Dendritic A-Current in Rhythmically Active PreBötzinger Complex Neurons in Organotypic Cultures from Newborn Mice.

The brainstem preBötzinger complex (preBötC) generates the inspiratory rhythm for breathing. The onset of neural activity that precipitates the inspiratory phase of the respiratory cycle may depend on the activity of type-1 preBötC neurons, which exhibit a transient outward K+ current, IA Inspiratory rhythm generation can be studied ex vivo because the preBötC remains rhythmically active in vitro, both in acute brainstem slices and organotypic cultures. Advantageous optical conditions in organotypic slice cultures from newborn mice of either sex allowed us to investigate how IA impacts Ca2+ transients occurring in the dendrites of rhythmically active type-1 preBötC neurons. The amplitude of dendritic Ca2+ transients evoked via voltage increases originating from the soma significantly increased after an IA antagonist, 4-aminopyridine (4-AP), was applied to the perfusion bath or to local dendritic regions. Similarly, glutamate-evoked postsynaptic depolarizations recorded at the soma increased in amplitude when 4-AP was coapplied with glutamate at distal dendritic locations. We conclude that IA is expressed on type-1 preBötC neuron dendrites. We propose that IA filters synaptic input, shunting sparse excitation, while enabling temporally summated events to pass more readily as a result of IA inactivation. Dendritic IA in rhythmically active preBötC neurons could thus ensure that inspiratory motor activity does not occur until excitatory synaptic drive is synchronized and well coordinated among cellular constituents of the preBötC during inspiratory rhythmogenesis. The biophysical properties of dendritic IA might thus promote robustness and regularity of breathing rhythms.SIGNIFICANCE STATEMENT Brainstem neurons in the preBötC generate the oscillatory activity that underlies breathing. PreBötC neurons express voltage-dependent currents that can influence inspiratory activity, among which is a transient potassium current (IA) previously identified in a rhythmogenic excitatory subset of type-1 preBötC neurons. We sought to determine whether IA is expressed in the dendrites of preBötC. We found that dendrites of type-1 preBötC neurons indeed express IA, which may aid in shunting sparse non-summating synaptic inputs, while enabling strong summating excitatory inputs to readily pass and thus influence somatic membrane potential trajectory. The subcellular distribution of IA in rhythmically active neurons of the preBötC may thus be critical for producing well coordinated ensemble activity during inspiratory burst formation.

Organotypic slice cultures containing the preBötzinger complex generate respiratory-like rhythms.

Study of acute brain stem slice preparations in vitro has advanced our understanding of the cellular and synaptic mechanisms of respiratory rhythm generation, but their inherent limitations preclude long-term manipulation and recording experiments. In the current study, we have developed an organotypic slice culture preparation containing the preBötzinger complex (preBötC), the core inspiratory rhythm generator of the ventrolateral brain stem. We measured bilateral synchronous network oscillations, using calcium-sensitive fluorescent dyes, in both ventrolateral (presumably the preBötC) and dorsomedial regions of slice cultures at 7-43 days in vitro. These calcium oscillations appear to be driven by periodic bursts of inspiratory neuronal activity, because whole cell recordings from ventrolateral neurons in culture revealed inspiratory-like drive potentials, and no oscillatory activity was detected from glial fibrillary associated protein-expressing astrocytes in cultures. Acute slices showed a burst frequency of 10.9 ± 4.2 bursts/min, which was not different from that of brain stem slice cultures (13.7 ± 10.6 bursts/min). However, slice cocultures that include two cerebellar explants placed along the dorsolateral border of the brainstem displayed up to 193% faster burst frequency (22.4 ± 8.3 bursts/min) and higher signal amplitude (340%) compared with acute slices. We conclude that preBötC-containing slice cultures retain inspiratory-like rhythmic function and therefore may facilitate lines of experimentation that involve extended incubation (e.g., genetic transfection or chronic drug exposure) while simultaneously being amenable to imaging and electrophysiology at cellular, synaptic, and network levels.

Potential market size and impact of hepatitis C treatment in low- and middle-income countries.

