Risk Of Cytomegalovirus Infection Research Articles

502: CMVIG Decreases the Risk of Cytomegalovirus Infection but Not Disease after Pediatric Lung Transplantation

A retrospective review of pediatric lung transplant recipients at fourteen sites in North America and Europe was conducted to evaluate the impact of adding cytomegalovirus immunoglobulin (CMVIG) prophylaxis to at least three weeks of intravenous ganciclovir in pediatric lung transplant recipients. Data were recorded for the first year after transplantation. Associations between time to CMV and risk factors, including CMVIG use, were assessed by multivariable Cox proportional hazards models. Of 599 subjects whose charts were reviewed, 329 received at least three weeks of ganciclovir with 62 (19%) receiving CMVIG. CMVIG was administered more frequently with CMV donor-positive/recipient-negative (D+/R−) serostatus (p<0.05). In multivariable models, subjects who did not receive CMVIG as part of their prophylaxis were three times more likely to develop CMV infection (HR 3.4; 95% CI 1.2, 9.5) independent of CMV serostatus. However, CMVIG administration was not associated with decreased risk of episodes of CMV disease. Receipt of CMVIG was not associated with decreased risks of post-transplant morbidities (acute rejection, respiratory viral infection or early bronchiolitis obliterans) or morbidity within the first year after pediatric lung transplantation. The use of CMVIG in addition to antiviral prophylaxis in pediatric lung transplantation requires further evaluation in pediatric lung transplant recipients.

Incidence and Risk of Cytomegalovirus Infection during Pregnancy in an Urban Area of Northern Italy

The fetal consequences of CMV infection make it one of the most serious infections contracted during pregnancy, but the scientific community is divided over the proposed implementation of preventive screening for anti-CMV antibodies. The aim of this study was to assess the incidence and risk of infection during pregnancy in 2817 women who underwent anti-CMV IgG and IgM antibody screening during the period 2005–2007. The prevalence of anti-CMV IgG antibodies was 68.3% (95% CI: 66.6–70.0); the seroconversion rate in the 892 seronegative women was 0.32%; the results of IgG avidity testing revealed an cumulative incidence of 1.4% (95% CI: 0.97–1.83), density incidence of 0.8% (as cases/pregnant woman-trimester) (95% CI: 0.47–1.13), and a risk of infection of 0.5% (95% CI: 0.24–0.76). The screening identified 13 cases of primary infection (84.6% of which occurred in the first trimester of pregnancy). The possibility to identify these cases and consequently to plan appropriate interventions, supports the use of screening during pregnancy, especially in the first trimester when the risk of infection is greater.

Cytomegalovirus infection in critically ill patients: a systematic review

IntroductionThe precise role of cytomegalovirus (CMV) infection in contributing to outcomes in critically ill immunocompetent patients has not been fully defined.MethodsStudies in which critically ill immunocompetent adults were monitored for CMV infection in the intensive care unit (ICU) were reviewed.ResultsCMV infection occurs in 0 to 36% of critically ill patients, mostly between 4 and 12 days after ICU admission. Potential risk factors for CMV infection include sepsis, requirement of mechanical ventilation, and transfusions. Prolonged mechanical ventilation (21 to 39 days vs. 13 to 24 days) and duration of ICU stay (33 to 69 days vs. 22 to 48 days) correlated significantly with a higher risk of CMV infection. Mortality rates in patients with CMV infection were higher in some but not all studies. Whether CMV produces febrile syndrome or end-organ disease directly in these patients is not known.ConclusionsCMV infection frequently occurs in critically ill immunocompetent patients and may be associated with poor outcomes. Further studies are warranted to identify subsets of patients who are likely to develop CMV infection and to determine the impact of antiviral agents on clinically meaningful outcomes in these patients.

