Sickle chimeras with genetically imposed reductions in circulating FII exhibit significant decreases in inflammation. Total (A) WBC, (B) neutrophil, (C) monocyte, and (D) platelet counts in HbS/FII^WT, HbS/FII^lox/−, HbA/FII^WT, and HbA/FII^lox/− mice are shown. (E) Plasma IL-6 and (F) plasma sVCAM-1 levels in HbS/FII^WT, HbS/FII^lox/−, HbA/FII^WT, and HbA/FII^lox/− cohorts. 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 posttransplantation. sVCAM-1 levels in female mice trended to be lower compared with males within each group. In male mice, sVCAM-1 levels HbS/FII^WT vs HbS/FII^lox/− mice were 17 965 ± 3406 ng/mL vs 12 870 ± 338 ng/mL, respectively. In female mice, sVCAM-1 levels in HbS/FII^WT vs HbS/FII^lox/− mice were 13 009 ± 1361 ng/mL vs 10 914 ± 937 ng/mL, respectively. The differences between the 2 sexes in the different groups were not statistically significant. 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, ***P < .001.