The observed associations between HIV viraemia, immunosuppression (lower CD4 cell count), ART initiation (with resultant recovery of the CD4 cell compartment and possible immune reconstitution inflammatory syndrome), and lower BMI, with greater risk of TB disease are well described.31, 32, 33, 34, 35, 36 In this study, site had an association with both Mtb sensitisation and TB disease. The gene discussed is CD4; the disease is tuberculosis.