Human cytomegalovirus (CMV)-specific CD8+ T cell responses are reduced in HIV-infected individuals with a history of CMV disease despite CD4+ T cell recovery

Cytomegalovirus Retinitis: Clinical Manifestations, Diagnosis and Treatment

Cytomegalovirus (CMV) retinitis is the most common eye disease associated with CMV infection in immunocompromised individuals. The CMVR may initially be asymptomatic; however, relatively mild vitreous inflammation at the onset may be an important differential point from other diseases in HIV patients. Fundus photography, CD4 T-cell count, and telemedicine could be used to screen and monitor the high-risk population, particularly in resource-limited regions. Retinitis generally starts in the peripheral retina and advances toward the posterior pole, which could develop to the characteristic "pizza pie" appearance marked by central retinal necrosis and intraretinal hemorrhage. CMVR causes vision loss if left untreated, and early antiviral therapy significantly reduces the risk of vision loss. Alongside traditional antiviral treatments, immunotherapies including CMV-specific adoptive T-cell therapy and CMV immunoglobulin (CMVIG) are emerging as promising treatment options due to their favorable tolerability and reduced mortality. This review comprehensively examines CMV retinitis, encompassing the clinical features, differential diagnosis, laboratory tests, and updated treatment strategies to inform clinical management.

Low frequency of cytomegalovirus (CMV) disease despite high prevalence of CMV viraemia in patients with advanced HIV infection: a clinical and immunological 48-week follow-up study

OBJECTIVES

The aim of the study was to investigate the dynamics of cytomegalovirus (CMV) replication and CMV-specific immune response recovery after antiretroviral treatment (ART) initiation in patients with advanced HIV infection.

METHODS

A prospective observational study of patients with HIV infection and CD4 counts of < 100 cells/µL was carried out (September 2015 to July 2018). HIV viral load (VL), CD4 count and CMV VL were determined by quantitative polymerase chain reaction (PCR) at baseline and at 4, 12, 24 and 48 weeks, and CMV-specific immune response was determined by QuantiFERON-CMV assay at baseline and 48 weeks. All patients were started on ART but only those with CMV end-organ disease (EOD) received anti-CMV treatment.

RESULTS

Fifty-three patients with a median age of 43.6 [interquartile range (IQR) 36.7-52.4] years were included in the study. At baseline, the median CD4 count was 30 cells/µL (IQR 20-60 cells/µL) and the median HIV VL was 462 000 HIV-1 RNA copies/mL (IQR 186 000-1 300 000 copies/mL). At baseline, 32% patients had detectable CMV viraemia but none had detectable CMV viraemia at 48 weeks. Only one of 53 (1.9%) patients developed EOD during follow-up. Seven (13.2%) patients were lost to follow-up and six (11.3%) died; none of the deaths was related to CMV. Similar percentages of patients had a CMV-specific immune response at baseline (71.7%) and at 48 weeks (70.0%). The magnitude of this response tended to increase over time [median 1.63 (IQR 0.15-5.77) IU/mL at baseline vs. median 2.5 (IQR 0.1-8.325) IU/mL at 48 weeks; P = 0.11]. We did not find any risk factors associated with 48-week mortality.

CONCLUSIONS

Although the prevalence of CMV viraemia in patients with advanced HIV infection remains high, achieving a good immunological recovery through ART is enough to suppress CMV viraemia, without an increased risk of CMV EOD. The prevalence of a CMV-specific immune response was high and endured over time.

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.

Low T-Cell Responses to Mitogen Stimulation Predicts Poor Survival in Recipients of Allogeneic Hematopoietic Stem Cell Transplantation

Background

Successful engraftment and reconstitution of the innate and adaptive immune system are associated with improved outcomes in recipients of allogeneic hematopoietic stem cell transplantation (HSCT). A clinically meaningful and simple biomarker of immunosuppression could potentially assist clinicians in their decision-making. We aimed to determine the relationship between T-cell production of interferon gamma (IFN-γ) in response to phytohemagglutinin (PHA) to clinical outcomes in HSCT recipients.

Methods

A prospective observational multicenter study of 73 adult allogeneic HSCT recipients was conducted in Melbourne, Australia. Eligible participants were >18 years and at risk of cytomegalovirus disease. T-cell responses to PHA were assessed at 3, 6, 9, and 12 months post-HSCT using the commercial quantiferon-cytomegalovirus assay, which quantifies IFN-γ production by ELISA following stimulation with PHA. A low response was defined as IFN-γ <0.5 IU/ml following stimulation with PHA.

Results

At 3 months post-HSCT, high responses to PHA (median IFN-γ 7.68 IU/ml) were seen in 63% of participants and low responses to PHA (median IFN-γ 0.06 IU/ml) in 37%. IFN-γ responses to PHA were significantly associated with the severity of acute graft versus host disease (AGVHD) (spearman r = −0.53, p < 0.001) and correlated with blood lymphocyte count (spearman r = 0.52, p < 0.001). Twelve month overall survival was greater in individuals with high compared to low IFN-γ response to PHA at 3 months [92 vs. 62%, respectively, Cox proportional hazard ratio (HR): 4.12 95% CI: 1.2–13.7, p = 0.02]. Non-relapse mortality (NRM) was higher in individuals with low IFN-γ response to PHA (competing risk regression HR 11.6 p = 0.02). In individuals with no AGVHD compared to AGVHD and high IFN-γ response to PHA compared to AGVHD and low IFN-γ response to PHA, 12-month survival was 100 vs. 80 vs. 52%, respectively (log rank test p < 0.0001).

