Cytomegalovirus Infection Facilitates the Costimulation of CD57+CD28- CD8 T Cells in HIV Infection and Atherosclerosis via the CD2-LFA-3 Axis.

CD8 T cells are emerging as important mediators in atherosclerosis and cardiovascular disease (CVD). Immune activation may play a particular role in people with HIV (PWH) who are at an increased risk of CVD, even after controlling for known CVD risk factors. Latent CMV infection is associated with increased CVD risk for both PWH and people without HIV, and human CMV-specific CD4 and CD8 T cells are enriched for an immunosenescent phenotype. We previously showed that CMV coinfection in PWH promotes vascular homing and activation of inflammatory CD4 T cells through the CD2-LFA-3 axis. However, the role of CD2/LFA3 costimulation of CD8 T cells in PWH with CMV has yet to be described. In the present study, we demonstrate that CD2 expression on CX3CR1+CD57+CD28- inflammescent CD8 T cells is increased on cells from CMV-seropositive PWH. In vitro CD2/LFA-3 costimulation enhances TCR-mediated activation of these inflammatory CD8 memory T cells. Finally, we show that LFA-3 is highly expressed in aortas of SIV-infected rhesus macaques and in atherosclerotic plaques of people without HIV. Our findings are consistent with a model in which CMV infection enhances CD2 expression on highly proinflammatory CD8 T cells that can then be stimulated by LFA-3 expressed in the vasculature, even in the absence of CD28 costimulation. This model, in which CMV infection exacerbates toxic cytokine and granzyme production by CD8 T cells within the vasculature, highlights a potential therapeutic target in atherosclerosis development and progression, especially for PWH.

CX3CL1 and IL-15 Promote CD8 T cell chemoattraction in HIV and in atherosclerosis.

Atherosclerotic cardiovascular disease (ASCVD) remains an important cause of morbidity in the general population and risk for ASCVD is increased approximately 2-fold in persons living with HIV infection (PLWH). This risk is linked to elevated CD8 T cell counts that are abundant in atherosclerotic plaques and have been implicated in disease pathogenesis yet the mechanisms driving T cell recruitment to and activation within plaques are poorly defined. Here we investigated the role of CD8 T cells in atherosclerosis in a non-human primate model of HIV infection and in the HIV-uninfected elderly; we sought to identify factors that promote the activation, function, and recruitment to endothelium of CX3CR1+ CD8 T cells. We measured elevated expression of CX3CL1 and IL-15, and increased CD8 T cell numbers in the aortas of rhesus macaques infected with SIV or SHIV, and demonstrated similar findings in atherosclerotic vessels of HIV-uninfected humans. We found that recombinant TNF enhanced the production and release of CX3CL1 and bioactive IL-15 from aortic endothelial cells, but not from aortic smooth muscle cells. IL-15 in turn promoted CX3CR1 surface expression on and TNF synthesis by CD8 T cells, and IL-15-treated CD8 T cells exhibited enhanced CX3CL1-dependent chemoattraction toward endothelial cells in vitro. Finally, we show that CD8 T cells in human atherosclerotic plaques have an activated, resident phenotype consistent with in vivo IL-15 and CX3CL1 exposure. In this report, we define a novel model of CD8 T cell involvement in atherosclerosis whereby CX3CL1 and IL-15 operate in tandem within the vascular endothelium to promote infiltration by activated CX3CR1+ memory CD8 T cells that drive further endothelial activation via TNF. We propose that these interactions are prevalent in aging and in PLWH, populations where circulating activated CX3CR1+ CD8 T cell numbers are often expanded.

Cytomegalovirus Coinfection Is Associated with Increased Vascular-Homing CD57+ CD4 T Cells in HIV Infection.

