Cytomegalovirus disease in the era of highly active antiretroviral therapy (HAART)

AIDS-related cytomegalovirus encephalitis in the late ART era: A retrospective cohort study at a referral center in Brazil

BACKGROUND

AIDS-related cytomegalovirus (CMV) encephalitis has declined in the combined antiretroviral therapy (ART) era in high-income countries. However, there is scarce information on CMV encephalitis in low- and middle-income countries. The objectives of this study were to identify the prevalence of AIDS-related CMV encephalitis and describe its main features.

METHODS

This was a retrospective cohort study carried out at a referral center in São Paulo, Brazil. We included adult people living with HIV/AIDS (PLWHA), hospitalized in 2019, with a CD4 cell count ≤100/mm³ and quantitation CMV DNA results in plasma. Cases with compatible neurological manifestations and detection of CMV DNA by polymerase chain reaction (PCR) in cerebrospinal fluid samples were defined as CMV encephalitis.

RESULTS

Among 761 PLWHA hospitalized, 248 (32.5%) cases were included in this study. Prevalence of CMV encephalitis was 2.4% (6/248) among all included cases and 7.7% (6/78) among individuals with neurological opportunistic diseases. The six patients with CMV encephalitis were males and had CD4 cell count <50/mm³. Five (83%) cases had CMV encephalitis as AIDS-defining disease and showed CMV DNA detection by PCR >50,000 UI/mL plasma. All six cases received anti-CMV therapy (ganciclovir, n = 4; ganciclovir plus foscarnet, n = 2) and five were discharged to home. CMV encephalitis was not uncommon among hospitalized PLWHA with neurological opportunistic diseases.

CONCLUSIONS

The epidemiological and immunological profile of individuals with CMV encephalitis was similar to that described in the pre-ART era, but in contrast, most cases were treated and discharged from the hospital.

The Frequency and Function of NKG2C+CD57+ Adaptive NK Cells in Cytomagalovirus Co-Infected People Living with HIV Decline with Duration of Antiretroviral Therapy

Human cytomegalovirus (CMV) infection drives the expansion and differentiation of natural killer (NK) cells with adaptive-like features. We investigated whether age and time on antiretroviral therapy (ART) influenced adaptive NK cell frequency and functionality. Flow cytometry was used to evaluate the frequency of adaptive and conventional NK cells in 229 CMV⁺ individuals of whom 170 were people living with HIV (PLWH). The frequency of these NK cell populations producing CD107a, CCL4, IFN-γ or TNF-α was determined following a 6-h antibody dependent (AD) stimulation. Though ART duration and age were correlated, longer time on ART was associated with a reduced frequency of adaptive NK cells. In general, the frequency and functionality of NK cells following AD stimulation did not differ significantly between treated CMV⁺PLWH and CMV⁺HIV^- persons, suggesting that HIV infection, per se, did not compromise AD NK cell function. AD activation of adaptive NK cells from CMV⁺PLWH induced lower frequencies of IFN-γ or TNF-α secreting cells in older persons, when compared with younger persons.

Diverse roles of heterogeneous nuclear ribonucleoproteins in viral life cycle

Understanding the host-virus interactions helps to decipher the viral replication strategies and pathogenesis. Viruses have limited genetic content and rely significantly on their host cell to establish a successful infection. Viruses depend on the host for a broad spectrum of cellular RNA-binding proteins (RBPs) throughout their life cycle. One of the major RBP families is the heterogeneous nuclear ribonucleoproteins (hnRNPs) family. hnRNPs are typically localized in the nucleus, where they are forming complexes with pre-mRNAs and contribute to many aspects of nucleic acid metabolism. hnRNPs contain RNA binding motifs and frequently function as RNA chaperones involved in pre-mRNA processing, RNA splicing, and export. Many hnRNPs shuttle between the nucleus and the cytoplasm and influence cytoplasmic processes such as mRNA stability, localization, and translation. The interactions between the hnRNPs and viral components are well-known. They are critical for processing viral nucleic acids and proteins and, therefore, impact the success of the viral infection. This review discusses the molecular mechanisms by which hnRNPs interact with and regulate each stage of the viral life cycle, such as replication, splicing, translation, and assembly of virus progeny. In addition, we expand on the role of hnRNPs in the antiviral response and as potential targets for antiviral drug research and development.

Frequency of Cytomegalovirus Viral Load in Iranian Human Immunodeficiency Virus-1-Infected Patients with CD4+ Counts <100 Cells/mm3

OBJECTIVES

The aim of present work was to assess cytomegalovirus (CMV) viremia in Iranian human immunodeficiency virus (HIV)-1-infected patients with a CD4+ count <100 cells/mm3 and to explore whether CMV DNA loads correlate with CD4+ cell counts or associated retinitis.

METHODS

This study was conducted at the AIDS research center in Iran on HIV-1-infected patients with CD4+ count <100 cells/mm3, antiretroviral therapy-naive, aged ≥18 years with no previous history of CMV end-organ disease (CMV-EOD).

RESULTS

Thirty-nine of 82 patients (47.56%) had detectable CMV viral load ranging from 66 to 485,500 IU/mL. CMV viral load in patients with retinitis ranges from 352 to 2,720 IU/mL, and it was undetectable in 2 patients. No significant associations between CMV viremia and CD4+ cell count was found (p value = 0.31), whereas significant association of CMV viremia in HIV-infected patients with retinitis was found (p < 0.02).

CONCLUSIONS

We estimated the frequency of CMV viral load infection in Iranian HIV-1-infected patients with a CD4+ cell count <100 mm3/mL in the largest national referral center for HIV-1 infection in Iran. Further research is required on the relevance of CMV viral load in diagnostic and prognostic value of CMV-EOD.

Where do we Stand after Decades of Studying Human Cytomegalovirus?

