Latent Cytomegalovirus Infection Research Articles

Antiviral Therapy Can Reverse the Development of Immune Senescence in Elderly Mice with Latent Cytomegalovirus Infection

Cytomegalovirus (CMV) infection leads to the development of adaptive and humoral immune responses that are among the largest for any pathogen, and intriguingly, the magnitude of the immune response increases with age, a phenomenon termed "memory inflation." Elevated CMV-specific immunity has been correlated with an increased mortality rate in elderly individuals and with impaired vaccination responses. The latent phase of CMV infection is characterized by intermittent episodes of subclinical viral reactivation and the production of immunogenic transcripts that may maintain memory inflation of virus-specific cytotoxic lymphocytes. However, the relative importance of CMV reactivation in the development of memory inflation is uncertain, as is the potential for antiviral treatment to reverse this effect. Here, we administered valaciclovir for up to 12 months in mice with established murine CMV (MCMV) infection. Treatment reduced the magnitude of the MCMV-specific CD8(+) T-lymphocyte response by 80%, and the residual MCMV tetramer-specific lymphocytes exhibited a less differentiated phenotype. In addition, latent MCMV infection suppressed the proportion of naïve CD8(+) T cells by 60% compared to antiviral-treated mice or MCMV-negative animals. Furthermore, treatment led to a reduction in influenza A viral loads following a challenge in elderly MCMV-infected animals and also reduced the differentiation of influenza virus-specific cytotoxic lymphocytes. These observations demonstrate that MCMV-specific memory inflation is maintained by viral replication and that therapeutic intervention could lead to improved immune function.

153. Latent CMV infection accounts for the age-related differences in the mobilization and egress of senescent CD8+ T-cells in response to acute exercise

Acute-exercise facilitates the trafficking of peripheral blood CD8+ T-cells, preferentially mobilizing effector-memory and senescent cells. Although this response appears to be greater in older subjects, it is also amplified in young people with latent cytomegalovirus (CMV) infection. As CMV prevalence increases with age, these age-related differences in the CD8+ T-cell response to exercise may be due to CMV. Sixteen young (Y, 20–35 years) and 16 older (O, 50–64 years) subjects cycled for 30-min at 80% peak-power. Eight participants in both Y and O were seropositive (pos) for CMV. Blood lymphocytes isolated before, immediately after and 1 h after exercise were analyzed for numbers and proportions of CD3+/CD8+ T-cells and, naive (KLRG1−/CD28+), memory (KLRG1+/CD28+) and senescent (KLRG1+/CD28−) subsets. Exercise increased numbers of senescent, memory and naive CD8+ T-cells, followed by an egress 1 h later. Age (+32%), CMV (+24%), and age-×-CMV interaction effects were found for proportions of senescent CD8+ T-cells. For senescent cells, CMVpos had an amplified ingress (61 vs 29%) and egress (66 vs 30%) compared to CMVneg, while Yneg and Oneg did not differ for ingress (29 vs 29%) or egress (31 vs 29%). However, this response was greater in Opos than Ypos for ingress (66 vs 55%) and egress (82 vs 50%). In conclusion, these data indicate that latent CMV infection may account for the apparent age-related effects on the CD8+ T-cell response to acute exercise.

Immune Senescence: Relative Contributions of Age and Cytomegalovirus Infection

Immune senescence, defined as the age-associated dysregulation and dysfunction of the immune system, is characterised by impaired protective immunity and decreased efficacy of vaccines. Recent clinical, epidemiological and immunological studies suggest that Cytomegalovirus (CMV) infection may be associated with accelerated immune senescence, possibly by restricting the naïve T cell repertoire. However, direct evidence whether and how CMV-infection is implicated in immune senescence is still lacking. In this study, we have investigated whether latent mouse CMV (MCMV) infection with or without thymectomy (Tx) alters antiviral immunity of young and aged mice. After infection with lymphocytic choriomeningitis virus (LCMV) or Vaccinia virus, specific antiviral T cell responses were significantly reduced in old, old MCMV-infected and/or Tx mice compared to young mice. Importantly, control of LCMV replication was more profoundly impaired in aged MCMV-infected mice compared to age-matched MCMV-naïve or young mice. In addition, latent MCMV infection was associated with slightly reduced vaccination efficacy in old Tx mice. In contrast to the prevailing hypothesis of a CMV-mediated restriction of the naïve T cell repertoire, we found similar naïve T cell numbers in MCMV-infected and non-infected mice, whereas ageing and Tx clearly reduced the naïve T cell pool. Instead, MCMV-infection expanded the total CD8+ T cell pool by a massive accumulation of effector memory T cells. Based on these results, we propose a new model of increased competition between CMV-specific memory T cells and any ‘de novo’ immune response in aged individuals. In summary, our results directly demonstrate in a mouse model that latent CMV-infection impairs immunity in old age and propagates immune senescence.

