Congenital dyserythropoietic anaemia type II (HEMPAS): characterization of aberrant intracellular organelles by immunogold electron microscopy.

Erythrocytes are reticulocytes obtained from peripheral blood of a congenital dyserythropoietic anaemia type II patient were examined by immunoelectron microscopy using anti-band 3 and anti-glycophorin A antibodies. Vacuoles which have membranous structures inside were stained heavily by these antibodies, indicating the presence of band 3 and glycophorin A in these vacuoles. Empty vacuoles which open to the cell surface and those present in cytoplasm were also stained by these antibodies at the inside of the wall. These observations suggest that the vacuoles are functioning for trapping and discarding the defective plasma membranes. On the other hand, small vesicles and ferritin-loaded vacuoles were not stained by these antibodies. In these experiments, peripheral cisternae and most of the intracellular membranous structures at blebs and clefts were not stained by the antibodies. Therefore, they are probably part of the endoplasmic reticulum or are derived from intracellular organelles but not from the plasma membranes.