Decreased expression of CCR6 on T cells in HIV-infected patients is associated with HIV disease progression and high capacity of CCR6 T cells in LTNPs to secrete IL-2 and TNF-α. Level of CCR6 expression on CD4⁺ T lymphocytes is analyzed with standard HIV disease progression parameters, viral load (A) and CD4⁺ T-cell number (B). Lymphocytes analyzed were obtained from 10 HIV-infected patients. Levels of CCR6 expression on both CD4 (C-D) and CD8 (E-F) T cells and in the 2 memory subsets defined as T_CM (CD45RA⁻/CCR7⁺; C,E) and T_EM (CD45RA⁻/CCR7⁻; D,F) in uninfected individuals (UI), in long-term nonprogressor HIV-infected patients (LTNP), in HIV-infected patients with standard course of disease (SCD), and in HIV-infected patients treated with HAART with controlled viremia (HAART). *P < .05, represents the significant difference between UI and SCD HIV-infected patients. #P < .05 represents the significant difference between HAART and SCD HIV-infected patients. Error bars represent SEM.