Cytomegalovirus Infection Impairs Immune Responses and Accentuates T-cell Pool Changes Observed in Mice with Aging

Prominent immune alterations associated with aging include the loss of naïve T-cell numbers, diversity and function. While genetic contributors and mechanistic details in the aging process have been addressed in multiple studies, the role of environmental agents in immune aging remains incompletely understood. From the standpoint of environmental infectious agents, latent cytomegalovirus (CMV) infection has been associated with an immune risk profile in the elderly humans, yet the cause-effect relationship of this association remains unclear. Here we present direct experimental evidence that mouse CMV (MCMV) infection results in select T-cell subset changes associated with immune aging, namely the increase of relative and absolute counts of CD8 T-cells in the blood, with a decreased representation of the naïve and the increased representation of the effector memory blood CD8 T-cells. Moreover, MCMV infection resulted in significantly weaker CD8 responses to superinfection with Influenza, Human Herpes Virus I or West-Nile-Virus, even 16 months following MCMV infection. These irreversible losses in T-cell function could not be observed in uninfected or in vaccinia virus-infected controls and were not due to the immune-evasive action of MCMV genes. Rather, the CD8 activation in draining lymph nodes upon viral challenge was decreased in MCMV infected mice and the immune response correlated directly to the frequency of the naïve and inversely to that of the effector cells in the blood CD8 pool. Therefore, latent MCMV infection resulted in pronounced changes of the T-cell compartment consistent with impaired naïve T-cell function.

Expansions of CD4+CD28– and CD8+CD28– T cells in Granulomatosis with Polyangiitis and Microscopic Polyangiitis Are Associated with Cytomegalovirus Infection But Not with Disease Activity

T helper cells lacking CD28 (CD4+CD28-) have been implicated in the pathogenesis of granulomatosis with polyangiitis (Wegener; GPA) and microscopic polyangiitis (MPA). Expansions of CD4+CD28- and CD8+CD28- T cells have also been associated with latent cytomegalovirus (CMV) infection. We assessed these T cells with and without coexpression of CD56 and CD57 in relation to vasculitis as well as CMV status. Blood from 16 patients in remission (12 GPA, 4 MPA), 18 patients with active vasculitis (12 GPA, 6 MPA), and 20 healthy controls was examined by flow cytometry for expression of CD4, CD8, CD56, CD57, and CD28 on T cells. The influence of age, CMV status, presence of disease, and disease activity on T cell subpopulations was tested with multiple regression analyses. In active vasculitis, the total numbers and proportion of lymphocytes were decreased. Total numbers of CD4+, CD8+, CD4+CD28-, CD8+CD28-, CD4+CD57+, and CD8+CD57+ T subpopulations were decreased to the same extent, implying unchanged proportions. Multivariate analyses showed no associations between vasculitis and CD28- or CD57+ T subpopulations, whereas immunoglobulin G antibodies to CMV were associated with expanded proportions of CD28- and CD57+ T cells, in both the CD4+ and the CD8+ compartments. CD28- and CD57+ T cells were associated with latent CMV infection and not with a diagnosis of GPA or MPA. Vasculitis assessment should include CMV status.

Vaccination in solid-organ transplantation candidates: time for a benefit/risk assessment.

Vaccination in solid-organ transplantation candidates: time for a benefit/risk assessment.