Conclusion

Low IFN-γ response to PHA at the 3-month time-point following allogeneic HSCT was predictive of reduced 12-month overall survival, increased NRM, and reduced survival in recipients with AGVHD. Assessing IFN-γ response to PHA post-HSCT may be a clinically useful immune biomarker.

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.

Low levels of mannan-binding lectin or ficolins are not associated with an increased risk of cytomegalovirus disease in HIV-infected patients

BACKGROUND

In HIV-infected patients, prediction of Cytomegalovirus (CMV) disease remains difficult. A protective role of mannan-binding lectin (MBL) and ficolins against CMV disease has been reported after transplantation, but the impact in HIV-infected patients is unclear.

METHODS

In a case-control study nested within the Swiss HIV Cohort Study, we investigated associations between plasma levels of MBL/ficolins and CMV disease. We compared HIV-infected patients with CMV disease (cases) to CMV-seropositive patients without CMV disease (controls) matched for CD4 T-cells, sampling time, and use of combination antiretroviral therapy. MBL and M-ficolin, L-ficolin, and H-ficolin were quantified using ELISA.

RESULTS

We analysed 105 cases and 105 matched controls. CMV disease was neither associated with MBL (odds ratio [OR] 1.03 per log(10) ng/mL increase (95% CI 0.73-1.45)) nor with ficolins (OR per log(10) ng/mL increase 0.66 (95% CI 0.28-1.52), 2.34 (95% CI 0.44-12.36), and 0.89 (95% CI 0.26-3.03) for M-ficolin, L-ficolin, and H-ficolin, respectively). We found no evidence of a greater association between MBL and CMV disease in patients with low CD4 counts; however in the multivariable analysis, CMV disease was more likely in patients with an increased HIV RNA (OR 1.53 per log(10) copies/mL; 95% CI 1.08-2.16), or a shorter duration of HIV-infection (OR 0.91 per year; 95% CI 0.84-0.98).

CONCLUSIONS

CMV disease is not associated with low levels of MBL/ficolins, suggesting a lack of a protective role in HIV-infected patients.

Biomarkers of immune dysfunction following combination antiretroviral therapy for HIV infection

Combination antiretroviral therapy (cART) has significantly reduced morbidity and mortality of HIV-infected patients, yet their life expectancy remains reduced compared with the general population. Most HIV-infected patients receiving cART have some persistent immune dysfunction characterized by chronic immune activation and premature aging of the immune system. Here we review biomarkers of T-cell activation (CD69, -25 and -38, HLA-DR, and soluble CD26 and -30); generalized immune activation (C-reactive protein, IL-6 and D-dimer); microbial translocation (lipopolysaccharide, 16S rDNA, lipopolysaccharide-binding protein and soluble CD14); and immune dysfunction of specific cellular subsets (T cells, natural killer cells and monocytes) in HIV-infected patients on cART and their relationship to adverse clinical outcomes including impaired CD4 T-cell recovery, as well as non-AIDS clinical events, such as cardiovascular disease.

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.

Understanding human T-cell-mediated immunoregulation through herpesviruses

Human herpesviruses have coevolved with humans over millions of years, and adaptation of latent infection within the cells of the immune system is a unique characteristic of many of these viruses. Following primary infection, these herpesviruses establish an asymptomatic-persistent infection in healthy individuals that is strictly controlled by virus-specific CD8(+) and CD4(+) T cells. Here, we provide a brief overview of how the human immune system interacts with these latent viruses and regulates the lifelong host-virus relationship in healthy virus carriers. Extensive studies on T-cell-mediated immune regulation over the last decade has allowed researchers to successfully translate these findings into the clinical setting to treat various herpesvirus-associated diseases in transplant patients and individuals with virus-associated malignancies. It is highly likely that these newly emerging T-cell-based therapeutic and diagnostic technologies will revolutionize the clinical management of patients with herpesvirus-associated diseases.

Immunobiology of human cytomegalovirus: from bench to bedside

SUMMARY

Following primary infection, human cytomegalovirus (HCMV) establishes lifelong latency and periodically reactivates without causing symptoms in healthy individuals. In the absence of an adequate host-derived immune response, this fine balance of permitting viral reactivation without causing pathogenesis is disrupted, and HCMV can subsequently cause invasive disease and an array of damaging indirect immunological effects. Over the last decade, our knowledge of the immune response to HCMV infection in healthy virus carriers and diseased individuals has allowed us to translate these findings to develop better diagnostic tools and therapeutic strategies. The application of these emerging technologies in the clinical setting is likely to provide opportunities for better management of patients with HCMV-associated diseases.