Percentage of CD4⁺ T cells in blood and mucosa. Percentage of CD4⁺ T cells, shown as a subset of CD3⁺ T cells, as determined by flow cytometry in peripheral blood (PB, closed symbols) and rectal mucosa (RMC, open symbols) across patient groups. Horizontal bars represent the median of each group. *P < .05, **P < .01, ***P < .001. All HIV-infected patient groups had significantly lower percentages of CD4⁺ T cells than seronegatives (P < .01).