Proportions of monocyte subsets are altered in HIV-1 disease. Whole blood samples were obtained from 57 HIV-1–infected donors and 23 healthy controls and the relative proportions of monocyte subsets were analyzed by flow cytometry. (A) Three monocyte subsets were identified by size and granularity and by CD14 and CD16 expression, and representative dot plots show monocyte subsets from 1 healthy control and 3 HIV-1–infected patients (patients i, ii, and iii). All 3 patients were male and were receiving antiretroviral therapy. Patients i and ii had VL < 400 copies/mL and CD4⁺ T-cell counts of 857 and 456 cells/μL, respectively. Patient iii was viremic (333 706 copies/mL) and had a CD4⁺ T-cell count of 132 cells/μL. (B) Summary data of monocyte subsets among healthy controls and HIV-1–infected patients with controlled (< 400 copies/mL) or uncontrolled (> 400 copies/mL) viremia.