A profile of immune response to herpesvirus is associated with radiographic joint damage in rheumatoid arthritis

IntroductionProgression of joint damage despite appropriate therapy remains a significant problem for patients with rheumatoid arthritis (RA). This study was undertaken to identify profiles of immune response that correlate with radiographic joint damage as a first step toward the discovery of new pathogenic mechanisms of joint destruction in RA.MethodsThe study included 58 patients with RA and 15 healthy controls. The profiles of cytokine release from peripheral blood mononuclear cells (PBMC) in response to stimulation for 48 hours with one of six stimuli, or in media alone, were measured. Immune response profiles identified for each stimulus were correlated with radiographic joint damage as defined by the Sharp-van der Heijde score (SHS), before and after multivariable adjustment. For profiles correlated with the SHS, the distributions of individual cytokines were evaluated in patients according to the severity of joint damage and compared to healthy controls.ResultsThe immune response profile for cytomegalovirus (CMV)/Epstein-Barr virus (EBV) stimulation was correlated with both the SHS total and erosion scores (r = 0.31, P = 0.018 and r = 0.33, P = 0.011, respectively). After adjusting for age, sex, disease duration, autoantibody status, CMV/EBV serological status, current disease activity, disability and treatments, the correlation of the CMV/EBV immune response and the SHS erosion score became stronger (r = 0.43, P < 0.003). The CMV/EBV immune response correlated with CMV IgG (r = 0.44, P < 0.001), but not with EBV IgG. The most important cytokines for the CMV/EBV immune response profile were IFN-γ, IL-2, IL-4, IL-5, IL-13 and IL-17A, all of which are associated with T-cell immunity. Both the summary immune response score and the individual responses of IFN-γ and IL-13 to CMV/EBV stimulation were associated with greater joint damage.ConclusionsA profile of immune response to purified CMV/EBV lysates is associated with radiographic joint damage. The correlation of this immune response to CMV serology implies possible involvement of latent CMV infection. Therefore, the findings suggest that the immune response to latent CMV infection could play a fundamental role in the progression of inflammation and structural joint damage in patients with RA.

Profilaxis de la infección por citomegalovirus en el trasplante renal

Cytomegalovirus (CMV) infection remains a major problem in renal transplant recipients. CMV produces not only febrile syndromes and/or visceral disease but also contributes to the development of acute rejection and chronic graft failure. Valganciclovir prophylaxis has represented a major advance in controlling this infection, but late CMV infection after prophylaxis can occur, especially when universal prophylaxis is used. The use of valganciclovir prophylaxis for 200 days is more effective than prophylaxis for 100 days but does not completely prevent this problem. Prophylaxis based on the detection of CMV viremia (early prophylaxis or preemptive therapy) may prevent the development of delayed CMV disease, but has the disadvantage of requiring more intensive monitoring of viremia and does not prevent the development of viremia and its potential consequences in the long term. This article reviews current recommendations for prophylaxis of CMV disease in renal transplantation.

Seroprevalence of cytomegalovirus antibodies amongst normal pregnant women in Nigeria.

ObjectiveCytomegalovirus (CMV), a ubiquitous virus belonging to the herpes family, is known to be transmitted frequently to developing fetuses in pregnancy. In an immunocompromised state like pregnancy, primary infection through blood transfusion or reactivation of a latent CMV infection can cause severe illness. The study was carried out to determine the seroprevalence of the immunoglobulin G (IgG) antibody to cytomegalovirus amongst pregnant women in correlation with previous exposure to blood transfusion.MethodsA cross sectional study was carried out amongst 179 HIV negative pregnant women attending the antenatal clinic of Lagos State University Teaching Hospital (LASUTH), Ikeja, Nigeria. Five mL of blood was collected and stored in a plain bottle, centrifuged on the same day and the serum stored at −20°C. All samples were screened for anti-CMV IgG antibodies using the enzyme linked immunosorbent assay (ELISA). Consenting participants were instructed to fill a semi-structured questionnaire to obtain demographic and other related information. Statistical analysis of the results was done using Pearson’s chi squared test for analytical assessment.ResultsA total of 97.2% of the pregnant women recruited for this study were anti-CMV IgG positive. Out of the 179 recruited for the study 174 responded to the question on previous history of blood transfusion, 14.9% of the respondents (26 of 174) had a previous history of blood transfusion and all tested positive to the anti-CMVIgG antibody. However, past history of blood transfusion and educational level were found to be insignificant to the risk of acquiring CMV infection.ConclusionThe seroprevalence of the CMV antibody amongst pregnant women in this environment is high in relation to findings in other developing countries. There is the need to assess anti-CMV immunoglobulin M antibodies in pregnant women, which is a determinant of active infection.

