Approximate number of mobile and cytoskeletally attached CD47 surface proteins per cell on normal and 4.2-deficient RBCs. Overall numbers of CD47 on normal RBCs⁷  partitioned into either mobile or cytoskeletally attached. CD47 levels for 4.2-Hammersmith heterozygote (4.2+/-), 4.2-Hammersmith homozygote (4.2-/- H), and 4.2-Nippon (4.2-/- N) RBCs are presented as relative to the normal referenced levels.