Irreversibly sickled cells and red cell survival in sickle cell anemia: a study with both DF32P and 51CR

For 25 subjects with sickle cell anemia the mean red cell life span measured with Di-isopropylfluorophosphite-32P (DF32P) was 17.32 +/- 4.51 days. Performed simultaneously, the half life (T1/2 of radioactively-labelled chromium 51Cr) was 10.11 +/- 2.82 days (14 subjects). Eight additional subjects, or more than 30 per cent of those studied using both red cell tags, had 51Cr red cell survival curves better described by two exponents than by one, apparently due to two different rates of 51Cr elution from the red cells. This finding limits the value of quantitative data obtained by this procedure. A negative correlation was found between the mean red cell life span measured with DF32P-tagged cells and the proportion of irreversibly sickled cells in venous or capillary blood. A similar negative correlation was found between the red cell half survival time measured with 51Cr-tagged cells and the proportion of irreversibly sickled cells. These data are compatible with the view that repeated sickling and, in particular, the formation of irreversibly sickled cells play a distinct role in the pathogenesis of hemolysis in sickle cell anemia.