Human cytomegalovirus (HCMV), a linear double-stranded DNA betaherpesvirus belonging to the family of Herpesviridae, is characterized by widespread seroprevalence, ranging between 56% and 94%, strictly dependent on the socioeconomic background of the country being considered. Typically, HCMV causes asymptomatic infection in the immunocompetent population, while in immunocompromised individuals or when transmitted vertically from the mother to the fetus it leads to systemic disease with severe complications and high mortality rate. Following primary infection, HCMV establishes a state of latency primarily in myeloid cells, from which it can be reactivated by various inflammatory stimuli. Several studies have shown that HCMV, despite being a DNA virus, is highly prone to genetic variability that strongly influences its replication and dissemination rates as well as cellular tropism. In this scenario, the few currently available drugs for the treatment of HCMV infections are characterized by high toxicity, poor oral bioavailability, and emerging resistance. Here, we review past and current literature that has greatly advanced our understanding of the biology and genetics of HCMV, stressing the urgent need for innovative and safe anti-HCMV therapies and effective vaccines to treat and prevent HCMV infections, particularly in vulnerable populations.

Immunization with Human Cytomegalovirus Core Fusion Machinery and Accessory Envelope Proteins Elicit Strong Synergistic Neutralizing Activities

Human cytomegalovirus (HCMV) core fusion machinery proteins gB and gH/gL, and accessory proteins UL128/UL130/UL131A, are the key envelope proteins that mediate HCMV entry into and infection of host cells. To determine whether these HCMV envelope proteins could elicit neutralizing activities synergistically, we immunized rabbits with individual or various combinations of these proteins adsorbed to aluminum hydroxide mixed with CpG-ODN. We then analyzed serum neutralizing activities with multiple HCMV laboratory strains and clinical isolates. HCMV trimeric gB and gH/gL elicited high and moderate titers of HCMV neutralizing activity, respectively. HCMV gB in combination with gH/gL elicited up to 17-fold higher HCMV neutralizing activities compared to the sum of neutralizing activity elicited by the individual proteins analyzed with both fibroblasts and epithelial cells. HCMV gB+gH/gL+UL128/UL130/UL131A in combination increased the neutralizing activity up to 32-fold compared to the sum of neutralizing activities elicited by the individual proteins analyzed with epithelial cells. Adding UL128/UL130/UL131A to gB and gH/gL combination did not increase further the HCMV neutralizing activity analyzed with fibroblasts. These data suggest that the combination of HCMV core fusion machinery envelope proteins gB+gH/gL or the combination of gB and pentameric complex could be ideal vaccine candidates that would induce optimal immune responses against HCMV infection.

Cytomegalovirus-associated esophageal stricture as a manifestation of the immune reconstitution inflammatory syndrome

Cytomegalovirus (CMV) esophagitis is well described in immunocompromised individuals, however, esophageal stricture due to CMV is rare. CMV disease in the setting of the immune reconstitution inflammatory syndrome (IRIS) usually takes the form of an immune-recovery uveitis or retinitis. We describe a young female patient with HIV who developed an esophageal stricture due to CMV within 6 months of starting antiretroviral therapy (ART). The patient responded well to treatment which involved 14 days of intravenous ganciclovir and esophageal dilatation. This is the first description of a patient developing gastrointestinal cytomegalovirus disease as a manifestation of IRIS.

Battle between Host Immune Cellular Responses and HCMV Immune Evasion

Human cytomegalovirus (HCMV) is ubiquitously prevalent. HCMV infection is typically asymptomatic and controlled by the immune system in healthy individuals, yet HCMV can be severely pathogenic for the fetus during pregnancy and in immunocompromised persons, such as transplant recipients or HIV infected patients. HCMV has co-evolved with the hosts, developed strategies to hide from immune effector cells and to successfully survive in the human organism. One strategy for evading or delaying the immune response is maintenance of the viral genome to establish the phase of latency. Furthermore, HCMV immune evasion involves the downregulation of human leukocyte antigens (HLA)-Ia molecules to hide infected cells from T-cell recognition. HCMV expresses several proteins that are described for downregulation of the HLA class I pathway via various mechanisms. Here, we review the wide range of immune evasion mechanisms of HCMV. Understanding the mechanisms of HCMV immune evasion will contribute to the development of new customized therapeutic strategies against the virus.

Immunization of Rabbits with Recombinant Human Cytomegalovirus Trimeric versus Monomeric gH/gL Protein Elicits Markedly Higher Titers of Antibody and Neutralization Activity

Congenital human cytomegalovirus (HCMV) infection and HCMV infection of immunosuppressed patients cause significant morbidity and mortality, and vaccine development against HCMV is a major public health priority. HCMV envelope glycoproteins gB, gH, and gL, which constitute the core fusion machinery, play critical roles in HCMV fusion and entry into host cells. HCMV gB and gH/gL have been reported to elicit potent neutralizing antibodies. Recently, the gB/gH/gL complex was identified in the envelope of HCMV virions, and 16–50% of the total gH/gL bound to gB, forming the gB/gH/gL complex. These findings make the gB/gH/gL a unique HCMV vaccine candidate. We previously reported the production of HCMV trimeric gB and gH/gL heterodimers, and immunization with a combination of trimeric gB and gH/gL heterodimers elicited strong synergistic HCMV-neutralizing activity. To further improve the immunogenicity of gH/gL, we produced trimeric gH/gL. Rabbits immunized with HCMV trimeric gH/gL induced up to 38-fold higher serum titers of gH/gL-specific IgG relative to HCMV monomeric gH/gL, and elicited ~10-fold higher titers of complement-dependent and complement-independent HCMV-neutralizing activity for both epithelial cells and fibroblasts. HCMV trimeric gH/gL in combination with HCMV trimeric gB would be a novel promising HCMV vaccine candidate that could induce highly potent neutralizing activities.

Development of novel vaccines against human cytomegalovirus

Congenital human cytomegalovirus (HCMV) infection and HCMV infection of the immunosuppressed patients cause significant morbidity and mortality, and vaccine development against HCMV is a major public health priority. Efforts to develop HCMV vaccines have been ongoing for 50 y, though no HCMV vaccine has been licensed; encouraging and promising results have obtained from both preclinical and clinical trials. HCMV infection induces a wide range of humoral and T cell-mediated immune responses, and both branches of immunity are correlated with protection. In recent years, there have been novel approaches toward the development of HCMV vaccines and demonstrated that vaccine candidates could potentially provide superior protection over natural immunity acquired following HCMV infection. Further, rationally designed HCMV protein antigens that express native conformational epitopes could elicit optimal immune response. HCMV vaccine candidates, using a multi-antigen approach, to maximize the elicited protective immunity will most likely be successful in development of HCMV vaccine.