B-006 DECREASE OF AUTOANTIBODIES AGAINST OXIDIZED LDL IN CYTOMEGALOVIRUS - RELATED CAROTID ATHEROSCLEROSIS

Background Autoantibodies against Oxidized low-density lipoproteins (oxLDL) were found to be protective at an early stage of atherosclerosis in our previous study.[Chen et al. Cardiology 2008;110:252–259.]Howerer, we suspected that latent human cytomegalovirus (HCMV) infection may modulate the protection of immune response in subclinical atherosclerosis. Methods An age-matched case-control study was constructed including 72 HCMV latent infection subjects and 41 non-HCMV latent infection healthy controls recruited from 2009 to 2010. HCMV latent infection is defined as presence of HCMV DNA, detected by nested PCR, in leucocytes but absence in plasma of subjects. Carotid atherosclerosis, lipid profile, oxLDL and autoantibody were also measured. Results Increase of intima-media thickness of common carotid artery (p = 0.018) indicated subclinical atherosclerosis in the HCMV latent infection subjects compared with non-HCMV latent infection healthy controls. Lower autoantibodies against oxLDL (p = 0.018), relatively higher level of oxLDL (p = 0.058), higher triglyceride (p = 0.014) and higher ratio of cholesterol to HDL (p = 0.009) were noted in the HCMV latent infection subjects. Conclusions We concluded HCMV latent infection may play a crucial role in the lessened production of protective autoantibodies against oxLDL. Based on the differences in lipid panel, interference with lipid metabolism may be one possible pathway for HCMV to precipitate the process of carotid atherosclerosis.

NK-cells have an impaired response to acute exercise and a lower expression of the inhibitory receptors KLRG1 and CD158a in humans with latent cytomegalovirus infection

NK-cells and γδ T-cells are cytotoxic effectors of the immune system that are preferentially mobilized into the blood compartment in response to acute stress and exercise. While infection history is known to alter the phenotype and exercise-responsiveness of CD8+ T-cells, the influence of latent cytomegalovirus (CMV) and Epstein-Barr virus (EBV) infections on the phenotypes and exercise-responsiveness of NK-cells and γδ T-cells are unknown. Twenty healthy males (age: 28.4±5.4 years) cycled for 30 min at 85% peak power. Blood lymphocytes isolated before, immediately after, and 1 h after exercise were surface stained for CD3, CD4, CD8, CD56, CD57, CD158a, KLRG1, and γδ-TCR antigens by four-color flow cytometry. CMV and EBV serostatus (pos/neg) was determined by ELISA. CMVpos had lower proportions of NK-cells expressing inhibitory receptors (KLRG1+ and CD158a+) and higher proportions of terminally differentiated NK-cells (KLRG1-/CD57+) compared to CMVneg. CMVpos mobilized far fewer (132 cells/μL vs. 245 cells/μL) NK-cells in response to exercise despite having similar baseline NK-cell counts and physiological responses to exercise as CMVneg, although terminally differentiated NK-cells were equally responsive to exercise regardless of CMV serostatus (p=0.658). EBVpos had higher proportions of CD8+ NK-cells, but cellular responses to exercise were not influenced by EBV. The frequency and exercise-responsiveness of γδ T-cells was not affected by CMV or EBV serostatus (p>0.05). In conclusion, latent CMV infection is associated with lowered numbers of NK-cells expressing inhibitory receptors and a blunted mobilization of NK-cells in response to acute exercise. This may indicate a compromised immune response to "fight-or-flight" situations in those infected with CMV.