Natural Killer Cell Receptor Repertoire and Their Ligands, and the Risk of CMV Infection After Kidney Transplantation

Cytomegalovirus (CMV) infection is the most common viral complication after solid organ transplantation (SOT). Whilst current immunosuppression is known to impair antiviral-specific T-cell immunity in SOT, a potential role for natural killer (NK) cells not affected by immunosuppressive therapy remains to be determined. To address this, we compared the genotype of the NK immunoglobulin-like receptor (KIR) genes and their HLA cognate ligands to the rate of CMV infection in 196 kidney transplant recipients. We have shown that the absence of the HLA-C ligand for inhibitory KIR and the presence of activating KIR genes in the recipients were both associated with a lower rate of CMV infection after transplantation. In a cohort of 17 recipients with acute CMV infection, NK cells were phenotyped over a period of time after diagnosis by their expression profile of C-type lectin receptors and capacity to secrete IFN-gamma. The increased expression of the activating C-type lectin receptors NKG2C and NKG2D was paralleled by the decreased IFN-gamma secretion during the early phase of CMV infection. In conclusion, our findings suggest that KIR/HLA genotype and expression of NKG2C and NKG2D might play a significant role in regulating NK cell function and anti-CMV immunity after kidney transplantation.

Reduced Risk of Cytomegalovirus Infection in Solid Organ Transplant Recipients Treated With Sirolimus: A Pooled Analysis of Clinical Trials

Introduction Cytomegalovirus (CMV) is an opportunistic infection that causes substantial morbidity and mortality in transplant recipients. This pooled analysis of Wyeth clinical trials explored the incidence of CMV infection in solid organ transplant recipients treated with sirolimus versus comparator immunosuppressant drugs. Methods Wyeth-conducted, multicenter, randomized, comparative trials with at least one non-sirolimus-containing arm and at least 6 months' complete data were included. Cases of CMV were investigator-identified. The occurrence of CMV in sirolimus-treated patients was assessed versus all other comparator agents, versus antimetabolite agents, and versus calcineurin inhibitors. Results Nine trials in recipients of renal, liver, and cardiac transplants met the inclusion criteria; eight enrolled de novo allograft recipients, and one was a conversion trial. The primary pooled analysis revealed an odd ratio for CMV infection of 0.64 (95% confidence interval [CI] 0.42 to 1.0, P = .047) on sirolimus versus comparator immunosuppressant drugs. The subanalysis of sirolimus versus antimetabolites showed an odds ratio for CMV of 0.39 (95% CI 0.19 to 0.81, P = .012), and for sirolimus versus calcineurin inhibitors the odds ratio was 0.58 (95% CI 0.34 to 1.01, P = .054). Conclusion This pooled analysis demonstrated a reduced risk of CMV infection among sirolimus-treated patients as compared to those receiving alternative forms of immunosuppression in Wyeth-sponsored clinical trials in solid organ transplantation. This risk reduction persisted in subgroup analyses stratified by class of comparator treatment.

Human CMV vaccine trials: What if CMV caused a rash?

There are no apparent biologic obstacles to immunization against fetal/placental infection with cytomegalovirus (CMV), and vaccine candidates have been developed. The major obstacles for a human CMV vaccine are difficulties associated with the design and execution of efficacy trials. These trials will be prolonged with difficulties in recruiting subjects, and hampered by several factors: First is a lack of public awareness of CMV, making recruitment into vaccine trials difficult. Second is that trials using fetal infection as an endpoint will be prolonged since vaccine administration must occur preconception. Third, behavioral changes by subjects will affect infection rates, and controls for behavioral changes will have to be in place in any clinical trial. Fourth, not all women are at equal risk for CMV infections. High risk women may become infected by contact with young children or via sexual activity. Thus, the mode of acquisition may be a confounding variable in vaccine efficacy trials. In spite of these potential obstacles, successful evaluation of CMV vaccines is possible and likely when considered against similar obstacles encountered by several other recently licensed vaccines.

Clinicopathologic characteristics of clinically relevant cytomegalovirus infection in inflammatory bowel disease

