Haematology and Cell Biology

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Browsing Haematology and Cell Biology by Author "Coetzee, Marius"

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    "Killer-cell immunoglobulin-like receptor haplotype diversity in three Free State population groups"
    (University of the Free State, 2006-11) Louw, Marius; De Kock, André; Louw, Vernon; Coetzee, Marius
    English: In the foregoing project, an investigation was made into the relative KIR gene frequencies of three South African cohorts. Playing an important part in innate immunity, KIR fill a vital gap between viral onsets and cell mediated humeral immunity. Being able to sense when cells are abnormal, NK cells possess the ability to destroy cells which show altered HLA molecules during KIR/HLA interaction. Ethnic cohorts that were investigated included African black, mixed ancestry and the Caucasian populations. From these individuals DNA material was extracted using a “salting out” method before SSP-PCR genotyping. Seventeen primer pairs were used in the identification of individual KIR genes. PCR products were electrophoresed against a molecular weight marker in order to verify the correct fragment size. Products were viewed on a UV light where observations were noted, and indicated as present or absent. Data was recorded onto a spreadsheet indicating the absence or presence of each particular gene. Tabulated results were used in the construction of graphs as well as χ2 calculations. These graphs were used in the critical analysis of linkage disequilibrium as well as comparative analysis between the ethnic cohorts. Findings indicate that all framework genes are present in all cohorts. The Black African and mixed ancestry cohorts have not been genotyped for the KIR genes before. Investigation within non-framework genes revealed the identification of several new haplotypes, with the majority observed within the mixed ancestry cohort. Positive linkage disequilibrium was detected between 2DL2-2DS2 and 2DL5B-2DS5 for both the black African and Caucasian cohorts while 2DL1-2DL2 and 2DL5B- 2DS5 linkages were found in the mixed ancestry population. No negative linkages were observed for any of the three cohorts.
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    Laboratory diagnosis and management of von Willebrand disease in South Africa
    (Thieme Medical Publishers, 2011) Meiring, Muriel; Coetzee, Marius; Kelderman, Mareli; Badenhorst, Philip
    Patients with von Willebrand disease (VWD) in South Africa are cared for in 17 Hemophilia Treatment Centers. The exact prevalence of the disease is uncertain, but 539 patients are annotated in registries. VWD patients are mostly diagnosed in the five largest academic centers, and the classification of the subtypes is performed by one of these, the VWD testing facility. An algorithm is used for the diagnosis of VWD. The distribution of subtypes diagnosed by the VWD reference center is 38%, 58%, and 4% for type 1, 2, and 3, respectively, and ~15% of plasma samples received are rejected due to poor storage and transport conditions. A novel single nucleotide polymorphism has been found in an African patient with type 2B VWD. From the type 1 VWDpatients who were diagnosed by the VWD testing facility, 45% seem to have an increased VWF clearance phenotype with a propeptide-to-antigen ratio of 1.9±0.3. VWD patients are treated with desmopressin, factor (F)VIII/VWF concentrate (Haemosolvate FVIII; National Bioproducts Institute, Durban, South Africa), and tranexamic acid. Haemosolvate FVIII contains a VWF antigen concentration of 167±27 IU/mL, a ristocetin cofactor activity of 100±29 IU/mL, a collagen binding activity of 99±29 IU/mL, normal VWF multimers, and a FVIII concentration of 50 IU/mL. Not all patients with VWD are currently classified, and many VWD patients in South Africa are probably undiagnosed.