Abnormalities of serum transcobalamins in sickle cell disease (HbSS) in Black Africa.

The unsaturated vitamin B12 binding capacity (UBBC) of serum, the three transcobalamins (TC I, TC II, TC III), and the total leucocyte and neutrophil counts have been studied in paediatric patients with sickle cell disease (SCD). Increase in the level of the binding capacities of TC I and TC II with concomitant increase of UBBC was observed in these children who also had increased total white blood and neutrophil counts. There was a significant reduction in the level of endogenous B12. These abnormalities are discussed in relation to the deficiency of the splenic reticuloendothelial function, immunologic defect, hepatic degenerative changes and aplastic crisis observed in SCD. These results lend support to the view that transcobalamins are involved in the defence mechanism of the body. The significant reduction in serum cobalamin in SCD suggests a higher demand on this vitamin for metabolic functions, especially for the sparing of folate.