Which stage of HIV infection is associated with a CD4+ T cell count below 200 cells/mm3?

A CD4+ T cell count below 200 cells/mm3 is a defining characteristic of AIDS (Acquired Immunodeficiency Syndrome), which is the most advanced stage of HIV infection. In this stage, the immune system is severely compromised, resulting in an increased susceptibility to opportunistic infections and various cancers.

The normalization of CD4+ T cell counts is crucial for assessing the immune function in individuals with HIV. In a healthy individual, CD4+ T cell counts typically range from 500 to 1,600 cells/mm3. When the count falls below 200 cells/mm3, the individual is classified as having AIDS, which indicates significant immune dysfunction and a higher risk of serious health complications.

In contrast, during acute HIV infection, patients may experience a transient increase in viral load but typically maintain a higher CD4+ T cell count. Clinical latency refers to a period where HIV is still present but often asymptomatic, and CD4+ counts are usually stable or only mildly decreased. Chronic HIV infection may see a gradual decline in CD4+ T cells, but it does not necessarily mean the count has dropped below the critical threshold defining AIDS.