Absolute CD4 T-cell counting in resource-poor settings: direct volumetric measurements versus bead-based clinical flow cytometry instruments

Flow cytometry is an accurate but expensive method to determine absolute CD4 cell counts. We compared different methods to measure absolute CD4 counts in blood samples from HIV-infected and uninfected subjects using a research/clinical flow cytometer (FACScan); a dedicated clinical instrument (FACSCount); and a volumetric, mobile, open-system flow cytometer equipped with 3 fluorescence and 2 light scatter detectors (Cyflow SL blue). The FACScan and Cyflow were used as single-platform instruments, but they differ in running cost, which is a central factor for resource-poor settings. Direct volumetric and bead-based CD4 measurements on the Cyflow were compared with 2 bead-based single-platform CD4 measurements on the FACSCount and on FACScan (TruCount) in "Le Dantec" Hospital, Dakar, Senegal, using whole blood samples from 102 HIV+ and 28 HIV- subjects. The agreement between the various measurement methods was evaluated by Bland-Altman analysis. Volumetric CD4 measurements on the Cyflow using a no-lyse-no-wash (NLNW) procedure and a lyse-no-wash (LNW) procedure correlated well with each other (R2 = 0.98) and with CD4 measurements on the FACSCount (R2 = 0.97) and FACScan (R2 = 0.97), respectively. Red blood cell lysis had no negative effect on the accuracy of absolute CD4 counting on the Cyflow. An excellent correlation was observed between bead-based CD4 measurements on the Cyflow and CD4 measurements on the FACSCount (R2 = 0.99) and FACScan (R2 = 0.99). Rigid internal and external quality control monitoring and adequate training of technicians were considered essential to generate accurate volumetric CD4 measurements on the Cyflow.     

Differences in circulating dendritic cell subtypes in peripheral, placental and cord blood in African pregnant women

Dendritic cells (DC) are important for induction of primary immune responses and immunological tolerance. Changes in the frequency of DC subsets were analyzed in peripheral blood from pregnant women (mPB) and compared to placental blood (PB) and cord blood (CB). DCs were identified by flow cytometry in whole blood as lineage negative and HLA-DR-positive cells. Different DC subtypes were identified with CD123 and CD11c markers. In these data, the percentage of DC was significantly lower in mPB, PB and CB than in control women, but the absolute number of DC was higher in CB, suggesting that numbers of DC in CB do not explain the decrease of the immune response in newborn infants. Myeloid DCs (MDC) decreased in all compartments of pregnant women compared to control women, especially in mPB where MDC became lower than lymphoid DCs. An increase of less differentiated DC was observed in mPB and CB from pregnant women. DCs in pregnant women were mainly immature DC with a proportion of CD83-positive DC, identical as control women. The levels of IFNgamma, TNFalpha, IL-2, IL-4, IL-5 and IL-10 were not different in the three compartments (mPB, PB, CB). In conclusion, the phenotype and subset of DCs were different in pregnant women than in control women, suggesting a role in maintenance of immune tolerance against the fetus. The distribution of DC subsets was different in mPB, PB and CB. Their role in the regulation of immune response remains to be elicited.     

Equine herpesvirus infections in yearlings in South-East Queensland

Twelve nasal swabs were collected from yearling horses with respiratory distress and tested for equid herpesvirus 1 (EHV-1) and equid herpesvirus 4 (EHV-4) by real-time PCR targeting the glycoprotein B gene. All samples were negative for EHV-1; however, 3 were positive for EHV-4. When these samples were tested for EHV-2 and EHV-5 by PCR, all samples were negative for EHV-2 and 11 were positive for EHV-5. All three samples that were positive for EHV-4 were also positive for EHV-5. These three samples gave a limited CPE in ED cells reminiscent of EHV-4 CPE. EHV-4 CPE was obvious after 3 days and was characterised by syncytia. None of the samples produced cytopathic effect (CPE) on African green monkey kidney (Vero) cells or hamster kidney (BSR) cells. Four of the samples, which were positive in the EHV-5 PCR, produced CPE on rabbit kidney (RK13) cells and equine dermis (ED) cells. EHV-5 CPE on both cell lines was slow and was apparent after four 7-day passages. On RK13 cells, the CPE was characteristic of equid herpesvirus, with the formation of syncytia. However, in ED cells, the CPE was characterised by ring-shaped syncytia. For the first time, a case of equine respiratory disease involving dual infection with EHV-4 and EHV-5 has been reported in Queensland (Australia). This was shown by simultaneously isolating EHV-4 and EHV-5 from clinical samples. EHV5 was recovered from all samples except one, suggesting that EHV5 was more prevalent in young horses than EHV2.     

