Red cell acetylcholinesterase activity in Plasmodium falciparum malaria

Red cell ACHE activity was determined in 19 patients with P. falciparum malaria, 13 patients during convalescence as well as in 6 normal subjects. There was no significant difference between the mean values of ACHE in red cells of these 3 groups. After separation these blood samples into 2 portions by centrifugation in 5% Ficoll solution, the parasitized red cells in the lower portion which are mostly ring forms contained the same amount of ACHE activity as those of the normal subjects and the non-parasitized red cells. However, the parasitized red cells in the upper portion which contained predominantly mature asexual forms revealed a significantly higher ACHE activity than those of the normal red cells. There was also a reverse relationship between red cell ACHE activity and the parasitaemia from this portion of blood sample. These findings indicated that although malarial parasite invaded and caused the red cell membrane damage, it did not inactivate ACHE. It may be concluded that ACHE was not responsible for the anaemia and excessive erythrocyte destruction in patients with P. falciparum malaria.