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Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is a potentially curative option for patients with hematologic diseases but is associated with high mortality and morbidity. Cytomegalovirus (CMV) infection is common in HSCT patients and modulates vitamin D metabolism in vitro. We aimed at validating CMV-associated vitamin D metabolism in vivo in HSCT., Methods: Patients treated for significant CMV viremia after HSCT were evaluated for CMV load before, during, and after antiviral treatment. RNA was isolated from whole-blood samples to test for regulation of key components of the vitamin D receptor (VDR) pathway during different phases of CMV viremia., Results: CMV viremia developed a mean time of 102 (±34) d post-HSCT. Maximum levels of CMV-DNA reached a mean of 5668 (±7257) copies/mL. VDR expression was downregulated to a mean of 64.3% (±42.5%) relative to the VDR expression pre-CMV viremia (P = 0.035) and lagged in recovery following antiviral treatment. Toll-like receptor (TLR) 2 mRNA was upregulated to 225.4% during CMV viremia relative to the expression pre-CMV viremia (P = 0.012) but not TLR6/7/8 and the TLR-adaptor protein MyD88. Levels of 25-OH vitamin D were reduced in all viremic patients (48.0 ± 4.8 versus 25.1 ± 3.7 ng/mL) and were even lower after periods of CMV viremia compared with the control group (48.3 ± 3.5 versus 17.8 ± 1.8 ng/mL; P = 0.008)., Conclusions: CMV viremia is associated with significant dysregulation of vitamin D metabolism in HSCT patients., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Previous studies on the association between cytomegalovirus (CMV) infection and cardiac allograft vasculopathy (CAV) were conducted on patients transplanted in the prevalganciclovir prophylaxis era. The aim of our study is to evaluate this relation in heart transplantation (HTx) recipients treated according to current prophylactic and immunosuppressive regimens., Methods: This single-center retrospective study included all consecutive adult patients that underwent HTx between January 1, 2000, and May 31, 2018. Clinically relevant CMV infection was defined as either plasma CMV DNAemia ≥ 1000 IU/mL with/without clinical symptoms or <1000 IU/mL with symptoms. The primary endpoint was first manifestation of CAV diagnosed by coronary angiography. For statistical analysis, the cause-specific hazard regression model was applied, with clinically relevant CMV infection and any CMV infection as time-dependent variables., Results: In total, 260 patients were included in the analysis. The median (interquartile range) follow-up was 7.88 (4.21-12.04) years. During the follow-up, clinically relevant CMV infection was diagnosed in 96 (37%) patients and CAV in 149 (57%) patients. In the multivariate regression analysis, independent predictors of CAV were: number of rejection episodes (cause-specific hazard ratio [95% confidence interval]: 1.18 [1.04-1.34], P = 0.01), hypertension (1.61 [1.11-2.34], P = 0.01), treatment with mycophenolate mofetil (0.68 [0.47-0.97], P = 0.03). No significant association was observed between CMV infection and CAV, except for patients who experienced a breakthrough CMV infection (n = 24) during prophylaxis (1.94 [1.11-3.40], P = 0.02)., Conclusions: In the era of contemporary immunosuppression and valganciclovir prophylaxis, a significant effect of CMV infection on the risk of CAV was seen only among HTx recipients with CMV breakthrough infection.

Cytomegalovirus (CMV) is a β-herpesvirus that establishes lifelong latency in infected hosts. Following transplantation of a latently infected organ, reactivation can occur and consists of a spectrum of clinically apparent syndromes from mild symptoms to tissue-invasive, resulting in both direct and indirect sequelae. Before the advent of effective antiviral agents, the primary treatment was reduction in immunosuppression (IS). While antiviral agents provide effective prophylaxis, there are several important caveats associated with their use, including drug toxicity and resistance. The traditional view attributes CMV reactivation and the ensuing clinical disease primarily to IS, either intrinsic to disease-related immune compromise or from the extrinsic administration of IS agents. However, previous data from both animal models and human subjects showed that inflammatory signals could induce upregulation of latent viral gene expression. New data demonstrate that ischemia/reperfusion is necessary and sufficient to induce CMV reactivation following murine transplantation of a latently infected graft. In this article, we review a growing body of evidence that suggests that reactivation of both human CMV and murine CMV is first triggered by molecular events that activate CMV gene expression and lytic infection and viral dissemination are then facilitated by IS. The initial activation of viral gene expression may be mediated by oxidative stress, DNA damage, or inflammatory cytokines, and these factors may act synergistically. New therapeutic approaches are needed to capture this complex array of targets.

Background: Cytomegalovirus (CMV)-infection remains a major cause of morbidity and mortality after lung transplantation. Treatment with currently available drugs poses treatment difficulties in some patients due to drug resistance or intolerability., Methods: We report a series of 4 lung transplant recipients with CMV-infection and treatment failure upon standard care due to antiviral drug resistance and treatment-limiting side effects. As rescue therapy letermovir recently approved for the prophylaxis of CMV-infection in patients after hematopoietic stem cell transplantation was initiated. Patients received 480 mg/day for a follow up of 36.1 ± 12.9 weeks. Efficacy and tolerability were assessed retrospectively., Results: Mild nausea, vomiting, and diarrhea were the only side effects of letermovir reported by a single patient. A small adjustment of the tacrolimus dose was mandatory upon treatment initiation with letermovir. CMV viral load could be decreased and cleared subsequently in all patients. CMV clearance was observed after 17.7 ± 12.6 weeks despite lack of CMV-immunity., Conclusions: CMV-infection and -disease were successfully managed with letermovir. Letermovir was well tolerated and effective in treating CMV-infections in lung transplant recipients failing on currently available antiviral agents.

Background: Cytomegalovirus (CMV) infection is a serious complication in immunosuppressed patients, specifically transplant recipients. Here, we describe the development and use of an assay to monitor the incidence and treatment of CMV viremia in a Cynomolgus macaque model of bone marrow transplantation (BMT) for tolerance induction. We address the correlation between the course of viremia and immune reconstitution., Methods: Twenty-one animals received a nonmyeloablative conditioning regimen. Seven received cyclosporine A for 28 days and 14 received rapamycin. A CMV polymerase chain reaction assay was developed and run twice per week to monitor viremia. Nineteen recipients were CMV seropositive before BMT. Immune reconstitution was monitored through flow cytometry and CMV viremia was tracked via quantitative polymerase chain reaction., Results: Recipients developed CMV viremia during the first month post-BMT. Two animals developed uncontrollable CMV disease. CMV reactivation occurred earlier in cyclosporine A-treated animals compared with those receiving rapamycin. Post-BMT, T-cell counts remained significantly lower compared with pretransplant levels until CMV reactivation, at which point they increased during the viremic phase and approached pretransplant levels 3 months post-BMT. Management of CMV required treatment before viremia reached 10 000 copies/mL; otherwise clinical symptoms were observed. High doses of ganciclovir resolved the viremia, which could subsequently be controlled with valganciclovir., Conclusions: We developed an assay to monitor CMV in Cynomolgus macaques. CMV reactivation occurred in 100% of seropositive animals in this model. Rapamycin delayed CMV reactivation and ganciclovir treatment was effective at high doses. As in humans, CD8 T cells proliferated during CMV viremia.

Background: In lung transplant recipients, immunosuppressive medications result in impaired antiviral immunity and a propensity for cytomegalovirus (CMV) reactivation within the lung allograft. Natural killer (NK) cells play a key role in immunity to CMV, with an increase in the proportion of NK cells expressing activating CD94-NKG2C receptors in the blood being a strong correlate of CMV infection. Whether a similar increase in NKG2C NK cells occurs in lung transplant recipients following CMV reactivation in the allograft and if such cells contribute to viral control remains unclear., Methods: In this pilot study, we longitudinally assessed the frequency and phenotype of NKG2C NK cells in the blood and bronchoalveolar lavage (BAL) of lung transplant recipients and stratified recipients based on their risk of developing CMV disease., Results: We observed an increase in the proportion of NKG2C NK cells in the blood and BAL of CMV high-risk patients, coincident with both the cessation of antiviral prophylaxis and subsequent detection of actively replicating CMV in the blood and lung allograft. Additionally, these NKG2C NK cells expressed killer-cell immunoglobulin-like receptors distinct from those of other NK subsets and BAL NKG2C NK cells possessed an activated phenotype. Finally, the frequency of NKG2C NK cells in the BAL may be inversely correlated with CMV blood titers., Conclusions: Monitoring the phenotype of NK cells postlung transplant may be a useful biomarker for monitoring patient levels of CMV immunity.

