Fully Differentiated HIV-1 Specific CD8+ T Effector Cells are More Frequently Detectable in Controlled than in Progressive HIV-1 Infection

Background: CD8+ T cells impact control of viral infections by direct elimination of infected cells and secretion of a number of soluble factors. In HIV-1 infection, persistent HIV-1 specific IFN-γ+ CD8+ T cell responses are detected in the setting of disease progression, consistent with functional impairment in vivo. Recent data suggest that impaired maturation, as defined by the lineage markers CD45RA and CCR7, may contribute to a lack of immune control by these responses. Methodology/Principal Findings: We investigated the maturation phenotype of epitope-specific CD8+ T cell responses directed against HIV-1 in 42 chronically infected, untreated individuals, 22 of whom were “Controllers” (median 1140 RNA copies/ml plasma, range less than 50 to 2520), and 20 “progressors” of whom had advanced disease and high viral loads (median 135,500 RNA copies/ml plasma, range 12100 to greater than 750000). Evaluation of a mean of 5 epitopes per person revealed that terminally differentiated CD8+ T cells directed against HIV-1 are more often seen in HIV-1 Controllers (16/22; 73%) compared to HIV-1 progressors (7/20; 35%)(p = 0.015), but the maturation state of epitope-specific responses within a given individual was quite variable. Maturation phenotype was independent of the HLA restriction or the specificity of a given CD8+ T cell response and individual epitopes associated with slow disease progression were not more likely to be terminally differentiated. Conclusions/Significance: These data indicate that although full maturation of epitope-specific CD8+ T cell responses is associated with viral control, the maturation status of HIV-1 specific CD8+ T cell responses within a given individual are quite heterogeneous, suggesting epitope-specific influences on CD8+ T cell function

Sensitivity and Specificity of Natural Language Processing Systems for Identification of Hospitalized People Who Use Drugs

Background: People who use drugs (PWUD) often lack access to optimal harm reduction and substance use disorder treatment tools. Tracking the epidemiology of acute care utilization by PWUD is crucial to improving systems of care. Chart reviews and International Classification of Diseases (ICD) codes are the most common systems of identifying hospitalizations of PWUD but are limited by high labor costs and inaccuracy. This study evaluates whether natural language processing (NLP) enhances the sensitivity and specificity of ICD-10 codes in identifying hospitalizations of PWUD. Methods: We analyzed admissions at Tufts Medical Center between 2018 and 2023. Two NLP tools (Regular Expression and Open Health NLP Toolkit) were developed to identify PWUD and were compared with ICD-10 algorithms. The NLP and ICD-10 algorithms were applied to all admissions, and demographic and hospitalization-related data were extracted. The research team manually reviewed notes written during 790 hospitalizations of PWUD as the gold standard. We calculated sensitivity, specificity, and net reclassification indices. Results: ICD-10 codes alone demonstrated low sensitivity (43%) but high specificity (99%). Adding NLP systems improved sensitivity up to 94%, though specificity decreased to 46%. Threshold adjustments (eg, notes flagged ≥50%) revealed a trade-off between sensitivity (47%) and specificity (96%). The most practical model-Regular Expression or ICD-10 codes-resulted in a sensitivity of 74% and specificity of 87%. Conclusions: NLP is an innovative tool that can create functional, cost-effective, and accurate systems of identifying hospitalized PWUD. These findings support further development of NLP technologies to improve health care equity for PWUD

Loss of HIV-1–specific CD8+ T Cell Proliferation after Acute HIV-1 Infection and Restoration by Vaccine-induced HIV-1–specific CD4+ T Cells

Virus-specific CD8+ T cells are associated with declining viremia in acute human immunodeficiency virus (HIV)1 infection, but do not correlate with control of viremia in chronic infection, suggesting a progressive functional defect not measured by interferon γ assays presently used. Here, we demonstrate that HIV-1–specific CD8+ T cells proliferate rapidly upon encounter with cognate antigen in acute infection, but lose this capacity with ongoing viral replication. This functional defect can be induced in vitro by depletion of CD4+ T cells or addition of interleukin 2–neutralizing antibodies, and can be corrected in chronic infection in vitro by addition of autologous CD4+ T cells isolated during acute infection and in vivo by vaccine-mediated induction of HIV-1–specific CD4+ T helper cell responses. These data demonstrate a loss of HIV-1–specific CD8+ T cell function that not only correlates with progressive infection, but also can be restored in chronic infection by augmentation of HIV-1–specific T helper cell function. This identification of a reversible defect in cell-mediated immunity in chronic HIV-1 infection has important implications for immunotherapeutic interventions

