[1] Univ Stellenbosch, Fac Hlth Sci, Dept Paediat & Child Hlth, ZA-7505 Tygerberg, South Africa
[2] Childrens Hosp, Dept Paediat & Child Hlth, ZA-7505 Tygerberg, South Africa
[3] Childrens Hosp, Desmond Tutu TB Ctr, ZA-7505 Tygerberg, South Africa
[4] Univ Stellenbosch, MRC, Ctr Cellular & Mol Biol, Dept Med Biochem, ZA-7505 Tygerberg, South Africa