Southern Africa Consortium for Research Excellence (SACORE): successes and challenges

Copyright © Mandala et al. Open access article distributed under the terms of CC BY.Published Online November 13, 2014 http://dx.doi.org/10.1016/S2214-109X(14)70321-

Performance of molecular methods for the detection of Salmonella in human stool specimens [version 2; peer review: 2 approved]

Background: The relationship between asymptomatic Salmonella exposure within the gastrointestinal tract and Salmonella bacteraemia is poorly understood, in part due to the low sensitivity of stool culture and the lack of validated molecular diagnostic tests for the detection of Salmonella in the stool. The study aimed to determine a reliable molecular diagnostic test for Salmonella in stool specimens. Methods: We optimised an in-house monoplex real-time polymerase chain reaction (PCR) for the detection of Salmonella ttr and InvA genes in stool by including a selenite broth pre-culture step for Salmonella before DNA extraction and validated their specificity against other local common pathogens. Then we assessed their performance against a well-validated multiplex PCR targeting the same ttr and InvA genes and against stool culture using clinical stool specimens collected from a cohort of 50 asymptomatic healthy Malawian children that were sampled at 1-month intervals over 12 months. We employed a latent Markov model to estimate the specificities and sensitivities of PCR methods. Results: Ttr and InvA primers were both able to detect all the different Salmonella serovars tested and had superior limits of detection when DNA was extracted after selenite pre-culture. Ttr sensitivity and specificity for monoplex-PCR were (99.53%, 95.46%) and for multiplex-PCR (90.30%, 99.30%) respectively. InvA specificity and specificity for using monoplex-PCR was (95.06%, 90.31%) and multiplex-PCRs (89.41%, 98.00%) respectively. Sensitivity and specificity for standard stool culture were 62.88% and 99.99%, respectively. Culture showed the highest PPV (99.73%), and monoplex-ttr had the highest NPV (99.67%). Conclusion: Test methods demonstrated high concordance, although stool culture and monoplexed ttr primers had superior specificity and sensitivity, respectively. The use of selenite pre-enrichment step increased Salmonella detection rate. Taken together, molecular detection methods used here could be used to reveal the true extent of both asymptomatic and symptomatic Salmonella exposure events

Lymphocyte subsets in human immunodeficiency virus-unexposed Brazilian individuals from birth to adulthood

Ethnic origin, genetics, gender and environmental factors have been shown to influence some immunologic indices, so that development of reference values for populations of different backgrounds may be necessary. We have determined the distribution of lymphocyte subsets in healthy Brazilian individuals from birth to adulthood. Lymphocyte subsets were determined using four-colour cytometry in a cross-sectional study of 463 human immunodeficiency virus-unexposed children and adults from birth through 49 years of age. Lymphocyte subsets varied according to age, as previously observed in other studies. However, total CD4+ T cell numbers were lower than what was described in the Pediatric AIDS Clinical Trials Group P1009 (PACTG P1009), which assessed an American population of predominantly African and Hispanic backgrounds until the 12-18 year age range, when values were comparable. Naïve percentages and absolute values of CD8+ T cells, as assessed by CD45RA expression, were also lower than the PACTG P1009 data for all analysed age ranges. CD38 expression on both CD4+ and CD8+ T cells was lower than the PACTG P1009 values, with a widening gap between the two studies at older age ranges. Different patterns of cell differentiation seem to occur in different settings and may have characteristic expression within each population.Universidade Federal de São Paulo (UNIFESP) Departamento de MedicinaCentro Assistencial Cruz de MaltaUniversidade Federal de São Paulo (UNIFESP) Departamento de PediatriaUNIFESP, Depto. de MedicinaUNIFESP, Depto. de PediatriaSciEL

SARS-CoV-2 and HIV-1: Should HIV-1-infected individuals in Sub-Saharan Africa be considered a priority group for the COVID-19 vaccines?

Since its emergence in 2019 SARS-CoV-2 has proven to have a higher level of morbidity and mortality compared to the other prevailing coronaviruses. Although initially most African countries were spared from the devastating effect of SARS-CoV-2, at present almost every country has been affected. Although no association has been established between being HIV-1-infected and being more vulnerable to contracting COVID-19, HIV-1-infected individuals have a greater risk of developing severe COVID-19 and of COVID-19 related mortality. The rapid development of the various types of COVID-19 vaccines has gone a long way in mitigating the devastating effects of the virus and has controlled its spread. However, global vaccine deployment has been uneven particularly in Africa. The emergence of SARS-CoV-2 variants, such as Beta and Delta, which seem to show some subtle resistance to the existing vaccines, suggests COVID-19 will still be a high-risk infection for years. In this review we report on the current impact of COVID-19 on HIV-1-infected individuals from an immunological perspective and attempt to make a case for prioritising COVID-19 vaccination for those living with HIV-1 in Sub-Saharan Africa (SSA) countries like Malawi as one way of minimising the impact of COVID-19 in these countries

Leukocyte counts and lymphocyte subsets in relation to pregnancy and HIV infection in Malawian women.