Background: Cytomegalovirus (CMV) is a common viral pathogen in transplant patients which often targets the stomach. However, the endoscopic characteristics of gastric CMV infection are not well established. We aimed to develop a predictive model using endoscopic findings for gastric CMV infection in renal transplant patients., Methods: A retrospective study of 287 kidney transplant recipients who underwent endoscopy with biopsy for suspected CMV infection from January 2006 to November 2015 at a tertiary referral hospital was performed. CMV infection was defined based on inclusion bodies in hematoxylin and eosin and immunohistochemical staining. Endoscopic and clinical parameters related to gastric CMV infection were selected by univariate analyses. Multivariate logistic regression was used to create a predictive model from β-coefficients., Results: CMV was present in 107 (37.7%) of the 287 patients. Multivariate analysis found age (odds ratio [OR], 0.964; 95% confidence interval [CI], 0.938-0.99; P = 0.008), erosions with surface exudate (OR, 5.34; 95% CI, 2.687-10.612; P < 0.001), raised shape of erosions (OR, 3.957; 95% CI, 1.937-8.083; P < 0.001), and antral location of ulcers (OR, 15.018; 95% CI, 5.728-39.371; P < 0.001) as independent predictive factors for gastric CMV infection. Using the predictive model created from this analysis, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 71.03%, 85.56%, 74.51%, 83.24%, and 80.14%, respectively. The area under the receiver operating characteristic curve of this model for detecting CMV infection was 0.850 (95% CI, 0.803-0.889; P < 0.001)., Conclusions: The predictive model with typical endoscopic findings may be useful for detecting gastric CMV infection in renal transplant patients.

Background: We provide the results of the first interventional study of cytomegalovirus (CMV)-specific immune monitoring to direct the length of antiviral prophylaxis in lung transplantation (LTx)., Methods: Patients (n = 118) at risk of CMV infection were randomized 1:2 to either 5 months or variable length valganciclovir prophylaxis (5-11 mo post-LTx), as determined by the QuantiFERON (QFN)-CMV assay. Patients with a negative QFN-CMV assay (< 0.2 IU/mL) received prolonged valganciclovir prophylaxis., Results: The primary endpoint that was the incidence of CMV infection in the lung allograft within 18 months of LTx was significantly reduced in the QFN-CMV directed arm (37% versus 58%, P = 0.03). Secondary endpoints that included blood viremia, acute rejection, and chronic lung allograft dysfunction did not differ between the 2 arms. Of the 80/118 patients who ceased antiviral prophylaxis at 5 months, the incidence of viremia (> 600 copies/mL) within the blood was significantly reduced in patients with a positive QFN-CMV assay compared with those without protective immunity (13% versus 67%, P = 0.0003), as was the incidence of severe viremia (> 10 000 copies/mL) (3% versus 50%, P < 0.001). Ceasing antiviral prophylaxis at 11 months in patients with a negative assay was associated with a 25% incidence of late CMV viremia., Conclusions: Cytomegalovirus immune monitoring allows an individualized approach to CMV prophylaxis and reduces late CMV infection within the lung allograft.

Background: Control of cytomegalovirus (CMV) infection after solid organ transplantation (SOT) requires a functional immune system. We assessed the association between quantitation and function of CMV-specific CD8+ T cells and CMV infection in SOT recipients., Methods: During a 10-year period, selected kidney, heart, lung, pancreas, liver, and composite tissue recipients were tested for CMV-specific CD8+ T cells immune competence (CMV-CD8+), as measured by enumeration, interferon-gamma production, and CD107a/b degranulation. Quantitative and functional data were used to assemble T-cell immune competence (TIC) score. CMV infection was diagnosed by polymerase chain reaction in blood and other samples or histopathology., Results: Of 130 patients tested, 59 had CMV infection or disease. The median onset to CMV infection was 10.5 months (interquartile range [IQR], 5.5-18.7). Gastrointestinal disease (28.8%), pneumonia (20.3%), and CMV syndrome (17%) were most common presentation. An impaired nonspecific or CMV-CD8+ TIC score was associated with tissue-invasive disease (hazard risk, 2.84, 95% confidence interval, 1.03-11.81; P = 0.04). Patients with impaired CMV-CD8+ TIC score had longer viremia duration (42.4 days vs 18.8 d; P < 0.001). Patients with impaired nonspecific or CMV-CD8+ TIC score had higher risk of relapse (68.8% vs 27.9%; hazard risk, 2.56; 95% confidence interval, 1.09-5.89; P = 0.03). Patients with CMV infection or disease had lower median absolute lymphocyte count (380 [IQR, 240-540] vs 940 [IQR, 551-1210] cells/mm; P < 0.0001) and CD4+ T cell count (29 cells/mm [IQR, 1.3-116.0] vs 325.5 cells/mm [IQR, 151.5-589.8]; P < 0.0001)., Conclusions: Nonspecific and CMV-specific CD8+ T-cell function correlated with the course of CMV after SOT, and measuring these has the potential to assist in its clinical management.

Background: Whether cytomegalovirus (CMV)-specific cell-mediated immunity (CMI) at prophylaxis cessation predicts D+/R+ kidney transplants at risk of late-onset CMV infection after receiving distinct induction therapies is still not well characterized., Methods: We prospectively assessed CMV-specific CMI predicting late-onset CMV infection at prophylaxis withdrawal and at earlier time-points, in 96 consecutive D+/R+ patients receiving either anti-interleukin 2-receptor antibody (anti-IL2RA; n = 50) or rabbit antithymoglobulin (n = 46). CMV-specific CMI was evaluated against CMV antigens (IE-1, pp65) using an IFN-γ ELISpot assay., Results: Fourteen (14.6%) of 96 patients developed late-onset CMV infection and 2 (2.1%) of 96 displayed disease. At 3 months, CMV-specific CMI frequencies were significantly lower in patients developing late-onset CMV infection (P < 0.001 for IE-1, P = 0.030 for pp65), regardless the type of induction therapy. Receiver operating characteristic curve analyses showed accurate CMV-specific CMI cutoffs (25 and 130 IFN-γ spots for IE-1 and pp65, respectively) classifying patients into high risk, intermediate risk, or low risk (log-rank = 0.006; hazard ratio, 4.084; 95% confidence interval, 1.431-11.651; P = 0.009), being IE-1 CMI the strongest predictor (odds ratio, 5.554; 95% confidence interval, 1.486-20.766; P = 0.011). Although the profound posttransplant CMV-specific CMI inhibition among rabbit antithymocyte globulin-treated patients precludes its use for risk stratification both before and early after kidney transplant, a similar proportion of at-risk patients could be identified before month 3 within anti-interleukin 2-receptor antibody-treated patients., Conclusions: Monitoring CMV-specific CMI at 3-month prophylaxis cessation discriminates kidney transplant recipient at risk of late-onset CMV infection, regardless the type of induction therapy.

Background: Cytomegalovirus (CMV) infection is implicated in endothelial dysfunction and graft damage after pediatric heart transplantation. CMV-specific immune responses are thought to be necessary for CMV viral control but there is little data in pediatric heart transplantation., Methods: We studied 28 consecutive pediatric heart transplant recipients for 1 year posttransplant. CMV T-cell expressing IFN-γ, TNF-α, and IL-2 in response to ex vivo stimulation with CMV lysates or peptides were measured. Circulating cytokines were measured in plasma. Generalized Additive Models were applied to the data to model changes of cell population dynamics over time., Results: CMV-specific T cell-mediated responses were impaired in the first 8 weeks posttransplant. During this period, 25% of patients had CMV viremia, of which those with VLs of 10 000 or more CMV deoxyribonucleic acid copies/mL were given ganciclovir. In this group, the frequency of CD4+ and CD8+ T cells producing IFN-γ and the CD8+CD57+ granzyme B+ T-cell population increased at 12 to 24 weeks and remained elevated for the duration of the study., Conclusions: We have shown that CMV viremia is associated with CMV-specific immune responses and increased CD8+CD57+ granzyme B+ cells at 1 year posttransplant; however, early responses were not predictive of impending CMV viremia. It remains to be seen if the early CMV immune response detected is associated with endothelial and allograft damage, in light of previous studies demonstrating increased vasculopathy in pediatric patients with CMV viremia.

