What percentage of CD4 cells is indicative of a high risk for progressing to AIDS?

A CD4 cell count of less than 200 cells/mm³ in the context of HIV infection is a key indicator that a patient is at high risk for progressing to AIDS. This threshold is part of the clinical definition of AIDS as per the CDC guidelines. Although the percentages themselves (10%, 20%, 30%, 40%) don't directly correlate with CD4 counts merely as percentages, a CD4 count significantly below the normal range marks a critical vulnerability in the immune system, leading to increased risk of opportunistic infections and other AIDS-defining conditions.

Given that a CD4 count of 10% would signify an extremely low absolute number of CD4 cells in the body, it aligns closely with levels that indicate significant immunosuppression. Thus, interpreting this option as indicative of increased risk is aligned with the clinical understanding that a low percentage of CD4 cells correlates with higher susceptibility to AIDS.

It’s important to note that other options, while higher, do not reflect the urgent concern and clinical implications of CD4 counts below the level defined to signify AIDS progression.