Mononeuritis multiplex: an uncommon neurological manifestation of cytomegalovirus reactivation in an HIV-infected patient

Background

Cytomegalovirus (CMV) reactivation with neurological involvement in patients with acquired immunodeficiency syndrome (AIDS) is increasingly rare since the introduction of antiretroviral therapy (ART). Manifestations include encephalitis, myelitis, polyradiculopathy and, less commonly, mononeuritis multiplex (MNM). We report a case of disseminated CMV disease with gastrointestinal and peripheral and central nervous system involvement in a patient with AIDS, manifesting primarily as MNM.

Case presentation

A 31-year old woman with AIDS presented with a clinical picture of MNM. Electromyography confirmed the clinical findings. CMV DNA was detected in cerebrospinal fluid (CSF) and blood. Gastrointestinal involvement was histologically documented. HIV RNA was also detected in CSF and brain MRI was consistent with HIV encephalopathy. A diagnosis of disseminated CMV disease (with esophagitis, colitis, encephalitis and MNM) and HIV encephalopathy was made. Treatment consisted of ganciclovir and foscarnet, followed by maintenance therapy with valganciclovir. Evolution was favorable and valganciclovir was stopped after sustained immune recovery following ART initiation.

Conclusion

We discuss the diagnostic approach to CMV neurological disease, with a focus on MNM and CMV encephalitis. Combination therapy with ganciclovir and foscarnet should be considered for all forms of neurological involvement, although available data are scarce. Since there is significant overlap between CMV encephalitis and HIV encephalopathy, ART drugs with higher CSF penetration may have to be considered. ART and immune recovery are essential to improve outcomes.

Novel trimeric human cytomegalovirus glycoprotein B elicits a high-titer neutralizing antibody response

Human cytomegalovirus (HCMV) is a major cause of disability in congenitally infected infants and in the immunosuppressed. There is currently no licensed prophylactic HCMV vaccine. The HCMV envelope glycoprotein B (gB) is considered a major vaccine target antigen based on its critical role in mediating viral-host cell fusion and thus viral entry. The natural conformation of HCMV gB within the viral envelope is a trimer, but there has been no reported success in producing a recombinant trimeric gB suitable for vaccine use. Phase II clinical trials of a monomeric recombinant gB protein demonstrated 50% efficacy in preventing HCMV infection in seronegative women of reproductive age, and in reducing viremia in solid organ transplantation recipients. We now report the production of a uniformly trimeric recombinant HCMV gB protein in Chinese ovary cells, as demonstrated by Western blot analysis under modified non-reducing conditions and size exclusion chromatography with multi-angle scattering. Immunization of mice with trimeric HCMV gB induced up to 11-fold higher serum titers of total gB-specific IgG relative to monomeric HCMV gB using Alum + CpG as adjuvants. Further, trimeric HCMV gB elicited 50-fold higher complement-independent and 20-fold higher complement-dependent HCMV neutralizing titers compared to monomeric HCMV gB using the fibroblast cell line, MRC-5, and up to 6-fold higher complement-independent and -dependent HCMV neutralizing titers using the epithelial cell line, ARPE-19. The markedly enhanced HCMV neutralizing activity in response to trimeric HCMV gB was also observed using an additional four distinct clinical HCMV isolates. These data support a role for trimeric HCMV gB as an important component for clinical testing of a prophylactic HCMV vaccine.

Prevalence and clinical characteristics of CMV coinfection among HIV infected individuals in Guinea-Bissau: a cross-sectional study

OBJECTIVES

To describe the prevalence of CMV in a cohort of HIV infected individuals in Guinea-Bissau, West Africa and to evaluate differences in patients' clinical characteristics associated with their CMV status.

METHODS

Newly diagnosed HIV infected adults were invited to participate in this cross-sectional study, from May until December 2015. Enrolled patients were interviewed and underwent a full physical examination focusing on CMV disease manifestations. Blood samples were analysed for CMV serology, QuantiFERON-CMV response and CMV DNA. Mortality follow-up were registered for one year after inclusion.

RESULTS

In total, 180 patients were enrolled. Anti-CMV IgG positivity was found in 100% (138/138) and 2.8% (4/138) were anti-CMV IgM positive. A positive QuantiFERON-CMV response was found in 85.7% (60/70) of the patients and 60.6% (83/137) had CMV viraemia. QuantiFERON-CMV response and detectable CMV DNA were associated with lower CD4 cell count, older age and upper gastrointestinal complaints. During one year of follow-up, the IRR for death among CMV DNA positive patients was 1.5 (P = 0.5).

CONCLUSIONS

CMV coinfection was detected among all enrolled patients and CMV viraemia was highly prevalent. Only age and upper gastrointestinal complaints were associated with the patients' CMV status.

Residual Immune Activation and Latency

The introduction of combination antiretroviral therapy (cART) in the 1990s has dramatically changed the course of HIV infection, decreasing the risk for both AIDS- and non-AIDS-related events. Cancers, cardiovascular disease (CVD), liver and kidney disease, neurological disorders and frailty have become of great importance lately in the clinical management as they represent the principal cause of death in people living with HIV who receive cART (Kirk et al. in Clin Infect Dis 45(1):103-10, 2007; Strategies for Management of Antiretroviral Therapy Study et al. N Engl J Med 355(22):2283-2296, 2006; Ances et al. J Infect Dis 201(3):336-340, 2010; Desquilbet et al. J Gerontol A Biol Sci Med Sci 62(11):1279-1286, 2007; Lifson et al. HIV Clin Trials 9(3):177-185, 2008). Despite the undeniable achievements of cART, we are now faced with its limitations: a considerable proportion of individuals, referred as to immunological non-responders, fails to reconstitute the immune system despite optimal treatment and viral suppression (Kelley et al. Clin Infect Dis 48(6):787-794, 2009; Robbins et al. Clin Infect Dis 48(3):350-361, 2009) and remains at high risk for opportunistic infections and non-AIDS-related events (Strategies for Management of Antiretroviral Therapy Study et al. N Engl J Med 355(22):2283-2296, 2006). Moreover, the generalized state of immune activation and inflammation, linked to serious non-AIDS events, persists despite successful HIV suppression with cART. Finally, the current strategies have so far failed to eradicate the virus, and inflammation appears a driving force in viral persistence. In the light of all this, it is of fundamental importance to investigate the pathophysiological processes that link incomplete immune recovery, immune activation and HIV persistence to design targeted therapies that could impact on the three.