Quantitation of HIV-1 RNA in dried blood spots by the real-time NucliSENS EasyQ HIV-1 assay in Senegal

Measurement of viral load in plasma remains the best marker for the follow-up of antiretroviral therapy. However, its use is limited in developing countries due to the lack of adequate facilities and equipment, and cryopreservation of plasma during storage and transportation. Practical and reliable methods adapted to field conditions for the collection, transportation and accurate measurement of HIV-1 viral load are needed for the optimum use of antiretroviral therapy in resource-limited countries. This study evaluated the use of dried blood spots (DBS) for the real-time quantitation of HIV-1 RNA levels with the NucliSENS EasyQ((R)) HIV-1 assay (bioMérieux, Lyon, France) under field conditions in Senegal (Africa). Dried blood spots and plasma from 41 patients living in suburban Dakar were used for determination of HIV-1 RNA concentrations and stability at 37 degrees C. Analysis was performed at the Dakar University Hospital laboratory. Extraction was done with the bioMérieux NucliSENS((R)) miniMAGtrade mark, and real-time detection was done with the bioMérieux NucliSENS((R)) EasyQ system. HIV-1 RNA concentrations in plasma were compared with concentrations in dried blood spots after 8 and 15 days at 37 degrees C. The study showed a strong concordance in RNA levels between plasma and dried blood spots, which appear to be very stable over time with no apparent degradation observed after 2 weeks at 37 degrees C (mean difference 0.065logIU/ml). These results suggest that the use of dried blood spots in combination with the NucliSENS EasyQ HIV-1 assay is well adapted for HIV-1 RNA level monitoring in centralized laboratories in developing countries.     

RNA versus DNA (NucliSENS EasyQ HIV-1 v1.2 versus Amplicor HIV-1 DNA test v1.5) for early diagnosis of HIV-1 infection in infants in Senegal

The objective of this study was to compare the performance of the NucliSENS EasyQ HIV-1 v1.2 platform (bioMérieux, France) to the Amplicor HIV-1 DNA test v1.5 (Roche Molecular Systems, Switzerland) in detecting HIV-1 infection in infants using venipuncture-derived whole blood in tubes and dried blood spots. A total of 149 dried blood spots and 43 EDTA-anticoagulated peripheral blood samples were collected throughout Dakar and other areas in Senegal from infants and children aged 3 weeks to 24 months who were born to HIV-1-infected mothers. Samples were tested using the NucliSENS and Amplicor technologies. The NucliSENS and Amplicor results were 100% concordant using either EDTA-anticoagulated peripheral blood or dried blood spots. Compared to Amplicor, the sensitivity and specificity of the NucliSENS test were 100%. The NucliSENS EasyQ HIV-1 RNA assay performed as well as the Amplicor HIV-1 DNA test in detecting HIV-1 infection in infants. In addition, this platform can give an indication of the viral load baseline. The NucliSENS EasyQ platform is a good alternative for early infant diagnosis of HIV-1 infection.     

Whipworm diversity in West African rodents: a molecular approach and the description of <Emphasis Type="Italic">Trichuris duplantieri</Emphasis> n. sp. (Nematoda: Trichuridae)

Whipworms were collected from rodents (Muridae) from six West African countries: Burkina-Faso, the Islamic Republic of Mauritania, and the Republics of Benin, Guinea, Mali and Senegal. Molecular sequences (ITS-1, 5.8S and ITS-2 of the ribosomal DNA gene) and morphometric characters were analysed in Trichuris (Nematoda: Trichuridae) specimens found in seven host species: Arvicanthis niloticus, Gerbilliscus gambianus, Gerbillus gerbillus, G. tarabuli, Mastomys erythroleucus, M. huberti and M. natalensis. Phylogenetic analyses revealed three clades, one recognised as Trichuris mastomysi, previously recorded in M. natalensis from Tanzania, and the other two previously undescribed. A new species named Trichuris duplantieri n. sp., found in Gerbillus spp. from Mauritania, was characterised using molecular and morphometric methods.     