Background: Few studies have directly compared preemptive therapy (PET) and antiviral prophylaxis (AP) for prevention of cytomegalovirus (CMV) disease in CMV seropositive (R+) orthotopic liver transplant (OLT) recipients., Methods: We prospectively assessed CMV disease and clinical outcomes among 160 consecutive R+ OLT recipients who received PET (weekly plasma CMV PCR for 3 months, oral valganciclovir 900 mg twice daily for CMV viremia >250 IU/mL, until 2 consecutive negative weekly PCR results) and compared them with a historical cohort of 156 R+ recipients who received AP (valganciclovir, 900 mg daily for 3 months)., Results: Patient characteristics were similar between PET and AP cohorts (P > 0.05 all comparisons). In the PET group, 24% (39/160) developed CMV viremia greater than 250 IU/mL at a median of 42 (range, 7-93) days post-OLT. CMV monitoring adherence in the PET cohort was 85% (1488/1760 required tests) and 86% (30/36) initiated PET within 3 days of the CMV result. By 12 months post-OLT, the incidence of CMV disease, acute allograft rejection, major infection, or death in the PET and AP cohorts was not significantly different: 2% versus 2%, 19% versus 16%, 10.5% versus 10.8%, and 5% versus 8%, respectively (P > 0.05 all comparisons). The estimated proportion of drug-exposed patients and average antiviral drug exposure were significantly lower with PET versus AP: 24% versus 100%, P < 0.001, and 15.8 versus 81 g per patient, P < 0.001, respectively., Conclusions: PET is feasible in a nonresearch setting and is associated with similar CMV disease rates and other clinically relevant outcomes to AP in CMV seropositive liver transplant recipients.

Background: Urinary CXC chemokine ligand 10 (CXCL10) is a promising biomarker for subclinical tubulointerstitial inflammation, but limited data exist regarding its correlation with (micro)vascular inflammation. Furthermore, no study has evaluated whether concomitant serum CXCL10 improves the discrimination for (micro)vascular inflammation., Methods: We investigated whether serum/urinary CXCL10 reflect subclinical inflammation within different renal compartments. Patients (n = 107) with 107 surveillance biopsies were classified as: normal histology (n = 47), normal histology with polyomavirus BK (BKV) or cytomegalovirus (CMV) viremia (n = 17), moderate-severe tubulointerstitial inflammation (tubulitis ≥2, n = 18), pure microvascular inflammation (n = 15), and isolated v lesions (n = 10). Serum and urinary CXCL10 Enzyme-linked Immunosorbent Assay was performed. An independent validation set was evaluated for urine CXCL10: normal histology (n = 14), normal histology with BKV or CMV viremia (n = 19), tubulitis ≥2 (n = 15), pure microvascular inflammation (n = 41), and isolated v lesions (n = 14)., Results: Elevated urinary CXCL10 reflected inflammation within the tubulointerstitial (urinary CXCL10/creatinine, 1.23 ng/mmol vs 0.46 ng/mmol; P = 0.02; area under the curve, 0.69; P = 0.001) and microvascular compartments (urinary CXCL10/creatinine, 1.72 ng/mmol vs 0.46 ng/mmol; P = 0.03; area under the curve, 0.69; P = 0.02) compared to normal histology. Intriguingly, urinary CXCL10 was predominantly elevated with peritubular capillaritis, but not glomerulitis (P = 0.04). Furthermore, urinary CXCL10 corresponded with BKV, but not CMV viremia (P = 0.02). These urine CXCL10 findings were confirmed in the independent validation set. Finally, serum CXCL10 was elevated with BKV and CMV viremia but was not associated with microvascular or vascular inflammation (P ≥ 0.19)., Conclusions: Urinary CXCL10 reflects subclinical inflammation within the tubulointerstitial and peritubular capillary spaces, but not the vascular/systemic compartments; this was consistent with BKV (tubulointerstitial) and CMV viremia (systemic). Serum CXCL10 was not a useful marker for (micro)vascular inflammation.

Background: Detectable cytomegalovirus (CMV)-specific T cells in CMV-seronegative kidney transplant recipients (KTRs) have been attributed to an absence of circulating antibodies despite CMV sensitization. The diagnostic value of CMV-specific T cells, however, needs to be implemented in risk stratification for CMV replication., Methods: Three hundred twenty-six KTRs were studied and classified with respect to CMV serostatus and presence of CMV-specific T cells. Samples were collected pretransplantation, at +1, +2, and +3 months posttransplantation. CMV-specific T cells directed to CMV-IE1 and CMV-pp65 were measured by interferon-γ Elispot assay., Results: Nineteen (28%) of 67 D+R- KTRs showed pretransplant CMV-specific T cells. Although no differences were observed for CMV replication, KTRs with CMV-specific T cells presented with lower initial and peak CMV loads (P < 0.05). KTRs with decreasing/undetectable CMV-IE1-specific T cells pretransplantation and posttransplantation were at greatest risk of CMV replication. KTRs with stable/increasing CMV-IE1-specific T cells from pretransplantation to posttransplantation, however, showed low risk of CMV replication (P < 0.001). One hundred sixty-two (80%) of 203 R+ KTRs showed pretransplant CMV-specific T cells. Decreasing/undetectable CMV-IE1-specific T cells from pretransplantation and posttransplantation identified those R+ KTRs at increased risk of CMV replication (65/80 KTRs; 81%; P < 0.001)., Conclusions: Despite CMV prophylaxis, D+R- KTRs are at greatest risk of CMV disease. Our data suggest that monitoring CMV-specific T cell kinetics from pretransplantation to posttransplantation, particularly directed to CMV-IE1, offers superior risk stratification compared with CMV serostatus alone.

Background: Desensitization with IVIG + rituximab combined with alemtuzumab induction gives HLA-sensitized patients an opportunity for successful kidney transplantation. However, it may be associated with a high risk for viral infections due to combined T cell and B cell depletion., Methods: Anti-cytomegalovirus (CMV) activity was assessed in 280 pretransplant and posttransplant blood samples from 33 desensitized patients who received alemtuzumab induction. CMV-specific CD8+ (CMV-Tc), CD4+ (CMV-Th) T cell activity, and natural killer (NK) cell number were measured by flow cytometry. Anti-CMV IgG was measured by enzyme-linked immunosorbent assay, and CMV DNA by polymerase chain reaction., Results: All 30 CMV sero (+) patients were (+) for CMV-Tc and/or Th predesensitization, while 3 sero (-) patients showed no CMV-T cell activity. CMV-Tc and/or Th became (-) in 50% to 70% of these sero (+) patients at 1 month post-alemtuzumab. However, 75% showed CMV-T cell (+) by 2 months and 95% did so by 3 months post-alemtuzumab. More than 50% of pretranslpant NK cell levels were detected post-alemtuzumab. Anti-CMV IgG levels did not decrease posttransplant in sero (+) patients. Four patients developed CMV viremia with clearance by 1.2 months, which correlated with an increase or appearance of CMV-T cells, even in the sero (-) patient., Conclusions: CMV-T cell activity, anti-CMV IgG, and NK cell-mediated antibody-dependent cell cytotoxicity were present in aleumtuzumab-treated CMV sero (+) patients. One sero (-) patient developed CMV-T cell responses post-CMV viremia. These results suggest that the IVIG + rituximab desensitization combined with alemtuzmab induction with triple immunosuppression maintenance does not result in prolonged suppression of anti-CMV immunity or increased risk for CMV infection.