The introduction of direct-acting antiviral agents (DAAs) has made hepatitis C infection curable in the vast majority of cases and the elimination of the infection possible. Although initially too costly for large-scale use, recent reductions in DAA prices in some low- and middle-income countries (LaMICs) has improved the prospect of many people having access to these drugs/medications in the future. This article assesses the pricing and financing conditions under which the uptake of DAAs can increase to the point where the elimination of the disease in LaMICs is feasible. A Markov simulation model is used to study the dynamics of the infection with the introduction of treatment over a 10-year period. The impact on HCV-related mortality and HCV incidence is assessed under different financing scenarios assuming that the cost of the drugs is completely paid for out-of-pocket or reduced through either subsidy or drug price decreases. It is also assessed under different diagnostic and service delivery capacity scenarios separately for low-income (LIC), lower-middle-income (LMIC) and upper-middle-income countries (UMIC). Monte Carlo simulations are used for sensitivity analyses. At a price of US$ 1680 per 12-week treatment duration (based on negotiated Egyptian prices for an all oral two-DAA regimen), most of the people infected in LICs and LMICs would have limited access to treatment without subsidy or significant drug price decreases. However, people in UMICs would be able to access it even in the absence of a subsidy. For HCV treatment to have a significant impact on mortality and incidence, a significant scaling-up of diagnostic and service delivery capacity for HCV infection is needed.

Addressing barriers to the prevention, diagnosis and treatment of hepatitis B and C in the face of persisting fiscal constraints in Europe: report from a high level conference.

In the WHO-EURO region, around 28 million people are currently living with chronic viral hepatitis, and 120,000 people die every year because of it. Lack of awareness and understanding combined with the social stigma and discrimination exacerbate barriers related to access to prevention, diagnosis and treatment services for those most in need. In addition, the persisting economic crisis has impacted on public health spending, thus posing challenges on the sustainable investment in promotion, primary and secondary prevention, diagnosis and treatment of viral hepatitis across European countries. The Hepatitis B and C Public Policy Association in cooperation with the Hellenic Center for Disease Prevention and Control together with 10 partner organizations discussed at the Athens High Level Meeting held in June 2014 recent policy developments, persisting and emerging challenges related to the prevention and management of viral hepatitis and the need for a de minimis framework of urgent priorities for action, reflected in a Call to Action (Appendix S1). The discussion confirmed that persisting barriers do not allow the full realisation of the public health potential of diagnosing and preventing hepatitis B and C, treating hepatitis B and curing hepatitis C. Such barriers are related to (a) lack of evidence-based knowledge of hepatitis B and C, (b) limited access to prevention, diagnosis and treatment services with poor patient pathways, (c) declining resources and (d) the presence of social stigma and discrimination. The discussion also confirmed the emerging importance of fiscal constraints on the ability of policymakers to adequately address viral hepatitis challenges, particularly through increasing coverage of newer therapies. In Europe, it is critical that public policy bodies urgently agree on a conceptual framework for addressing the existing and emerging barriers to managing viral hepatitis. Such a framework would ensure all health systems share a common understanding of definitions and indicators and look to integrate their responses to manage policy spillovers in the most cost-effective manner, while forging wide partnerships to sustainably and successfully address viral hepatitis.

Where next for hepatitis B and C surveillance?

Hepatitis B and C infections are responsible for significant burden of disease accounting for 1.3 million deaths globally. There is a lack of quality data on the burden of disease due to these infections. One approach to informing policy makers on trends in hepatitis B and C is through case reporting of diagnosed cases. Data on these cases can identify outbreaks of hepatitis and monitor trends in acute and chronic infection. The European Centers for Disease Control (ECDC) has developed standardized case definitions and a harmonized reporting framework. Two articles in this issue summarize the trends in hepatitis B and C infection in Europe. The results show considerable variability in reported cases across countries, reflecting in part differences in testing practices. Risk factor information highlights the continued importance of injecting drug use as a risk factor for hepatitis C infection. Hepatitis case reporting provides valuable information, and more complete reporting will improve the utility of the data. For a comprehensive epidemiologic assessment of the burden of hepatitis, case reporting should be complemented by other sources of data, such as serologic and behavioural surveys.

Challenges towards Economic Fuel Generation from Renewable Electricity: The Need for Efficient Electro-Catalysis.

Utilizing renewable sources of energy is very attractive to provide the growing population on earth in the future but demands the development of efficient storage to mitigate their intermittent nature. Chemical storage, with energy stored in the bonds of chemical compounds such as hydrogen or carbon-containing molecules, is promising as these energy vectors can be reserved and transported easily. In this review, we aim to present the advantages and drawbacks of the main water electrolysis technologies available today: alkaline and PEM electrolysis. The choice of electrode materials for utilization in very basic and very acid conditions is discussed, with specific focus on anodes for the oxygen evolution reaction, considered as the most demanding and energy consuming reaction in an electrolyzer. State-of-the-art performance of materials academically developed for two alternative technologies: electrolysis in neutral or seawater, and the direct electrochemical conversion from solar to hydrogen are also introduced.