Cytotoxic CD4 T cells are linked to cardiovascular morbidities and accumulate in both HIV and CMV infections, both of which are associated with increased risk of cardiovascular disease (CVD). In this study, we identify CMV coinfection as a major driver of the cytotoxic phenotype, characterized by elevated CD57 expression and reduced CD28 expression, in circulating CD4 T cells from people living with HIV infection, and investigate potential mechanisms linking this cell population to CVD. We find that human CD57+ CD4 T cells express high levels of the costimulatory receptor CD2 and that CD2/LFA-3 costimulation results in a more robust and polyfunctional effector response to TCR signals, compared with CD28-mediated costimulation. CD57+ CD4 T cells also express the vascular endothelium-homing receptor CX3CR1 and migrate toward CX3CL1-expressing endothelial cells in vitro. IL-15 promotes the cytotoxic phenotype, elevates CX3CR1 expression, and enhances the trafficking of CD57+ CD4 T cells to endothelium and may therefore be important in linking these cells to cardiovascular complications. Finally, we demonstrate the presence of activated CD57+ CD4 T cells and expression of CX3CL1 and LFA-3 in atherosclerotic plaque tissues from HIV-uninfected donors. Our findings are consistent with a model in which cytotoxic CD4 T cells contribute to CVD in HIV/CMV coinfection and in atherosclerosis via CX3CR1-mediated trafficking and CD2/LFA-3-mediated costimulation. This study identifies several targets for therapeutic interventions and may help bridge the gap in understanding how CMV infection and immunity are linked to increased cardiovascular risk in people living with HIV infection.

Effects of Tocilizumab in COVID-19 patients: a cohort study.

BACKGROUND: Due to the lack of proven therapies, we evaluated the effects of early administration of tocilizumab for COVID-19. By inhibition of the IL-6 receptor, tocilizumab may help to mitigate the hyperinflammatory response associated with progressive respiratory failure from SARS-CoV-2. METHODS: A retrospective, observational study was conducted on hospitalized adults who received intravenous tocilizumab for COVID-19 between March 23, 2020 and April 10, 2020. RESULTS: Most patients were male (66.7%), Hispanic (63.3%) or Black (23.3%), with a median age of 54 years. Tocilizumab was administered at a median of 8 days (range 1-21) after initial symptoms and 2 days (range 0-12) after hospital admission. Within 30 days from receiving tocilizumab, 36 patients (60.0%) demonstrated clinical improvement, 9 (15.0%) died, 33 (55.0%) were discharged alive, and 18 (30.0%) remained hospitalized. Successful extubation occurred in 13 out of 29 patients (44.8%). Infectious complications occurred in 16 patients (26.7%) at a median of 10.5 days. After tocilizumab was administered, there was a slight increase in PaO2/FiO2 and an initial reduction in CRP, but this effect was not sustained beyond day 10. CONCLUSIONS: Majority of patients demonstrated clinical improvement and were successfully discharged alive from the hospital after receiving tocilizumab. We observed a rebound effect with CRP, which may suggest the need for higher or subsequent doses to adequately manage cytokine storm. Based on our findings, we believe that tocilizumab may have a role in the early treatment of COVID-19, however larger randomized controlled studies are needed to confirm this.

Blood cell oxidative stress precedes hemolysis in whole blood-liver slice co-cultures of rat, dog, and human tissues.

A novel in vitro model to investigate time-dependent and concentration-dependent responses in blood cells and hemolytic events is studied for rat, dog, and human tissues. Whole blood is co-cultured with a precision-cut liver slice. Methimazole (MMI) was selected as a reference compound, since metabolism of its imidazole thione moiety is linked with hematologic disorders and hepatotoxicity. An oxidative stress response occurred in all three species, marked by a decline in blood GSH levels by 24 h that progressed, and preceded hemolysis, which occurred at high MMI concentrations in the presence of a liver slice with rat (>or=1000 microM at 48 h) and human tissues (>or=1000 microM at 48 h, >or=750 microM at 72 h) but not dog. Human blood-only cultures exhibited a decline of GSH levels but minimal to no hemolysis. The up-regulation of liver genes for heme degradation (Hmox1 and Prdx1), iron cellular transport (Slc40a1), and GSH synthesis and utilization (mGST1 and Gclc) were early markers of the oxidative stress response. The up-regulation of the Kupffer cell lectin Lgals3 gene expression indicated a response to damaged red blood cells, and Hp (haptoglobin) up-regulation is indicative of increased hemoglobin uptake. Up-regulation of liver IL-6 and IL-8 gene expression suggested an activation of an inflammatory response by liver endothelial cells. In summary, MMI exposure led to an oxidative stress response in blood cells, and an up-regulation of liver genes involved with oxidative stress and heme homeostasis, which was clearly separate and preceded frank hemolysis.

