Favism: current problems and investigations.

Haemolytic favism is a severe, acute anaemia which occurs in glucose-6-phosphate dehydrogenase deficient individuals, usually following the ingestion of Vicia faba seeds. Current interest is focused on the nature of the active substances of Vicia faba and on the causes of the varying susceptibility among G6PD-deficient individuals to episodes of severe haemolysis. The results of experiments in vitro favour the hypothesis that Vicia faba contains several active substances which may act in a synergistic way. Red cell acid phosphatase and thalassaemia genes appear to play a remarkable role in conditioning the susceptibility to severe haemolysis in G6PD-deficient subjects. In addition to erythrocyte enzymes and to enzymes which intervene in the absorption and metabolism of the active substances of Vicia faba, another field for future investigations may be that of plasma factors which influence the stability of reduced glutathione in the red cells.