Sickle chimeras with 10% of normal FII levels have diminished pulmonary pathology. (A-C) Representative lung sections of HbS/FII^WT mice (left panels) compared with that of HbS/FII^lox/− mice (right panels) showing: (A) increased inflammatory infiltrate in HbS/FII^WT lungs compared with HbS/FII^lox/− lungs. Objective, ×10. (B) Increased alveolar macrophages in HbS/FII^WT lungs compared with HbS/FII^lox/− lungs. Objective, ×40. (C) Increased edema around blood vessels in HbS/FII^WT lungs vs its lack in HbS/FII^lox/− lungs. Objective, ×40. Black arrows indicate the pathology described in each panel. Images are representative of 6 to 9 mice per experimental group. 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.