Red cell (RBC) deformability and
membrane-bound immunoglobulin G (
IgG) were studied to better understand premature clearance of erythrocytes in
hereditary spherocytosis. Averaged deformability profiles from cells having comparable cell age revealed that
splenectomy was more beneficial for
spectrin/
ankyrin-deficient than for band 3-deficient RBCs.
Splenectomy prevented an early loss of young cells in both types of deficiencies. It had an additional beneficial effect on
spectrin/
ankyrin-deficient but not band 3-deficient RBCs. It prolonged the survival of mature
spectrin/
ankyrin-deficient RBCs such that they lost their deformability more slowly than RBCs from patients who had not undergone
splenectomy. Band 3-deficient RBCs lost their deformability at the same rate before and after
splenectomy. In HS patients with band 3 deficiency who underwent
splenectomy, RBC deformability inversely correlated with the number of RBC-bound
IgG (up to 140 molecules per cell). In
spectrin/
ankyrin deficiency, RBC-bound
IgG remained at control levels (60
IgG or less per cell). It appears that
spectrin/
ankyrin-deficient RBCs escaped opsonization by releasing band 3-containing vesicles because their band 3 content and deformability dropped in parallel with increasing cell age. Band 3-deficient RBCs did not lose band 3 with increasing cell age. Hence, it is possible that band 3 clusters required for bivalent binding of low-affinity-
IgG, naturally occurring
antibodies were retained in band 3-deficient RBCs with a relative excess of skeletal
proteins but were released from
spectrin/
ankyrin-deficient RBCs, in which vesicle budding was facilitated by an impaired skeleton.