(A) Schema of immunosuppression. C57Bl/6 mice (N=7–8/group) received immunosuppression on days −1, 0, 1, 3, 6, 8 and 2×1012/kg AAV8 LP1 hFIX on day 0. (B) Normal levels of CD4+ T cells in the peripheral blood of mice CyA/NDC4 when compared to untreated animals (n=2 in each group) as shown by specific staining for CD3 (PE) and CD4 (FITC). (C) Transduction efficiency is unaffected by concurrent administration of immunosuppression. hFIX levels were measured by ELISA on day 98 (n=6) mean ±SEM (D) Attenuation of humoral response to capsid by immunosuppression. Anti-AAV antibody was measure by ELISA on day 98 (n=6). Results shown as mean ±SEM.