Cytomegalovirus (CMV) gene expression is repressed in latency due to heterochromatinization of viral genomes. In murine CMV (MCMV) latently infected mice, viral genomes are bound to histones with heterochromatic modifications, to enzymes that mediate these modifications, and to adaptor proteins that may recruit co-repressor complexes. Kinetic analyses of repressor binding show that these repressors are recruited at the earliest time of infection, suggesting that latency may be the default state. Kidney transplantation leads to epigenetic reprogramming of latent viral chromatin and reactivation of immediate early gene expression. Inflammatory signaling pathways, which activate transcription factors that regulate the major immediate early promoter (MIEP), likely mediate the switch in viral chromatin.

Human cytomegalovirus hijacks host cell metabolism, increasing the flux of carbon from glucose to malonyl-CoA, the committed precursor to fatty acid synthesis and elongation. Inhibition of acetyl-CoA carboxylase blocks the production of progeny virus. To probe further the role of fatty acid metabolism during infection, we performed an siRNA screen to identify host cell metabolic enzymes needed for the production of infectious cytomegalovirus progeny. The screen predicted that multiple long chain acyl-CoA synthetases and fatty acid elongases are needed during infection, and the levels of RNAs encoding several of these enzymes were upregulated by the virus. Roles for acyl-CoA synthetases and elongases during infection were confirmed by using small molecule antagonists. Consistent with a role for these enzymes, mass spectrometry-based fatty acid analysis with(13)C-labeling revealed that malonyl-CoA is consumed by elongases to produce very long chain fatty acids, generating an approximately 8-fold increase in C26-C34 fatty acid tails in infected cells. The virion envelope was yet further enriched in C26-C34 saturated fatty acids, and elongase inhibitors caused the production of virions with lower levels of these fatty acids and markedly reduced infectivity. These results reveal a dependence of cytomegalovirus on very long chain fatty acid metabolism.

BACKGROUND::

Congenital cytomegalovirus (cCMV) is a common congenital infection and a leading non-genetic cause of sensorineural hearing loss (SNHL). CMV exhibits extensive genetic variability and infection with multiple CMV strains (mixed infection) was shown to be common in cCMV. The role of mixed infections in disease and outcome remains to be defined.

METHODS::

Genotyping of envelope glycoproteins, UL55 (gB), UL73 (gN) and UL75 (gH) was performed on saliva specimens from 79 infants from the ongoing CMV and Hearing Multicenter Screening Study (CHIMES) and on blood and urine specimens from 52 infants who participated in natural history studies at the University of Alabama at Birmingham. Genotyping of UL144 and US28 was also performed in the CHIMES cohort. The association of individual genotypes and mixed infection with clinical findings at birth and SNHL was examined.

RESULTS::

Thirty seven of 131 infants (28%) were symptomatic at birth and 26 (20%) had SNHL at birth. All known genotypes of UL55, UL75, UL73, and US28 were represented and no particular genotype was associated with symptomatic infection or SNHL. UL144 subtype C was more common in symptomatic babies but not associated with SNHL. Mixed infection was observed in 59 infants (45%) and not associated with symptoms (p = 0.43) or SNHL at birth (p = 0.82). In the cohort of 52 infants with long-term hearing outcome, mixed infection at birth was not predictive of SNHL.

CONCLUSIONS::

Mixed infection is common in infants with cCMV but is neither associated with symptomatic infection nor with SNHL.

Cytomegalovirus (CMV) retinitis may occur in profoundly immunocompromised patients and be the initial AIDS-defining infection. The incidence and prevalence of CMV retinitis has declined substantially in the era of highly active antiretroviral therapy (HAART); nevertheless, it remains a leading cause of ocular morbility. We report the case of a 40-year-old man with blurred vision and pain in the right eye, three weeks after the initiation of effective HAART treatment. Ocular examination revealed a panuveitis causing an anterior chamber reaction with hypopyon and a dense vitreous haze. An endogenous endophthalmitis was suspected and treatment was ensued, without improvement. A vitreous tap was performed, and a positive polymerase chain reaction for CMV was found. A diagnosis of immune recovery uveitis (IRU) was made, and the patient responded to treatment with valganciclovir and dexamethasone. IRU is an intraocular inflammation that develops in patients with HAART-induced immune recovery and inactive CMV retinitis, although cases of active CMV retinitis have been described. Presentation with panuveitis and hypopion is rare and may be misleading regarding diagnosis and management.

