FACS analysis of cytochrome b₅₅₈ on granulocyte membrane. (A) Control: normal granulocytes expressing cytochrome b₅₅₈. (B) Patient’s granulocytes before BMT negative for cytochrome b₅₅₈. (C) Patient’s sister (heterozygous carrier and bone marrow donor) presenting two distinct granulocyte populations, negative and positive for cytochrome b₅₅₈. (D) Patient after BMT with two granulocyte populations negative and positive for cytochrome b₅₅₈.