Fetal haemoglobin and malaria.

The distribution and growth of Plasmodium falciparum was compared in red blood-cells containing either adult or fetal haemoglobins. In in-vitro cultures, cord blood-cells were invaded more readily, but there was a paucity of parasites in cells containing haemoglobin F in the blood of infected infants aged 3-6 months. These findings suggest that P. falciparum may preferentially invade young, metabolically active erythrocytes. There was a significant retardation of parasite growth in vitro in cells containing haemoglobin F. This latter finding suggests a further mechanism for the resistance to malaria in the first months of life and for high gene frequencies (in areas in which malaria was endemic) of the thalassaemias and related haemoglobinopathies in which the rate of decline of fetal-haemoglobin production is retarded.