Ameeta S. Kalokhe

Distinct Effector Memory CD4+ T Cell Signatures in Latent Mycobacterium tuberculosis Infection, BCG Vaccination and Clinically Resolved Tuberculosis

Two billion people worldwide are estimated to be latently infected with Mycobacterium tuberculosis (Mtb) and are at risk for developing active tuberculosis since Mtb can reactivate to cause TB disease in immune-compromised hosts. Individuals with latent Mtb infection (LTBI) and BCG-vaccinated individuals who are uninfected with Mtb, harbor antigen-specific memory CD4+ T cells. However, the differences between long-lived memory CD4+ T cells induced by latent Mtb infection (LTBI) versus BCG vaccination are unclear. In this study, we characterized the immune phenotype and functionality of antigen-specific memory CD4+ T cells in healthy BCG-vaccinated individuals who were either infected (LTBI) or uninfected (BCG) with Mtb. Individuals were classified into LTBI and BCG groups based on IFN-γ ELISPOT using cell wall antigens and ESAT-6/CFP-10 peptides. We show that LTBI individuals harbored high frequencies of late-stage differentiated (CD45RA−CD27−) antigen-specific effector memory CD4+ T cells that expressed PD-1. In contrast, BCG individuals had primarily early-stage (CD45RA−CD27+) cells with low PD-1 expression. CD27+ and CD27− as well as PD-1+ and PD-1− antigen-specific subsets were polyfunctional, suggesting that loss of CD27 expression and up-regulation of PD-1 did not compromise their capacity to produce IFN-γ, TNF-α and IL-2. PD-1 was preferentially expressed on CD27− antigen-specific CD4+ T cells, indicating that PD-1 is associated with the stage of differentiation. Using statistical models, we determined that CD27 and PD-1 predicted LTBI versus BCG status in healthy individuals and distinguished LTBI individuals from those who had clinically resolved Mtb infection after anti-tuberculosis treatment. This study shows that CD4+ memory responses induced by latent Mtb infection, BCG vaccination and clinically resolved Mtb infection are immunologically distinct. Our data suggest that differentiation into CD27−PD-1+ subsets in LTBI is driven by Mtb antigenic stimulation in vivo and that CD27 and PD-1 have the potential to improve our ability to evaluate true LTBI status.

Aspergillus endocarditis: a review of the literature.

We present a case of cardiac device-related Aspergillus endocarditis in a patient with a pacemaker and an allogeneic bone marrow transplant to segue into a review of the Aspergillus endocarditis literature. Aspergillus endocarditis should be suspected in patients with underlying immunosuppression, negative cultures, and a vegetation on echocardiography. Diagnosis ultimately requires confirmation by tissue histology and culture. The optimal treatment approach often requires aggressive surgical debridement in conjunction with prolonged antifungal therapy.

Biomarkers on patient T cells diagnose active tuberculosis and monitor treatment response

BACKGROUND The identification and treatment of individuals with tuberculosis (TB) is a global public health priority. Accurate diagnosis of pulmonary active TB (ATB) disease remains challenging and relies on extensive medical evaluation and detection of Mycobacterium tuberculosis (Mtb) in the patients sputum. Further, the response to treatment is monitored by sputum culture conversion, which takes several weeks for results. Here, we sought to identify blood-based host biomarkers associated with ATB and hypothesized that immune activation markers on Mtb-specific CD4+ T cells would be associated with Mtb load in vivo and could thus provide a gauge of Mtb infection. METHODS Using polychromatic flow cytometry, we evaluated the expression of immune activation markers on Mtb-specific CD4+ T cells from individuals with asymptomatic latent Mtb infection (LTBI) and ATB as well as from ATB patients undergoing anti-TB treatment. RESULTS Frequencies of Mtb-specific IFN-γ+CD4+ T cells that expressed immune activation markers CD38 and HLA-DR as well as intracellular proliferation marker Ki-67 were substantially higher in subjects with ATB compared with those with LTBI. These markers accurately classified ATB and LTBI status, with cutoff values of 18%, 60%, and 5% for CD38+IFN-γ+, HLA-DR+IFN-γ+, and Ki-67+IFN-γ+, respectively, with 100% specificity and greater than 96% sensitivity. These markers also distinguished individuals with untreated ATB from those who had successfully completed anti-TB treatment and correlated with decreasing mycobacterial loads during treatment. CONCLUSION We have identified host blood-based biomarkers on Mtb-specific CD4+ T cells that discriminate between ATB and LTBI and provide a set of tools for monitoring treatment response and cure. TRIAL REGISTRATION Registration is not required for observational studies. FUNDING This study was funded by Emory University, the NIH, and the Yerkes National Primate Center.

