Erythrocyte membrane skeleton abnormalities in hereditary spherocytosis

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Abstract
Erythrocyte ghosts from 8 individuals with hereditary spherocytosis [HS] were compared with respect to their protein compositions as judged by SDS [sodium dodecyl sulfate] gel electrophoresis, their ease of spectrin extractability, and their freeze-etch EM appearance after incubation in conditions designed to promote aggregation of the intramembrane particles. Four of these HS cases were unrelated, while the other 4 represented 2 generations from a single family, including a pair of identical twins, 1 of whom had not undergone splenectomy when this investigation was initiated. Of the 4 unrelated cases, 1 showed no departures from normal under the conditions of this investigation, whereas the other 3 exhibited features which suggested a membrane skeleton lesion. In 1 of these there was a reduced proportion of spectrin tetramers relative to dimers in 4.degree. C extracts, while the 2 remaining cases exhibited abnormal intramembrane particle aggregation. The 4 related cases had almost identical variations from normal. Spectrin was not extractable from their ghost membranes during a mild extraction incubation which removed spectrin from normal control ghosts. However, the intramembrane particle aggregation subsequently induced in these ghosts was of a degree unobtainable in normal ghosts without such spectrin extraction. In addition the ghosts from 1 twin, the only one of these patients who had not undergone splenectomy at the start of this investigation, showed a reduced amount of band 4.2. However, when this patient''s blood was re-tested after splenectomy, this protein was found to be at normal levels. HS apparently is not a single disease, but is rather a term used to describe a variety of different molecular lesions of the erythrocyte membrane skeleton with similar clinical manifestations.