Aerobic fitness is associated with lower proportions of senescent blood T-cells in man

Senescent T-cells accumulate with age, lowering the naïve T-cell repertoire and increasing host infection risk. As this response is likely to be influenced by certain lifestyle factors, we examined the association between aerobic fitness (VO(2max)) and the age-related accumulation of senescent T-cells. Blood lymphocytes from 102 healthy males (18-61 yr) were analyzed for KLRG1, CD57, CD28, CD45RA, CD45RO surface expression on CD4+ and CD8+ T-cells by 4-color flow cytometry. Advancing age (yr) was positively associated with the proportion (%) of senescent (KLRG1+/CD57+; KLRG1+/CD28-) CD4+ (B=1.00; 1.02) and CD8+ (B=0.429; 1.02) T-cells and inversely associated with naïve (KLRG1-/CD28+) CD4+ (B=-1.000) and CD8+ (B=-0.993) T-cells. VO(2max) was inversely associated with senescent CD4+ (B=-0.97) and CD8+ (B=-0.240). Strikingly, age was no longer associated with the proportions of senescent or naïve T-cells after adjusting for VO(2max), while the association between VO(2max) and these T-cell subsets withstood adjustment for age, BMI and percentage body fat. Ranking participants by age-adjusted VO(2max) revealed that the highest tertile had 17% more naïve CD8+ T-cells and 57% and 37% less senescent CD4+ and CD8+ T-cells, respectively, compared to the lowest tertile. VO(2max) was not associated with latent cytomegalovirus (CMV), Epstein-Barr virus (EBV) or herpes simplex virus-1 (HSV-1) infection, indicating that the moderating associations of VO(2max) were not confounded by persistent viral infections. This is the first study to show that aerobic fitness is associated with a lower age-related accumulation of senescent T-cells, highlighting the beneficial effects of maintaining a physically active lifestyle on the aging immune system.

CD4+CD28− T cell expansion in granulomatosis with polyangiitis (Wegener's) is driven by latent cytomegalovirus infection and is associated with an increased risk of infection and mortality

Expanded populations of CD4+CD28- T cells with a cytotoxic phenotype have been repeatedly reported in patients with granulomatosis with polyangiitis (Wegener's) (GPA). In healthy individuals expansion of this T cell population follows cytomegalovirus (CMV) infection. We undertook this study to investigate whether CMV infection may be responsible for driving the expansion of CD4+CD28- T cells in GPA patients and how this might relate to clinical features. Forty-eight GPA patients and 38 age-matched healthy donors were included in the study. CMV-specific IgG in serum was detected by enzyme-linked immunosorbent assay. Flow cytometric analysis was used to study T cell populations and phenotype. The presence of CMV in renal biopsy tissue from GPA patients was investigated by immunohistochemistry and polymerase chain reaction (PCR). Clinical information was obtained from patient records. Populations of CD4+CD28- T cells were only expanded in CMV-seropositive GPA patients and controls. In CMV-seropositive GPA patients we observed negative correlations between the percentages of CD4+CD28- T cells and both the percentage of naive T cells and the glomerular filtration rate at presentation. There was a significant association between the percentage of CD4+CD28- T cells and risk of infection and mortality. CMV could not be detected in renal tissue by PCR or immunohistochemistry. CMV seropositivity itself was not a risk factor for infection in a cohort of 182 patients with antineutrophil cytoplasmic antibody-associated vasculitis who had been recruited into clinical trials performed by the European Vasculitis Study Group. The expansion of CD4+CD28- T cells in GPA patients is associated with CMV infection and leads to a reduction in the number of naive T cells in peripheral blood. Patients with expanded CD4+CD28- T cells have significantly increased mortality and risk of infection.

