FIG 16.

Data illustrating the centrifugal gradient separation of erythrocytes by age (C.D.F. is the cumulative distribution function) among G6PD-normal, African A− variant, and Mediterranean variant donors (A, B, and C, respectively). The extent to which G6PD activity declines with the age of the red blood cells in the same gradient and from the same donors is also shown (G, H, and I, respectively). G6PD activity in normal donors (G) decreases slightly with age, whereas in African A− variant donors (H), young red cells exhibit almost normal G6PD activity, but it declines more sharply with age. Mediterranean variant donor red blood cells (I) have very low levels of activity among the youngest reticulocytes and undetectable activity among older cells. Reproduced from Piomelli et al. (263) with permission of the Journal of Clinical Investigation.