Mark J. Siedner

The Fatty Acid Biosynthesis Enzyme FabI Plays a Key Role in the Development of Liver-Stage Malarial Parasites

The fatty acid synthesis type II pathway has received considerable interest as a candidate therapeutic target in Plasmodium falciparum asexual blood-stage infections. This apicoplast-resident pathway, distinct from the mammalian type I process, includes FabI. Here, we report synthetic chemistry and transfection studies concluding that Plasmodium FabI is not the target of the antimalarial activity of triclosan, an inhibitor of bacterial FabI. Disruption of fabI in P. falciparum or the rodent parasite P. berghei does not impede blood-stage growth. In contrast, mosquito-derived, FabI-deficient P. berghei sporozoites are markedly less infective for mice and typically fail to complete liver-stage development in vitro. This defect is characterized by an inability to form intrahepatic merosomes that normally initiate blood-stage infections. These data illuminate key differences between liver- and blood-stage parasites in their requirements for host versus de novo synthesized fatty acids, and create new prospects for stage-specific antimalarial interventions.

Circulating clonotypic B cells in classic Hodgkin lymphoma

Although Hodgkin and Reed-Sternberg (HRS) cells are B lymphoid cells, they are unlike any normal cells of that lineage. Moreover, the limited proliferative potential of HRS cells belies the clinical aggressiveness of Hodgkin lymphoma (HL). More than 20 years ago, the L428 HL cell line was reported to contain a small population of phenotypic B cells that appeared responsible for the continued generation of HRS cells. This observation, however, has never been corroborated, and such clonotypic B cells have never been documented in HL patients. We found that both the L428 and KM-H2 HL cell lines contained rare B-cell subpopulations responsible for the generation and maintenance of the predominant HRS cell population. The B cells within the HL cell lines expressed immunoglobulin light chain, the memory B-cell antigen CD27, and the stem cell marker aldehyde dehydrogenase (ALDH). Clonal CD27(+)ALDH(high) B cells, sharing immunoglobulin gene rearrangements with lymph node HRS cells, were also detected in the blood of most newly diagnosed HL patients regardless of stage. Although the clinical significance of circulating clonotypic B cells in HL remains unclear, these data suggest they may be the initiating cells for HL.

Trends in CD4 Count at Presentation to Care and Treatment Initiation in Sub-Saharan Africa, 2002–2013: A Meta-analysis

BACKGROUND Both population- and individual-level benefits of antiretroviral therapy (ART) for human immunodeficiency virus (HIV) are contingent on early diagnosis and initiation of therapy. We estimated trends in disease status at presentation to care and at ART initiation in sub-Saharan Africa. METHODS We searched PubMed for studies published January 2002-December 2013 that reported CD4 cell count at presentation or ART initiation among adults in sub-Saharan Africa. We abstracted study sample size, year(s), and mean CD4 count. A random-effects meta-regression model was used to obtain pooled estimates during each year of the observation period. RESULTS We identified 56 articles reporting CD4 count at presentation (N = 295 455) and 71 articles reporting CD4 count at ART initiation (N = 549 702). The mean estimated CD4 count in 2002 was 251 cells/µL at presentation and 152 cells/µL at ART initiation. During 2002-2013, neither CD4 count at presentation (β = 5.8 cells/year; 95% confidence interval [CI], -10.7 to 22.4 cells/year), nor CD4 count at ART initiation (β = -1.1 cells/year; 95% CI, -8.4 to 6.2 cells/year) increased significantly. Excluding studies of opportunistic infections or prevention of mother-to-child transmission did not alter our findings. Among studies conducted in South Africa (N = 14), CD4 count at presentation increased by 39.9 cells/year (95% CI, 9.2-70.2 cells/year; P = .02), but CD4 count at ART initiation did not change. CONCLUSIONS CD4 counts at presentation to care and at ART initiation in sub-Saharan Africa have not increased over the past decade. Barriers to presentation, diagnosis, and linkage to HIV care remain major challenges that require attention to optimize population-level benefits of ART.

Altered Virome and Bacterial Microbiome in Human Immunodeficiency Virus-Associated Acquired Immunodeficiency Syndrome

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.