CMV Infection after Transplant from Cord Blood Compared to Other Alternative Donors: The Importance of Donor-Negative CMV Serostatus

Cytomegalovirus (CMV) infection and disease are important complications after hematopoietic stem cell transplant, particularly after transplant from alternative donors. Allogeneic cord blood transplantation (CBT) is being increasingly used, but immune recovery may be delayed. The aim of this study was to compare CMV infection in CBT with transplants from unrelated or mismatched related donors, from now on defined as alternative donors. A total of 165 consecutive transplants were divided in 2 groups: (1) alternative donors transplants (n = 85) and (2) CBT recipients (n = 80). Donor and recipient (D/R) CMV serostatus were recorded. The incidence of CMV infection, its severity, timing, and outcome were compared. Median follow-up was 257 days (1-1328). CMV infection was monitored by CMV antigenemia and expressed as CMV Ag positive cell/2 × 10(5) polymorphonuclear blood cells. There was a trend toward a higher cumulative incidence of CMV infection among CBT than alternative donor transplant recipients (64% vs 51%, P = .12). The median time to CMV reactivation was 35 days, and was comparable in the 2 groups (P = .8). The maximum number of CMV-positive cells was similar in the 2 groups (11 versus 16, P = .2). The time interval between the first and the last positive CMV antigenemia was almost 4 times longer in CBT compared with alternative donor transplants (109 vs 29 days, respectively, P = .008). The incidence of late CMV infection was also higher in CBT (62% vs 24%, P < .001). The incidence of early and late CMV infection in CBT was similar to D-/R+ alternative transplants, and higher than in D+/R+ alternative transplants: early infection, 72% in CBT versus 69% in D-/R+ alternative versus 55% in D+/R+ alternative (P = .21); and late infection, 67% in CBT versus 60% in D-/R+ alternative versus 7% in D+/R+ alternative (P < .001). Transplant-related mortality and overall survival were similar between the groups: 34% versus 36% (P = .6) and 54% versus 46% (P = .3) for alternative transplant and CBT, respectively. Longer duration and higher incidence of late CMV infection was seen in CBT patients, when compared with alternative donor transplants, whereas no difference in mortality was observed. The duration and incidence of late CMV infection were similar when D-/R+ CBT were compared with D-/R+ alternative donor transplants.

Latent CMV And EBV Infections And The Mobilization Of Viral-specific And Senescent T-cells With Exercise

Reactivating latent viruses cause senescent T-cells to accumulate within the so-called "immune space", reducing the naïve T-cell repertoire and increasing host infection risk. Although senescent T-cells (i.e. KLRG1+/CD57+) are mobilised into the blood by acute exercise, the impact of latent cytomegalovirus (CMV) and Epstein-Barr virus (EBV) infections on this response is unknown. It remains to be determined also if the mobilized cells react with epitopes of the CMV or EBV virus in those infected. PURPOSE: To determine: (1) if CMV and EBV specific T-cells are mobilised into blood in response to acute exercise; and (2) the impact of latent CMV and EBV infections on the exercise-responsiveness of senescent T-cells. METHODS: Twenty-four healthy males (age 28.5 ± 5) completed a 30-min cycling protocol at 85% of maximum power. Mononuclear cells were isolated from blood before, immediately after and 1hour after exercise and labelled with MHC class I Pentamers specific to CMV (pp65) or EBV (LMP-2) and anti CD3 and CD8 antibodies. Naïve (KLRG1-/CD28+/CD57-), effector-memory (KLRG1+/CD28+/CD57-) and senescent (KLRG1+/CD28-/CD57+) phenotypes were determined on pentamer positive and negative CD8+ T-cells by flow cytometry. ELISA tests were used to determine CMV and EBV serostatus. RESULTS: Exercise increased the numbers of CMV and EBV-specific T-cells by 158% and 200% respectively (p<.01), and altered the proportions of senescent (+44%) and naïve (-20%) CD8+ T-cells (p<.05). CMV seropositive (n = 10) had a greater (+136%; p<.01) proportion of senescent and a lower (-33%; p<.01) proportion of naïve CD8+ T-cells compared to seronegative (n= 14), and demonstrated a blunted senescent T-cell response to exercise (+38% vs +51%; p<.01). Senescent markers on both CMV and EBV-specific T-cells increased with exercise (+53% and +76% respectively; p<.05). EBV serostatus did not influence the proportions or exercise response of the CD8+ T-cell populations (p>.05). CONCLUSION: CD8+ T-cells specific to CMV and EBV are mobilized into blood with acute exercise; however, the relative exercise responsiveness of senescent T-cells is blunted with CMV infection. Future work should determine the fate of the mobilized senescent cells and the potential impact that exercise might have on creating "immune space" in those infected with CMV.