Axon targeting of the alpha 7 nicotinic receptor in developing hippocampal neurons by Gprin1 regulates growth.

Cholinergic signaling plays an important role in regulating the growth and regeneration of axons in the nervous system. The α7 nicotinic receptor (α7) can drive synaptic development and plasticity in the hippocampus. Here, we show that activation of α7 significantly reduces axon growth in hippocampal neurons by coupling to G protein-regulated inducer of neurite outgrowth 1 (Gprin1), which targets it to the growth cone. Knockdown of Gprin1 expression using RNAi is found sufficient to abolish the localization and calcium signaling of α7 at the growth cone. In addition, an α7/Gprin1 interaction appears intimately linked to a Gαo, growth-associated protein 43, and CDC42 cytoskeletal regulatory pathway within the developing axon. These findings demonstrate that α7 regulates axon growth in hippocampal neurons, thereby likely contributing to synaptic formation in the developing brain.

Protocol to dissect and dissociate the mouse brainstem for single-cell RNA-seq applications.

Processing dissociated cells for transcriptomics is challenging when targeting small brain structures, like brainstem nuclei, where cell yield may be low. Here, we present a protocol for dissecting, dissociating, and cryopreserving mouse brainstem that allows asynchronous sample collection and downstream processing of cells obtained from brainstem tissue in neonatal mice. Although we demonstrate this protocol with the isolated preBötzinger complex and downstream SmartSeq3 cDNA library preparation, it could be readily adapted for other brainstem areas and library preparation approaches.

Prostaglandin E2 Exerts Biphasic Dose Response on the PreBötzinger Complex Respiratory-Related Rhythm.

Inflammation in infants can cause respiratory dysfunction and is potentially life-threatening. Prostaglandin E2 (PGE2) is released during inflammatory events and perturbs breathing behavior in vivo. Here we study the effects of PGE2 on inspiratory motor rhythm generated by the preBötzinger complex (preBötC). We measured the concentration dependence of PGE2 (1 nM-1 µM) on inspiratory-related motor output in rhythmic medullary slice preparations. Low concentrations (1-10 nM) of PGE2 increased the duration of the inspiratory burst period, while higher concentrations (1 µM) decreased the burst period duration. Using specific pharmacology for prostanoid receptors (EP1-4R, FPR, and DP2R), we determined that coactivation of both EP2R and EP3R is necessary for PGE2 to modulate the inspiratory burst period. Additionally, biased activation of EP3 receptors lengthened the duration of the inspiratory burst period, while biased activation of EP2 receptors shortened the burst period. To help delineate which cell populations are affected by exposure to PGE2, we analyzed single-cell RNA-Seq data derived from preBötC cells. Transcripts encoding for EP2R (Ptger2) were differentially expressed in a cluster of excitatory neurons putatively located in the preBötC. A separate cluster of mixed inhibitory neurons differentially expressed EP3R (Ptger3). Our data provide evidence that EP2 and EP3 receptors increase the duration of the inspiratory burst period at 1-10 nM PGE2 and decrease the burst period duration at 1 µM. Further, the biphasic dose response likely results from differences in receptor binding affinity among prostanoid receptors.

[Aetiologies of pleural effusions in HIV-infected patients in Abidjan, Côte-d'Ivoire]. / Etiologies des pleurésies chez les patients infectés par le VIH a Abidjan, Côte-d'Ivoire.

From December 1995 to March 1996 a cross sectional study was carried out in the pulmonary Medicine Unit of Treichville in Abidjan. In order to specify the main aetiologies of pleural effusion, an investigation was conducted among 35 adult patients (19 men and 16 women) suffering from pleuritis. Overall, the mean age was 32.2 years (range: 19-53 years). All the patients underwent a standard chest x-ray a skin test with 10 units of tuberculin, a whole blood cells count with CD4 T cells count and HIV test. The following analysis were performed on the pleural fluid for all patients: cytological, bacteriological and mycobacteriological examination. Some patients underwent as well a pleural biopsy performed by Abram's needle. Pleural fluid was clear in 24 cases (69%). Empyema was found in 8 cases (23%) and hemorrhagic fluid in 3 cases (9%). Tuberculosis was the dominant aetiology of pleuritis noted in 29 patients (83%), followed by far by non-tuberculous bacterial infections in 6 patients (17%). Tuberculosis associated with common bacterial infections was noted in 3 cases.

