Sickle chimeras with 10% circulating FII exhibit a modest increase in PT and diminished evidence of coagulation activation. (A) PT values in FII^WT mice (with 100% circulating FII) and FII^lox/− mice (with ∼10% FII levels), and cohorts of FII^WT and FII^lox/− mice transplanted with either bone marrow from donor Berkeley mice expressing HbA (HbA/FII^WT and HbA/FII^lox/−) or donor Berkeley sickle mice expressing HbS (HbS/FII^WT and HbS/FII^lox/−). (B) D-dimer levels in HbS/FII^WT, HbS/FII^lox/−, HbA/FII^WT, and HbA/FII^lox/− mice. The bar indicates the median. Each symbol represents an individual animal. Mice used as transplant recipients were of similar ages (8-10 weeks) with equal numbers of males and females distributed among the experimental groups. Fully chimeric sickle or normal mice were followed for a year after transplantation. Cohorts were analyzed by Mann-Whitney U test and statistical significance between FII^WT and FII^lox/− chimeras is indicated by asterisks: **P < .01, *P < .05.