The role of blood groups in preventing or enhancing HIV infection in Botswana

Thesis (DPhil (Biomedical Science))--Cape Peninsula University of Technology, 2019.Knowledge of population vulnerabilities to infectious diseases is key in managing many public health problems and for mapping appropriate strategies for prevention or intervention. A number of genes associated with resistance to HIV infection, such as the double deletion of 32 base pairs in the CCR5 gene , have been described and potentially account for lower HIV infections in some populations. The magnitude of the HIV pandemic in Sub-Saharan Africa warrants an investigation of the peculiar genetic factors that may have exacerbated its spread. An understanding of the genetic factors that are involved may aid in the development of specific strategies for prevention such as vaccine development, genetic counselling as well as gene therapy. The aim of this project was therefore to study the relationship between blood groups and HIV-infection in Botswana. HIV infection in Africa has not been linked to particular blood groups. The project was undertaken in two phases from December 2012 to December 2017. In the first phase, 346 subjects of known HIV status (negative or positive) were phenotyped for 23 erythrocyte antigens via standard scientific procedures. A Chi-square analysis was used to determine those antigens associated with increased or reduced risk of HIV infection. In the second phase, 120 samples were phenotyped for the protective blood group (RhC) and the risk-associated groups (Lub and P1). The samples were also characterized according to their laboratory results for viral load, lymphocyte sub-populations, complete blood count and blood chemistry, including total cholesterol. Some of the samples were also assessed for erythrocyte-associated viral RNA. Generally, the prevalence of the blood groups in the general population in Botswana did not differ with the known prevalence for Africans broadly. Three novel findings were established. First, the blood group Rh(C) was associated with a 40% risk reduction for HIV infection. Immunologically, carriage of the C antigen was associated with a more robust cell-mediated immunity as evidenced by enhanced cytotoxic T cell counts. Moreover, this antigen occurred with a frequency lower than 30% in all countries where HIV prevalence was high. There was therefore an inverse relationship between Rh(C) frequency and HIV prevalence. An examination of reports from previous studies revealed that the pattern was consistent in Africa, Europe, Asia, South America and Caribbean countries. It appears that the population frequency of this antigen explains, at least in part, a genetic factor that puts some African populations at higher risk for HIV infection. These results are novel in that Rh antigens have not been previously associated with immunity in any reports. Novel findings regarding the P1 blood group was its association with a double risk for HIV infection. While the plasma viral load did not differ between P1-positive and P1-negative subjects, P1-positive erythrocyte lysate yielded more viral RNA than P1-negative cells, implying more intracellular HIV RNA. Intra-erythrocytic viral RNA was detected even in patients with an undetectable plasma viral load. Glycosphingolipids, of which P1 is an example, have been documented to promote viral fusion to cells independent of CD4 receptors or other ligands. In at least one report, the presence of sphingolipids in lipid rafts was considered to be sufficient for viral fusion. The presence of viral RNA even in erythrocyte lysates corroborates this phenomenon and potentially explains the double risk of HIV infection observed. The occurrence of HIV RNA in erythrocyte lysate is a novel finding that suggests a new viral reservoir. Apparently, P1 has a high frequency among Africans and low in other races

Immunohaematological reference values for HIV-negative healthy adults in Botswana

BACKGROUND: Clinical laboratories in Botswana have relied entirely on the reference intervals for normal immunohaematological values provided by manufacturers' kits and textbooks. OBJECTIVES: The aim of this study was to determine the means, medians, 2.5th and 97.5th percentile reference intervals, for normal immunohaematological values in healthy adults in Botswana. METHOD: A total of 261 healthy participants comprising 126 men (48%) and 135 (52%) women were enrolled in the southern part of Botswana, and immunological and haematological laboratory parameters were measured. RESULTS: The mean age was 28.8 (95% Confidence Interval [CI] 27.7-29.8) years, with a median of 27 years and a range 18-66 years. The mean haemoglobin level was significantly lower for women (12.4 g/dL; 95% CI 12.1% - 12.7%) than men (15.1 g/dL; 95% CI 14.9% - 15.3%). The women's haemoglobin reference values (9.0 g/dL - 15.0 g/dL) levels were lower than observed in predominantly White populations (12.0 g/dL - 16.0 g/dL), but comparable with regional consensus reference intervals (9.5 g/dL - 15.8 g/dL) recently defined for East and Southern Africa. CONCLUSION: The established values provide an important tool for patient management and could influence decisions on inclusion of participants and adverse events in clinical trials conducted locally