Impact Of CMV And EBV Infections On The Exercise-induced Mobilization Of Nk-cells And γδ T-cells

PURPOSE: Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) infect 60% and 80% of the US population, respectively. These persistent viruses compromise immunity to novel pathogens by increasing the frequency of senescent CD8+ T-cells in the periphery; however, less is known about their effects of on the phenotype characteristics of other cytotoxic lymphocytes, such as NK-cells and γδ T-cells. As cytotoxic lymphocytes are preferentially mobilized into the blood in response to acute exercise, we examined the impact of latent CMV and EBV infections on the phenotype characteristics and exercise-responsiveness of NK-cells and γδ T-cells. METHODS: 22 healthy males (Age: 28 ± 5 yrs) completed a 30-min cycling protocol at 85% of maximum power. Lymphocytes isolated from whole blood before, immediately after, and 1-hour after exercise were labeled with monoclonal antibodies to identify CD3-/CD56+ NK-cells and their cell-surface expression of KLRG1, CD57, CD8, and CD158a by flow cytometry. Additionally, CD4+ and CD8+ T-cells were assessed for expression of KLRG1, CD56, and γδ-TCR. ELISA was used to determine CMV and EBV serostatus. Exercise and serostatus main effects, and exercise x serostatus interaction effects, were detected using linear mixed models. RESULTS: CMV infection is associated with a blunted exercise response of NK-cells (+260% vs. +78%; p<0.001) and a lower proportion of NK-cells expressing the inhibitory receptors KLRG1 (53% vs. 44%; p<0.05) and CD158a (14% vs. 8%; p<.05). Higher proportions of cytotoxic CD8+ NK-cells were found with EBV infection (42% vs. 31%; p<.05), but EBV did not affect the relative response of these cells to exercise. Higher proportions of cytotoxic CD56+/CD8+ (12% vs. 18%; p<.01) and effector-memory KLRG1+/CD8+ T-cells (38% vs. 49%; p<.01) were found in the CMV infected, who also exhibited a greater relative mobilization of KLRG1+/CD8+ T-cells with exercise (+26% vs +33%; p<.01). CMV and EBV infection did not influence the frequency of CD4+ or CD8+ γδ T-cells or their response to exercise. CONCLUSION: CMV infection is associated with a downregulation of NK-cell inhibitory receptors and a blunted NK-cell mobilization with exercise. This implies that NK-cell immune surveillance may be impaired in CMV infected individuals both at rest and following an acute bout of exercise.

Análisis de infección por citomegalovirus y sus consecuencias en el trasplante renal: revisión de una década

Cytomegalovirus (CMV) is one of the most important pathogens in renal transplant patients. It can cause infection and illness, as well as serious direct and indirect consequences. Descriptive retrospective observational study of all kidney transplants performed in the Hospital La Fe of Valencia between 1994 and 2005 (n=996). The diagnosis of CMV disease and disease was performed by serology, culture, pp65 antigenemia determination or quantification of CMV-PCR (polymerase chain reaction) in peripheral blood. Prophylaxis included acyclovir in 20 patients (2.4%), ganciclovir in 478 (56.8%), valganciclovir in 166 (19.7%) and none in 178 (21%). CMV serology was positive in 802 donors (83%) and in 860 recipients (89%). Among the recipients who suffered from CMV disease (N=60), four lost the graft and six died. Early infection and early disease were significantly more frequent (p<0.05) in positive donor-negative recipient cases (D+/R-). Having early or late infection was associated with death from any cause (OR 2.03, CI 95% 1.24 to 3.31, p<0.05). Early or late CMV infection was associated with increased graft loss from any cause (OR 1.97, CI 95% 1.14 to 3.43, p<0.05). After logistic regression, the association between CMV infection and death from all causes remained significant. In renal transplant patients, having CMV infection was associated with death from any cause.