Background: Renal transplantation is the preferred treatment for patients with end-stage renal disease. Human cytomegalovirus (HCMV) activation is associated with decreased renal graft function and survival. Human cytomegalovirus encodes several immune modulatory proteins, including the G protein-coupled receptor US28, which scavenges human chemokines and modulates intracellular signaling., Methods: Our aim was to identify the expression and localization of US28 in renal allograft biopsies by immunohistochemistry and determine its role in viral spreading in vitro., Results: Immunohistochemistry revealed US28 in 31 of 34 renal transplant biopsies from HCMV-seropositive donors. Expression was independent of HCMV viremia or IgG serostatus. US28 was predominantly expressed in the cytoplasm of vascular smooth muscle cells (VSMCs) and tubular epithelial cells, with a median positivity of 20% and 40%, respectively. Also, US28-positive cells were present within arterial neointima. In contrast to US28, HCMV-encoded immediate early antigen was detected in less than 5% of VSMCs, tubular epithelial cells, interstitial endothelium, interstitial inflammatory infiltrates, and glomerular cells.Primary VSMCs were infected with green fluorescent protein-tagged wild type or US28-deficient HCMV. The viral spreading of US28-deficient HCMV, via culture medium or cell-to-cell transmission, was significantly impeded as shown by green fluorescent protein (ie, infected) cell quantification and quantitative real-time polymerase chain reaction. Additionally, the number and size of foci was smaller., Conclusions: In summary, HCMV-encoded US28 was detected in renal allografts from HCMV-positive donors independent of viremia and serostatus. Also, US28 facilitates HCMV spreading in VSMCs in vitro. Because the vasculature is affected in chronic renal transplant dysfunction, US28 may provide a potential target for therapeutic intervention.

Background: Graft-versus-host (GvH) disease (GvHD) remains a serious concern for patients undergoing antiviral cellular therapy. Despite the major improvements in cellular immunotherapy, the immunogenicity of virus-specific T cells has not yet been fully defined. This present study aims to examine how cytomegalovirus (CMV)-specific cytotoxic T lymphocytes (CTLs) respond to allogeneic antigen stimulation and whether they give rise to GvHD target tissue damage., Methods: Cytomegalovirus-specific CTLs were isolated by the IFN-γ secretion assay (gamma-catch) from healthy seropositive volunteers and expanded in vitro. The levels of intracellular IFN-γ, cytotoxic activity, IFN-γ and granzyme B secretion, and CD25 expression were measured using flow cytometry (fluorescence-activated cell sorting). The ability of CMV-CTLs to induce GvHD target tissue damage was evaluated using the human in vitro skin explant assay (skin explant assay)., Results: Cytomegalovirus-specific CTLs responded specifically to CMV-phosphoprotein 65 stimulation by secreting IFN-γ and killing virus peptide loaded autologous phytohemagglutinin (PHA) blasts. Compared with unselected peripheral blood mononuclear cells, CMV-CTLs induced significantly less severe cutaneous GvH tissue damage. This observation coincided with low levels of CD25 expression, as well as IFN-γ and granzyme B secretion after allogeneic antigen stimulation in both the mixed lymphocyte reaction and in the skin explant assay., Conclusions: Cytomegalovirus-specific CTLs isolated by the IFN-γ secretion assay from HLA-unmatched healthy donors exhibited a high level of anti-CMV potency without inducing significant cutaneous GvH tissue damage in vitro. This finding provides novel evidence supporting the safe use of in vitro expanded CMV-CTLs as an antiviral therapy in transplant patients with refractory CMV infections.

The immune response to cytomegalovirus (CMV) infection is highly complex, including humoral, cellular, innate, and adaptive immune responses. Detection of CMV by the innate immune system triggers production of type I IFNs and inflammatory cytokines which initiate cellular and humoral responses that are critical during the early viremic phase of CMV infection. Sustained control of CMV infection is largely accounted for by cellular immunity, involving various T-cell and B-cell subsets. In solid organ transplant patients, global suppression of innate and adaptive immunities by immunosuppressive agents limits immunological defense, including inhibition of natural killer cell activity with ongoing lowering of Ig levels and CMV-specific antibody titers. This is coupled with a short-term suppression of CMV-specific T cells, the extent and duration of which can predict risk of progression to CMV viremia. CMV immunoglobulin (CMVIG) preparations have the potential to exert immunomodulatory effects as well as providing passive immunization. Specific CMVIG antibodies and virus neutralization might be enhanced by modulation of dendritic cell activity and by a decrease in T-cell activation, effects which are of importance during the initial phase of infection. In summary, the role of CMVIG in reconstituting specific anti-CMV antibodies may be enhanced by some degree of modulation of the innate and adaptive immune responses, which could help to control some of the direct and indirect effects of CMV infection.

Cytomegalovirus (CMV) is a highly complex pathogen which, despite modern prophylactic regimens, continues to affect a high proportion of thoracic organ transplant recipients. The symptomatic manifestations of CMV infection are compounded by adverse indirect effects induced by the multiple immunomodulatory actions of CMV. These include a higher risk of acute rejection, cardiac allograft vasculopathy after heart transplantation, and potentially bronchiolitis obliterans syndrome in lung transplant recipients, with a greater propensity for opportunistic secondary infections. Prophylaxis for CMV using antiviral agents (typically oral valganciclovir or intravenous ganciclovir) is now almost universal, at least in high-risk transplants (D+/R-). Even with extended prophylactic regimens, however, challenges remain. The CMV events can still occur despite antiviral prophylaxis, including late-onset infection or recurrent disease, and patients with ganciclovir-resistant CMV infection or who are intolerant to antiviral therapy require alternative strategies. The CMV immunoglobulin (CMVIG) and antiviral agents have complementary modes of action. High-titer CMVIG preparations provide passive CMV-specific immunity but also exert complex immunomodulatory properties which augment the antiviral effect of antiviral agents and offer the potential to suppress the indirect effects of CMV infection. This supplement discusses the available data concerning the immunological and clinical effects of CMVIG after heart or lung transplantation.

Cytomegalovirus (CMV) infection negatively influences both short- and long-term outcomes after cardiothoracic transplantation. In heart transplantation, registry analyses have shown that CMV immunoglobulin (CMVIG) with or without virostatic prophylaxis is associated with a significant reduction in mortality and graft loss versus no prophylaxis, particularly in high-risk donor (D)+/recipient (R)- transplants. Randomized comparative trials are lacking but retrospective data suggest that addition of CMVIG to antiviral prophylaxis may reduce rates of CMV-related events after heart transplantation, including the incidence of acute rejection or chronic allograft vasculopathy. However, available data consistently indicate that when CMVIG is used, it should be administered with concomitant antiviral therapy, and that evidence concerning preemptive management with CMVIG is limited, but promising. In lung transplantation, CMVIG should again only be used with concomitant antiviral therapy. Retrospective studies have shown convincing evidence that addition of CMVIG to antiviral prophylaxis lowers CMV endpoints and mortality. The current balance of evidence suggests that CMVIG prophylaxis reduces the risk of bronchiolitis obliterans syndrome, but a controlled trial is awaited. Overall, the relatively limited current data set suggests that prophylaxis with CMVIG in combination with antiviral therapy appears effective in D+/R- heart transplant patients, whereas in lung transplantation, addition of CMVIG in recipients of a CMV-positive graft may offer an advantage in terms of CMV infection and disease.

Intravenous ganciclovir and, increasingly, oral valganciclovir are now considered the mainstay of treatment for cytomegalovirus (CMV) infection or CMV disease. Under certain circumstances, CMV immunoglobulin (CMVIG) may be an appropriate addition or, indeed, alternative. Data on monotherapy with CMVIG are limited, but encouraging, for example in cases of ganciclovir intolerance. In cases of recurrent CMV in thoracic transplant patients after a disease- and drug-free period, adjunctive CMVIG can be considered in patients with hypogammaglobulinemia. Antiviral-resistant CMV, which is more common among thoracic organ recipients than in other types of transplant, can be an indication for introduction of CMVIG, particularly in view of the toxicity associated with other options, such as foscarnet. Due to a lack of controlled trials, decision-making is based on clinical experience. In the absence of a robust evidence base, it seems reasonable to consider the use of CMVIG to treat CMV in adult or pediatric thoracic transplant patients with ganciclovir-resistant infection, or in serious or complicated cases. The latter can potentially include (i) treatment of severe clinical manifestations, such as pneumonitis or eye complications; (ii) patients with a positive biopsy in end organs, such as the lung or stomach; (iii) symptomatic cases with rising polymerase chain reaction values (for example, higher than 5.0 log10) despite antiviral treatment; (iv) CMV disease or CMV infection or risk factors, such as CMV-IgG-negative serostatus; (vi) ganciclovir intolerance; (vii) patients with hypogammaglobulinemia.