Natural Killer Cells in Human Immunodeficiency Virus-1 Infection: Spotlight on the Impact of Human Cytomegalovirus

Human cytomegalovirus (HCMV) has been closely associated with the human race across evolutionary time. HCMV co-infection is nearly universal in human immunodeficiency virus-1 (HIV-1)-infected individuals and remains an important cofactor in HIV-1 disease progression even in the era of effective antiretroviral treatment. HCMV infection has been shown to have a broad and potent influence on the human immune system and has been linked with the discovery and characterization of adaptive natural killer (NK) cells. Distinct NK-cell subsets, predominately expressing the activating receptor NKG2C and the marker of terminal differentiation CD57, expand in response to HCMV. These NK-cell populations engaged in the long-lasting interaction with HCMV, in addition to characteristic but variable expression of surface receptors, exhibit reduced expression of signaling proteins and transcription factors expressed by canonical NK cells. Broad epigenetic modifications drive the emergence and persistence of HCMV-adapted NK cells that have distinct functional characteristics. NKG2C⁺ NK-cell expansions have been observed in HIV-1 infected patients and other acute and chronic viral infections being systematically associated with HCMV seropositivity. The latter is potentially an important confounding variable in studies focused on the cellular NK-cell receptor repertoire and functional capacity. Here, focusing on HIV-1 infection we review the evidence in favor of “adaptive” changes likely induced by HCMV co-infection in NK-cell subsets. We highlight a number of key questions and how insights into the adaptive behavior of NK cells will inform new strategies exploiting their unique properties in the fight against HIV-1.

Mechanisms of human cytomegalovirus infection with a focus on epidermal growth factor receptor interactions

Human cytomegalovirus (HCMV) is a widespread opportunistic herpesvirus that causes severe diseases in immunocompromised individuals. It has a high prevalence worldwide that is linked with socioeconomic factors. Similar to other herpesviruses, HCMV has the ability to establish lifelong persistence and latent infection following primary exposure. HCMV infects a broad range of cell types. This broad tropism suggests that it may use multiple receptors for host cell entry. The identification of receptors used by HCMV is essential for understanding viral pathogenesis, because these receptors mediate the early events necessary for infection. Many cell surface components have been identified as virus receptors, such as epidermal growth factor receptor (EGFR), which is characterized by tyrosine kinase activity and plays a crucial role in the control of key cellular transduction pathways. EGFR is essential for HCMV binding, signaling, and host cell entry. This review focuses on HCMV infection via EGFR on different cell types and its implications for the cellular environment, viral persistence, and infection.

Radiological characteristics of pulmonary cryptococcosis in HIV-infected patients

Background

Current understanding of human immunodeficiency virus (HIV)-associated pulmonary cryptococcosis (PC) is largely based on studies performed about 2 decades ago which reported that the most common findings on chest radiograph were diffuse interstitial infiltrates. Few studies are available regarding the computed tomography (CT) findings. The aim of this study was to characterize chest CT features of HIV-associated PC.

Methods

HIV patients with cryptococccal infection and pulmonary abnormalities on Chest CT between September 2010 and May 2016 in the Second Affiliated Hospital of the Southeast University were retrospectively analyzed. Confirmed cases of tumors, mycobacterial infections and other fungal infections were excluded from the analysis.

Results

60 cases were identified. The median CD4 T-cell counts were 20 cells/μL (range, 0–205 cells/μL). Chest CT scans demonstrated nodular lesions in 93.3% of the studied patients. Those nodular lesions were usually cavitated and solitary nodule was the most common form. Pleural effusions and pneumonic infiltrates occurred in 11.6% and 31.7% of the cases respectively. Those lesions were usually had co-existing nodular lesions. Etiological analysis suggested that 76.8% of the nodular lesions could have a relationship with PC that 12.5% of the nodular lesions were “laboratory-confirmed” cases, 48.2% were “clinically confirmed” cases and 16.1% were “clinically probable” cases. 85.7% of the pleural effusions could be “clinically confirmed” cases of PC. At least, 38.5% of the diffuse pneumonic infiltrates may be clinically attributed to pneumocystis pneumonia.

Conclusions

This study suggested that pulmonary nodules but not diffuse pneumonia are the most common radiological characteristics of HIV-associated PC. HIV-infected patients with pulmonary nodules on Chest CT should particularly be screened for cryptococcal infection.

Replication of CMV in the gut of HIV-infected individuals and epithelial barrier dysfunction

Although invasive cytomegalovirus (CMV) disease is uncommon in the era of antiretroviral therapy (ART), asymptomatic CMV coinfection is nearly ubiquitous in HIV infected individuals. While microbial translocation and gut epithelial barrier dysfunction may promote persistent immune activation in treated HIV infection, potentially contributing to morbidity and mortality, it has been unclear whether CMV replication in individuals with no symptoms of CMV disease might play a role in this process. We hypothesized that persistent CMV replication in the intestinal epithelium of HIV/CMV-coinfected individuals impairs gut epithelial barrier function. Using a combination of state-of-the-art in situ hybridization technology (RNAscope) and immunohistochemistry, we detected CMV DNA and proteins and evidence of intestinal damage in rectosigmoid samples from CMV-positive individuals with both untreated and ART-suppressed HIV infection. Two different model systems, primary human intestinal cells differentiated in vitro to form polarized monolayers and a humanized mouse model of human gut, together demonstrated that intestinal epithelial cells are fully permissive to CMV replication. Independent of HIV, CMV disrupted tight junctions of polarized intestinal cells, significantly reducing transepithelial electrical resistance, a measure of monolayer integrity, and enhancing transepithelial permeability. The effect of CMV infection on the intestinal epithelium is mediated, at least in part, by the CMV-induced proinflammatory cytokine IL-6. Furthermore, letermovir, a novel anti-CMV drug, dampened the effects of CMV on the epithelium. Together, our data strongly suggest that CMV can disrupt epithelial junctions, leading to bacterial translocation and chronic inflammation in the gut and that CMV could serve as a target for therapeutic intervention to prevent or treat gut epithelial barrier dysfunction during HIV infection.

