1. Department of Medicine, University of Cape Town, Cape Town, South Africa
2. Department of Pathology, Groote Schuur Hospital, Cape Town, South Africa; and
3. South African Medical Research Council Centre for Tuberculosis Research/Department of Science and Technology/National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, Division of Molecular Biology and Human Genetics, Stellenbosch University, Stellenbosch, South Africa