Comparison of intraperitoneal versus intravenous delivery of BDD porcine fVIII–expressing MSCs. Plasma fVIII activity levels (closed symbols) were measured at several time points following intraperitoneal (A, n = 4) or intravenous (B, n = 5) transplantation of unbound BDD porcine fVIII–expressing MSCs into hemophilia A mice. Anti–porcine fVIII ELISA (○) and Bethesda titers (▵) are shown (mean ± standard deviation). In panels A and B, one plasma sample was not available in sufficient quantity for Bethesda analysis (n = 3 and n = 4, respectively).