Splenectomy prolongs in vivo survival of erythrocytes differently in spectrin/ankyrin- and band 3-deficient hereditary spherocytosis

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 deform-ability 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.