Pathophysiology of favism

Abstract

Haemolytic crises occurring in G6PD-deficient individuals after ingestion of fava beans (favism) are much less frequent than in the past. However, favism is a unique natural model of oxidant damage in vivo, useful for the study of senescent or damaged red blood cells (RBC) clearance from circulation. The following aspects have been considered: 1. Pathophysiology of favism, including incidence, salient features, and sequence of events. 2. RBC alterations during the haemolytic crisis: biochemical, rheological and morphological alterations occurring in RBC isolated at different stages of the crisis. 3. Toxic substances of Vicia faba and their mechanism of action: treatment of G6PD-deficient RBC with divicine or isouramil (redox substances present in fava beans) provokes the same changes as observed during favism. 4. Intravascular vs. extravascular haemolysis: extravascular (i.e. phagocytic) removal of damages RBC seems predominant in favism. 5. The signal for RBC removal: in analogy with a recent model for recognition and removal of oxidant-stressed or senescent RBC, we propose removal of fava bean damaged RBC be mediated by apposition of antiband 3 antibodies and complement C3 fragments, recognized as non-self recognition signal by monocytes and macrophages.