Reversal of ineffective erythropoiesis in pernicious anaemia following vitamin B12 therapy.

Ineffective erythropoiesis was quantitated in a series of patients with pernicious anaemia at different times in relation to vitamin B12 therapy by measuring the incorporation of [15N]delta aminolaevulinic acid and [15N]glycine into early labelled bilirubin. Prior to therapy ineffective erythropoiesis was grossly increased but this was reversed within 24 h of giving vitamin B12, suggesting that most of the existing megaloblasts are enabled to mature into circulating red cells.