Figure 5.

Frequency of Th17 T Cells after Vector Administration

(A and B) Frequency of Th17 (CD4⁺, CD196⁺, IL-17a⁺) cells (A) or ratio of Th17 cells to Tregs (CD4⁺CD25⁺FoxP3⁺) (B) after AAV-hFIX gene therapy. The fraction CD4⁺ PBMCs that were also CD196⁺, IL-17a⁺ was analyzed relative to the pre-IS and pre-gene therapy (week −1) level of each animal. Each line represents an individual animal. The mean change in Th17 cell frequency and the ratio compared with Tregs from baseline at week 7 (∗), prior to the detection of the anti-hFIX immune response, was significantly higher in the two animals that developed inhibitors (1002 and 1003) compared with the four animals that did not develop inhibitors (1001, 2001, 2102, and 2003): 230% ± 60% and 880% ± 470% baseline, respectively, compared with 80% ± 30% and 84% ± 140%, respectively, baseline; p < 0.03 determined with a two-sided t test.