Cytomegalovirus infections in unrelated cord blood transplantation in pediatric patients: incidence, risk factors, and outcomes

Stem cells from umbilical cord blood (CB) have increasingly become a viable alternate source of progenitor cells for hematopoietic cell transplantation (HSCT). Cytomegalovirus (CMV) is thought to contribute significantly to HSCT morbidity and mortality. Retrospective case-control study in patients at tertiary care center. We determined the incidence, risk factors and outcomes for CMV infection and disease after unrelated cord blood transplantation (UCBT) in children. Between 2003 and 2007, 73 pediatric patients underwent UCBT and 68% of recipients were CMV seropositive. The overall incidence of CMV infection, early and late CMV infection was 58.9% (43/73), 62.8% (27/43), and 37.4% (16/43), respectively. in patients with early CMV infection, 6 of 27 (22%) patients progressed to develop CMV end-organ disease including pneumonitis and retinitis. High levels CMV antigenemia ≥70 infected cells by pp65 antigenemia assay + PMNs, P=.237) were associated with a higher risk of progression to CMV disease. The development of CMV infections was higher in CMV-seropositive recipients (P<.001) and in those who developed graft-versus-host-diseases (GVhD) (P<.001). other risk factors for CMV infection include the use of high-dose corticosteroids (P<.001) and older age of the recipient at the time of transplant (P<.002). Late CMV infection was strongly associated with a previous history of early CMV infection (P<.001). CMV infection is a significant complication in UCBT recipients in pediatric patients and is associated with an increase in transplant-related morbidity and mortality. Risk factors for CMV infections after UCBT include GvHD, use of corticosteroids, underlying diseases (hematologic malignancies) and older age. Late CMV infection was strongly associated with a previous history of CMV infection.

Transmission of Murine Cytomegalovirus in Breast Milk: a Model of Natural Infection in Neonates

Vertical transmission of viruses in breast milk can expose neonates to infectious pathogens at a time when the capacity of their immune system to control infections is limited. We developed a mouse model to study the outcomes of acquisition of murine cytomegalovirus (MCMV) when neonates are breastfed by mothers with acute or latent infection. Breast milk leukocytes collected from lactating mice were examined for the presence of MCMV IE-1 mRNA by reverse transcription-PCR (RT-PCR) with Southern analysis. As determined by this criterion, breast milk leukocytes from both acute and latent mothers were positive for MCMV. This mimics the outcome seen in humans with latent cytomegalovirus infection, where reactivation of virus occurs specifically in the lactating mammary gland. Interestingly, intraperitoneal injection of breast milk collected from mothers with latent infection was sufficient to transfer MCMV to neonatal mice, demonstrating that breast milk was a source of virus. Furthermore, we found that MCMV was transmitted from infected mothers to breastfed neonates, with MCMV IE-1 mRNA or infectious virus present in multiple organs, including the brain. In fact, 1 day of nursing was sufficient to transmit MCMV from latent mothers to breastfed neonatal mice. Together, these data validate this mouse model of vertical transmission of MCMV from mothers with acute or latent MCMV infection to breastfed neonates. Its relevance to human disease should prove useful in future studies designed to elucidate the immunological and pathological ramifications of neonatal infection acquired via this natural route.

Genetic Labeling Reveals Altered Turnover and Stability of Innate Lymphocytes in Latent Mouse Cytomegalovirus Infection

Mouse CMV (MCMV) infection rapidly induces the proliferation of NK cells, which correlates with immunological protection. Whether NK cells primed during acute response against MCMV are maintained for the long term is not known. In this study, we used TcrdH2BeGFP mice in which maturing NK cells are genetically labeled with a pulse of very stable histone-2B-eGFP. In this system, we found that the reporter protein was diluted out upon NK cell division during acute MCMV infection. At the same time, mature NK cells in uninfected mice showed only very limited turnover in vivo. Three months after primary infection when MCMV latency was established, the majority of peripheral NK cells still displayed a higher record of proliferation than NK cells in mock-infected controls. This observation included both Ly49H(+) and Ly49H(-) NK cells. Conversely, naive NK cells did not show more proliferation after transfer into latently MCMV-infected mice than that after transfer into mock-infected control mice. This indicated that the observed alterations of the NK cell compartment in MCMV latency were "legacy" (i.e., resulting from prior events during the initial immune response). Together, these results suggest that antiviral immune responses induce sustained alterations of innate lymphocyte populations that extend far beyond the first days of acute infection.