Loss of IFNα/βR on monocytes correlates with markers of disease progression in HIV-1 infection. Univariate linear regression analysis was used to assess relationships of disease markers with IFNα/βR expression. In HIV-1–infected persons, monocyte expression of IFNα/βR correlated with absolute CD4⁺ T-cell count (A; P < .001), correlated inversely with HIV-1 RNA level (B; P < .001), and correlated inversely with CD38 expression on memory (CD45RO⁺) CD8⁺ T cells (C; P < .001). In panel C, there was no significant correlation between monocyte IFNα/βR and CD38 expression on memory CD8 T cells in uninfected persons.