Treg-cell accumulation in progressor hosts interferes with CMI. (A) Significant increase of percentages of CD8⁺ T cells in LT of 6 HIVprogs and 5 HIVnps compared with 5 uninfected controls. (B-D) Expression of IFN-γ (B), perforin (C), and granzyme B (D) mRNA. Results are expressed in RU after normalization on GAPDH mRNA. Phenotyping of LT perforinand granzyme B–expressing cells confirmed that they were CD3⁺ and CD8⁺ (> 95%; data not shown). (E-G) Expression of IFN-γ (E), perforin (F), and granzyme B (G) mRNA in LT of SIVprogs, SIVnps, and uninfected animals. Results are expressed in RU after normalization on GAPDH mRNA. (H-I) Increased ratio of perforin to FOXP3 mRNA expression in nonprogressors compared with progressors (Mann-Whitney test).