Multidrug-Resistant Tuberculosis Drug Susceptibility and Molecular Diagnostic Testing

Abstract:Multidrug-resistant tuberculosis (MDR TB), defined by resistance to the 2 most effective first-line drugs, isoniazid and rifampin, is on the rise globally and is associated with significant morbidity and mortality. Despite the increasing availability of novel rapid diagnostic tools for Mycobacterium tuberculosis (Mtb) drug susceptibility testing, the clinical applicability of these methods is unsettled. In this study, the mechanisms of action and resistance of Mtb to isoniazid and rifampin, and the utility, advantages and limitations of the available Mtb drug susceptibility testing tools are reviewed, with particular emphasis on molecular methods with rapid turnaround including line probe assays, molecular beacon-based real-time polymerase chain reaction and pyrosequencing. The authors conclude that neither rapid molecular drug testing nor phenotypic methods are perfect in predicting Mtb drug susceptibility and therefore must be interpreted within the clinical context of each patient.

Review ArticleMultidrug-Resistant Tuberculosis Drug Susceptibility and Molecular Diagnostic Testing

Abstract:Multidrug-resistant tuberculosis (MDR TB), defined by resistance to the 2 most effective first-line drugs, isoniazid and rifampin, is on the rise globally and is associated with significant morbidity and mortality. Despite the increasing availability of novel rapid diagnostic tools for Mycobacterium tuberculosis (Mtb) drug susceptibility testing, the clinical applicability of these methods is unsettled. In this study, the mechanisms of action and resistance of Mtb to isoniazid and rifampin, and the utility, advantages and limitations of the available Mtb drug susceptibility testing tools are reviewed, with particular emphasis on molecular methods with rapid turnaround including line probe assays, molecular beacon-based real-time polymerase chain reaction and pyrosequencing. The authors conclude that neither rapid molecular drug testing nor phenotypic methods are perfect in predicting Mtb drug susceptibility and therefore must be interpreted within the clinical context of each patient.

Intimate Partner Violence Among HIV-Infected Crack Cocaine Users

HIV-infected crack cocaine users are at high risk for HIV transmission and disease progression because they encounter difficulty practicing safe sex, entering and remaining in HIV care, and taking antiretroviral therapy (ART). We hypothesized intimate partner violence (IPV) occurs frequently in this population and contributes to these shortcomings. From December 2006 to April 2010 inpatient HIV-infected crack users were recruited from Grady Memorial (Atlanta, GA) and Jackson Memorial Hospitals (Miami, FL). Participants were screened for IPV using a 5-item tool that was adapted from a previously validated instrument, the STaT. IPV survivors were questioned about support service utilization. Multivariable analysis was conducted to evaluate the association between IPV and unprotected sexual intercourse and sexually transmitted infection (STI) diagnosis in the prior 6 months, use of outpatient HIV care in the past year, and current ART use. We enrolled 343 participants, the majority African Americans of low socioeconomic status. The estimated IPV prevalence was 56%, highest in women (68%) and gay, bisexual, and transgendered men (71%). In multivariable analysis, IPV was associated with diminished ART use (adjusted prevalence ratios [adjPRs] 0.57; 95% confidence interval [CI] 0.41-0.80), unprotected sexual intercourse (adjPR 1.34; 95% CI 1.08-1.68) and STI diagnosis in the prior 6 months (adjPR 3.49; 95% CI 1.60-7.62). After experiencing abuse, IPV survivors most commonly turned to emergency services; however, 38% reported not using any supportive services. This study highlights that IPV occurs frequently among HIV-infected crack users and is associated with outcomes known to facilitate HIV transmission and disease progression. Reduced utilization of outpatient HIV care, ART nonadherence, and new STI diagnoses in this population should trigger IPV screening and support services referral.

