1. Division of Pulmonology, Department of Internal Medicine, Charlotte Maxeke Johannesburg Academic Hospital.
2. Faculty of Health Sciences, University of the Witwatersrand Medical School, Johannesburg, South Africa.
3. Medical Research Council Unit for Inflammation and Immunity, Department of Immunology, Faculty of Health Sciences, University of Pretoria.
4. Tshwane Academic Division of the National Health Laboratory Service, Pretoria, South Africa.