Erythrocyte Membrane Vacuole Formation in Hereditary Spherocytosis

S ummary . There is impaired drug‐induced vacuole formation in red cells from patients with hereditary spherocytosis (HS). The spherocytic shape per se accounts in part for the decreased vacuole formation seen, but there are constraints in HS red cell vacuole formation above that explicable by spheroidicity. Electron‐microscopy indicates that the vacuoles produced in HS have one‐third normal diameter. We propose that the decreased vacuole formation in HS is a result of a genetically determined abnormality of the membrane which limits its ability to invaginate and deform. The variability in vacuole formation from one HS family to another, but relative consistency within families, suggests that hereditary spherocytosis comprises a syndrome of related erythrocyte membrane disorders. Vacuole fromation in ghosts in normal in HS. This unanticipated finding suggests that the phenomenon of ghost endocytic vacuole formation may have requiements that by‐pass the defect in the HS membrane.