Inflammescent CX3CR1+CD57+CD8+ T cells are generated and expanded by IL-15.

HIV infection is associated with an increase in the proportion of activated CD8+ memory T cells (Tmem) that express CX3CR1, but how these cells are generated and maintained in vivo is unclear. We demonstrate that increased CX3CR1 expression on CD8+ Tmem in people living with HIV (PLWH) is dependent on coinfection with human CMV, and CX3CR1+CD8+ Tmem are enriched for a putatively immunosenescent CD57+CD28- phenotype. The cytokine IL-15 promotes the phenotype, survival, and proliferation of CX3CR1+CD57+CD8+ Tmem in vitro, whereas T cell receptor stimulation leads to their death. IL-15-driven survival is dependent on STAT5 and Bcl-2 activity, and IL-15-induced proliferation requires STAT5 and mTORC1. Thus, we identify mechanistic pathways that could explain how "inflammescent" CX3CR1+CD57+ CD8+ Tmem dominate the overall memory T cell pool in CMV-seropositive PLWH and that support reevaluation of immune senescence as a nonproliferative dead end.

Development of a Standardized Data Collection Tool for Evaluation and Management of Coronavirus Disease 2019.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 ) is responsible for coronavirus disease 2019 (COVID-19), a disease that had not been previously described and for which clinicians need to rapidly adapt their daily practice. The novelty of SARS-CoV-2 produced significant gaps in harmonization of definitions, data collection, and outcome reporting to identify patients who would benefit from potential interventions. METHODS: We describe a multicenter collaboration to develop a comprehensive data collection tool for the evaluation and management of COVID-19 in hospitalized patients. The proposed tool was developed by a multidisciplinary working group of infectious disease physicians, intensivists, and infectious diseases/antimicrobial stewardship pharmacists. The working group regularly reviewed literature to select important patient characteristics, diagnostics, and outcomes for inclusion. The data collection tool consisted of spreadsheets developed to collect data from the electronic medical record and track the clinical course after treatments. RESULTS: Data collection focused on demographics and exposure epidemiology, prior medical history and medications, signs and symptoms, diagnostic test results, interventions, clinical outcomes, and complications. During the pilot validation phase, there was <10% missing data for most domains and components. Team members noted improved efficiency and decision making by using the tool during interdisciplinary rounds. CONCLUSIONS: We present the development of a COVID-19 data collection tool and propose its use to effectively assemble harmonized data of hospitalized individuals with COVID-19. This tool can be used by clinicians, researchers, and quality improvement healthcare teams. It has the potential to facilitate interdisciplinary rounds, provide comparisons across different hospitalized populations, and adapt to emerging challenges posed by the pandemic.

CD161 Expression on Mucosa-Associated Invariant T Cells is Reduced in HIV-Infected Subjects Undergoing Antiretroviral Therapy Who Do Not Recover CD4+ T Cells.

BACKGROUND: Mucosa-associated invariant T (MAIT) cells are a recently identified class of innate-like T cells that are involved in the mucosal immune response. MAIT cells are characterized by expression of TCR Vα7.2 and CD161. In HIV infection, there is a profound early loss of MAIT cells from the circulation that never fully recovers, even after prolonged viral control with antiretroviral therapy (ART). METHODS: We analyzed PBMCs from fresh whole blood from HIV-negative or ART-treated HIV-positive donors with full (Immune Success) or impaired (Immune Failure) CD4+ T- cell recovery by flow cytometry for T-cell markers, TCR Vα7.2, and CD161. The PBMCs were cultured with or without TCR-mediated stimulation, and CD161 expression was assessed on Vα7.2+ T cells. Interferon-γ (IFNγ) production was assessed by intracellular cytokine staining. RESULTS: We found a decrease in the percentage of CD3+ T cells that expressed CD161 and the percentage of Vα7.2+ T cells that expressed CD161, in HIV-infected individuals. We also found a significant increase in the percentage of T cells that were Vα7.2+CD161- in immune failure compared to controls, accompanied by an increase in the percentage of Vα7.2+CD161- T cells that express CD8+ in donors with immune failure, but not immune success. After TCR stimulation in vitro, Vα7.2+ T cells reduced expression of CD161, yet Vα7.2+CD161- cells from immune failure donors retained the ability to express IFNγ on stimulation. CONCLUSIONS: Our findings suggest that in immune failure patients, the reduction in peripheral MAIT cells is due, at least in part, to a loss in CD161 expression, and is not merely the result of trafficking into mucosal tissues or cell death. These CD161- cells retain their function.

