Changes in CD4/CD8 T cell ratio in subjects with type 1 diabetes receiving hOKT3γ1(Ala-Ala) in relation to EBV status at study entry, and correlation between changes in CD4⁺ and CD8⁺ T cells in vitro during culture with anti-CD3 mAb and in vivo following treatment with anti-CD3 mAb. (A) The difference in the CD4/CD8 T cell ratio 3 months after treatment with hOKT3γ1(Ala-Ala) from the ratio before drug treatment in individuals who were EBV seropositive (n = 12) or seronegative (n = 7) at study entry was determined. The dark lines indicate the mean values for the group. A decrease in the CD4/CD8 T cell ratio (below the dotted line) occurred in both EBV-seropositive and -seronegative subjects. (B) PBMCs from patients with type 1 diabetes mellitus who received anti-CD3 mAb were studied 1.5–2 years after mAb treatment, at which time the changes in CD4/CD8 T cell ratio seen after mAb treatment had resolved. The patients were designated as clinical responders (filled circles) or nonresponders (open circles) based on their C-peptide responses at 12 months compared with baseline. The cells were cultured with hOKT3γ1(Ala-Ala), and the percentages of CD4⁺ and CD8⁺ T cells were determined after 6 days. The Pearson correlation coefficient was calculated to compare the ratio of CD4⁺/CD8⁺ T cells in vitro with the analysis of CD4^+/CD8⁺ T cells in vivo 3 months after mAb treatment (8), and the level of significance was tested with correlation procedure SAS (r = 0.6; P = 0.024). The line indicates the relationship between the changes in vitro and in vivo [in vivo CD4/CD8 ratio = 0.174 + 0.865 (in vitro CD4/CD8 ratio)].