In this study we aimed to identify clinically relevant patterns of cytomegalovirus (CMV) infection in inflammatory bowel disease. Twenty-two patients with severe ulcerative colitis (UC), 12 with moderate UC, and 16 with Crohn's disease were studied retrospectively. We confirmed CMV infection immunohistochemically. The patients were classified into three groups according to the density of CMV-infected cells. Clinicopathologic features were compared between the groups. Dense CMV infection was found only in five patients with severe UC. Scattered CMV infection was found in nine patients with severe UC, three with moderate UC, and one patient with Crohn's disease, and in three controls (normal mucosa from early colorectal cancer specimens). For patients with severe UC, severity of CMV infection tended to correlate with older age and more rapid deterioration, including toxic megacolon and panperitonitis. The dense CMV group took significantly higher final daily doses of steroids before the operation, and showed steroid resistance. The frequency of emergency surgery was higher and postoperative hospital stay was significantly longer in the dense CMV group. No significant differences were observed in sex, disease duration, steroid administration (total amount or duration), or frequencies of other therapies among the three groups. Immunohistochemically, CMV positivity in endothelial cells around the ulcer base was a significant feature in dense CMV infection, compared with scattered CMV infection. Older patients with severe steroid-resistant UC may be at particular risk for CMV infection. Dense CMV infection, especially when it occurs predominantly in endothelial cells, may be a useful marker for clinically relevant CMV infection.

Cytomegalovirus Infection after Allogeneic Transplantation: Comparison of Cord Blood with Peripheral Blood and Marrow Graft Sources

Cytomegalovirus (CMV) infection is an important complication following allogeneic hematopoietic stem cell transplant (HSCT), but the natural history in the cord blood setting has not been well studied. We assessed CMV infection episodes in 753 consecutive allogeneic HSCT recipients at the University of Minnesota between January 1, 1998 and December 31, 2003. The 6-month cumulative incidence of viremia/antigenemia was 22% by day +182: 21% (95% confidence interval 16%-26%) in cord blood recipients (UCB), 24% (20%-28%) in marrow (BM), and 22% (16%-28%) using peripheral blood grafts (PBSC). CMV disease incidence was 6% (2%-10%) in UCB, 8% (5%-11%) in BM, and 9% (6%-12%) in PBSC. In multivariate analysis, CMV infection (viremia/antigenemia and disease) was significantly more likely in patients who were seropositive to CMV, in those with acute graft versus host disease, and in those receiving T cell-depleted grafts. Graft source did not independently contribute to the risk of CMV infection and did not impact survival after CMV infection. These data confirm that recipient CMV serostatus remains the dominant risk factor for CMV infection. Recipients of UCB have similar risks of CMV infection, responses to antiviral therapy, and survival following CMV infection as recipients of either marrow or PBSC.

Sirolimus exposure during the early post‐transplant period reduces the risk of CMV infection relative to tacrolimus in renal allograft recipients

There are limited data regarding the role of individual maintenance immunosuppressive agents in the development of cytomegalovirus (CMV) infection. We examined the association between exposure to sirolimus (SRL) and risk of CMV infection after kidney transplantation when compared with tacrolimus (TCL). This is a retrospective observational study of adult renal allograft recipients transplanted between 2001 and 2005 at our center. Patients received anti-lymphocyte antibody induction, and mycophenolate mofetil with either SRL or TCL +/- prednisone. D+/R- patients received valganciclovir 900 mg/d and CMV + patients 450 mg/d for three months. CMV infection was diagnosed with pp65 antigenemia testing prompted by clinical suspicion. A total of 14 Cases with CMV infection and 129 Controls were identified for primary analysis, and 11 D+/R- Cases and 19 D+/R- Controls for secondary analysis. The groups were comparable in both analyses, except for D+/R- serostatus in the primary analysis. All 14 Cases were on TCL for at least three months prior to diagnosis of CMV infection. In the primary analysis, zero Cases, but 30.2% and 34.9% of Controls (p = 0.009 and 0.004), and in secondary analysis, zero Cases, but 31.6% and 42.1% of Controls (p = 0.046 and 0.013), were on SRL at one and three months, respectively. In the primary analysis, zero Cases vs. 45 Controls (p = 0.004), and in secondary analysis, zero Cases vs. eight Controls (p = 0.013), were on SRL for at least three months early post-transplantation. These findings suggest that SRL as a component of a multidrug immunosuppressive regimen decreases the risk of CMV infection after kidney transplantation when compared with TCL.

