Clinical trial of young red blood cells prepared by apheresis.

Transfusion of young red blood cells (YRBC) with prolonged survival should result in increased intervals between transfusions and, therefore, decreased transfusion-associated iron loading. A prospective clinical trial comparing YRBC transfusions prepared by apheresis versus washed or frozen red cell transfusions was performed in five children with transfusion-dependent thalassemia. A total of 152 YRBC units, evaluated by reticulocyte enrichment and pyruvate kinase activity, were transfused. While a slightly longer interval between transfusions was observed during the time period of YRBC versus the time period after (30.0 +/- 1.5 days versus 27.9 +/- 1.1 days, respectively, p less than 0.02), there was no associated decrease in mg of iron transfused per kg. The effectiveness of transfused YRBC units was less than predicted by in vitro and in vivo studies.