Detailed hematologic and biochemical studies in a patient with lead poisoning demonstrate that the potential life span of red cells produced under these circumstances is normal. A shortened mean red cell survival results entirely from the random destruction of some cells. The reduced half-life ( T 1 2 ) of chromium-labeled red cells in this condition is shown to result both from hemolysis and from an increased rate of edition of chromium from the tagged cells. The hemolytic effect of lead is a direct effect on mature red blood cells, which occurs independently of the effects of lead on heme biosynthesis in erythroid precursors. Treatment with EDTA rapidly reverses the latter but not the former. Although lead is an inhibitor of heme biosynthesis in vitro, the presence of both an increased rate of effective erythropoiesis and an increased “early labeled peak” indicates that heme biosynthesis may be increased in the lead-poisoned patient.
Read full abstract