Eryptosis in hereditary spherocytosis and thalassemia: role of glycoconjugates Sumanta Basu & Debasis Banerjee & Sarmila Chandra & Abhijit Chakrabarti Received: 7 April 2008 / Revised: 12 September 2008 / Accepted: 21 August 2009 / Published online: 16 September 2009 # Springer Science + Business Media, LLC 2009 Abstract The present work is aimed to study the mechanism of faster erythrocyte clearance in hereditary spherocytosis (HS), a heterogeneous disorders characterized by alterations in the proteins of the red cell membrane skeleton along with different kinds of thalassemia. The maximum exposure of phosphatidylserine (PS) is found in HS compared to those in both α- and β-thalassemia. Interestingly, in HS more PS exposed cells were found in younger erythrocytes compared to normal and the thalassemics where aged cells showed higher loss of PS asymmetry. Loss of sialic acid and GlcNAc bearing glycoconjugates, presumably the glycophorins, was also found upon aging. The loss of PS asymmetry together with the cell surface glycoproteins mediated by membrane vesiculation, seemed to play key role in early clearance of erythrocytes from circulation following a mechanism similar to HbEβ-thalassemia. Keywords PS asymmetry . Flow cytometry . Glycoconjugates . Hereditory spherocytosis . Thalassemia Abbreviations HS Hereditory spherocytosis HE Hereditory elliptocytosis PS Phosphatidylserine FITC Fluorescein-5-isothiocyate AV-FITC Fluorescein-5-isothiocyate labeled Annexin V WGA-FITC Fluorescein-5-isothiocyate labeled Wheat Germ Agglutinin PWM-FITC Fluorescein-5-isothiocyate labeled Poke Weed Mitogen Ca 2+ /A23187 1 mM Ca 2+ with 4 μM of A23187 GlcNAc N-acetyl-D-glucosamine Neu5Ac N-acetyl-D-neuraminic acid MFI Mean fluorescence intensity SEM Standard error of the mean PBS Phosphate buffered saline containing 2.7 mM KCl, 1.5 mM KH 2 PO 4 , 137 mM NaCl, 8.1 mM Na 2 HPO 4 , 0.01% NaN 3 pH 7.4 Introduction Erythrocytes have a lifetime of 120 days in circulation. In most cases, they do not undergo hemolysis, but are removed by phagocytes [1]. Like apoptosis, programmed cell death occurs in erythrocyte, termed as ‘eryptosis’ [2, 3]. Eryptosis is a caspase independent process [2, 4]. An aging antigen derived from the cleavage of band 3 has been implicated in eryptosis [5–7]. CD47, the integrin-associated protein and a part of Rhesus core complex, also acts as a self-marker on erythrocytes and have some role on spleen- mediated clearance [8]. Erythrocyte membrane is asymmet- S. Basu : A. Chakrabarti Biophysics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India A. Chakrabarti (*) Structural Genomics Section, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India e-mail: abhijit.chakrabarti@saha.ac.in D. Banerjee Department of Pathology, Ramakrishna Mission Seva Prathisthan, Kolkata 700026, India S. Chandra Department of Hemato-Oncology, Kothari Medical Centre, Kolkata 700027, India Glycoconj J (2010) 27:717–722 DOI 10.1007/s10719-009-9257-6