Détection fortuite de <Emphasis Type="Italic">cmy</Emphasis>-2 et <Emphasis Type="Italic">dha</Emphasis>-1 chez des isolats d’<Emphasis Type="Italic">Escherichia coli</Emphasis> producteurs de BLSE au Sénégal

Cephalosporinases, which are naturally present in some enterobacterial species, can be mobilized by transposons, migrate to plasmids, and spread into other species such as Escherichia coli. The aim of this study was to characterize genes responsible for the production of extended-spectrum β-lactamases (ESBL) in E. coli isolates from urinary origin isolated in two hospitals in Senegal. Thus, a fortuitous discovery of plasmidic cephalosporinase in two isolates was noted. One of the isolates produced dha-1 associated with ESBL CTX-M-14, the other produced cmy-2, ESBL CTXM-15, tem-1 penicillinase, and oxa-1. This confirms the circulation of multidrug-resistant bacteria producing plasmidic cephalosporinase in Senegal. However, a large study is needed to better understand the prevalence and the nature of the genes involved.     

The predictor of mortality outcome in adult patients with Ebola virus disease during the 2014–2015 outbreak in Guinea

The purpose of this study was to examine the association of any demographic and clinical factors with mortality outcome among adult patients with Ebola virus disease (EVD) in Guinea. This retrospective observational study analyzed medical records of laboratory confirmed EVD adult patients during the 2014–2015 EVD outbreak in Guinea. The associations between any demographic or clinical variables and mortality outcome of EVD were assessed using univariate and multivariate logistic regression analyses. Of 2,310 EVD adult patients included for analysis, the overall case fatality rate was 68.1%. Univariate analyses identified factors possibly associated with mortality outcome, including patient age (p?<?0.001), history of visiting or close contact with a suspected or confirmed EVD patient (p?=?0.035), and seven clinical symptoms on admission, i.e., fever (p?=?0.003), hiccups (p?<?0.001), vomiting (p?=?0.003), diarrhea (p?<?0.001), cough (p?=?0.001), sore throat (p?=?0.016), and unexplained bleeding (p?=?0.021). The multivariate analysis showed that patient age was independently associated with mortality outcome of EVD (OR?=?1.06; 95%CI?=?1.03–1.09; p?<?0.001), while none the of clinical symptoms on admission were significantly associated with the mortality outcome. Our analysis indicates that older age was the only independent factor associated with death among EVD adult patients in Guinea. This suggests that older EVD patients should receive intensive medical care and be carefully monitored.     

Comparative genomic hybridization of ductal carcinoma in situ of the breast—evidence of multiple genetic pathways

There is strong evidence that ductal carcinoma in situ (DCIS) represents a precursor lesion of invasive breast cancer. In order to analyse specific chromosomal alterations of DCIS, 38 paraffin-embedded specimens of DCIS and six associated invasive carcinomas were examined by means of comparative genomic hybridization (CGH). Losses of 16q material were seen almost exclusively in well- and intermediately-differentiated DCIS. These two subgroups differed in the average number of genetic imbalances, 2·5 and 5·5 respectively. Additionally, a higher frequency of gains of 1q and losses of 11q material was seen in intermediately-differentiated in contrast to well-differentiated DCIS. Poorly-differentiated DCIS displayed a higher frequency of amplifications (17q12, 11q13) and a higher average rate of genetic imbalances (7·1). Analysis of adjacent invasive breast carcinoma revealed a genetic pattern almost identical to the one seen in the DCIS counterpart. These data characterize DCIS as a genetically far-advanced, heterogeneous lesion and as a direct precursor of invasive breast cancer. Copyright © 1999 John Wiley & Sons, Ltd.