Rapid epidemic expansion of the SARS-CoV-2 Omicron variant in southern Africa

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic in southern Africa has been characterised by three distinct waves. The first was associated with a mix of SARS-CoV-2 lineages, whilst the second and third waves were driven by the Beta and Delta variants, respectively1-3. In November 2021, genomic surveillance teams in South Africa and Botswana detected a new SARS-CoV-2 variant associated with a rapid resurgence of infections in Gauteng Province, South Africa. Within three days of the first genome being uploaded, it was designated a variant of concern (Omicron) by the World Health Organization and, within three weeks, had been identified in 87 countries. The Omicron variant is exceptional for carrying over 30 mutations in the spike glycoprotein, predicted to influence antibody neutralization and spike function4. Here, we describe the genomic profile and early transmission dynamics of Omicron, highlighting the rapid spread in regions with high levels of population immunity

The role of red blood cells in enhancing or preventing HIV infection and other diseases.

Aim. To highlight the apparently neglected role of erythrocyte antigens in the epidemiology of infectious diseases, especially HIV, with the prime objective of stimulating research in this area. Method. A literature search was performed on the PubMed for relevant papers from 1984 to 2013, the era covering active HIV research. This was achieved by using the phrases “erythrocyte blood groups HIV” (81 papers) or “red cell antigen, blood groups, and HIV” (60 papers). A manual Google Scholar search was done and supplemented by original papers referenced by various authors. However, the review was limited by the relative scarcity of papers on the subject, and only papers written in English were reviewed during the period October 2012 to September 2013. Results. Many communicable and noncommunicable diseases are associated with specific blood groups. Examples of these diseases are discussed in detail. HIV has been shown to bind to erythrocytes, and candidate erythrocyte-binding molecules and mechanisms are also discussed. Moreover, erythrocyte-HIV binding is associated with increased viral infectivity, thus, underscoring the need to study this phenomenon and its implications for HIV epidemiology. Conclusion. Erythrocyte antigens may be important in the pathogenesis and epidemiology of many diseases, including HIV

Comparative prevalence of risk-associated and risk-lowering blood group phenotypes among Botswana, Northern India and Caucasian ethnicities.

<p>Comparative prevalence of risk-associated and risk-lowering blood group phenotypes among Botswana, Northern India and Caucasian ethnicities.</p

Red cell blood group antigens associated with HIV infection in multivariable logistic regression analysis.

<p>Red cell blood group antigens associated with HIV infection in multivariable logistic regression analysis.</p

Results of a logistic regression model showing the effect of red cell blood group antigens on HIV status using all five significant antigens.

<p>Results of a logistic regression model showing the effect of red cell blood group antigens on HIV status using all five significant antigens.</p

Immunohaematological reference values for HIV-negative healthy adults in Botswana

Background: Clinical laboratories in Botswana have relied entirely on the reference intervals for normal immunohaematological values provided by manufacturers’ kits and textbooks. Objectives: The aim of this study was to determine the means, medians, 2.5th and 97.5th percentile reference intervals, for normal immunohaematological values in healthy adults in Botswana. Method: A total of 261 healthy participants comprising 126 men (48%) and 135 (52%) women were enrolled in the southern part of Botswana, and immunological and haematological laboratory parameters were measured. Results: The mean age was 28.8 (95% Confidence Interval [CI] 27.7–29.8) years, with a median of 27 years and a range 18–66 years. The mean haemoglobin level was significantly lower for women (12.4 g/dL; 95% CI 12.1% – 12.7%) than men (15.1 g/dL; 95% CI 14.9% – 15.3%). The women’s haemoglobin reference values (9.0 g/dL – 15.0 g/dL) levels were lower than observed in predominantly White populations (12.0 g/dL – 16.0 g/dL), but comparable with regional consensus reference intervals (9.5 g/dL – 15.8 g/dL) recently defined for East and Southern Africa. Conclusion: The established values provide an important tool for patient management and could influence decisions on inclusion of participants and adverse events in clinical trials conducted locally