Surveillance of cytomegalovirus (CMV) DNAemia in pediatric allogeneic stem cell transplantation: incidence and outcome of CMV infection and disease

Cytomegalovirus (CMV) remains a serious problem after hematopoietic stem cell transplantation (HSCT). To investigate the incidence of CMV infection and outcome we retrospectively analyzed 70 consecutive pediatric allogeneic HSCTs monitored by CMV polymerase chain reaction (PCR), with at least 1-year follow-up or until death. All patients at risk for CMV infection (CMV-seropositive patients and CMV-seronegative recipients transplanted from CMV-seropositive donors) received hyperimmune anti-CMV globulins whereas in the group of HSCT patients with both donor and recipient CMV negativity, polyvalent immunoglobulins were given, both at a dose of 400 mg/kg. All patients received acyclovir at prophylactic doses for at least 6 months. Patients were monitored twice a week by CMV PCR. Patients with 2 positive results for CMV DNAemia received ganciclovir for 14 days and continued until 2 consecutive negative results were obtained. The incidence of CMV DNAemia was 12.8% (9/70) in the whole group, with significant higher risk for patients with CMV-seropositive recipient status, 8 out of 22 (36%), vs. patients with seronegative status, 1 out of 48 (2%) (P=0.0002). Three out of 9 patients with DNAemia developed CMV disease despite adequate preemptive treatment. The transplant-related mortality was higher in the CMV-seropositive recipient group (P=0.05). Age, use of hyperimmune anti-CMV globulins at a high dose, and the low incidence of graft-versus-host disease might be contributing factors to this low incidence.

Patients at high risk for CMV infection and disease show delayed CD8+ T-cell immune recovery after allogeneic stem cell transplantation

Human cytomegalovirus (CMV) is a major cause of death after transplantation. The frequency of pp65-specific T cells was examined in 38 HLA-A2+ stem cell recipients during the first year after transplantation. Patients were divided into four groups based on donor/recipient serostatus: d+/r+ (n=17), d+/r- (n=7), d-/r+ (n=9) and d-/r- (n=5). Peripheral blood mononuclear cells were stimulated with the CMVpp65 peptide NLVPMVATV, and the specific T-cell frequency was assessed by interferon gamma (IFN-gamma) ELISPOT assay. Responding T cells were characterized by flow cytometry revealing a terminal differentiated effector phenotype. Surveillance of CMV infection was carried out by real-time polymerase chain reaction (n=26) or immunofluorescence (n=12). Infection was present in 7/9 d-/r+ high-risk patients, and CMV disease occurred exclusively in this group with delayed or absent virus-specific T-cell recovery. In contrast, 16/24 intermediate-risk patients showed CMV-specific T cells. Our data suggest that CMV infection and disease rates are elevated in high-risk patients with delayed CMV-specific T-cell immune reconstitution and lower in those with early recovery of T-cell immunity. We recommend preferring CMV seropositive donors for CMV seropositive recipients, as this should lead to durable CMV-specific T-cell responses soon after transplantation with consecutive protection from CMV disease.

The impact of donor cytokine gene polymorphisms on the incidence of cytomegalovirus infection after kidney transplantation

Cytomegalovirus (CMV) seronegative recipients of kidneys from CMV seropositive donors are at a high risk of CMV infection after transplantation since viruses in the allograft may reactivate in patients without prior immunity. We hypothesized that the genetic background of the graft has an influence on the incidence of infection. Effects of IL10, IL6 and IFNG gene polymorphisms, known to affect CMV infectivity, were investigated in 71 CMV seronegative recipients of grafts from CMV seropositive cadaver donors. Donor IL10(− 1082 AA) genotype reduced the incidence of CMV infection ( p = 0.031) and CMV episodes in these patients tended to occur later (AA: median 83 days, AG/GG: median 45 days, p = 0.072). In multivariate analysis, other explaining factors than the donor IL10(− 1082 AA) genotype alone did not improve Cox hazard model (HR = 0.3, 95% CI = 0.09–0.96, p = 0.043). Recipient polymorphisms did not reduce the incidence of CMV infection. We conclude that donor IL10 gene polymorphisms may influence the likelihood of CMV infection in the high risk patients investigated.