Background: Infection with human cytomegalovirus (CMV) is a significant cause of morbidity and mortality in solid organ and hematopoietic stem cell transplant (HSCT) recipients., Methods: The present study explored the safety, feasibility, and immunogenicity of CMV pp65 messenger RNA-loaded autologous monocyte-derived dendritic cells (DC) as a cellular vaccine for active immunization in healthy volunteers and allogeneic HSCT recipients. Four CMV-seronegative healthy volunteers and three allogeneic HSCT recipients were included in the study. Four clinical-grade autologous monocyte-derived DC vaccines were prepared after a single leukapheresis procedure and administered intradermally at a weekly interval., Results: De novo induction of CMV-specific T-cell responses was detected in three of four healthy volunteers without serious adverse events. Of the HSCT recipients, none developed CMV disease and one of two patients displayed a remarkable threefold increase in CMV pp65-specific T cells on completion of the DC vaccination trial., Conclusion: In conclusion, our DC vaccination strategy induced or expanded a CMV-specific cellular response in four of six efficacy-evaluable study subjects, providing a base for its further exploration in larger cohorts.

Background: Cytomegalovirus (CMV) disease occurs in 16% to 20% of low-risk, CMV-positive renal transplant recipients. The cutoffs for quantitative real-time polymerase chain reaction (qPCR) or phosphoprotein (pp65) antigenemia (pp65emia) for starting preemptive therapy have not been well established., Methods: We measured qPCR and pp65emia weekly from day 7 to day 120 after transplantation, in anti-CMV immunoglobulin G–positive donor and recipient pairs. Patients and physicians were blinded to the test results. Suspicion of CMV disease led to the order of new tests. In asymptomatic viremic patients, the highest pp65emia and qPCR values were used, whereas we considered the last value before diagnosis in those with CMV disease., Results: We collected a total of 1,481 blood samples from 102 adult patients. Seventeen patients developed CMV disease, 54 presented at least one episode of viremia that cleared spontaneously, and 31 never presented viremia. Five patients developed CMV disease after the end of the study period. The median (95% confidence interval) pp65emia and qPCR values were higher before CMV disease than during asymptomatic viremia (6 [9–82] vs. 3 [1–14] cells/10(6) cells; P<0.001 and 3,080 [1,263–15,605] vs. 258 [258–1,679] copies/mL; P=0.008, respectively). The receiver operating characteristic curve showed that pp65emia 4 cells/10(6) cells or greater showed a sensitivity and specificity to predict CMV disease of 69% and 81%, respectively (area, 0.769; P=0.001), with a positive predictive value of 37% and a negative predictive value of 93%. For qPCR 2,000 copies/mL or higher, the positive predictive value and negative predictive value were 57% and 91%, respectively (receiver operating characteristic area, 0.782; P=0.000)., Conclusion: With these cutoffs, both methods are appropriate for detecting CMV disease.

Background: We report on a pilot study investigating the feasibility of early immunosuppression withdrawal after liver transplantation (LT) using antithymocyte globulin (ATG) induction and rapamycin., Methods: LT recipients received 3.75 mg/kg per day ATG from days 0 to 5 followed by rapamycin-based immunosuppression. In the absence of acute rejection (AR), rapamycin was withdrawn after month 4. Immunomonitoring included analysis of peripheral T-cell phenotypes and clonality, cytokine production in mixed lymphocyte reaction, and characterization of intragraft infiltrating cells., Results: Ten patients were enrolled between October 2009 and July 2010. In the first three patients, complete withdrawal of immunosuppression after month 4 led to AR. No further withdrawals of immunosuppressive were attempted. Two AR occurred in the remaining seven patients. ATG induced profound T-cell depletion followed by CD8(+) T-cell reexpansion exhibiting memory/effector-like phenotype associated with progressive oligoclonal T-cell expansion (Vβ/HPRT ratio) and gradually enhanced anti-cytomegalovirus and anti-Epstein-Barr virus T-cell frequencies. Patients developing AR were characterized by decreased TCAIM expression. AR were associated with increased donor-specific production of interferon (IFN)-γ and interleukin (IL)-17, increased intragraft expression of IFN-γ mRNA, and significant CD8(+) T-cell infiltrates colocalizing with IL-17(+) cells., Conclusion: High-dose ATG followed by short-term rapamycin treatment failed to promote early operational tolerance to LT. AR correlates with expansion of memory-type CD8(+) T cells and increased levels of IFN-γ and IL-17 in mixed lymphocyte reaction and in the graft. This suggests that resistance and preferential expansion of effector memory T-cell in lymphopenic environment could represent the major barrier for establishment of tolerance to LT in approaches using T-cell-depleting induction.

Background: Data on how different immunosuppressive drugs affect cytomegalovirus (CMV)-specific T-cell responses may help guide more rational modification of immunosuppression in patients with CMV replication. We assessed the in vitro effects of individual standard and novel immunosuppressive drugs on a broad range of CMV-specific T-cell responses., Methods: Peripheral blood mononuclear cells from healthy CMV-seropositive donors were preincubated with serial dilutions of tacrolimus, mycophenolate (MPA), sirolimus, tofacitinib, and belatacept. CMV-pp65 or CMV-pp72 peptide pools were used for stimulation. CMV-specific cytokine (Th1 and Th2) and chemokine responses were determined (a total of 5400 measurements). P<0.01 was set as significant., Results: After CMV stimulation, dose-dependent suppression of Th1, Th2, and chemokines was seen, but significant differences between drugs were present. For example, tacrolimus was more potent in inhibiting CMV-specific Th1 cytokines versus Th2, whereas MPA preferentially inhibited Th2 cytokines. In a comparison of the relative potency of each drug at different dosing ranges, tacrolimus had the strongest Th1 inhibitory effect (median inhibition of interferon-γ at 97.5%; P=0.004-0.008) followed by sirolimus (median inhibition at 82.4%). The remaining agents (MPA, belatacept, and tofacitinib) had less apparent dose-dependent effects on interferon-γ (belatacept median inhibition at 21.5%; P=0.004 vs. tacrolimus)., Conclusion: Immunosuppression-specific and dose-dependent reductions in CMV-specific cytokine release were observed with significant differences in Th1 versus Th2 profiles and in relative potency of the drugs.

Background: In renal transplant recipients, mammalian target of rapamycin (mTOR) inhibitors have been reported to protect against cytomegalovirus (CMV) disease. Here, we questioned whether mTOR inhibitors specifically influence human CMV-induced T-cell responses., Methods: We studied renal transplant recipients treated with prednisolone, cyclosporine A (CsA), and mycophenolate sodium (MPS) for the first 6 months after transplantation followed by double therapy consisting of prednisolone/everolimus, which is an mTOR inhibitor (P/EVL; n=10), prednisolone/CsA (P/CsA; n=7), or prednisolone/MPS (P/MPS; n=9). All patients were CMV-IgG positive before transplantation. CMV reactivation was detectable in the first 6 months after transplantation and not thereafter. None of the patients included in this study suffered from CMV disease. Both CD27CD8 and CD27CD28CD4 effector-type T-cell counts, known to be associated with CMV infection, were measured before transplantation and at 6 and 24 months after transplantation. Additionally, we determined both number and function of CMV-specific CD8 T cells at these time points., Results: The number of total CD8 T cells, CD27CD8 T cells, and CD28CD4 T cells increased significantly after switch to therapy with P/EVL but not after switch to P/CsA or P/MPS. Specifically, CMV-specific CD8 T-cell counts significantly increased after switch to therapy with P/EVL. Furthermore, the mTOR inhibitor sirolimus strongly inhibited alloresponses in vitro, whereas it did not affect CMV-specific responses., Conclusion: We observed a significant increase in (CMV-specific) effector-type CD8 and CD4 T-cell counts in everolimus-treated patients. These findings may at least in part explain the reported low incidence of CMV-related pathology in everolimus-treated patients.