PROBLEM: We investigated leukocyte and lymphocyte subsets in HIV-infected or HIV-uninfected, pregnant or non-pregnant Malawian women to explore whether HIV infection and pregnancy may act synergistically to impair cellular immunity. METHOD OF STUDY: We recruited 54 pregnant and 48 non-pregnant HIV-uninfected women and 24 pregnant and 20 non-pregnant HIV-infected Malawian women. We compared peripheral blood leukocyte and lymphocyte subsets between women in the four groups. RESULTS: Parturient HIV-infected and HIV-uninfected women had more neutrophils (each P<.0001), but fewer lymphocytes (P<.0001; P=.0014) than non-pregnant women. Both groups had fewer total T cells (P<.0001; P=.002) and CD8(+) T cells (P<.0001; P=.014) than non-pregnant women. HIV-uninfected parturient women had fewer CD4(+) and γδ T cells, B and NK cells (each P<.0001) than non-pregnant women. Lymphocyte subset percentages were not affected by pregnancy. CONCLUSION: Malawian women at parturition have an increased total white cell count due to neutrophilia and an HIV-unrelated pan-lymphopenia

HIV infection has a profound effect on hematological factors but not on electrolyte profile of Malawian adults presenting with uncomplicated malaria and severe malaria

Alinane U Munyenyembe,1 Kamunkhwala Gausi,1 Tonney S Nyirenda,2 Jasmin Hiestand,3 Jane Mallewa,3 Wilson L Mandala1,4 1Malawi-Liverpool Wellcome Trust, Malaria Immunology Department, Blantyre, Malawi; 2Pathology Department, College of Medicine, Blantyre, Malawi; 3Medicine Department, College of Medicine, Blantyre, Malawi; 4Academy of Medical Sciences, Biological Sciences Department, Malawi University of Science & Technology, Thyolo, Malawi Aim: Although malaria and HIV infections independently affect the electrolyte and hematologic profiles, little is known of how these profiles are affected in individuals coinfected with malaria and HIV. We therefore conducted this study to investigate the electrolyte and hematologic profiles of Malawian adults presenting with either uncomplicated malaria (UM), severe malaria (SM), and those presenting with HIV and UM or HIV and SM.Methods: Study participants were recruited at Queen Elizabeth Central Hospital, and malaria infection was confirmed by rapid diagnostic test and malaria slides, and full blood count, HIV, and wet chemistries were analyzed.Results: Sodium, potassium, calcium, and chloride levels of all 4 study groups were similar to those of healthy controls. Both HIV-infected groups (UM and SM) had lower red blood cell counts and lower hemoglobin concentration than the reference range. Platelet counts were lower in both HIV-uninfected SM cases (64×109/L) and in the HIV-infected SM cases (66×109/L) compared to the reference range (115–290×109/L). HIV– UM cases had higher proportion and absolute counts of neutrophils and white blood cell counts compared to the HIV+ UM cases.Conclusion: HIV infection did not affect the electrolyte profile of Malawian adults presenting with UM or SM but had an effect on red blood cells, Hb concentration, neutrophils, and platelet counts. Keywords: Plasmodium falciparum malaria, HIV infection, electrolytes, hematologic values, HIV-malaria co-infection, Malawian Adult

HIV infection compounds the lymphopenia associated with cerebral malaria in Malawian children

Aim: Cerebral malaria (CM), unlike severe malarial anemia (SMA), has previously been characterized by pan-lymphopenia that normalizes in convalescence, while HIV infection is associated with depletion of CD4+ T cells. In this study, we investigate whether HIV infection in Malawian children exacerbates the pan-lymphopenia associated with CM. Methods: We investigated the absolute and percentage lymphocyte-subset counts and their activation and memory status in Malawian children presenting with either CM who were HIV-uninfected (n=29), HIV-infected (n=9), or SMA who were HIV-uninfected (n=30) and HIV-infected (n=5) in comparison with HIV-uninfected children without malaria (n=42) and HIV-infected children without malaria (n=4). Results: HIV-infected CM cases had significantly lower absolute counts of T cells (P=0.006), CD4+ T cells (P=0.0008), and B cells (P=0.0014) than HIV-uninfected CM cases, and significantly lower percentages of CD4+ T cells than HIV-uninfected CM cases (P=0.005). HIV-infected SMA cases had significantly lower percentages of CD4+ T cells (P=0.001) and higher CD8+ T cells (P=0.003) in comparison with HIV-uninfected SMA cases. HIV-infected SMA cases had higher proportions of activated T cells (P=0.003) expressing CD69 than HIV-uninfected SMA cases. Conclusion: HIV infection compounds the perturbation of acute CM and SMA on lymphocytes, exacerbating subset-specific lymphopenia in CM and increasing activation status in SMA, potentially exacerbating host immunocompromise