Reticulocyte Function in PNH: in vitro Study of Haemoglobin Synthesis

The functional ability of PNH reticulocytes was studied by in vitro investigations on reticulocyte‐rich suspensions obtained from the blood of eight patients with PNH. The parameter used was the incorporation of 59Fe and of glycine‐2‐14C, and the results were related to RNA content of the reticulocytes. Iron appeared to enter the PNH cells normally but a relatively small amount was protein bound. In contrast to the behaviour of normal reticulocytes in control experiments, in the PNH reticulocytes there was little or no iron incorporation. The block of haem synthesis was also demonstrated by a four to five fold reduction in incorporation of glycine into haem. Globin synthesis appeared to be unaffected. These findings support the suggestion that in PNH there is a disturbance of the integrated process of cell maturation, demonstrable at the reticulocyte level.