CMV retinitis was diagnosed in 24 (1.6%) of the 1,515 study patients, 14 (5%) of 308 patients with CD4 <50 /μL, 20 (4%) of 490 with CD4 <100 /μL, 24 (3%) of 731 with CD4 <200 /μL, and none among patients with CD4 count ≥200 /μL. This evidence concerns the gene CD4 and cytomegalovirus retinitis.