Background: Several studies proved that virus-specific T-cells play a pivotal role in controlling cytomegalovirus (CMV) infection in adult allogeneic hematopoietic stem-cell transplant (HSCT) patients. Fewer data are available in pediatric HSCT settings, when immature and inexperienced immune system may affect antiviral immune reconstitution., Methods: We analyzed prospectively the CMV-specific T-cell reconstitution in a cohort of 31 pediatric allogeneic HSCT recipients at 30, 60, 90, 120, 180, and 360 days after HSCT., Results: Depending on donor-recipient CMV serostatus, we observed distinct patterns and kinetics of CMV-specific T-cell immune reconstitution: during the early time-points, patients displayed a severe reduction in CMV-specific T-cell recovery in both CMV seropositive donor (D+) group and CMV seronegative donor (D-) on CMV seropositive recipients (R+). From day 90 onward, statistical significant differences in the profile of T-cell immune reconstitution emerged between D+ and D-. The pattern of immune reconstitution was characterized by heterogeneous kinetics and efficiencies: we report cases of: (1) spontaneous antiviral T-cell recovery with no previous viremia, (2) immune T-cell recovery anticipated by CMV viremia, and (3) no T-cell immune reconstitution despite previous viremia episodes., Conclusions: Given the heterogeneous scenarios of antiviral T-cell immune recovery in pediatric allogeneic HSCT, we conclude that the evaluation of the antiviral immune reconstitution is a promising and appealing system for identifying patients at higher risk of CMV infection. The use of interferon-γ ELISPOT test is a valid tool for immunological monitoring and predicting CMV viremia in pediatric HSCT.

Background: A CD8+ T-cell response to cytomegalovirus (CMV) has been associated with control of viral replication. Assessment shortly after the onset of asymptomatic viremia could help significantly refine preemptive strategies., Methods: We conducted a prospective study of organ transplant recipients who developed asymptomatic low-level viremia not initially requiring antiviral therapy. Cell-mediated immunity (CMI) was measured shortly after viremia onset and longitudinally using the Quantiferon-CMV assay. The primary outcome was the ability to predict spontaneous clearance versus virologic and/or clinical progression., Results: We enrolled 42 transplant patients, of which 37 were evaluable. Viral load at onset was 1140 copies/mL (interquartile range 655-1542). Spontaneous viral clearance occurred in 29 of 37 (78.4%) patients and 8 of 37(21.6%) had clinical and/or virologic progression requiring antivirals. At baseline, a positive CMI test (interferon-γ≥0.2 IU/mL) was present in 26 of 37(70.3%) patients. In patients with a positive CMI, the incidence of subsequent spontaneous viral clearance was 24 of 26 (92.3%) compared with 5 of 11 (45.5%) in patients with a negative CMI at onset (P=0.004). The absolute interferon-γ production was higher in patients with spontaneous clearance versus progression at all time points tested. Analysis of different cutoffs for defining a positive test suggested that the best threshold was 0.1 or 0.2 IU/mL of interferon-γ., Conclusions: CMI assessment shortly after the onset of CMV viremia may be useful to predict progression versus spontaneous viral clearance, thereby helping guide the need for antiviral therapy and refining current preemptive strategies.

Background: It has been suggested that preemptive therapy against cytomegalovirus (CMV) infection after transplantation promotes a CMV-specific immune response. Our objective was to determine whether solid-organ transplant patients at high risk for CMV infection treated preemptively acquire a CMV-specific immune response and whether the acquired immune response confers immunity by controlling subsequent CMV replication episodes and by protecting from late-onset CMV disease., Methods: Patients were followed up for 18 months after transplantation. CMV viral load was determined using real-time polymerase chain reaction assays, and the T-cell immune response was characterized by intracellular cytokine staining., Results: The 21 patients studied developed CMV replication episodes at a median of 4 weeks (range 2-8 weeks) after transplantation and a CMV-specific T-cell response within a median of 12 weeks (range 10-20 weeks). The decline in the incidence of CMV replication episodes is inversely correlated with the acquisition of the CMV-specific T-cell response (linear regression r=0.781, Pearson correlation=-0.883; P=0.001). There were no CMV replication episodes after week 47 of transplantation. In addition, after acquisition of the immune response, 42 replication episodes were cleared without treatment. The time taken for immune clearance of replication correlated with the peak viral load (P=0.01). No incidence of CMV early or late-onset disease was detected., Conclusions: Our results demonstrate that preemptive therapy is a safe and an effective strategy for the control of CMV infection in solid-organ transplant recipients at high risk for CMV infection. This is the first study that reports a therapeutic effect of the acquisition of CMV-specific immune response during preemptive treatment., (© 2011 by Lippincott Williams & Wilkins)

Background: We assessed the impact of a preemptive strategy after discontinuation of antiviral prophylaxis in the prevention of late-onset cytomegalovirus (CMV) disease in a cohort of kidney transplant recipients., Methods: Patients undergoing kidney transplantation at the University Hospital of Lausanne (CHUV) between November 2003 and November 2007 were included if they were donor or recipient (D/R) seropositive for CMV. All patients received 3 months of prophylaxis with valganciclovir, followed by monitoring of CMV DNAemia by polymerase chain reaction (PCR) every 15 days during 3 additional months. Valganciclovir was restarted if CMV PCR was more than or equal to 10,000 copies/mL. The primary endpoint of the study was the incidence of late-onset CMV disease. RESULTS.: Eighty-six kidney transplant recipients were included; 30 patients were D+/R- and 56 patients were R+ for CMV. At 6 months posttransplant, CMV DNAemia had occurred in 31 of 86 (36%) patients: 13 of 30 (43%) in the D+/R- group and 18 of 56 (32%) in the R+ group (P = 0.35). In the D+/R- group, among the 13 patients with CMV DNAemia, 7 (54%) patients developed late-onset CMV disease, simultaneously to the first positive viral load (n = 5) or after detection of low-grade viremia (n = 2). Only two patients received a preemptive treatment. In the R+ group, all positive PCR results were below the established cutoff. Thus, these 18 patients were not treated, and none of them developed late-onset CMV disease (R+ vs. D+/R-: P < 0.001)., Conclusions: Within the limitations of a noncontrolled study, our data indicate that a preemptive strategy after 3 months of valganciclovir prophylaxis for CMV is not useful in R+ kidney transplant recipients. In D+/R- patients, this approach should be further evaluated.

Background: The economic merit of universal prophylaxis and preemptive therapy in the management of cytomegalovirus (CMV) infection for serology positive (R+) kidney transplant patients remains undefined. We performed cost effectiveness and cost utility modeling comparing these two approaches., Methods: The incidence of CMV infection under universal prophylaxis and preemptive therapy was determined among 653 R+ patients from our institution and 416 R+ patients from various clinic trials, respectively. Standardized decision tree analysis and Markov transitional models were used to calculate cost and quality-adjusted life years (QALYs) from the prototypical clinical data and published literature. Incremental cost effectiveness and cost utility were calculated as dollars for one case of infection avoided and one QALY gained over 10 years, respectively. One- and two-way sensitivity analyses were performed., Results: The incidence of CMV infection was 4.1% and 55.5% within the first year after transplant for universal prophylaxis and preemptive therapy, respectively. Compared with preemptive therapy, universal prophylaxis incurred $1464 more in direct cost while saving $7309 in indirect cost, and resulted in a net gain of 0.209 in QALYs per patient over a 10-year period. Thus, universal prophylaxis dominates over preemptive therapy with a cost saving of $27,967 for 1 QALY gained. This cost saving was sensitive to the variation in the rate of CMV infection and disease with each approach., Conclusion: Universal prophylaxis in CMV R+ kidney transplant patients is clinically effective and cost saving. It should be considered as the preferred approach.

Background: The objectives of this study are to investigate the impact of cytomegalovirus (CMV) donor (D)/recipient (R) serostatus on kidney transplant outcomes in recipients who received CMV prophylaxis and to investigate the association of individual antiviral agents (acyclovir, ganciclovir, and valganciclovir) with outcomes in high-risk recipients (D+/R-)., Methods: By using the Organ Procurement and Transplant Network/United Network for Organ Sharing database, 25,058 deceased donor kidney recipients (≥ 18 years, 2004-2008) who received CMV prophylaxis were stratified into four groups: D+/R+ (11,875), D-/R+ (6046), D+/R- (4555), and D-/R- (2582). The impact of CMV D/R serostatus on acute rejection (6 months and 1 year posttransplant) and long-term outcomes of death-censored graft failure and mortality were compared. The impact of the individual antiviral agent on long-term outcome was further evaluated in the high-risk group (D+/R-)., Results: In multivariate analysis, CMV D/R status was not associated with acute rejection. Compared with D-/R-, D+/R- was associated with an increased risk for death-censored graft failure (hazard ratio=1.28, P=0.01), all-cause mortality(hazard ratio=1.36, P=0.003), and mortality because of viral infection (hazard ratio=8.36, P=0.04). In the D+/R- group, valganciclovir usage was associated with a decreased risk for death-censored graft failure (hazard ratio=0.65, P=0.007) and mortality because of viral infection (hazard ratio=0.22, P=0.03) compared with ganciclovir usage., Conclusions: CMV mismatch (D+/R-) was no longer a risk factor for acute rejection in kidney recipients who received antiviral prophylaxis but was still an independent risk factor for death-censored graft failure, all-cause mortality, and viral infection-related mortality.