Cytomegalovirus Prophylaxis With Intravenous Polyvalent Immunoglobulin in High-Risk Renal Transplant Recipients

Cytomegalovirus (CMV) seronegative renal allograft recipients (R−), particularly those with a graft from a CMV-seropositive donor (D+), are at high risk for primary CMV infection. CMV resistance to antiviral oral therapy is an emerging problem in renal transplantation, prompting development of new prophylactic strategies. We retrospectively studied the 1-year posttransplantation incidence of CMV infection in high-risk renal transplant recipients, in whom polyvalent intravenous immunoglobulins (IVIg) were used as prophylaxis. Forty R− patients received immunoprophylaxis by polyvalent IVIg (0.25 g/kg weekly for 8 weeks, starting on the operative day). CMV serological tests remained negative in eight patients (20%). Eight patients (20%) had asymptomatic CMV infection while 24 (60%) developed CMV syndrome and were treated with gancyclovir (10 mg/kg/day intravenously for 3 weeks). None had CMV disease or opportunistic infection. Six patients (15%) had biopsy-proven acute rejection, which followed CMV syndrome in three cases. One-year renal allograft and patient survivals were 95% and 97.5%, respectively. Mean serum creatinine level was 124 ± 33 μmol/L at 1 year. Clinical tolerance of IVIg was excellent, without any episode of acute renal failure. Polyvalent IVIg provides effective prophylaxis in renal transplant recipients at high risk for CMV infection and is associated with excellent 1-year allograft survival. Because of their immunomodulatory functions, IVIg may have a beneficial effect on the incidence of acute and chronic rejection and allograft survival. A randomized prospective study is required to evaluate long-term effects of CMV prophylaxis with polyvalent IVIg compared to antiviral agents in renal transplant recipients.

Cytomegalovirus as an occupational risk in daycare educators.

Cytomegalovirus (CMV) infection continues to be an important occupational risk in the daycare setting. A comprehensive update of scientific evidence is timely to inform and promote appropriate preventive measures. A review of the literature was conducted to examine the evidence for an occupational risk of CMV infection in daycare educators. Sources included Medline, government documents and additional references from published bibliographies. The key words used for searches were 'child day care centres' or 'nurseries' and 'cytomegalovirus' or 'cytomegalovirus infection'. EIGHT CMV SEROPREVALENCE STUDIES ON DAYCARE EDUCATORS IN INDUSTRIALIZED COUNTRIES WERE FOUND: four in the United States, three in Canada and one in Italy. Risk factors for seropositivity were older age, nonwhite race, foreign birth, birth in a low- or middle-income country, diaper changing, having children at home, and a child to educator ratio greater than 6:1 in children 18 to 35 months of age. Risk factors for seroconversion were younger age and working with young children. These studies suggest that daycare centres may be a high-risk setting for CMV infection. Recommendations to prevent CMV infection in this setting include handwashing, selective serological screening, avoiding work with younger children if pregnant and, in some cases, preventive leave from work. Evaluation and expert opinion of the effectiveness of various preventive options for CMV acquisition are needed to ensure that recommendations are evidence-based.

Predictive Factors for Cytomegalovirus Infection After Orthotopic Liver Transplantation Using an Ultrasensitive Polymerase Chain Reaction Assay

The predictive factors for cytomegalovirus (CMV) infection in de novo liver transplant patients were determined at 3 months posttransplantation. We included all consecutive patients except those who died or who had lost their graft within 1 month posttransplant. We recorded both donor (D) and recipient (R) data. Immunosuppression utilized tacrolimus, steroids, with or without mycophenolate mofetil, and/or induction therapy with anti-CD25 monoclonal antibodies. CMV prophylaxis was administered only to those at high risk of CMV infection, namely, D+/R− patients. These cases received intravenous ganciclovir at 500 mg/d for the first 2 weeks followed by oral ganciclovir at 500 mg for the following 3 months. The median time to CMV infection was 1 month. The significant predictive factors for CMV infection were D/R CMV status, ( P = .002): D+/R+ versus other patients ( P = .01), D−/R− versus other patients ( P = .002), D+ versus D− ( P = .009). In addition infection was associated with the original liver disease (hepatitis C virus infection or alcohol-related cirrhosis; P = .03), R+ vs. R− ( P = .03), donor age (<45 or >45 years; P = .01), lymphocyte count at M2 (< or >1300/mm 3; P = .02), hemoglobin levels at 1 and 3 months, and platelet and white blood cell counts at day 7. The independent predictive factors were recipient CMV sero-status (R+ vs R−; odds ratio = 10.2), donor age >45 years (odds ratio = 11.4) and lymphocyte count at M2 <1300/mm 3 (odds ratio = 7.33). This study showed that the major factors associated with CMV infection were recipient CMV status, donor age, and lymphocyte count.