Review of cytomegalovirus coinfection in HIV-infected individuals in Africa

BACKGROUND

Cytomegalovirus (CMV) infection among HIV-infected individuals may cause end-organ disease, which is an AIDS-defining condition. Evidence from high-income countries suggests that CMV may alter the outcome of HIV infection, other than causing end-organ diseases. We reviewed literature on HIV and CMV coinfection in Africa.

METHODS

Systematic review of published studies on HIV and CMV coinfection in Africa using the PubMed database.

RESULTS

High CMV seroprevalence was found throughout Africa, exceeding 90% in most populations. Retinitis, pneumonia, and colitis were the most commonly reported CMV manifestations in HIV-infected individuals. Among patients with pulmonary symptoms, the prevalence of CMV pneumonitis varied from 20% to over 60%, whereas CMV was found in 0% to 14% of patients with gastrointestinal manifestations. Cytomegalovirus retinitis was found in 0% to 2.6% of examined HIV-infected individuals. The diagnostics of CMV end-organ diseases were found complex and difficult to interpret in African settings. Cytomegalovirus viremia was correlated with significantly lower CD4 cell count and increase in activated and apoptosis vulnerable T-lymphocytes. Also, CMV coinfection was found to be associated with increased transmission and progression of HIV infection. Moreover, detectable CMV DNA was an independent predictor of HIV transmission and mortality among HIV-infected individuals.

CONCLUSIONS

Cytomegalovirus is highly prevalent in Africa and a common cause of disease manifestations in HIV-infected individuals among all age groups. Cytomegalovirus coinfection in HIV-infected individuals in Africa is associated with increased transmission and mortality of HIV, but it is a neglected area of research.

Association of CMV-Specific T Cell-Mediated Immunity with CMV DNAemia and Development of CMV Disease in HIV-1-Infected Individuals

BACKGROUND

Among HIV-1-infected individuals, cytomegalovirus (CMV) reactivation and disease occur in the setting of advanced immunosuppression. The value of a standardized assessment of CMV-specific T-cell mediated immunity by the CMV QuantiFERON assay (CMV-QFT) has not yet been thoroughly investigated in HIV-1-infected subjects.

METHODS

Prospective, longitudinal study in 153 HIV-1-infected subjects with a CD4+ T cell count < 350/μL who simultaneously underwent CMV-QFT, CMV serology testing and CMV-DNA quantification. Factors associated with CMV-QFT were evaluated. Clinical screening for CMV manifestations was then performed every 3 months.

RESULTS

Among the 141 CMV IgG-seropositive individuals the CMV-QFT assay yielded reactive results in 84% (118/141), negative results in 15% (21/141) and indeterminate (negative mitogen IFN-gamma response) results in 1% (2/141) of subjects. The mean actual CD4+ T cell count was significantly higher in CMV-QFT reactive subjects, when compared to CMV-QFT non-reactive individuals (183 ± 102 vs. 126 ± 104 cells/μL, P = 0.015). A significantly lower proportion of CMV-QFT reactive vs. non-reactive patients displayed CMV DNAemia > 100 copies/mL (23% (27/118) vs. 48% (11/23), P = 0.02). Furthermore, a statistically significant inverse association between mitogen IFN-gamma response and CMV-DNAemia > 1000 copies/mL was observed (P < 0.001). During the observational period, 5 CMV end-organ manifestations were observed. In three of the CMV cases the CMV-QFT yielded indeterminate results.

CONCLUSIONS

While CMV-QFT reactivity indicates CMV-specific immunity, indeterminate results due to negative mitogen IFN-gamma response might reflect HIV-1-induced immunodeficiency. Thus, dependency upon CD4+ T cell count should be considered when interpreting CMV-QFT results.

Hydrogen Peroxide Induce Human Cytomegalovirus Replication through the Activation of p38-MAPK Signaling Pathway

Human cytomegalovirus (HCMV) is a major risk factor in transplantation and AIDS patients, which induces high morbidity and mortality. These patients infected with HCMV experience an imbalance of redox homeostasis that cause accumulation of reactive oxygen species (ROS) at the cellular level. H₂O₂, the most common reactive oxygen species, is the main byproduct of oxidative metabolism. However, the function of H₂O₂ on HCMV infection is not yet fully understood and the effect and mechanism of N-acetylcysteine (NAC) on H₂O₂-stimulated HCMV replication is unclear. We, therefore, examined the effect of NAC on H₂O₂-induced HCMV production in human foreskin fibroblast cells. In the present study, we found that H₂O₂ enhanced HCMV lytic replication through promoting major immediate early (MIE) promoter activity and immediate early (IE) gene transcription. Conversely, NAC inhibited H₂O₂-upregulated viral IE gene expression and viral replication. The suppressive effect of NAC on CMV in an acute CMV-infected mouse model also showed a relationship between antioxidants and viral lytic replication. Intriguingly, the enhancement of HCMV replication via supplementation with H₂O₂ was accompanied with the activation of the p38 mitogen-activated protein kinase pathway. Similar to NAC, the p38 inhibitor SB203580 inhibited H₂O₂-induced p38 phosphorylation and HCMV upregulation, while upregulation of inducible ROS was unaffected. These results directly relate HCMV replication to H₂O₂, suggesting that treatment with antioxidants may be an attractive preventive and therapeutic strategy for HCMV.

In vitro drug combination studies of Letermovir (AIC246, MK-8228) with approved anti-human cytomegalovirus (HCMV) and anti-HIV compounds in inhibition of HCMV and HIV replication

Despite modern prevention and treatment strategies, human cytomegalovirus (HCMV) remains a common opportunistic pathogen associated with serious morbidity and mortality in immunocompromised individuals, such as transplant recipients and AIDS patients. All drugs currently licensed for the treatment of HCMV infection target the viral DNA polymerase and are associated with severe toxicity issues and the emergence of drug resistance. Letermovir (AIC246, MK-8228) is a new anti-HCMV agent in clinical development that acts via a novel mode of action and has demonstrated anti-HCMV activity in vitro and in vivo. For the future, drug combination therapies, including letermovir, might be indicated under special medical conditions, such as the emergence of multidrug-resistant virus strains in transplant recipients or in HCMV-HIV-coinfected patients. Accordingly, knowledge of the compatibility of letermovir with other HCMV or HIV antivirals is of medical importance. Here, we evaluated the inhibition of HCMV replication by letermovir in combination with all currently approved HCMV antivirals using cell culture checkerboard assays. In addition, the effects of letermovir on the antiviral activities of selected HIV drugs, and vice versa, were analyzed. Using two different mathematical techniques to analyze the experimental data, (i) additive effects were observed for the combination of letermovir with anti-HCMV drugs and (ii) no interaction was found between letermovir and anti-HIV drugs. Since none of the tested drug combinations significantly antagonized letermovir efficacy (or vice versa), our findings suggest that letermovir may offer the potential for combination therapy with the tested HCMV and HIV drugs.