Background: Cytomegalovirus (CMV) is one of the major infections encountered posttransplantation. UK Guidelines (2003) recommend CMV prophylaxis or screening with preemptive treatment for all high risk recipients. Studies predating the widespread use of CMV prophylaxis have shown that CMV seronegative recipients (R-) receiving a renal allograft from a CMV seropositive donor (D+) have worse outcomes than those avoiding primary CMV infection. Therefore, it has been suggested that CMV matching should be a part of the UK national deceased donor kidney allocation scheme., Methods: We examined patient and allograft survival according to donor and recipient CMV serostatus in 10,190 UK adult and pediatric deceased donor renal transplant recipients transplanted between 2000 and 2007. We also ascertained CMV prophylaxis strategies in all UK renal transplant units., Results: Twenty-one of the 22 UK renal transplant centers used prophylactic oral valganciclovir for 3 months posttransplant in the D+R- transplants, having done so for a median of 4 years. Unadjusted data showed that D+R+ rather than D+R- transplants had the lowest patient and allograft survivals at 3 years posttransplant. However, after adjustment for donor age, there was no significant effect of donor and recipient CMV serostatus on allograft or patient survival., Conclusions: These findings suggest that in an era where CMV prophylaxis is used routinely in D+R- transplants, the previously noted adverse effects of primary CMV infection on allograft and patient survival can be avoided (perhaps through a reduction in the incidence and/or severity of primary CMV infection), without using a CMV-matching allocation scheme.

Background: Xenotransplantation with pig organs is being considered to alleviate donor organ shortages; however, the risk of introducing porcine viruses into humans is heightened in this setting. The goal of this study was to determine the infectious potential of porcine cytomegalovirus (PCMV), a xenozoonotic virus of interest, in human fibroblasts in vitro., Methods: Confluent human cells were incubated with live PCMV, heat-killed PCMV, or medium alone. Infection was investigated by testing for viral-induced cytopathic effect, assaying viral transcription by nested RT-PCR and subsequent sequencing, and detecting viral protein expression by Western blotting. Plaque neutralization experiments were also performed., Results: Cells incubated with PCMV demonstrated significant cytopathic effect by 7 days postinfection, and reverse-transcriptase polymerase chain reaction sequencing identified PCMV DNA polymerase in these infected cells. In Western blots, monoclonal antibodies (mAbs) to human CMV glycoprotein B and pig serum presumed to contain anti-PCMV antibodies detected characteristic proteins in experimentally infected human cells and positive controls but not in negative controls. Furthermore, one of these mAbs and the pig serum neutralized PCMV infection in vitro., Conclusions: These results are a first demonstration that PCMV can infect human fibroblasts in vitro.

Twenty-one pediatric liver transplant recipients were enrolled in a study comparing prophylaxis followed by preemptive therapy (10 patients) versus preemptive therapy alone (11 patients) for prevention of human cytomegalovirus (HCMV) disease. In the prophylaxis arm, patients were treated with ganciclovir for 30 days, then preemptive therapy was initiated with virologic monitoring for pp65 antigenemia. In the preemptive therapy arm, patients were treated on reaching 100,000 DNA copies/mL whole blood. An interim analysis showed that, although numbers of both infected and treated patients were comparable in the two arms, the median number of total days of antiviral therapy per patient (30 vs. 18, P<0.01) was significantly higher in the prophylaxis arm. No case of HCMV disease occurred in either arm. Therefore, the trial was interrupted and prophylaxis replaced with preemptive therapy alone. In parallel, the development of T-cell-mediated immune response was found to be comparable in both arms.

Background: Cytomegalovirus (CMV) infection in recipients of cardiac transplants is associated with higher rates of morbidity. A recent phase III trial showed highly significantly (P<0.001) lower CMV rates with the proliferation signal inhibitor everolimus compared to azathioprine (AZA). To better define this association, data on CMV risk factors were collected retrospectively and analyzed., Methods: Data on CMV risk factors from a multicenter phase III trial on de novo heart transplant recipients (n=634) receiving a triple immunosuppressive regimen randomized to everolimus 1.5 mg/day (group 1), everolimus 3 mg/day (group 2), or AZA (group 3) were merged with prospectively collected CMV-related outcome data and analyzed., Results: CMV-positive donors (D+) and CMV-negative recipients (R-) were evenly distributed across groups 1-3 at 36/209 (17.2%), 48/211 (22.7%), and 38/214 (17.8%), respectively. CMV prophylaxis had been given for a mean (SD) of 175 (127.8), 183 (137.1), and 177 (132.9) days, respectively. In the high-risk D+/R- subgroup with prophylaxis, the proportions of patients with CMV infection compared with group 3 (12/29 [41.4%]) were 3/25 (12.0%) in group 1 (P=0.031) and 6/36 (16.7%) in group 2 (P=0.049). In D+/R+ subgroups either with or without prophylaxis, the everolimus groups had less CMV disease (P<0.001). The incidence of CMV syndrome, organ involvement, and laboratory evidence was lower with everolimus use compared to AZA., Conclusions: Everolimus is associated with lower rates of CMV infection, syndrome, or organ involvement, suggesting an additional advantage from the use of everolimus in cardiac transplant recipients.

Background: Significant changes in coronary artery structure, including intimal thickening and vessel remodeling, occur early after cardiac transplantation. The degree to which these changes compromise coronary lumen dimensions, and the clinical factors that affect these changes, remain controversial., Methods: Thirty-eight adult cardiac transplant recipients underwent coronary angiography and volumetric intravascular ultrasound (IVUS) evaluation of the left anterior descending artery within 8 weeks of transplantation and at 1 year. Clinical parameters including donor and recipient characteristics, rejection episodes, and serology were prospectively recorded. Two-dimensional IVUS measurements and vessel, lumen and plaque volume were calculated at both time points and compared. Multivariate regression analysis was performed to reveal clinical predictors of change in coronary dimensions., Results: During the first year after transplantation, significant decreases in vessel size (negative remodeling) and lumen size were observed with significant increases in plaque burden based on IVUS analyses. Loss of lumen volume correlated significantly with the degree of negative remodeling (R=0.82, P<0.0001), but not with changes in plaque burden (R=0.08, P=0.64). Patients with the greatest increase in plaque volume had significantly less negative remodeling (R=0.53, P=0.0006). Transplant recipient cytomegalovirus (CMV) antibody seropositivity and lack of aggressive prophylaxis against CMV infection/reactivation were significant independent predictors of greater negative remodeling (P<0.01 and P=0.03, respectively) and greater lumen loss (P=0.02 and P=0.03, respectively)., Conclusion: Negative remodeling is primarily responsible for coronary artery lumen loss during the first year after cardiac transplantation. CMV seropositivity and lack of aggressive CMV prophylaxis correlate with increased negative remodeling, resulting in greater lumen loss.