Impaired Hepatitis C Virus-Specific T Cell Responses and Recurrent Hepatitis C Virus in HIV Coinfection

BACKGROUND: Hepatitis C virus (HCV)-specific T cell responses are critical for spontaneous resolution of HCV viremia. Here we examined the effect of a lymphotropic virus, HIV-1, on the ability of coinfected patients to maintain spontaneous control of HCV infection. METHODS AND FINDINGS: We measured T cell responsiveness by lymphoproliferation and interferon-γ ELISPOT in a large cohort of HCV-infected individuals with and without HIV infection. Among 47 HCV/HIV-1-coinfected individuals, spontaneous control of HCV was associated with more frequent HCV-specific lymphoproliferative (LP) responses (35%) compared to coinfected persons who exhibited chronic HCV viremia (7%, p = 0.016), but less frequent compared to HCV controllers who were not HIV infected (86%, p = 0.003). Preservation of HCV-specific LP responses in coinfected individuals was associated with a higher nadir CD4 count (r (2) = 0.45, p < 0.001) and the presence and magnitude of the HCV-specific CD8(+) T cell interferon-γ response (p = 0.0014). During long-term follow-up, recurrence of HCV viremia occurred in six of 25 coinfected individuals with prior control of HCV, but in 0 of 16 HIV-1-negative HCV controllers (p = 0.03, log rank test). In these six individuals with recurrent HCV viremia, the magnitude of HCV viremia following recurrence inversely correlated with the CD4 count at time of breakthrough (r = −0.94, p = 0.017). CONCLUSIONS: These results indicate that HIV infection impairs the immune response to HCV—including in persons who have cleared HCV infection—and that HIV-1-infected individuals with spontaneous control of HCV remain at significant risk for a second episode of HCV viremia. These findings highlight the need for repeat viral RNA testing of apparent controllers of HCV infection in the setting of HIV-1 coinfection and provide a possible explanation for the higher rate of HCV persistence observed in this population

Microbial Translocation Is Associated with Increased Monocyte Activation and Dementia in AIDS Patients

Elevated plasma lipopolysaccharide (LPS), an indicator of microbial translocation from the gut, is a likely cause of systemic immune activation in chronic HIV infection. LPS induces monocyte activation and trafficking into brain, which are key mechanisms in the pathogenesis of HIV-associated dementia (HAD). To determine whether high LPS levels are associated with increased monocyte activation and HAD, we obtained peripheral blood samples from AIDS patients and examined plasma LPS by Limulus amebocyte lysate (LAL) assay, peripheral blood monocytes by FACS, and soluble markers of monocyte activation by ELISA. Purified monocytes were isolated by FACS sorting, and HIV DNA and RNA levels were quantified by real time PCR. Circulating monocytes expressed high levels of the activation markers CD69 and HLA-DR, and harbored low levels of HIV compared to CD4+ T-cells. High plasma LPS levels were associated with increased plasma sCD14 and LPS-binding protein (LBP) levels, and low endotoxin core antibody levels. LPS levels were higher in HAD patients compared to control groups, and were associated with HAD independently of plasma viral load and CD4 counts. LPS levels were higher in AIDS patients using intravenous heroin and/or ethanol, or with Hepatitis C virus (HCV) co-infection, compared to control groups. These results suggest a role for elevated LPS levels in driving monocyte activation in AIDS, thereby contributing to the pathogenesis of HAD, and provide evidence that cofactors linked to substance abuse and HCV co-infection influence these processes

Shigellosis in men who have sex with men: an overlooked opportunity to counsel with pre-exposure prophylaxis for HIV

In the absence of other epidemiological exposures, shigellosis in men who have sex with men (MSM) suggests engagement in high-risk sexual encounters. Infection and diagnosis of shigellosis in MSM presents a potentially overlooked opportunity to discuss the availability of pre-exposure prophylaxis medications to prevent incident HIV infections. </jats:p

Hepatitis C Virus Is Associated With Increased Mortality Among Incarcerated Hospitalized Persons in Massachusetts

Abstract Hepatitis C virus (HCV) is curable, but incarcerated populations face barriers to treatment. In a cohort of incarcerated hospitalized patients in Boston, Massachusetts, HCV infection was associated with increased mortality. Access to HCV treatment in carceral settings is crucial to avoid unnecessary death and to support HCV elimination efforts.</jats:p