Robust Hierarchically Structured Biphasic Ambipolar Oxide Photoelectrodes for Light-Driven Chemical Regulation and Switchable Logic Applications.

Tunable ambipolar photoelectrochemical behavior emerges from microdomains of nanostructured p-type CuFeO2 and n-type Fe2 O3 that arise from a single facile solution-processed thin film. The switchable operation of this system is controlled by chemical, optical, or electronic inputs with a uniquely high photocurrent response (on the order of 1 mA cm-2 ), suitable for robust practical application as an oxygen photoregulator.

Sociodemographic factors associated with participation by HIV-1-positive pregnant women in an intervention to prevent mother-to-child transmission of HIV in Cote d'Ivoire.

Many HIV-1-seropositive women in Africa who are offered antiretroviral prophylaxis to prevent mother-to-child transmission (MTCT) of HIV do not begin interventions. Research on barriers to participation has not addressed the possible effects of women's sociocultural and economic circumstances. We examined these factors at an MTCT prevention programme in Abidjan, Cote d'Ivoire. We interviewed two groups of women after they had received HIV-positive test results and had been invited by the programme staff to return for monthly follow-up visits before beginning short-course zidovudine prophylaxis. Participants (n = 30) completed follow-up visits and prophylaxis. Non-participants (n = 27) refused or discontinued follow-up visits and did not begin zidovudine. Fewer non-participants had been born in Cote d'Ivoire (67% vs. 97%) or were Ivorian nationals (48% vs. 77%); they had lived in the country for less time (21 vs. 26 median years). They were less likely to be French-literate (37% vs. 77%), and more of them reported having had Koranic education only (18% vs. 0). They more often reported miscarriages, stillbirths, or infant deaths (69% vs. 33%), and had partners with low-ranked jobs (63% vs. 30%). Our findings suggest that the non-participants were more marginal socioculturally and economically in Ivorian society than participants. Greater attention to mitigating the effects of broader structural factors on women's participation in interventions may increase the effectiveness of MTCT prevention in Africa.

Prevention of mother-to-child transmission of HIV-1 in Africa.

PIP: With the prevalence of HIV among pregnant women higher than 35% in some parts of sub-Saharan Africa, the number of HIV-infected children will continue to grow. It is estimated that almost 70% of the approximately 500,000 children who became infected with HIV in 1995 were born in sub-Saharan Africa. An effective intervention to prevent the vertical transmission of HIV is therefore most urgently needed in Africa. Following the release of the results of the AIDS Clinical Trials Group (ACTG) 076 study, the routine use of zidovudine (AZT) among HIV-infected pregnant women in the US and Europe has resulted in a significant reduction in the rate of mother-to-child vertical HIV transmission. However, most women in Africa will not benefit from these advances in the immediate future due to inadequate prenatal health care, the unavailability of prenatal HIV testing, and the high cost and complexity of the recommended regimen. Researchers need to build upon the findings of developed countries to identify feasible, effective, and implementable interventions to reduce the vertical transmission of HIV as well as to prevent HIV infection among women and to protect the health of HIV-infected women in Africa. Rates and timing of vertical HIV transmission, risk factors associated with vertical HIV transmission, and prevention interventions are discussed.^ieng

Impact of the 1994 expanded World Health Organization AIDS case definition on AIDS surveillance in university hospitals and tuberculosis centers in Côte d'Ivoire.

