CMV retinopathy in the antiretroviral therapy era: prevention, diagnosis, and management

Post-CD19 Chimeric Antigen Receptor T-Cell Therapy Cytomegalovirus Retinitis

The purpose of this case report was to present a case of cytomegalovirus (CMV) retinitis in a patient with diffuse large B-cell lymphoma (DLBCL) post-CD19 chimeric antigen receptor (CAR) T-cell therapy. A 43-year-old female patient who was complaining of metamorphopsia and sudden blurring in the vision of her left eye was referred to the ophthalmology department. The patient had DLBCL and was started on systemic chemotherapy, which showed no response to therapy and disease progression. Therefore, she was diagnosed with primary refractory DLBCL and treated with CAR T-cell therapy.

The visual acuity of the left eye was 20/25 in the left eye on the Snellen visual acuity chart. The dilated fundus examination of the left eye demonstrated a diffuse yellowish retinal infiltration radiating from the optic disc involving the inferior macula and inferotemporal arcade. A color fundus image of the left eye showed a creamy infiltrate involving the inferior half of the macula sparing the fovea with subtle small white lesions in the midperiphery. Horizontal cross-section optical coherence tomography (OCT) of the macula of the left eye showed islands of destruction of all the retinal layers, which are replaced with moderately hyperreflective material; these infiltrates spare the fovea but with subfoveal fluid. Further systemic evaluation indicated CMV viremia reactivation and an absolute CD4+ cells count of 13 cells/mcL. Thus, she was diagnosed with CMV retinitis.

After three days of the initial presentation, she received the first intravitreal ganciclovir injection; 17 days after presentation, she received five intravitreal ganciclovir injections. The patient responded well to intravitreal ganciclovir therapy. She regained very good vision, and the visual acuity was 20/20 in both eyes. Early recognition and initiation of proper treatment are crucial. Thus, any visual complaints in patients with immunodeficiency should be taken seriously and should be further assessed. As the right eye had retinal scaring indicating previous retinitis, prophylactic treatment with ganciclovir could have been used to reduce the risk of retinitis development in the left eye.

Cytomegalovirus retinitis and antiretroviral treatment: A fifteen year experience

Background

South Africa’s public antiretroviral treatment (ART) programme has undergone progressive changes since its introduction in 2004. The effect of this on the burden of the AIDS-defining opportunistic infection, cytomegalovirus retinitis (CMVR), in SA, has not been fully appreciated.

Objectives

To determine the effect of ART availability in the public sector of SA on the trend in the number of cases of newly diagnosed CMVR over time.

Methods

This is a retrospective study from 01 November 2002 to 31 August 2017 that took place at a tertiary hospital in the KwaZulu-Natal (KZN) province.

Results

A total of 383 participants were included in the study, with 60.1% being female and 94% of black African origin. The mean age of patients was 34.08 years (SD ± 7.24). A linear trend model suggested an overall linear decrease in the number of new cases of CMVR per year (R² of 0.67). The average number of new cases of CMVR per year prior to ART being available to all persons living with HIV (PLWH) with a CD4+ ≤ 350 cells/μL and after was 34 and 13, respectively, and the difference (61.76%) between these values was statistically significant, P = 0.001. The median CD4+ count at diagnosis of CMVR was 22 (interquartile range: 9–51.25) cells/μL. An overall 51% of patients in this study were on ART at diagnosis of CMVR. There was a higher proportion of patients on ART ≤ 6 months (63.3%), compared with those on ART > 6 months (36.7%), and the difference was statistically significant, P < 0.01.

Conclusion

ART has resulted in a decrease in the burden of CMVR on ophthalmic services for many in KZN, particularly following the introduction of ART for all PLWH with a CD4 ≤ 350 cells/μL.

CMV-Specific CD8 T Cell Differentiation and Localization: Implications for Adoptive Therapies

Human cytomegalovirus (HCMV) is a ubiquitous virus that causes chronic infection and, thus, is one of the most common infectious complications of immune suppression. Adoptive transfer of HCMV-specific T cells has emerged as an effective method to reduce the risk for HCMV infection and/or reactivation by restoring immunity in transplant recipients. However, the CMV-specific CD8⁺ T cell response is comprised of a heterogenous mixture of subsets with distinct functions and localization, and it is not clear if current adoptive immunotherapy protocols can reconstitute the full spectrum of CD8⁺ T cell immunity. The aim of this review is to briefly summarize the role of these T cell subsets in CMV immunity and to describe how current adoptive immunotherapy practices might affect their reconstitution in patients. The bulk of the CMV-specific CD8⁺ T cell population is made up of terminally differentiated effector T cells with immediate effector function and a short life span. Self-renewing memory T cells within the CMV-specific population retain the capacity to expand and differentiate upon challenge and are important for the long-term persistence of the CD8⁺ T cell response. Finally, mucosal organs, which are frequent sites of CMV reactivation, are primarily inhabited by tissue-resident memory T cells, which do not recirculate. Future work on adoptive transfer strategies may need to focus on striking a balance between the formation of these subsets to ensure the development of long lasting and protective immune responses that can access the organs affected by CMV disease.

