Heinz bodies are seen in -

In G6PD deficient individuals oxidants cause both intravascular and extravascular hemolysis. Oxidants exposure to G6PD deficient red cells causes cross linking of reactive sulfhydril groups on globin chains which become denatured and form membrane bound precipitates known as Heinz bodies. Ref: Robbins and Cotran Pathologic basis of disease.South Asia Edition volume 1.page no 634