Risk Factors Associated With Cytomegalovirus Infection in Orthotopic Liver Transplant Patients

Our objective was to investigate the potential risk factors associated with cytomegalovirus (CMV) infection. Patients and Methods From January 1999 to December 2001, 163 liver transplantations were performed in 154 patients. The study inclusion criteria were absence of retransplantation and survival of more than 6 months. One hundred fifteen patients met the inclusion criteria. We determined variables such as age, gender, and number of hemecomponents as well as serum IgG CMV status of donors and recipients. We recorded the immunosuppression used by each patient. CMV infection was detected by positive antigenemia. Results Recipient mean age was 50 years. The etiology of cirrhosis was viral ( n = 57; 49.6%), alcoholic ( n = 20; 17.4%), virus and alcohol ( n = 15; 13.0%), cryptogenic ( n = 14; 12.2%), or other causes ( n = 9; 7.8%). CMV infection was positive in 75 patients (65.8%). There was no relation between infection and age, gender, or CMV IgG donor recipient status, or the number of hemecomponent units. The risk was 3.8-fold higher for patients receiving a three-drug compared with a two-drug regimen. When cyclosporine was used instead of tacrolimus, the risk of CMV infection was 4.3-fold higher. Logistic regression analysis revealed cyclosporine (OD=5.8) and a three-drug regimen (OD=6.7) to have stronger associations with CMV infection. Conclusion The use of cyclosporine (OD=5.8) and a three-drug regimen (OD=6.7) are risk factors for CMV infection.

24-Week Oral Ganciclovir Prophylaxis in Kidney Recipients Is Associated with Reduced Symptomatic Cytomegalovirus Disease Compared to a 12-Week Course

Cytomegalovirus (CMV) infection is associated with reduced graft and patient survival among kidney recipients. The highest risk of CMV infection occurs in CMV-naive recipients of kidneys from seropositive donors (D+/R-). Optimal CMV prophylaxis is not established. This prospective cohort study compared the safety and efficacy of prophylaxis with 12 versus 24 weeks of oral ganciclovir. We prospectively administered 24 weeks ganciclovir to 31 D+/R- recipients. The control group comprised 39 patients transplanted in the immediately preceding era who received a 12-week course of prophylaxis. All patients received cytolytic therapy within the first month, as well as a tacrolimus-based maintenance regimen. A logistic regression model was fit to examine the relationship between 24 weeks ganciclovir prophylaxis and the odds of developing CMV infection by one year. Groups were matched, though the 12-week cohort had more delayed graft function than their 24-week counterparts (45% vs. 29%, P=0.04). CMV infection occurred in 31% and 7% patients in the 12-week and 24-week groups, respectively (P<or=0.01). Mean time to development of CMV infection was 17.5+/-2.2 weeks in the 12-week, and 22.0+/-10.0 weeks in the 24-week, groups (P=0.79). Both 24 weeks ganciclovir prophylaxis (O.R. 0.15, 95% C.I. 0.03-0.91, P=0.04) and delayed graft function (O.R. 4.49, 95% C.I. 1.67-36.56, P<0.01) were associated with CMV infection. Oral ganciclovir prophylaxis for 24 weeks is associated with a lower risk of symptomatic CMV disease than a 12-week course in high risk D+/R- kidney recipients.

Choice of Antibody Immunotherapy Influences Cytomegalovirus Viremia in Simultaneous Pancreas-Kidney Transplant Recipients