Rationally designed chemokine-based toxin targeting the viral G protein-coupled receptor US28 potently inhibits cytomegalovirus infection in vivo

The use of receptor-ligand interactions to direct toxins to kill diseased cells selectively has shown considerable promise for treatment of a number of cancers and, more recently, autoimmune disease. Here we move the fusion toxin protein (FTP) technology beyond cancer/autoimmune therapeutics to target the human viral pathogen, human cytomegalovirus (HCMV), on the basis of its expression of the 7TM G protein-coupled chemokine receptor US28. The virus origin of US28 provides an exceptional chemokine-binding profile with high selectivity and improved binding for the CX3C chemokine, CX3CL1. Moreover, US28 is constitutively internalizing by nature, providing highly effective FTP delivery. We designed a synthetic CX3CL1 variant engineered to have ultra-high affinity for US28 and greater specificity for US28 than the natural sole receptor for CX3CL1, CX3CR1, and we fused the synthetic variant with the cytotoxic domain of Pseudomonas Exotoxin A. This novel strategy of a rationally designed FTP provided unparalleled anti-HCMV efficacy and potency in vitro and in vivo.

Role of the immune system in HIV-associated neuroinflammation and neurocognitive implications

Individuals living with HIV who are optimally treated with combination antiretroviral therapy (cART) can now lead an extended life. In spite of this remarkable survival benefit from viral suppression achieved by cART in peripheral blood, the rate of mild to moderate cognitive impairment remains high. A cognitive decline that includes impairments in attention, learning and executive function is accompanied by increased rates of mood disorders that together adversely impact the daily life of those with chronic HIV infection. The evidence is clear that cells in the brain are infected with HIV that has crossed the blood-brain barrier both as cell-free virus and within infected monocytes and T cells. Viral proteins that circulate in blood can induce brain endothelial cells to release cytokines, invoking another source of neuroinflammation. The difficulty of efficient delivery of cART to the central nervous system (CNS) contributes to elevated viral load in the CNS, resulting in a persistent HIV-associated neurocognitive disorders (HAND). The pathogenesis of HAND is multifaceted, and mounting evidence indicates that immune cells play a major role. HIV-infected monocytes and T cells not only infect brain resident cells upon migration into the CNS but also produce proinflammatory cytokines such as TNF and IL-1ß, which in turn, further activate microglia and astrocytes. These activated brain resident cells, along with perivascular macrophages, are the main contributors to neuroinflammation in HIV infection and release neurotoxic factors such as excitatory amino acids and inflammatory mediators, resulting in neuronal dysfunction and death. Cytokines, which are elevated in the blood of patients with HIV infection, may also contribute to brain inflammation by entering the brain from the blood. Host factors such as aging and co-morbid conditions such as cytomegalovirus co-infection and vascular pathology are important factors that affect the HIV-host immune interactions in HAND pathogenesis. By these diverse mechanisms, HIV-1 induces a neuroinflammatory response that is likely to be a major contributor to the cognitive and behavior changes seen in HIV infection.

Self-boosting vaccines and their implications for herd immunity

Advances in vaccine technology over the past two centuries have facilitated far-reaching impact in the control of many infections, and today's emerging vaccines could likewise open new opportunities in the control of several diseases. Here we consider the potential, population-level effects of a particular class of emerging vaccines that use specific viral vectors to establish long-term, intermittent antigen presentation within a vaccinated host: in essence, "self-boosting" vaccines. In particular, we use mathematical models to explore the potential role of such vaccines in situations where current immunization raises only relatively short-lived protection. Vaccination programs in such cases are generally limited in their ability to raise lasting herd immunity. Moreover, in certain cases mass vaccination can have the counterproductive effect of allowing an increase in severe disease, through reducing opportunities for immunity to be boosted through natural exposure to infection. Such dynamics have been proposed, for example, in relation to pertussis and varicella-zoster virus. In this context we show how self-boosting vaccines could open qualitatively new opportunities, for example by broadening the effective duration of herd immunity that can be achieved with currently used immunogens. At intermediate rates of self-boosting, these vaccines also alleviate the potential counterproductive effects of mass vaccination, through compensating for losses in natural boosting. Importantly, however, we also show how sufficiently high boosting rates may introduce a new regime of unintended consequences, wherein the unvaccinated bear an increased disease burden. Finally, we discuss important caveats and data needs arising from this work.