‘Pitted’ erythrocytes: impaired formation in splenectomized subjects with congenital spherocytosis

Abstract

'Pitted' erythrocyte counts are widely used in the quantitative assessment of functional hyposplenism and in the prediction of recurrence of splenic function in splenectomized subjects. Both of these functions require counts from electively splenectomized controls for comparison. The 'pitted' erythrocyte counts in patients splenectomized for congenital spherocytosis are lower than those found in subjects whose spleens were removed electively for other reasons. This appears to be due to the specific membrane defect which impairs the formation of the vacuoles which are responsible for the appearance of 'pitted' erythrocytes under the interference-phase microscope.

Pocked erythrocyte counts in patients with hereditary spherocytosis before and after splenectomy

“…We noted elevated pocked erythrocyte counts in patients with hereditary spherocytosis after splenectomy, and the values were no different than those observed in other asplenic individuals. We are unable to explain why the findings of O'Grady et a1 [3] differ from ours. Since the erythrocytic vesicles that characterize the pocked erythrocyte are felt to represent autophagic vacuoles accumulating during red cell aging [ 121, one would not necessarily expect a primary membrane defect like hereditary spherocytosis to significantly affect this process.…”

“…O'Grady and co-workers [3] recently reported that among 15 patients with hereditary spherocytosis, 13 had pocked erythrocyte counts within the normal range. These normal pocked erythrocyte values, in spite of the asplenic state, were attributed to failure of the red blood cells to form vacuoles as a consequence of the primary erythrocyte membrane defect in hereditary spherocytosis [3]. Pocked erythrocyte counts in patients with hereditary spherocytosis prior to splenectomy were not studied by these workers.…”

“…Following splenectomy, pocked erythrocyte numbers rise within weeks [ 10-121 to stable values of 20 to 70%. The only surgically asplenic patients reported not to have elevated pocked erythrocyte counts are individuals following splenic trauma, who have a "born-again" spleen resulting from splenosis [5], and patients with hereditary spherocytosis [3]. O'Grady and co-workers [3] recently reported that among 15 patients with hereditary spherocytosis, 13 had pocked erythrocyte counts within the normal range.…”

“…Patients with splenic hypofunction due to sickle cell hemoglobinopathies usually have intermediate values [6-81. Little information is available about pocked erythrocyte counts in other forms of hemolytic anemia. The only published reports provide contradictory results about pocked erythrocyte levels in patients with hereditary spherocytosis following splenectomy [3,9]. The purpose of this study was to examine pocked erythrocyte numbers in patients with hereditary spherocytosis, both before and after splenectomy .…”

Pitted erythrocytes in splenectomized subjects with congenital spherocytosis and in subjects splenectomized for other reasons

“…Recently, Grady et a1 (13) demonstrated that splenectomized patients with congenital spherocytosis had considerably lower counts of pitted erythrocytes than patients splenectomized for other reasons. This finding contrasts with earlier reports (2,14).…”