CMV retinitis in HIV patients is particularly likely when CD4 count falls below which level?

CMV retinitis in HIV patients is particularly likely when CD4 count falls below which level?

• A. 200 cells/mm3
• B. 50 cells/mm3
• C. 100 cells/mm3
• D. 350 cells/mm3

Answer: (B)

CMV retinitis occurs when the immune system, especially CD4 T cells, is severely depleted. CD4 cells are key to controlling latent CMV; when counts fall very low, CMV can reactivate and invade the retina, causing retinitis with potentially irreversible vision loss. The classic point at which risk becomes markedly higher is a CD4 count below 50 cells per cubic millimeter. Above this level, the risk diminishes substantially, whereas thresholds like 200 or 100 are more associated with other opportunistic infections. Therefore, the level below which CMV retinitis is particularly likely is 50 cells/mm3.

CMV retinitis occurs when the immune system, especially CD4 T cells, is severely depleted. CD4 cells are key to controlling latent CMV; when counts fall very low, CMV can reactivate and invade the retina, causing retinitis with potentially irreversible vision loss. The classic point at which risk becomes markedly higher is a CD4 count below 50 cells per cubic millimeter. Above this level, the risk diminishes substantially, whereas thresholds like 200 or 100 are more associated with other opportunistic infections. Therefore, the level below which CMV retinitis is particularly likely is 50 cells/mm3.