The remaining 602 subjects represented a broad spectrum of treated and untreated HIV infection: 77 were antiretroviral-untreated and recently infected (estimated infection duration of less than 180 days); 176 were antiretroviral-untreated and chronically infected (median CD4 count of 525 cells/mm3); 203 were antiretroviral-treated and had undetectable plasma HIV RNA levels (median CD4 of 503 cells/mm3); and 146 were antiretroviral-treated had a detectable plasma HIV RNA level (median CD4 count of 277 cells/mm3). Here, CD4 is linked to HIV infectious disease.