Human fibroblasts provide immunosuppressive functions that are partly mediated by the tryptophan-catabolizing enzyme indoleamine-2,3-dioxygenase (IDO). Moreover, upon stimulation with inflammatory cytokines human fibroblasts exhibit broad-spectrum antimicrobial effector functions directed against various clinically relevant pathogens and these effects are also IDO-dependent. Therefore human fibroblasts are suggested to be involved in the control of immune reactions during infectious diseases. As human cytomegalovirus (HCMV) represents a pathogen frequently found in immunocompromised hosts and IDO is involved in the control of HCMV growth, we here investigated the impact of HCMV infection on IDO-mediated antimicrobial and immunoregulatory effects. We show that infection with HCMV substantially impairs IFN-γ-induced IDO-activity in human fibroblasts in a dose and time dependent fashion. Consequently, these cells are no longer able to restrict bacterial and parasitic growth and, furthermore, loose their IDO-mediated immunosuppressive capacity. Our results may have significant implications for the course of HCMV infection during solid organ transplantation: we suggest that loss of IDO-mediated antimicrobial and immunoregulatory functions during a HCMV infection might at least in part explain the enhanced risk of organ rejection and infections observed in patients with HCMV reactivation after solid organ transplantation.

Introduction.

Kidney transplantation and its conventional treatment can lead to increased risk of diabetes mellitus outbreak in normoglycemic recipients. Also, uncontrolled hyperglycemia may increase allograft loss and decrease patient survival. We aimed to assess the frequency of hyperglycemia in transplant patients and its risk factors. Materials and Methods. A retrospective study was performed on 3342 adult kidney transplant recipients between 2008 and 2010. Demographic and laboratory data were collected. All laboratory tests were done in a one laboratory, and hyperglycemia was defined as a fasting plasma glucose level greater than 125 mg/dL.  Univariable and multivariable logistic regression analyses were used to determine the risk factors of hyperglycemia following kidney transplantation.

Results.

There were 2120 men (63.4%) and 1212 women (36.3%) included in the study. The prevalence of hyperglycemia was 22.5%. Hyperglycemia was significantly higher in patients with cytomegalovirus infection (P = .001), elevated serum creatinine (P < .001), low high-density lipoprotein cholesterol (P = .01), and increased blood levels of cyclosporine (P < .001). After adjusting for covariates by multivariate logistic regression, the hyperglycemia rate was significantly higher for patients with a cyclosporine trough level greater than 250 ng/mL (P < .001), a serum creatinine level greater than 1.5 mg/dL (P < .001), and a high-density lipoprotein cholesterol less than 45 mg/dL  (P = .03).

Conclusions.

This study indicated that hyperglycemia is a common metabolic disorder in Iranian kidney transplant patients. Risk factors for hyperglycemia were higher cyclosporine level, impaired kidney function, and reduced high-density lipoprotein cholesterol values.

Congenital infection with human cytomegalovirus (CMV) is a major cause of morbidity, including sensorineural hearing loss (SNHL), in newborns. Antiviral therapy with ganciclovir (GCV) and its oral prodrug, valganciclovir (VAL-GCV) are increasingly being administered to infected infants, toward the goal of improving neurodevelopmental and auditory outcomes. In this case report, we describe a symptomatic congenitally infected infant treated with VAL-GCV in whom GCV resistance was suspected, based on a 50-fold increase in viral load after 6 weeks of oral therapy. Analyses of CMV sequences from both blood and urine demonstrated populations of viruses with M460V and L595F mutations in the UL97 phosphotransferase gene. In contrast, analysis of viral DNA retrieved from the newborn dried blood spot demonstrated wild-type UL97 sequences. DNAemia resolved after the discontinuation of VAL-GCV. Long-term VAL-GCV therapy in congenitally infected infants can select for resistant viral variants, and anticipatory virological monitoring may be warranted.