Rethinking the "pre" in pre-therapy counseling: No benefit of additional visits prior to therapy on adherence or Viremia in Ugandans initiating ARVs

Background Many guidelines recommend adherence counseling prior to initiating antiretrovirals (ARVs), however the additional benefit of pre-therapy counseling visits on early adherence is not known. We sought to assess for a benefit of adherence counseling visits prior to ARV initiation versus adherence counseling during the early treatment period. Methods We performed a secondary analysis of data from a prospective cohort of HIV-infected patients in Mbarara, Uganda. Adults were enrolled upon initiation of ARVs. Our primary exposure of interest was ARV adherence counseling prior to initiating therapy (versus concurrent with initiation of therapy). Our outcomes of interest were: 1) average adherence >90% in first three months; 2) absence of treatment interruptions >72 hours in first three months; and 3) Viral load >400 copies/ml at the three month visit. We fit univariable and multivariable regression models, adjusted for predictors of ARV adherence, to estimate the association between additional pre-therapy counseling visits and our outcomes. Results 300 participants had records of counseling, of whom 231 (77%) completed visits prior to initiation of ARVs and 69 (23%) on or shortly after initiation. Median age was 33, 71% were female, and median CD4 was 133 cell/ml. Median 90-day adherence was 95%. Participants who completed pre-therapy counseling visits had longer delays from ARV eligibility to initiation (median 49 vs 14 days, p<0.01). In multivariable analyses, completing adherence counseling prior to ARV initiation was not associated with average adherence >90% (AOR 0.8, 95%CI 0.4–1.5), absence of treatment gaps (AOR 0.7, 95%CI 0.2–1.9), or HIV viremia (AOR 1.1, 95%CI 0.4–3.1). Conclusions Completion of adherence counseling visits prior to ARV therapy was not associated with higher adherence in this cohort of HIV-infected patients in Uganda. Because mortality and loss-to-follow-up remain high in the pre-ARV period, policy makers should reconsider whether counseling can be delivered with ARV initiation, especially in patients with advanced disease.

Association Between Human Immunodeficiency Virus Infection and Stiffness of the Common Carotid Artery

Background and Purpose— Individuals with human immunodeficiency virus (HIV) who use highly active antiretroviral therapy (HAART) may have an increased risk for cardiovascular-related events, although the underlying mechanism remains unclear. We tested the hypothesis that carotid arterial stiffness was higher among persons using HAART compared to HAART-naïve and HIV-uninfected persons. Methods— Between 2004 and 2006, we performed high-resolution B-mode ultrasound on 2789 HIV-infected and HIV-uninfected participants of the Womens Interagency HIV Study (1865 women) and the Multicenter AIDS Cohort Study (924 men) and determined carotid arterial distensibility, which is a direct measure of carotid arterial stiffness. We used generalized estimating equations to evaluate the association between distensibility and HIV infection, CD4+ cell count, and exposure to HAART adjusted for demographic, behavioral, and clinical characteristics. Results— In multivariable analysis, distensibility was 4.3% lower (95% confidence interval, −7.4% to −1.1%) among HIV-infected vs uninfected participants. Among HIV-infected participants with <200 CD4+ cells, distensibility was 10.5% lower (95% confidence interval, −14.5% to −6.2%) than that among HIV-uninfected participants, and this effect did not differ significantly by cohort or race. Concurrent HAART use was independently associated with lower distensibility among Multicenter AIDS Cohort Study participants but not among Womens Interagency HIV Study participants. Conclusions— Our finding that advanced HIV-related immunosuppression was associated with increased carotid arterial stiffness independent from the effects of traditional atherosclerosis risk factors suggests that the etiologic mechanism underlying reports of an increased cardiovascular disease risk among HIV-infected individuals might involve HIV-related immunosuppression leading to vascular dysfunction and arterial stiffening.

GPS-measured distance to clinic, but not self-reported transportation factors, are associated with missed HIV clinic visits in rural Uganda

Objective:Studies of the association between transportation barriers and HIV-related health outcomes have shown both positive and negative effects, possibly because a reliable, validated measure of transportation barriers has not been identified. Design:Prospective cohort study of HIV-infected patients in rural Uganda. Methods:Participants were enrolled from the HIV clinic at the regional referral hospital in Mbarara, Uganda as part of the Uganda AIDS Rural Treatment Outcomes (UARTO) Study. We collected the following measures of transportation barriers to HIV clinic: global positioning systems (GPS)-tracked distance measured by driving participants to their homes along their typical route; straight-line GPS distance from clinic to home, calculated with the Great Circle Formula; self-reported travel time; and self-reported travel cost. We assessed inter-measure agreement using linear regression, correlation coefficients and &kgr; statistics (by measure quartile) and validated measures by fitting linear regression models to estimate associations with days late for clinic visits. Results:One hundred and eighty-eight participants were tracked with GPS. Seventy-six percent were women, with a median age of 40 years and median CD4 cell count of 193 cells/&mgr;l. We found a high correlation between GPS-based distance measures (&bgr; = 0.74, P < 0.001, R2 = 0.92, &kgr; = 0.73), but little correlation between GPS-based and self-reported measures (all R2 ⩽ 0.4). GPS-based measures were associated with days late to clinic (P < 0.001); but neither self-reported measure was associated (P > 0.85). Conclusion:GPS-measured distance to clinic is associated with HIV clinic absenteeism and should be prioritized over self-reported measures to optimally risk-stratify patients accessing care in rural, resource-limited settings.