Background: The role of valganciclovir in the prevention of cytomegalovirus (CMV) disease in high-risk seropositive transplant patients is not known., Methods: We prospectively followed 301 seropositive solid organ transplant recipients to assess the efficacy and safety of valganciclovir (VGCV) in the prevention of CMV disease in high-risk patients. Asymptomatic patients with an antigenemia test >or=25 positive cells/2x10(5) polymorphonuclear cells received valganciclovir 900 mg twice a day as preemptive therapy until resolution of antigenemia (minimum 14 days). Additionally, patients treated with antilymphocytic drugs for more than 6 days received prophylaxis with VGCV 900 mg once a day during 90 days. Mean follow-up was 14 months (range 6-20 months)., Results: Thirty-eight patients received VGCV; 24 as preemptive therapy and 14 due to the use of antilymphocytic drugs. No patient developed CMV disease during the follow-up. Viral load (antigenemia) decreased a mean of 78% from baseline after 7 days of VGCV therapy (P=0.024) and 98% at day 14 (P=0.029). Two patients showed a relapse of the antigenemia test >or=25 positive cells and were successfully treated with a repeated course of VGCV. Leukopenia (<2500/mm3) developed in 3/24 (12.5%) recipients in the preemptive therapy group and required to discontinuing the drug in one of them., Conclusions: VGCV is safe and highly efficacious in the prevention of CMV disease in high-risk seropositive organ transplant recipients.

Background: Up to date, 24 hands/thumbs have been transplanted in 18 patients. We herein report on cytomegalovirus (CMV) infection, disease, and the adopted treatment., Methods: Immunosuppression consisted of tacrolimus-based triple-drug therapy with antithymocyte globuline or CD25-receptor antagonist induction. Donor/recipient CMV match was negative/negative (n=8), negative/positive (n=3), positive/positive (n=3), positive/negative (n=3) and unknown in one case. Six patients (three +/-, two +/+, and one -/+) received gancyclovir i.v. followed by oral gancyclovir or valgancyclovir for prophylaxis., Results: Patient and graft survival at a mean follow-up of 42.9 months were 100% and 91%, respectively. Of all patients tested for CMV, 45.5% developed CMV infection or disease. Two patients that were given a CMV-positive graft showed very high viral loads (550 and 1200/200000 leukocytes) after transplantation. Gancyclovir treatment failed to permanently control CMV in 80% of the patients experiencing CMV infection. Those patients requiring more toxic second-line therapies (foscarnet/cidofovir) suffered from side effects such as nephrotoxicity, nausea, vomiting, and diarrhea., Conclusions: CMV infection/disease complicated the postoperative course after composite tissue allograft (CTA) transplantation in five of nine recipients challenged with the virus. The close time correlation suggests an association between virus replication and rejection in some cases. CMV represents the major infectious threat in CTA transplantation. Therefore, CMV-mismatch should be avoided and prophylaxis with valgancyclovir and anti-CMV hyperimmunoglobulin should be mandatory.

Primary cytomegalovirus (CMV) infection is a major cause of morbidity and mortality in recipients after solid organ transplantation (SOT). Widespread and prolonged use of antiviral drugs has changed the natural course of CMV disease by delaying its onset and causing drug resistance. CMV induces a strong cellular immune response, even in immunosuppressed patients, and has developed strategies to evade this immune surveillance. This review summarizes challenges in managing CMV infection in transplant recipients and highlights current insights in the cellular immune response against CMV.

Background: In transplantation settings, cytomegalovirus (CMV) infection is a common complication. CMV infection is associated with a higher incidence of graft rejection in solid organ transplantation and graft-versus-host disease in bone marrow transplantation. The underlying mechanism of this association could be the generation of CMV-specific CD8 T cells capable of cross-reacting with alloantigens present on graft and host, respectively., Methods: Whereas as to date, no direct ex vivo analysis can be performed of the CD8 T-cell repertoire directed at allo-major histocompatibility complex (MHC) class I molecules, virus-specific cells can be readily enumerated by use of MHC-peptide tetrameric complexes. In this study, the authors used this technique to analyze potential overlapping CD8 T-cell repertoires between self-MHC-viral peptide and allo-MHC complexes by stimulating CMV-specific CD8 T cells with alloantigens. RESULTS.: The authors found that CMV-specific CD8 T cells are activated and proliferate on stimulation with alloantigens., Conclusions: Although these cells are cytotoxic against CMV-peptide pulsed target cells, no cytotoxicity of CMV-specific cells to alloantigens could be detected, inferring that there are other mechanisms of graft damage by alloantigen-stimulated virus-specific CTL.

Background: The precise knowledge of cytomegalovirus (CMV) status is important in a variety of clinical settings such as transplantation or blood transfusion. There are, however, various situations where an immunoglobulin-based diagnostic approach has limitations., Methods: The CMV status of 388 individuals was determined by the analysis of both CMV-specific immunoglobulins and cellular immunity using a standard enzyme-linked immunosorbent assay and a rapid-flow cytometric approach, respectively., Results: In 386 of 388 individuals, both assays yielded concordant results in assigning the CMV status (294 positive and 92 negative). In 2 of 94 (2.1%) CMV immunoglobulin (Ig) G-negative individuals, CMV-specific CD4 T cells were detectable. Repeated testing of the index and follow-up samples yielded one positive and one marginally positive IgG titer., Conclusions: Both assays yielded highly concordant results. Thus, the T-cell-based approach may represent a reliable alternative for defining CMV status in any clinical situation where serologic testing is limited by borderline titers or by the presence of passively administered antibodies.

Background: Human cytomegalovirus (CMV) is a ubiquitous herpesvirus that is an important complication of bone marrow and allogeneic stem-cell transplant (HSCT). CD8 T-lymphocytes have an important role in immunity against CMV, but correlation between antigen-specific subpopulations of these cells and protection are still unclear., Methods: Flow analysis with fluorescently-conjugated human leukocyte antigen (HLA) class I tetramers (Tet) was used to investigate levels of CMV-specific CD8 T-lymphocytes in peripheral blood monocyte cells (PBMC) samples from HSCT donors and recipients and their ability to produce interferon (IFN)-gamma on stimulation with either CMV antigenic peptide or nonspecific mitogenic stimulation. Chromium release assays were used to evaluate ex vivo CMV-specific cytotoxicity associated with the PBMC samples., Results: Use of Tet in conjunction with fluorescently conjugated anti-T-cell receptor (TCR) beta-chain variable (Vbeta) monoclonal antibodies indicated that the Vbeta repertoires associated with Tet cells seen in two HSCT recipients were similar to the Vbeta repertoires of the Tet cells in their HSCT donors. Significant ex vivo cytotoxicity against peptide-loaded targets was measured from several recipient samples after transplant. However, PBMC from the HSCT donors, even when containing populations of CMV-specific Tet cells capable of secreting IFN-gamma in response to peptide stimulation, possessed no ex vivo CMV-specific cytotoxicity., Conclusions: We hypothesize that in the setting of the reconstituting immune system of HSCT recipients, CMV reactivation may stimulate a functional change in CMV-specific CD8 T-lymphocytes, rendering them able to directly lyse target cells presenting CMV antigens without in vitro stimulation. These findings have important implications for development of vaccines designed to induce protective cellular immunity to CMV in transplant recipients.

Background: Cytomegalovirus (CMV) infection is a significant cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). Recipients of T-cell-depleted (TCD) transplants may be more susceptible to CMV infection as a result of the reduction in transferred T cell immunity. We sought to determine the effect of prior donor and patient CMV exposure on the incidence of CMV infection after TCD allogeneic HSCT., Methods: We retrospectively examined CMV antigen testing results in all patients who had undergone CD6+ TCD related and unrelated donor allogeneic HSCT at our institution from 1996 to 1999. All 124 patients who had documented donor and recipient CMV serologies pretransplant and had undergone CMV antigen testing before day +100 posttransplant were included in the analysis., Results: Forty-one percent of seropositive recipients and 1% of seronegative recipients developed evidence of CMV reactivation (odds ratio 54.1, 95% confidence interval [CI] 6.9-424.1, P<0.001). Prior donor CMV exposure did not place seronegative recipients at increased risk of CMV conversion. Multivariable analysis indicated that prior donor CMV exposure significantly reduced the risk of CMV reactivation in seropositive recipients by 81% (odds ratio 0.19, 95% CI 0.04-0.91, P=0.04). Grades II to IV acute graft-versus-host disease (GVHD) was associated with CMV conversion (P=0.04) when seropositive recipients underwent HSCT from CMV-negative donors, but not when the donor was CMV-seropositive (P=0.54)., Conclusions: The CMV serology status of the recipient, rather than the donor, was the primary determinant of risk for CMV conversion after TCD allogeneic HSCT. Despite CD6+ T-cell depletion, immunity against CMV seemed to be transferred with the donor graft and protected seropositive HSCT recipients from CMV reactivation.