Search

Tuberculous meningitis (TBM) is a devastating infection of the central nervous system lacking an adequate point-of-care diagnostic test. We conducted a prospective cohort study of 550 Zambian adults with suspected TBM to determine the diagnostic accuracy of cerebrospinal fluid (CSF) Xpert MTB/RIF, CSF lipoarabinomannan (LAM), urine LAM, CSF total protein, and CSF glucose compared with the gold standard of CSF culture. We categorized patients with a positive CSF tuberculosis (TB) culture as definite TBM. We also assessed inpatient and 1-year mortality on definite TBM patients when CSF Xpert MTB/RIF results were available in real time to treating physicians relative to a historical comparison cohort in whom Xpert results were not available in real time. Of the 550 patients, 474 (86.2%) were HIV-infected and 105/550 (19.1%) had definite TBM based on a positive CSF culture. The sensitivity/specificity of the diagnostic tests were CSF Xpert MTB/RIF, 52.9%/94.2%; CSF LAM, 21.9%/94.2%; urine LAM, 24.1%/76.1%; and CSF glucose 100 mg/dl, 66.3%/90%. A model including CSF Xpert MTB/RIF, CSF LAM, CSF glucose, and CSF total protein demonstrated an area under the receiver operating curve of 0.90. The inpatient and 1-year mortality for definite TBM was 43% and 57%, respectively. There was low sensitivity for the diagnosis of TBM across all diagnostics tests. CSF Xpert MTB/RIF and CSF LAM are highly specific for the diagnosis of TBM. Despite the use of Xpert MTB/RIF for diagnostic purpose in real time, TBM was still associated with a high mortality in Zambian patients.

Human immunodeficiency virus (HIV) infection is associated with increased intestinal translocation of microbial products and enteropathy as well as alterations in gut bacterial communities. However, whether the enteric virome contributes to this infection and resulting immunodeficiency remains unknown. We characterized the enteric virome and bacterial microbiome in a cohort of Ugandan patients, including HIV-uninfected or HIV-infected subjects and those either treated with anti-retroviral therapy (ART) or untreated. Low peripheral CD4 T cell counts were associated with an expansion of enteric adenovirus sequences and this increase was independent of ART treatment. Additionally, the enteric bacterial microbiome of patients with lower CD4 T counts exhibited reduced phylogenetic diversity and richness with specific bacteria showing differential abundance, including increases in Enterobacteriaceae, which have been associated with inflammation. Thus, immunodeficiency in progressive HIV infection is associated with alterations in the enteric virome and bacterial microbiome, which may contribute to AIDS-associated enteropathy and disease progression.

Due to the stringent population bottleneck that occurs during sexual HIV-1 transmission, systemic infection is typically established by a limited number of founder viruses. Elucidation of the precise forces influencing the selection of founder viruses may reveal key vulnerabilities that could aid in the development of a vaccine or other clinical interventions. Here, we utilize deep sequencing data and apply a genetic distance-based method to investigate whether the mode of sexual transmission shapes the nascent founder viral genome. Analysis of 74 acute and early HIV-1 infected subjects revealed that 83% of men who have sex with men (MSM) exhibit a single founder virus, levels similar to those previously observed in heterosexual (HSX) transmission. In a metadata analysis of a total of 354 subjects, including HSX, MSM and injecting drug users (IDU), we also observed no significant differences in the frequency of single founder virus infections between HSX and MSM transmissions. However, comparison of HIV-1 envelope sequences revealed that HSX founder viruses exhibited a greater number of codon sites under positive selection, as well as stronger transmission indices possibly reflective of higher fitness variants. Moreover, specific genetic "signatures" within MSM and HSX founder viruses were identified, with single polymorphisms within gp41 enriched among HSX viruses while more complex patterns, including clustered polymorphisms surrounding the CD4 binding site, were enriched in MSM viruses. While our findings do not support an influence of the mode of sexual transmission on the number of founder viruses, they do demonstrate that there are marked differences in the selection bottleneck that can significantly shape their genetic composition. This study illustrates the complex dynamics of the transmission bottleneck and reveals that distinct genetic bottleneck processes exist dependent upon the mode of HIV-1 transmission.

CD8(+) T cells contribute to the control of HIV, but it is not clear whether initial immune responses modulate the viral set point. We screened high-risk uninfected women twice a week for plasma HIV RNA and identified 12 hyperacute infections. Onset of viremia elicited a massive HIV-specific CD8(+) T cell response, with limited bystander activation of non-HIV memory CD8(+) T cells. HIV-specific CD8(+) T cells secreted little interferon-γ, underwent rapid apoptosis, and failed to upregulate the interleukin-7 receptor, known to be important for T cell survival. The rapidity to peak CD8(+) T cell activation and the absolute magnitude of activation induced by the exponential rise in viremia were inversely correlated with set point viremia. These data indicate that rapid, high magnitude HIV-induced CD8(+) T cell responses are crucial for subsequent immune control of acute infection, which has important implications for HIV vaccine design.