Assessment of the efficacy and safety of pre-emptive anti-cytomegalovirus (CMV) therapy in HIV-infected patients with CMV viraemia

A number of studies have demonstrated that cytomegalovirus (CMV) viraemia is a strong predictor for CMV end-organ disease (EOD) and death in HIV-infected patients. We assess the efficacy and safety of pre-emptive anti-CMV therapy (PACT) for preventing these events. We performed a retrospective study of all HIV-infected patients seen in our institution who had detectable CMV viraemia in 2007. Seventy-one patients with advanced HIV disease (median CD4 cell count = 61 cells/mm3) were studied. Sixteen patients received PACT (mainly valganciclovir). Patients who received PACT had lower CD4 cell counts and higher blood CMV DNA levels. The cumulative incidence of CMV EOD and death at one year was 44% and 21% in patients with and without PACT, respectively ( p = 0.013). Both PACT and high blood CMV DNA levels were significantly associated with CMV EOD and death in unadjusted analysis. In adjusted analyses, only blood CMV DNA levels remained significantly associated with the risk of CMV EOD and death, whereas PACT was associated with a non-significant trend towards reduced CMV EOD or death (hazard ratio: 0.25, p = 0.13). Five patients with PACT experienced severe drug-related adverse events. In conclusion, the use of PACT in HIV-infected patients with CMV viraemia could improve outcome but is associated with significant toxicity.

Cell-mediated immunity to human CMV infection: a brief overview

The cellular immune response to human cytomegalovirus (HCMV) has different components originating from both the adaptive and innate immune systems. There is a significant global interest in understanding how the immune system keeps HCMV under control, in particular with a view to situations where HCMV infection causes severe damage. Such settings include HIV infection, transplantation, and maybe most importantly perinatal medicine, HCMV being a major cause of sometimes catastrophic birth defects. The development of an active HCMV vaccine has proven very difficult but some recent successes raise hope that this might be available in the future. However, adoptive transfer of HCMV-specific T cells has been successfully used to prevent CMV disease after bone marrow transplantation for many years. In fact, the CD8 T cell response has been thought to be the most important effector response, with numerous reports focusing on specific T cell subsets recognizing select peptides in select human leukocyte antigen (HLA) contexts. However, it is becoming increasingly clear now that other cells, first and foremost CD4 T cells, but also gamma/delta (γ/δ) T cells and natural killer cells, are critically involved in the cellular immune response to HCMV. This commentary aims to provide a brief overview of the field.

Role of human cytomegalovirus tegument proteins in virion assembly

Like other herpesviruses, human cytomegalovirus (HCMV) contains a unique proteinaceous layer between the virion envelope and capsid, termed the tegument. Upon infection, the contents of the tegument layer are delivered to the host cell, along with the capsid and the viral genome, where they facilitate the initial stages of virus replication. The tegument proteins also play important roles in virion assembly and this dual nature makes them attractive potential targets for antiviral therapies. While our knowledge regarding tegument protein function during the initiation of infection has been the subject of intense study, their roles in assembly are much less well understood. In this review, we will focus on recent studies that highlight the functions of HCMV tegument proteins during assembly, and pose key questions for further investigation.

The tiers and dimensions of evasion of the type I interferon response by human cytomegalovirus

Human cytomegalovirus (HCMV) is a member of the β-herpesvirus family that invariably occupies hosts for life despite a consistent multi-pronged antiviral immune response that targets the infection. This persistence is enabled by the large viral genome that encodes factors conferring a wide assortment of sophisticated, often redundant phenotypes that disable or otherwise manipulate impactful immune effector processes. The type I interferon system represents a first line of host defense against infecting viruses. The physiological reactions induced by secreted interferon act to effectively block replication of a broad spectrum of virus types, including HCMV. As such, the virus must exhibit counteractive mechanisms to these responses that involve their inhibition, tolerance, or re-purposing. The goal of this review is to describe the impact of the type I interferon system on HCMV replication and to showcase the number and diversity of strategies employed by the virus that allow infection of hosts in the presence of interferon-dependent activity.

CNS-immune reconstitution inflammatory syndrome in the setting of HIV infection, part 2: discussion of neuro-immune reconstitution inflammatory syndrome with and without other pathogens

SUMMARY

While the previous review of CNS-IRIS in the HIV-infected patient on highly active antiretroviral therapy (Part 1) dealt with an overview of the biology, pathology, and neurologic presentation of this condition and a discussion of the atypical imaging findings in PML-IRIS and cryptococcal meningitis-IRIS due to the robust inflammatory response, the current review (Part 2) discusses the imaging findings in other commonly encountered organisms seen in association with CNS-IRIS, namely, VZV, CMV, HIV, Candida organisms, Mycobacterium tuberculosis, and Toxoplasma gondii. Also described is the imaging appearance of CNS-IRIS when not associated with a particular organism. Recognition of these imaging findings will give credence to the diagnosis of CNS-IRIS and will allow the clinician to institute changes in medical management, if necessary, so that immune reconstitution and improved patient outcome can occur with time.

Cytomegalovirus colitis following azacitidine therapy

The present report describes the first recognized case of cytomegalovirus (CMV) colitis following azacitidine therapy. A 66-year-old woman with myelodysplastic syndrome developed CMV colitis, which responded to treatment with ganciclovir. Currently, patients receiving azacitidine do not undergo CMV testing, or receive prophylaxis or CMV-free blood products; however, this policy needs to be revised.