OBJECTIVE: To assess the impact of the 1994 expanded World Health Organization (WHO) AIDS case definition on AIDS surveillance in Côte d'Ivoire. DESIGN: Prospective AIDS case surveillance. METHODS: From March 1994 through December 1996, passive AIDS case surveillance was conducted at the three university hospitals in Abidjan, and active AIDS case surveillance was conducted at the eight tuberculosis (TB) centers in Côte d'Ivoire. Standardized questionnaires were administered and blood samples for HIV serologic testing were collected from the patients evaluated. The numbers of persons who met the modified 1985 WHO clinical AIDS case definition (Bangui definition) and the 1994 expanded WHO AIDS case definition were determined, and the clinical characteristics of these patients were assessed. RESULTS: Of 8648 university hospital patients, 3658 (42.3%) met the clinical and/or the expanded case definition: 744 (20.3%) HIV-seropositive persons met only the expanded definition, 44 (1.2%) HIV-seropositive persons met only the clinical definition, 2334 (63.8%) HIV-seropositive persons met both definitions, and 536 (14.7%) HIV-seronegative persons met only the clinical definition. Of 18,661 TB center patients, 9664 (51.8%) met the clinical and/or the expanded definition: 5685 (58.8%) HIV-seropositive persons met only the expanded definition, none of the HIV-seropositive persons met only the clinical definition (by definition), 2625 (27.2%) HIV-seropositive persons met both definitions, and 1354 (14.0%) HIV-seronegative persons met only the clinical definition. CONCLUSIONS: Because of the inclusion of multiple severe HIV-related illnesses into the expanded definition, the number of reportable AIDS cases in HIV-seropositive patients increased 31.3% in the university hospitals, and 217% in the TB centers. The inclusion of HIV seropositivity as a criterion for the expanded definition also enhanced the specificity of AIDS case reporting, eliminating 536 cases in the university hospitals and 1354 cases in the TB centers in HIV-seronegative patients who had clinical signs of AIDS. The use of the 1994 expanded definition for surveillance purposes should be encouraged in areas of the developing world where HIV serologic testing is available.

Protease sequences from HIV-1 group M subtypes A-H reveal distinct amino acid mutation patterns associated with protease resistance in protease inhibitor-naive individuals worldwide. HIV Variant Working Group.

BACKGROUND: Although numerous mutations that confer resistance to protease inhibitors (PRI) have been mapped for HIV-1 subtype B, little is known about such substitutions for the non-B viruses, which globally cause the most infections. OBJECTIVES: To determine the prevalence of PRI-associated mutations in PRI-naive individuals worldwide. DESIGN: Using the polymerase chain reaction, protease sequences were amplified from 301 individuals infected with HIV-1 subtypes A (79), B (95), B' (19), C (12), D (26), A/E (23), F (26), A/G (11), and H (3) and unclassifiable HIV-1 (7). Amplified DNA was directly sequenced and translated to amino acids to analyze PRI-associated major and accessory mutations. RESULTS: Of the 301 sequences, 85% contained at least one codon change giving substitution at 10, 20, 30, 36, 46, 63, 71, 77, or 82 associated with PRI resistance; the frequency of these substitutions was higher among non-B (91%) than B (75%) viruses (P < 0.0005). Of these, 25% carried dual and triple substitutions. Two major drug resistance-conferring mutations, either 20M or 30N, were identified in only three specimens, whereas drug resistance accessory mutations were found in 252 isolates. These mutations gave distinct prevalence patterns for subtype B, 63P (62%) > 77I (19%) > 10I/V/R (6%) = 361 (6%) = 71T/V (6%) > 20R (2%), and non-B strains, 36I (83%) > 63P (17%) > 10I/V/R (13%) > 20R (10%) > 77I (2%), which differed statistically at positions 20, 36, 63, 71, and 77. CONCLUSIONS: The high prevalence of PRI-associated substitutions represent natural polymorphisms occurring in PRI-naive patients infected with HIV-1 strains of subtypes A-H. The significance of distinct mutation patterns identified for subtype B and non-B strains warrants further clinical evaluation. A global HIV-1 protease database is fundamental for the investigation of novel PRI.

Impact of HIV infection on the development, clinical presentation, and outcome of tuberculosis among children in Abidjan, Côte d'Ivoire.