Domestic violence against women in India: A systematic review of a decade of quantitative studies

ABSTRACT Domestic violence (DV) is prevalent among women in India and has been associated with poor mental and physical health. We performed a systematic review of 137 quantitative studies published in the prior decade that directly evaluated the DV experiences of Indian women to summarise the breadth of recent work and identify gaps in the literature. Among studies surveying at least two forms of abuse, a median 41% of women reported experiencing DV during their lifetime and 30% in the past year. We noted substantial inter-study variance in DV prevalence estimates, attributable in part to different study populations and settings, but also to a lack of standardisation, validation, and cultural adaptation of DV survey instruments. There was paucity of studies evaluating the DV experiences of women over age 50, residing in live-in relationships, same-sex relationships, tribal villages, and of women from the northern regions of India. Additionally, our review highlighted a gap in research evaluating the impact of DV on physical health. We conclude with a research agenda calling for additional qualitative and longitudinal quantitative studies to explore the DV correlates proposed by this quantitative literature to inform the development of a culturally tailored DV scale and prevention strategies.

Impaired Degranulation and Proliferative Capacity of Mycobacterium tuberculosis–Specific CD8+ T Cells in HIV-Infected Individuals With Latent Tuberculosis

Human immunodeficiency virus (HIV)-infected individuals with latent Mycobacterium tuberculosis infection have substantially higher rates of progression to active tuberculosis than HIV-uninfected individuals with latent tuberculosis. To explore HIV-induced deficits in M. tuberculosis-specific CD8+ T-cell functions, we compared interferon γ production, degranulation, and proliferation of CD8+ T cells in response to M. tuberculosis peptides (ESAT-6/CFP-10) between HIV-infected (median CD4+ T-cell count, 522 cells/µL; interquartile range, 318-585 cells/µL) and HIV-uninfected individuals with latent tuberculosis from South Africa. We found that M. tuberculosis-specific degranulation and proliferative capacities were impaired in the HIV-infected group. Thus, our results suggest that HIV coinfection compromises CD8+ T-cell functions in latent tuberculosis.

Delivering a "dose of hope": a faith-based program to increase older african americans' participation in clinical trials.

Background Underrepresentation of older-age racial and ethnic minorities in clinical research is a significant barrier to health in the United States, as it impedes medical research advancement of effective preventive and therapeutic strategies. Objective The objective of the study was to develop and test the feasibility of a community-developed faith-based intervention and evaluate its potential to increase the number of older African Americans in clinical research. Methods Using a cluster-randomized design, we worked with six matched churches to enroll at least 210 persons. We provided those in the intervention group churches with three educational sessions on the role of clinical trials in addressing health disparity topics, and those in the comparison group completed surveys at the same timepoints. All persons enrolled in the study received ongoing information via newsletters and direct outreach on an array of clinical studies seeking participants. We evaluated the short-, mid-, and longer-term effects of the interventional program on clinical trial-related outcomes (ie, screening and enrollment). Results From 2012 to 2013, we enrolled a balanced cohort of 221 persons in the program. At a 3-month follow-up, mean intention to seek information about clinical trials was higher than baseline in both treatment (mu=7.5/10; sigma=3.1) and control arms (mu=6.6/10; sigma=3.3), with the difference more pronounced in the treatment arm. The program demonstrated strong retention at 3-month (95.4%, 211/221) and 6-month timepoints (94.1%, 208/221). Conclusions The “Dose of Hope” program addressed an unmet need to reach an often overlooked audience of older African Americans who are members of churches and stimulate their interest in clinical trial participation. The program demonstrated its appeal in the delivery of effective messages and information about health disparities, and the role of clinical research in addressing these challenges.

Primary Human Immunodeficiency Virus Infection and Rhabdomyolysis

Objectives: Over the past few years we have seen 3 patients with primary HIV infection and rhabdomyolysis in our institution. Methods: We report our 3 cases in addition to the review of the English-language literature for all reported cases of rhabdomyolysis and primary HIV infection. Results: In addition to our 3 cases we found 11 cases of primary HIV infection presenting with rhabdomyolysis. Conclusion: In patients presenting with rhabdomyolysis and no obvious precipitating factor, primary HIV infection should be included on the differential count.