Incomplete immune recovery in HIV infection: mechanisms, relevance for clinical care, and possible solutions

Treatment of HIV-infected patients with highly active antiretroviral therapy (HAART) usually results in diminished viral replication, increasing CD4+ cell counts, a reversal of most immunological disturbances, and a reduction in risk of morbidity and mortality. However, approximately 20% of all HIV-infected patients do not achieve optimal immune reconstitution despite suppression of viral replication. These patients are referred to as immunological nonresponders (INRs). INRs present with severely altered immunological functions, including malfunction and diminished production of cells within lymphopoetic tissue, perturbed frequencies of immune regulators such as regulatory T cells and Th17 cells, and increased immune activation, immunosenescence, and apoptosis. Importantly, INRs have an increased risk of morbidity and mortality compared to HIV-infected patients with an optimal immune reconstitution. Additional treatment to HAART that may improve immune reconstitution has been investigated, but results thus far have proved disappointing. The reason for immunological nonresponse is incompletely understood. This paper summarizes the known and unknown factors regarding the incomplete immune reconstitution in HIV infection, including mechanisms, relevance for clinical care, and possible solutions.

Evaluation of glycoprotein B genotypes and load of CMV infecting blood leukocytes on prognosis of AIDS patients

BACKGROUND

Cytomegalovirus (CMV) remains an important pathogen to immunocompromised patients even in the era of HAART. The present study aimed at evaluating the influence of CMV viral load and its gB genotypes on AIDS patients' outcome.

METHODS

Blood samples of 101 AIDS patients were collected and tested for HIV load, CD4 - cell count and opportunistic pathogens, including CMV. Semi-nested PCRs were run to detect CMV genome and in the positive samples, gB genotyping and CMV load were established using enzymatic restriction and real time PCR, respectively. All patients were clinically followed for four years.

RESULTS

In thirty patients (31%) CMV was detected and all fatal cases (n = 5) occurred in this group of patients (p = 0.007), but only two patients had CMV disease (1.9%). However, viral load was not statistically associated with any analyzed parameter. The most frequently observed CMV genotype was gB2 (45.16%) followed by gB3 (35.48%). gB2 genotype was more frequently found in patients with CD4-cell counts under 200 cells/mm³ (p = 0.0017), and almost all fatal cases (80%) had gB2 genotype.

CONCLUSIONS

Our study suggests that CMV and its polymorphisms in biologically relevant genes, such as the gB encoding ORF, may still influence the prognosis and outcome of AIDS patients. The gB2 genotype was associated to patient's bad outcome.

Early inhibitors of human cytomegalovirus: state-of-art and therapeutic perspectives

Human cytomegalovirus (HCMV) infection is associated with severe morbidity and mortality in immunocompromised individuals, mainly transplant recipients and AIDS patients, and is the most frequent cause of congenital malformations in newborn children. To date, few drugs are licensed for the treatment of HCMV infections, most of which target the viral DNA polymerase and suffer from many drawbacks, including long-term toxicity, low potency, and poor bioavailability. In addition, the emergence of drug-resistant viral strains is becoming an increasing problem for disease management. Finally, none of the current anti-HCMV drugs have been approved for the treatment of congenital infections. For all these reasons, there is still a strong need for new anti-HCMV drugs with novel mechanisms of action. The first events of the virus replication cycle, including attachment, entry, immediate-early gene expression, and immediate-early functions—in particular that of Immediate-Early 2 protein—represent attractive targets for the development of novel antiviral compounds. Such inhibitors would block not only the expression of viral immediate-early proteins, which play a key role in the pathogenesis of HCMV infection, but also the host immunomodulation and the changes to cell physiology induced by the first events of virus infection. This review describes the current knowledge on the initial phases of HCMV replication, their validation as potential novel antiviral targets, and the development of compounds that block such processes.

QuantiFERON®-CMV assay for the assessment of cytomegalovirus cell-mediated immunity

Cytomegalovirus (CMV) infection has historically been a major complication among immunocompromised patients, such as solid-organ and stem-cell transplant recipients and patients with advanced HIV infection. While the introduction of antiretroviral therapy has almost eradicated CMV infection in HIV-infected patients, CMV disease remains a significant problem in transplant recipients once antiviral prophylaxis is discontinued. QuantiFERON(®)-CMV allows the assessment of cellular immunity against CMV by detecting the production of IFN-γ following in vitro stimulation with CMV antigens. Preliminary studies have shown a correlation between a lack of detectable cell-mediated immunity measured by the QuantiFERON-CMV assay and a higher incidence of CMV infection and disease in immunocompromised patients. Measurement of cell-mediated immunity against CMV appears to be a promising strategy to identify patients at highest risk for the development of CMV disease and, therefore, to individualize preventive strategies for CMV in transplant recipients.

The importance of detecting cytomegalovirus infections in studies evaluating new therapies for severe sepsis

Cytomegalovirus infection is present in the majority of the population and is associated with substantial morbidity and mortality in immunocompromised patients. Recently, this viral infection has also been reported in nonimmunocompromised critically ill patients. We hypothesize that active cytomegalovirus infection may confound survival outcomes in severe sepsis trials. Scenarios based on three published studies on activated protein C were used as real examples for statistical simulations looking for how much bias in favor of or against activated protein C would be observed in single-arm studies (scenario 1), phase II trials (scenario 2A/2B), and phase III trials (scenario 3A/3B). Scenario 1 simulations evaluated a single-arm study and demonstrated that confounding biases could cause an absolute decrease of 5.7% to an increase of 6.1% on mortality rates of similar studies. Scenarios 2A and 3A evaluated phase II and III trials assuming that activated protein C is truly effective; they showed that trials with an imbalance on the proportion of active cytomegalovirus infection between study arms could lead to false-negative rates (β errors) in up to 25% of phase II trials and up to 42% of phase III trials. Scenarios 2B and 3B assumed that activated protein C was truly ineffective; they showed that imbalanced cytomegalovirus infection between arms would cause false-positive rates (α errors) in up to 5% of phase II and up to 7% of all phase III trials. The inclusion of an imbalanced proportion of patients with active cytomegalovirus infection may severely compromise the reliability of outcome results of severe sepsis trials independent of their design. Even randomized trials could have a much higher probability of false-negative rates for a new therapy than designed. Future severe sepsis trials should consider including active cytomegalovirus infection as a prospective covariate.