OBJECTIVE: To assess the impact of HIV infection upon the development, clinical presentation, and outcome of tuberculosis (TB) among children. DESIGN: Case-control study and prospective cohort study. METHODS: From March 1994 to November 1995, children aged 0-9 years with newly diagnosed TB were enrolled at the two outpatient TB centers and the two principal university hospitals in Abidjan, Côte d'Ivoire. Children were examined, blood samples were collected for HIV serology and lymphocyte phenotyping, chest radiography was performed, and gastric aspirates and sputum samples were collected for acid-fast bacilli smear and culture. Children were then followed every 2 months during a standard 6-month course of anti-TB therapy. To examine risk factors for TB, age- and sex-matched healthy control children were enrolled from among the siblings of children referred for TB skin testing. RESULTS: Overall, 161 children with TB were enrolled, including 39 (24%) with culture-confirmed pulmonary TB, 80 (50%) with clinically diagnosed pulmonary TB, and 42 (26%) with extrapulmonary TB. Children with TB were significantly more likely than 161 control children to be HIV-seropositive (19 versus 0%), to have a past TB contact (55 versus 16%) and to live in very low socioeconomic status housing (24 versus 6%). No significant differences between HIV-seropositive and seronegative children were found in the distribution of radiologic abnormalities for pulmonary TB or in the site of extrapulmonary TB. The mortality rate in HIV-seropositive children was significantly higher than in seronegative children (23 versus 4%; relative risk, 3.6; 95% confidence interval, 2.0-6.6), and all deaths in HIV-seropositive children with available lymphocyte subtyping results occurred in those with a CD4 percentage of < 10%. CONCLUSIONS: This study documents the importance of HIV infection as an independent risk factor for the development of TB in children, and demonstrates that HIV-related immunosuppression is a critical risk factor for mortality in this population.

Effect of interventions to control sexually transmitted disease on the incidence of HIV infection in female sex workers.

OBJECTIVE: To compare the seroincidence of HIV infection among female sex workers in Abidjan, Côte d'Ivoire before and during an intervention study to control sexually transmitted diseases (STD) and to study the effect of two STD diagnosis and treatment strategies on the prevalence of STD and on the seroincidence of HIV infection. METHOD: A screening facility for STD and HIV had been available since October 1992 for female sex workers. From June 1994, women who were HIV seronegative or HIV-2 positive during the screening could enroll in the intervention study in which participants reported once a month to a confidential clinic where they received health education, condoms and STD treatment if indicated. Women in the study were randomized either to a basic STD diagnosis and treatment strategy, which included a gynecologic examination when symptomatic, or to an intensive strategy that included a gynecologic examination regardless of symptoms. An outcome assessment every 6 months included a gynecologic examination, HIV serology and laboratory tests for STD. RESULTS: Of 542 women enrolled in the study, 225 (42%) had at least one outcome assessment. The HIV-1 seroincidence rate during the intervention study was significantly lower than before the study (6.5 versus 16.3 per 100 person-years; P = 0.02). During the study, the HIV-1 seroincidence rate was slightly lower in the intensive than in the basic strategy (5.3 versus 7.6 per 100 person-years; P = 0.5). CONCLUSION: National AIDS control programs should consider adopting as policy the type of integrated approach used in this intervention study for HIV prevention in female sex workers.

Lack of protection against HIV-1 infection among women with HIV-2 infection.

OBJECTIVE: To assess whether HIV-2 infection protects against HIV-1 infection by comparing the rate of HIV-1 seroconversion among HIV-negative and HIV-2-seropositive women followed in a cohort study in Abidjan, Côte d'Ivoire. DESIGN: Prospective cohort study METHODS: HIV seroconversion was assessed in 266 HIV-seronegative, 129 HIV-1-seropositive, and 127 HIV-2-seropositive women participating in a closed cohort study of mother-to-child transmission of HIV conducted during 1990-1994. Participants were seen every 6 months, and blood samples were obtained. All blood samples were screened for HIV antibodies by enzyme immunoassay (EIA) and confirmed by line immunoassay (LIA) and Western blot. Among women who were HIV-seronegative at enrolment, seroconversion was defined as new EIA-reactivity confirmed on LIA and Western blot. Among HIV-1- or HIV-2-seropositive women, seroconversion to dual reactivity was defined as new dual reactivity on the LIA that was confirmed by reactivity on both HIV-1- and HIV-2-monospecific EIA. RESULTS: Five HIV-seronegative women became HIV-1-seropositive [seroconversion rate, 1.1 per 100 person-years; 95% confidence interval (CI), 0.3-2.5), and none became HIV-2-seropositive. No HIV-1-seropositive women became HIV-1/2 dually reactive, whereas six HIV-2-seropositive women acquired HIV-1 seroreactivity and thus became HIV-1/2 dually reactive (seroconversion rate 2.9 per 100 person-years; 95% CI, 1.1-6.3). HIV-2-seropositive women were more likely to acquire HIV-1 seroreactivity than were HIV-seronegative women (rate ratio, 2.7; 95% CI, 0.7-11.2), but this difference was not statistically significant (P>0.15). CONCLUSION: HIV-2 infection does not appear to protect against HIV-1 infection.

