infection in 315 CMV-seropositive kidney transplant (KT) recipients. Patients were managed either by antiviral prophylaxis or preemptive therapy. CMV infection occurred in 140 patients (44.4%), including 13 episodes of disease. After adjusting for various clinical covariates, patients harboring T-allele genotypes of interleukin-28B (IL28B) (rs12979860) SNP had lower incidence of CMV infection (adjusted hazard ratio [aHR]: 0.66; 95% confidence interval [CI]: 0.46-0.96; p-value = 0.029). In the analysis restricted to patients not receiving prophylaxis, carriers of the TT genotype of toll-like receptor 9 (TLR9) (rs5743836) SNP had lower incidence of infection (aHR: 0.61; 95% CI: 0.38-0.96; p-value = 0.035), whereas the GG genotype of dendritic cell-specific ICAM 3-grabbing nonintegrin (DC-SIGN) (rs735240) SNP exerted the opposite effect (aHR: 1.86; 95% CI: 1.18-2.94; p-value = 0.008). An independent association was found between the number of unfavorable SNP genotypes carried by the patient and the incidence of CMV infection. In conclusion, specific SNPs in IL28B, TLR9 and DC-SIGN genes may play a role in modulating the susceptibility to CMV infection in CMV-seropositive KT recipients.

Impact of antibiotic resistance on the development of recurrent and relapsing symptomatic urinary tract infection in kidney recipients

We sought to determine the frequency, risk factors, and clinical impact of recurrent urinary tract infections (UTI) in kidney transplant recipients. Of 867 patients who received a kidney transplant between 2003 and 2010, 174 (20%) presented at least one episode of UTI. Fifty-five patients presented a recurrent UTI (32%) and 78% of them could be also considered relapsing episodes. Recurrent UTI was caused by extended-spectrum betalactamase (ESBL)-producing Klebsiella pneumoniae (31%), followed by non-ESBL producing Escherichia coli (15%), multidrug-resistant (MDR) Pseudomonas aeruginosa (14%), and ESBL-producing E. coli (13%). The variables associated with a higher risk of recurrent UTI were a first or second episode of infection by MDR bacteria (OR 12; 95%CI 528), age >60 years (OR 2.2; 95%CI 1.15.1), and reoperation (OR 3; 95%CI 1.37.1). In addition, more relapses were recorded in patients with UTI caused by MDR organisms than in those with susceptible microorganisms. There were no differences in acute rejection, graft function, graft loss or 1 year mortality between groups. In conclusion, recurrent UTI is frequent among kidney recipients and associated with MDR organism. Classic risk factors for UTI (female gender and diabetes) are absent in kidney recipients, thus highlighting the relevance of uropathogens in this population.

Factors related to the development of CMV-specific CD8+ T cell response in CMV-seropositive solid organ transplant candidates

This cross-sectional study analyzes factors associated with the development of CMV-specific CD8+ response, measured by IFNg production after cytomegalovirus (CMV) peptide stimulation, in CMV-seropositive solid organ transplantation candidates. A total of 114 candidates were enrolled, of whom 22.8% (26/114) were nonreactive (IFNγ < 0.2 IU/mL). Multivariate logistic regression analysis showed that age, HLA alleles and organ to be transplanted were associated with developing CMV-specific CD8+ immunity (reactive; IFNγ ≥ 0.2 IU/mL). The probability of being reactive was higher in candidates over 50 than in those under 50 (OR 6.33, 95%CI 1.93-20.74). Candidates with HLA-A1 and/or HLA-A2 alleles had a higher probability of being reactive than those with non-HLA-A1/non-HLA-A2 alleles (OR 10.97, 95%CI 3.36-35.83). Renal candidates had a higher probability of being reactive than lung (adjusted OR 8.85, 95%CI 2.24-34.92) and liver candidates (OR 4.87, 95%CI 1.12-21.19). The AUC of this model was 0.84 (p < 0.001). Positive and negative predictive values were 84.8% and 76.9%, respectively. In renal candidates longer dialysis was associated with an increased frequency of reactive individuals (p = 0.040). Therefore, although the assessment of CMV-specific CD8+ response is recommended in all R+ candidates, it is essential in those with a lower probability of being reactive, such as non-renal candidates, candidates under 50 or those with non-HLA-A1/non-HLA-A2 alleles.

Multicenter comparison of laboratory performance in cytomegalovirus and Epstein-Barr virus viral load testing using international standards

BACKGROUND

Infections with cytomegalovirus (CMV) and Epstein-Barr virus (EBV) remain important in solid organ transplantation. Quantitative viral nucleic acid testing is a major advance to patient management. These assays are limited by a lack of standardization, resulting in viral load measurements that differ among clinical laboratories. The variability in viral load measurements makes interpretation of multicenter clinical trials data difficult. This study compares the current practices in CMV and EBV viral load testing at four large transplant centers participating in multicenter Clinical Trials in Organ Transplantation and the Clinical Trials in Organ Transplantation in Children (CTOT and CTOTC).

METHODS

Viral load testing was performed on well-defined viral preparations according to standard operating procedures at each site.

RESULTS

Among centers, CMV viral load testing was accurate compared to WHO International Standards and within acceptable variation for this testing method. Epstein-Barr virus viral load data were more variable and less accurate despite the use of international standards.

CONCLUSIONS

These data suggest that comparison of CMV, but not EBV, viral load measurements at these sites is possible using current assays and control standards. Standardization of these assays is facilitated using the WHO International Standards and will allow comparison of viral load results among transplant centers. Assay standardization must be performed prior to initiation of multicenter trials.