"Good syndrome" is defined as the combination of thymoma, hypogammaglobulinemia, low numbers of peripheral B cells and variable defects in cell-mediated immunity with a CD4 T lymphopenia and an inverted CD4/CD8+ T-cell ratio. Although thymomas associated with "Good syndrome" are mostly benign, this humoral immunodeficiency may be associated with high risk of metastatic spread thymoma. This report concerns a case of high risk thymoma associated with recurrent lower respiratory tract infections finally revealing "Good syndrome". A 56 years old man, with no history of myasthenia or respiratory tract infection, was investigated for cough and chest pain. Computed tomography (CT) scan showed a 80×80×30mm mass in the anterior mediastinum suggestive of lymphoma or thymoma. This mass infiltrated the brachiocephalic trunk and the right pleura. An (18)F-fluorodeoxyglucose positron emission tomography/CT ((18)F-FDG PET/CT) has been performed showing high uptake in the thoracic mass (SUVmax 8.6) associated with right and left hypermetabolic hilar lymph nodes suggesting high risk thymoma. Surgery consisted of an enlarged thymectomy and lymphadenectomy. Histopathological examination showed a type B2 lymphoepithelial thymoma with capsular effraction. The patient underwent radiotherapy on the mediastinum. In follow-up, the patient presented several lower respiratory tract infections treated with probabilistic antibiotherapy and corticosteroids. A respiratory tract infection occured six months after the end of radiotherapy. Fluorine-18-FDG PET/CT showed a high uptake in bilateral ground glass opacities of the two lower lobes and hypermetabolic bilateral hilar lymph nodes. A new (18)F-FDG PET/CT scan was performed three months later attesting the migratory character of the lung opacities and allowed to rule out an unlikely metastatic spread. Complete blood count was normal but lymphocyte immunophenotyping showed significant decrease in B and T CD4 lymphocytes. Total IgG were slightly lower than the normal range (6.92g/L), with low IgG1 (4.68g/L) and IgM levels (0.34g/L), suggesting "Good syndrome". Tests for bacteriological, viral, fungal or parasitic infection performed repeatedly were negative. Antibiotics and gamma globulin injections (administered three years later) were required to treat these recurrent lower respiratory tract infections and to secure prophylaxis against pneumocystis carinii (trimethoprim-sulfamethoxazole). Immunodeficiency worsened whereas no recurrence of thymoma was observed after six years of follow-up. Although the association of thymoma and immunologic disease is common and refers up to 74% of cases, 6% to 11% of patients with a history of thymoma develop "Good syndrome" in the following years. These patients are deemed to be at high risk for developing severe sinus or pulmonary infections with encapsulated bacteria, but also viral (in particular cytomegalovirus), parasitic (pneumocystis) or fungal (candida) infections. Chronic diarrhea, of infectious origin or not, is common, cytomegalovirus retinitis and refractory gastrointestinal ulcers have also been reported. The diagnosis of thymoma preceded the diagnosis of hypogammaglobulinemia or infection in up to 42.4%, of the patients with an interval of 3 months to 18 years. "Good syndrome" occasionally progresses even after thymectomy and/or corticosteroid treatment. To our knowledge, no imaging report of FDG-PET/CT findings of "Good syndrome" has been reported. In conclusion, the association of thymoma, recurrent infectious episodes especially of the respiratory tract and hypogammaglobulinemia is suggestive of "Good syndrome". This diagnosis should be considered when (18)F-FDG PET/CT shows hypermetabolic lung opacities in a patient with a history of thymoma.

Congenital cytomegalovirus (CMV) is a leading cause of disability, including sensorineural hearing loss, developmental delay, and mental retardation. Understanding risk factors for acquisition of CMV infection in adolescent females will help determine vaccine strategies.Females (12-17 years) were recruited from primary care settings in Cincinnati, Galveston, Houston, and Nashville from June 2006 to July 2010 for a seroepidemiologic study, from which seronegative participants were recruited for a CMV vaccine trial. Participants (n = 1585) responded to questions regarding potential exposures. For those with young children in the home (n = 859), additional questions were asked about feeding and changing diapers, and for those > 14 years of age (n = 1162), questions regarding sexual activity were asked. Serum was evaluated for CMV antibody using a commercial immunoglobulin G assay.Cytomegalovirus antibody was detected in 49% of participants. In the univariate analyses, CMV seroprevalence was significantly higher among African Americans, those with children < 3 years of age in the home, and those with a history of oral, anal, or vaginal intercourse. Among those with young children in the home, feeding children and changing diapers further increased the association with CMV infection. However, in the final multivariate analysis, only African Americans and household contact with young children were associated with CMV infection.By age 12, evidence of CMV infection was common. Multiple factors regarding race and personal behaviors likely contribute to seroconversion earlier in life.

BACKGROUND:

Cytomegalovirus (CMV) is the most common cause of congenital virus infection. Infection of guinea pigs with guinea pig CMV (GPCMV) can provide a useful model for the analysis of its pathogenesis as well as for the evaluation of vaccines. Although glycoprotein B (gB) vaccines have been reported to reduce the incidence and mortality of congenital infection in human clinical trials and guinea pig animal models, the mechanisms of protection remain unclear.

METHODS:

To understand the gB vaccine protection mechanisms, we analyzed the spread of challenged viruses in the placentas and fetuses of guinea pig dams immunized with recombinant adenoviruses expressing GPCMV gB and β-galactosidase, rAd-gB and rAd-LacZ, respectively.

RESULTS:

Mean body weight of the fetuses in the dams immunized with rAd-LacZ followed by GPCMV challenge 3 weeks after immunization was 78% of that observed for dams immunized with rAd-gB. Under conditions in which congenital infection occurred in 75% of fetuses in rAd-LacZ-immunized dams, only 13% of fetuses in rAd-gB-immunized dams were congenitally infected. The placentas were infected less frequently in the gB-immunized animals. In the placentas of the rAd-LacZ- and rAd-gB-immunized animals, CMV early antigens were detected mainly in the spongiotrophoblast layer. Focal localization of viral antigens in the spongiotrophoblast layer suggests cell-to-cell viral spread in the placenta. In spite of a similar level of antibodies against gB and avidity indices among fetuses in each gB-immunized dam, congenital infection was sometimes observed in a littermate fetus. In such infected fetuses, CMV spread to most organs.

CONCLUSIONS:

Our results suggest that antibodies against gB protected against infection mainly at the interface of the placenta rather than from the placenta to the fetus. The development of strategies to block cell-to-cell viral spread in the placenta is, therefore, required for effective protection against congenital CMV infection.