Performance of Rapid Syphilis Tests in Venous and Fingerstick Whole Blood Specimens

Objective: Rapid syphilis screening could facilitate case-identification during U.S. outbreaks. Goal: The goal of this study was to determine the performance of 3 rapid syphilis tests in whole blood specimens in the laboratory and in patients at a sexually transmitted disease (STD) clinic. Study: We tested whole blood samples from STD clinic patients with 3 rapid tests and compared results with the serum treponemal pallidum particle agglutination (TP-PA) test. We evaluated the best performing of the 3 rapid tests on fingerstick specimens from STD clinic patients. Results: The Abbott Determine TP (n = 127) had the highest sensitivity (88%; 95% confidence interval [CI], 81–96%) and lowest rate of indeterminate tests (0.8%), followed by Guardian Biosciences One Step (n = 116) (sensitivity 72%; 95% CI, 60–84%; indeterminate 6.5%), and Phoenix Biotech Trep-Strip IV (n = 71) (sensitivity 70%; 95% CI, 54–85%; indeterminate 30.3%). All 3 tests were 100% specific. The Abbott Determine TP showed excellent performance on fingerstick specimens (n = 99), exhibiting 100% sensitivity (95% CI, 93–100%), 100% specificity, and 2.9% indeterminate. Conclusions: The Abbott Determine TP test was an easy and accurate test that could facilitate rapid detection of syphilis in at-risk patients.

High acceptability for cell phone text messages to improve communication of laboratory results with HIV-infected patients in rural Uganda: a cross-sectional survey study

BackgroundPatient-provider communication is a major challenge in resource-limited settings with large catchment areas. Though mobile phone usership increased 20-fold in Africa over the past decade, little is known about acceptability of, perceptions about disclosure and confidentiality, and preferences for cell phone communication of health information in the region.MethodsWe performed structured interviews of fifty patients at the Immune Suppression Syndrome clinic in Mbarara, Uganda to assess four domains of health-related communication: a) cell phone use practices and literacy, b) preferences for laboratory results communication, c) privacy and confidentiality, and d) acceptability of and preferences for text messaging to notify patients of abnormal test results.ResultsParticipants had a median of 38 years, were 56% female, and were residents of a large catchment area throughout southwestern Uganda. All participants expressed interest in a service to receive information about laboratory results by cell phone text message, stating benefits of increased awareness of their health and decreased transportation costs. Ninety percent reported that they would not be concerned for unintended disclosure. A minority additionally expressed concerns about difficulty interpreting messages, discouragement upon learning bad news, and technical issues. Though all respondents expressed interest in password protection of messages, there was also a strong desire for direct messages to limit misinterpretation of information.ConclusionsCell phone text messaging for communication of abnormal laboratory results is highly acceptable in this cohort of HIV-infected patients in rural Uganda. The feasibility of text messaging, including an optimal balance between privacy and comprehension, should be further studied.

Real-Time PCR Assay for Detection of Quinolone-Resistant Neisseria gonorrhoeae in Urine Samples

ABSTRACT A need exists for the development of applicable surveillance tools to detect fluoroquinolone-resistant Neisseria gonorrhoeae (QRNG) in urine samples. We describe here a real-time PCR assay for detecting mutations in the Ser91 codon of the gyrA gene of N. gonorrhoeae in urine specimens. We tested 96 urine samples collected along with Gonorrhea Isolate Surveillance Project (GISP) urethral swab samples and compared the results with matched MICs of ciprofloxacin, as reported by the regional GISP laboratory. We then tested 100 urine specimens, known to be gonorrhea positive by nucleic acid amplification testing, provided by females to challenge the real-time PCR assay with urine specimens containing potentially less target DNA content than specimens from symptomatic males. With an MIC threshold of 0.125 μg of ciprofloxacin/ml, our assay correctly identified resistance in 41 of 44 (93.2%; 95% confidence interval [CI] = 81.3 to 98.6%) corresponding resistant culture specimens and correctly identified 51 of 51 (100%; 95% CI = 93.0 to 100%) susceptible specimens. One specimen did not amplify. The assay successfully amplified the gyrA amplicon and determined a susceptibility genotype in 72 of 100 (72%) urine specimens collected from female patients. We developed an assay for detecting QRNG in urine specimens that correlated well with MIC results of cultured specimens and had moderate sensitivity with urine specimens. This methodology might fulfill the need for a QRNG detection system for urine specimens, a useful characteristic in the age of nucleic acid amplification testing for gonococcal infection.