[Erythrocyte membrane and hereditary spherocytosis].

Hereditary spherocytosis (HS) is the most common hemolytic anemia caused by intrinsic defects of the erythrocyte membrane. Recent investigations have been directed toward the cytoskeleton of affected cells, and in some patients, the following several molecular lesions have been identified: (1) an abnormal spectrin incapable of binding to band 4.1 in dominantly inherited HS, (2) a deficiency of spectrin in severe, recessively inherited HS, (3) a deficiency of ankyrin and spectrin in severe, atypical HS, and (4) complete or partial defect of band 4.2 in some Japanese cases with HS. However, in the majority of patients with HS, the molecular lesion still remains unclear. We determined the transport rate of phosphoenolpyruvate (PEP) in HS erythrocytes, which was found to be specifically lower by almost half of the rate in erythrocytes from normal subjects or patients with other anemias. Since PEP is transported via band 3, the phenomenon may be a reflection of either structural abnormality of band 3 or dysfunction of band 3 caused by other primary lesions. Further investigations is needed to elucidate the underlying molecular defects in majority of patients with HS.