In this article, we compared the binormal and the Lehmann receiver operating characteristic (ROC) curves using extensive simulation studies and real data sets related to HIV. We ran a large set of simulation studies with a wide range of distributions, varying sample sizes, and different degrees of overlap between the diseased and non-diseased population distributions. Simulation results suggest that the binormal ROC model performs better for normal data. However, for non-normal data, the Lehman model outperforms the binormal model. The discrepancies between the performances of the two models were more apparent for larger sample sizes or larger degree of separation between the distributions of the diseased and non-diseased subjects. Like the binormal model, the Lehman model provides smooth estimates of ROC curves and a closed-form expression for the area under the ROC curve. Moreover, the Lehmann model can also be used to obtain covariate-adjusted ROC curves and accommodates inference of correlated and longitudinal biomarkers. Thus, the Lehman model should be considered as an alternative when the restrictive distributional assumptions of the binormal model are not met. [ABSTRACT FROM AUTHOR]

The human gut mucosa is a major site of human immunodeficiency virus (HIV) infection and infection-associated pathogenesis. Increasing evidence shows that natural killer (NK) cells have an important role in control of HIV infection, but the mechanism(s) by which they mediate antiviral activity in the gut is unclear. Here, we show that two distinct subsets of NK cells exist in the gut, one localized to intraepithelial spaces (intraepithelial lymphocytes, IELs) and the other to the lamina propria (LP). The frequency of both subsets of NK cells was reduced in chronic infection, whereas IEL NK cells remained stable in spontaneous controllers with protective killer immunoglobulin-like receptor/human leukocyte antigen genotypes. Both IEL and LP NK cells were significantly expanded in immunological non-responsive patients, who incompletely recovered CD4+ T cells on highly active antiretroviral therapy (HAART). These data suggest that both IEL and LP NK cells may expand in the gut in an effort to compensate for compromised CD4+ T-cell recovery, but that only IEL NK cells may be involved in providing durable control of HIV in the gut.

The receiver operating characteristic (ROC) curve is a commonly used graphical summary of the discriminative capacity of a thresholded continuous scoring system for a binary outcome. Estimation and inference procedures for the ROC curve are well-studied in the cross-sectional setting. However, there is a paucity of research when both biomarker measurements and disease status are observed longitudinally. In a motivating example, we are interested in characterizing the value of longitudinally measured CD4 counts for predicting the presence or absence of a transient spike in HIV viral load, also time-dependent. The existing method neither appropriately characterizes the diagnostic value of observed CD4 counts nor efficiently uses status history in predicting the current spike status. We propose to jointly model the binary status as a Markov chain and the biomarkers levels, conditional on the binary status, as an autoregressive process, yielding a dynamic scoring procedure for predicting the occurrence of a spike. Based on the resulting prediction rule, we propose several natural extensions of the ROC curve to the longitudinal setting and describe procedures for statistical inference. Lastly, extensive simulations have been conducted to examine the small sample operational characteristics of the proposed methods. [ABSTRACT FROM AUTHOR]

We evaluated the association of alcohol consumption and depression, and their effects on HIV disease progression among women with HIV. The study included 871 women with HIV who were recruited from 1993-1995 in four US cities. The participants had physical examination, medical record extraction, and venipuncture, CD4+T-cell counts determination, measurement of depression symptoms (using the self-report Center for Epidemiological Studies-Depression Scale), and alcohol use assessment at enrollment, and semiannually until March 2000. Multilevel random coefficient ordinal models as well as multilevel models with joint responses were used in the analysis. There was no significant association between level of alcohol use and CD4+ T-cell counts. When participants were stratified by antiretroviral therapy (ART) use, the association between alcohol and CD4+ T-cell did not reach statistical significance. The association between alcohol consumption and depression was significant (p<0.001). Depression had a significant negative effect on CD4+ T-cell counts over time regardless of ART use. Our findings suggest that alcohol consumption has a direct association with depression. Moreover, depression is associated with HIV disease progression. Our findings have implications for the provision of alcohol use interventions and psychological resources to improve the health of women with HIV. [ABSTRACT FROM AUTHOR]

Group interventions for health-related issues such as cancer and HIV infection have demonstrated effectiveness and are widely used, yet the question of dosage for group interventions has received little attention. This study examined the longitudinal effect of varying doses of a group intervention for coping with AIDS-related loss in 158 HIV-positive women and men. Grief and psychiatric distress were assessed at baseline, postintervention, and at 4-, 8-, and 12-month follow-ups. Longitudinal data analyses using mixed models were conducted to examine differences in outcome by dosage. Results show that both grief and psychiatric distress were inversely related to dosage across time, indicating that the higher the intervention exposure, the greater the reduction in distress and grief. The clinical significance of change by dosage was also considered. [ABSTRACT FROM AUTHOR]

The authors sought to study the longitudinal effects of a cognitive- behavioral group intervention for coping with AIDS bereavement among a diverse sample of adults who were HIV positive. Participants (N = 267) were randomly assigned to receive the 12-week intervention or individual therapy upon request. Measures were administered at baseline, postintervention, and 4-, 8-, and 12-month follow-ups. Longitudinal data were analyzed with linear mixed models to examine change in grief by condition across the study period and the effect of the intervention on grief through its interaction with psychiatric distress. The authors used the Grief Reaction Index to assess grief and the Symptom Checklist-90-Revised to assess global psychiatric distress. Participants in both conditions reported decreases in grief severity. However, among those with higher levels of psychiatric distress, participants in the group intervention had significantly lower grief severity scores compared with participants in the individual therapy condition. The long-term effectiveness of this AIDS-bereavement intervention for psychiatrically distressed people with HIV/AIDS supports the need for tailored interventions among those at risk for complicated grief responses. [ABSTRACT FROM AUTHOR]

The article studies the effects of a coping intervention on transmission risk behavior among HIV-positive people and those with a history of childhood sexual abuse. Participants in the HIV and trauma coping intervention decreased their frequency of unprotected sexual intercourse more than participants in the support intervention condition for all partners and for HIV-negative and for serostatus unknown partners.