In addition, IPT (isoniazid preventive therapy) use (AIRR = 0.35 (95% CI = 0.22–0.48)), WHO Stage I and II (AIRR = 0.70 (95% CI = 0.61–0.94)) and higher base line CD4 count (AIRR = 0.96 (95% CI = .94–0.99)) significantly reduced the incidence of TB. This evidence concerns the gene CD4 and tuberculosis.