Brief Report: Elevated Red Cell Distribution Width Identifies Elevated Cardiovascular Disease Risk in Patients With HIV Infection.

Red cell distribution width (RDW) is linked to cardiovascular risk in the general population, an association that might be driven by inflammation. Whether this relationship holds for patients with HIV infection has not been previously studied. Using a large clinical registry, we show that elevated RDW (>14.5%) is independently associated with increased risk of coronary artery disease {odds ratio [OR] 1.39 [95% confidence interval (CI): 1.25 to 1.55]}, peripheral vascular disease [OR 1.41 (95% CI: 1.29 to 1.53)], myocardial infarction [1.43 (95% CI: 1.25 to 1.63)], heart failure [OR 2.23 (95% CI: 1.99 to 2.49)], and atrial fibrillation [OR 1.96 (95% CI: 1.64 to 2.33)]. In conclusion, in the context of the inflammatory milieu that accompanies HIV infection, RDW remains a powerful marker of cardiovascular disease.

Rheumatic Heart Disease Treatment Cascade in Uganda.

BACKGROUND: Rheumatic heart disease (RHD) is a leading cause of premature death and disability in low-income countries; however, few receive optimal benzathine penicillin G (BPG) therapy to prevent disease progression. We aimed to comprehensively describe the treatment cascade for RHD in Uganda to identify appropriate targets for intervention. METHODS AND RESULTS: Using data from the Uganda RHD Registry (n=1504), we identified the proportion of patients in the following care categories: (1) diagnosed and alive as of June 1, 2016; (2) retained in care; (3) appropriately prescribed BPG; and (4) optimally adherent to BPG (>80% of prescribed doses). We used logistic regression to investigate factors associated with retention and optimal adherence. Overall, median (interquartile range) age was 23 (15-38) years, 69% were women, and 82% had clinical RHD. Median follow-up time was 2.4 (0.9-4.0) years. Retention in care was the most significant barrier to achieving optimal BPG adherence with only 56.9% (95% confidence interval, 54.1%-59.7%) of living subjects having attended clinic in the prior 56 weeks. Among those retained in care, however, we observed high rates of BPG prescription (91.6%; 95% confidence interval, 89.1%-93.5%) and optimal adherence (91.4%; 95% confidence interval, 88.7-93.5). Younger age, latent disease status, and access to care at a regional center were the strongest independent predictors of retention and optimal adherence. CONCLUSIONS: Our study suggests that improving retention in care-possibly by decentralizing RHD services-would have the greatest impact on uptake of antibiotic prophylaxis among patients with RHD in Uganda.

Development of a recombinant vaccine against aerosolized plague.

Although few diseases have had a greater impact on human history, currently there is no vaccine available for protection against plague that is licensed by the Food and Drug Administration (FDA). DynPort Vaccine Company LLC, a CSC company (DVC), is managing the advanced development of a recombinant plague vaccine (rF1V) for the United States Department of Defense that will provide protection against plague aerosols, the most likely form a biological weapon would take. The vaccine was originally developed at the United States Army Medical Research Institute of Infectious Diseases (USAMRIID). To meet the requirements for licensure in the shortest possible time, DVC developed a strategy for the integration of data from USAMRIID with data from clinical and nonclinical studies conducted by DVC. This strategy is based on the parallel development and validation of assays for the analysis of animal and human immune responses to the vaccine that facilitated the transfer of the candidate from the developing lab at USAMRIID. These assays also form the foundation of our approach to the licensure of the rF1V vaccine using the FDA Animal Rule.