Evaluation of HIV serial and parallel serologic testing algorithms in Abidjan, Côte d'Ivoire.

OBJECTIVE: To evaluate HIV serologic testing algorithms based on a combination of three enzyme linked immunosorbent assays (ELISA) for the confirmation of HIV infection in Abidjan, Côte d'Ivoire, where HIV-2 and HIV-1 non-B subtypes are prevalent. METHODS: A total of 1069 human sera with known serologic status, in addition to a seroconversion and low titer antibody panel were initially tested by six ELISA to determine the sensitivity, specificity and delta values of the assays. On the basis of the performance of the assays, three ELISA (Enzygnost, ICE 1.0.2, and Vironostika) were selected for use in a parallel and serial testing algorithm in analyzing 8283 consecutively collected sera. In the parallel testing algorithm, sera concordantly reactive or non-reactive by Enzygnost and ICE 1.0.2 were considered as true positive or true negative, respectively. In the serial algorithm, sera reactive by Enzygnost were retested by ICE 1.0.2. Sera with discordant results were tested by Vironostika, and the results was considered definitive. All reactive sera, plus a random sample of negative sera were tested for confirmation by Peptilav. In addition, a random sample of reactive sera was tested by Western blot. RESULTS: All ELISA had 100% sensitivity; specificities ranged from 96.8 to 100%. Positive and negative delta values of the ELISA were high (range, 6.89 to 46.07 and -2.05 to -5.75, respectively). Of the 8283 sera, 2054 were considered true positives and were correctly classified by the parallel testing algorithm (sensitivity, 100%). Of the 6229 true negative sera, 6226 were negative by the parallel testing algorithm (specificity, 99.95%). The sensitivity of the serial algorithm was 99.96%, and specificity was 99.95%. None of the 250 concordant ELISA-negative sera in the algorithm that were randomly tested in Peptilav was positive; similarly, all of the 103 concordant ELISA-positive sera were confirmed by Western blot. The three-ELISA algorithm resulted in reagent cost-savings of at least 50% compared with the Peptilav-based algorithm. CONCLUSION: These results suggest that a combination of ELISA using different principles or antigens in a serial or parallel algorithm is an efficient and cost-effective alternative to the standard algorithm in areas where HIV-1 and HIV-2 are prevalent.

Cervicovaginal anti-HIV antibodies in HIV-seronegative female sex workers in Abidjan, Côte d'Ivoire.

OBJECTIVE: To detect anti-HIV antibodies in cervicovaginal secretions of HIV-seronegative female sex workers and to evaluate whether the presence of these antibodies is associated with increased sexual exposure. METHODS: A cross-sectional study was carried out at a confidential clinic for female sex workers in Abidjan, Côte d'Ivoire. The participants were 342 HIV-seronegative female sex workers in whom a cervicovaginal lavage was collected. The main outcome measures were the detection of antibodies to HIV-1 in cervicovaginal lavages using an in-house and a commercial (Seradyn Sentinel; Calypte Biomedical Corporation, Berkeley, California, USA) enzyme immunoassay; the detection of semen in cervicovaginal lavages; and the assessment of epidemiological and biological markers of sexual exposure to HIV. RESULTS: Cervicovaginal anti-HIV antibodies were detected in 7.3 and 29.8% of women using in-house enzyme-linked immunosorbent assay (ELISA) and Seradyn Sentinel respectively. All cervicovaginal secretions found to be positive by in-house ELISA were also positive by Seradyn Sentinel. In a minority of women, ranging from 2.9% by in-house ELISA to 12.3% by Seradyn Sentinel, the anti-HIV antibodies were present in vaginal fluids that did not contain semen. Sexual exposure to HIV was similar in women with anti-HIV antibodies in their semen-free cervicovaginal secretions compared with women without anti-HIV antibodies in their cervicovaginal secretions. CONCLUSIONS: Cervicovaginal HIV-specific antibodies were detected in a minority of sexually exposed HIV-seronegative female sex workers in Abidjan. The lack of association between increased sexual exposure to HIV and presence of cervicovaginal HIV-specific antibodies suggests that the production of genital HIV-specific antibodies in exposed seronegative women depends on the ability of individual women to mount specific mucosal immunity to HIV antigens, the determinants of which are currently unknown.