AIDS Cholangiopathy in an Asymptomatic, Previously Undiagnosed Late-Stage HIV-Positive Patient from Kenya

AIDS-associated cholangiopathy is a form of biliary tract inflammation with stricture formation seen in AIDS patients who are severely immunosuppressed. It is no longer common in countries in which HAART therapy is widely employed but is still seen in underdeveloped countries. The majority of patients are symptomatic at the time of presentation. Herein, we describe a seventy-four-year-old woman who presented with unilateral leg swelling after a prolonged airplane flight. She was otherwise entirely asymptomatic. Routine laboratory testing was notable for a hypochromic microcytic anemia, slight leukopenia, and mild hypoalbuminemia. Liver enzymes were all elevated. Deep venous thrombosis was confirmed, and a CT scan of the chest disclosed no pulmonary emboli. However, the visualized portion of the abdomen showed dilatation of the common bile and pancreatic ducts. This was confirmed on ultrasonography and MRCP, and no obstructive lesions were noted. An ERCP revealed a dilated common bile duct without filling defects or strictures. A balloon occlusion cholangiogram showed strictures and beading of the intrahepatic ducts. Shortly thereafter, serology for HIV returned positive along with a depressed CD4 cell count, and the patient was diagnosed with AIDS-associated cholangiography.

Recombinant mouse cytomegalovirus expressing a ligand for the NKG2D receptor is attenuated and has improved vaccine properties

Human CMV (HCMV) is a major cause of morbidity and mortality in both congenitally infected and immunocompromised individuals. Development of an effective HCMV vaccine would help protect these vulnerable groups. NK group 2, member D (NKG2D) is a potent activating receptor expressed by cells of the innate and adaptive immune systems. Its importance in HCMV immune surveillance is indicated by the elaborative evasion mechanisms evolved by the virus to avoid NKG2D. In order to study this signaling pathway, we engineered a recombinant mouse CMV expressing the high-affinity NKG2D ligand RAE-1γ (RAE-1γMCMV). Expression of RAE-1γ by MCMV resulted in profound virus attenuation in vivo and lower latent viral DNA loads. RAE-1γMCMV infection was efficiently controlled by immunodeficient hosts, including mice lacking type I interferon receptors or immunosuppressed by sublethal γ-irradiation. Features of MCMV infection in neonates were also diminished. Despite tight innate immune control, RAE-1γMCMV infection elicited strong and long-lasting protective immunity. Maternal RAE-1γMCMV immunization protected neonatal mice from MCMV disease via placental transfer of antiviral Abs. Despite strong selective pressure, the RAE-1γ transgene did not exhibit sequence variation following infection. Together, our results indicate that use of a recombinant virus encoding the ligand for an activating NK cell receptor could be a powerful approach to developing a safe and immunogenic HCMV vaccine.

Transient immunosuppression: a bridge between infection and the atypical autoimmunity of Guillain-Barré syndrome?

Guillain-Barré syndrome (GBS) is an acute, usually monophasic, disorder of the peripheral nervous system that is assumed to be of immune-mediated pathogenesis. However, several clinical features and experimental findings of GBS are uncharacteristic for an immune-mediated disorder and set this condition apart from other disorders with a putative immune-mediated pathogenesis. These features include, among others, the monophasic nature of GBS, the lack of response to immunosuppressive (unlike immunomodulatory) therapy, the absence of a typical association with immunogenetic background and the inability to establish a valid and relevant animal model. We suggest a comprehensive hypothesis for the pathogenesis of GBS that is based on the assumption that the condition is due to a transient (or occasionally chronic) immune deficiency, as in most cases GBS follows an infection with pathogens known to induce immunosuppression. Such infections may be followed by breakdown of immune tolerance and induction of an immune attack on peripheral nerves. Mounting of the immune-mediated assault might be triggered either by the same infective pathogen or by secondary infection. Clearance of the infection and resumption of a normal immune response and tolerance eventually terminate the immune-mediated damage to the peripheral nerves and enable recovery. This hypothesis assumes that the entire sequence of events that culminates in GBS is due to transient exogenous factors and excludes a significant role for inherent host susceptibility, which explains the monophasic nature of the disorder.

[Massive alveolar hemorrhage due to cytomegalovirus (CMV) and HIV infection]

Alveolar hemorrhage may be a complication of diseases with local and systemic manifestations. Both share the same pathophysiological concept: damage to the alveolar microcirculation. It is a clinical entity that generates a diagnostic challenge for the physician. Early recognition favors aggressive treatment, which can improve the outcome. Despite the technological advances in its diagnosis and treatment, it is still a condition having high morbidity and mortality. We present the case of a 42-year old woman diagnosed of massive alveolar hemorrhage induced by cytomegalovirus (CMV) and HIV infection. Its presentation is atypical because most reported cases have occurred as a pneumonic process, episodes of massive hemorrhage being uncommon. The diagnosis was documented by bronchoscopy with bronchoalveolar lavage and etiological diagnosis with molecular techniques using reverse transcription polymerase chain reaction.

The role of the human cytomegalovirus UL111A gene in down-regulating CD4+ T-cell recognition of latently infected cells: implications for virus elimination during latency

The capacity of human cytomegalovirus (HCMV) to establish and maintain a latent infection from which it can later reactivate ensures its widespread distribution in the population, but the mechanisms enabling maintenance of latency in the face of a robust immune system are poorly understood. We examined the role of the HCMV UL111A gene, which encodes homologs of the immunosuppressive cytokine interleukin-10 in the context of latent infection of myeloid progenitor cells. A UL111A deletion virus was able to establish, maintain, and reactivate from experimental latency in a manner comparable with parental virus, but major histocompatibility complex class II levels increased significantly on the surfaces of cells infected with the deletion virus. Importantly, there was an increase in both allogeneic and autologous peripheral blood mononuclear cells and CD4(+) T-cell responses to UL111A deletion virus-infected myeloid progenitors, indicating that loss of the capacity to express viral interleukin-10 during latency results in latently infected cells becoming more readily recognizable by a critical arm of the immune response. The detection of a viral gene that suppresses CD4(+) T-cell recognition of latently infected cells identifies an immune evasion strategy that probably enhances the capacity of HCMV to persist in a latent state within the human host.