The importance of HAART and its resultant effect on CD4+ count in controlling progression or reactivation of CMV retinitis cannot be overemphasized; in fact, in patients whose immune system is reconstituted (CD4+ count ≥ 100 cells/mL at two or more consecutive visits at least 6 months apart), HAART is probably more important than targeted anti-CMV treatment. The gene discussed is CD4; the disease is cytomegalovirus retinitis.