Simultaneous pancreas-kidney (SPK) transplantation in type 1 diabetic patients requires immunotherapy against allo- and autoreactive T-cells. Cytomegalovirus (CMV) infection is a major cause for morbidity after transplantation and is possibly related to recurrent autoimmunity. In this study, we assessed the pattern of CMV viremia in SPK transplant recipients receiving either antithymocyte globulin (ATG) or anti-CD25 (daclizumab) immunosuppressive induction therapy. We evaluated 36 SPK transplant recipients from a randomized cohort that received either ATG or daclizumab as induction therapy. Patients at risk for CMV infection received oral prophylactic ganciclovir therapy. The CMV DNA level in plasma was measured for at least 180 days using a quantitative real-time PCR. Recipient peripheral blood mononuclear cells were cross-sectionally HLA tetramer-stained for CMV-specific CD8(+) T-cells. Positive CMV serostatus in donors was correlated with a higher incidence of CMV viremia than negative serostatus. In patients at risk, daclizumab induction therapy significantly prolonged CMV-free survival. CMV viremia occurred earlier and was more severe in patients with rejection episodes than in patients without rejection episodes. CMV-specific CD8(+) T-cell counts were significantly lower in patients developing CMV viremia than in those who did not. Despite their comparable immunosuppressive potential, daclizumab is safer than ATG regarding CMV infection risk in SPK transplantation. ATG-treated rejection episodes are associated with earlier and more severe infection. Furthermore, high CMV-specific tetramer counts reflect antiviral immunity rather than concurrent viremia because they imply low viremic activity. These findings may prove valuable in the discussion on both safety of induction therapy and recurrent autoimmunity in SPK and islet transplantation.

56 Changing patterns in the risk for Cytomegalovirus infection and disease and treatment-related outcomes in the Era of preemptive antiviral therapy

56 Changing patterns in the risk for Cytomegalovirus infection and disease and treatment-related outcomes in the Era of preemptive antiviral therapy

Artificial Antigen-Presenting Cells Permit Selective In Vitro Generation of CMV-Specific T-Cells of Desired HLA Allelic Restriction for Adoptive Immunotherapy in Recipients of HLA Disparate Allografts.

Cytomegalovirus (CMV) infections remain a major cause of morbidity and mortality following allogeneic hematopoietic cell transplantation. For recipients of HLA haplotype disparate grafts, the risk of CMV infection is especially high and extends late into the post-transplant period. Early clinical trials indicate that adoptive transfer of ex vivo generated CMV-specific T-cells from the donor can be effective in the treatment and prevention of such infections. However, because seropositive donor T-cells sensitized with autologous infected or antigen loaded APCs regularly exhibit a repertoire of CMV-specific T-cells restricted by one or two immunodominant HLA alleles, such T-cells will only be effective if these immunodominant alleles are shared by the infected host. For example, among donors inheriting HLA-B*0702, CD8+ T-cell responses to CMV-pp65 peptides are usually, and often exclusively, restricted by this allele.To address this limitation, we tested whether artificial antigen-presenting cells, consisting of murine 3T3 cells transduced to express human B7.1, LFA1, ICAM1, β 2M and HLA-A*0201 alpha chain (Papanicolaou et al., Blood 2003), could be used to generate CMV-specific T-cells restricted by this allele in a series of normal donors inheriting HLA-A*A0201 and HLA-B*0702. Accordingly, T-cells were sensitized in vitro with either autologous monocyte-derived DCs or AAPCs expressing HLA-A*A0201, each loaded with a pool of 138 overlapping pentadecapeptides spanning the CMV-pp65 protein. Thereafter, specificity of responding T-cells was identified by mapping epitopes using an intersecting matrix of peptide subpools and measuring T-cells producing IFN-γ following secondary restimulation. HLA restriction was identified by analysis of T-cell cytotoxic responses against panels of EBV BLCL sharing single HLA alleles with the donor and loaded with the targeted peptide. Findings were confirmed by quantitation of T-cell binding tetramers containing targeted epitopes bound to either HLA-A*0201 or B*0702. In each of the donors, sensitization with DCs loaded with the peptide pool resulted in the generation of CMV-pp65-specific T-cells specific for epitopes predominantly or exclusively presented by HLA-B*0702. In contrast, sensitization with peptide pool loaded AAPC led to the generation of high numbers of T-cells recognizing separate CMV-pp65 epitopes in the context of HLA-A*A0201. These HLA-A*0201-restricted T-cells were also able to lyse peptide-loaded BLCLs or PBMCs expressing HLA-A*0201. Taken together, these studies demonstrate that AAPCs expressing single HLA alleles can be used to generate fully functional T-cells specific for epitopes presented by subdominant HLA alleles. This strategy may thus permit generation of virus-specific T-cells of desired HLA-restriction for adoptive immunotherapy in HLA-disparate transplant recipients.