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Presence of immunoglobulins, C3 and cytolytic C5b‐9 complement components on the surface of erythrocytes from patients with β‐thalassaemia/HbE disease
Author(s) -
Malasit Prida,
Mahasorn Weerawuth,
Mongkolsapaya Juthathip,
Singhathong Benjawan,
Fucharoen Suthat,
Wasi Prawase,
Bhakdi Sucharit
Publication year - 1997
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1046/j.1365-2141.1997.d01-2070.x
Subject(s) - cytolysis , antibody , immunology , immunoradiometric assay , complement system , complement membrane attack complex , chemistry , microbiology and biotechnology , biology , biochemistry , radioimmunoassay , cytotoxic t cell , in vitro
The occurrence of IgG, IgM, IgA, C3 and C5b‐9 complement complexes on erythrocytes from 43 patients with β‐thalassaemia HbE disease was investigated. Indirect immunoradiometric assays using radioiodinated protein A were employed to quantify the individual components. We confirmed that circulating erythrocytes from thalassaemic patients contained elevated amounts of IgG, and small but significant amounts of C3. In addition, small but significant amounts of C5b‐9 were detected. Levels of cell‐bound IgG, C3 and C5b‐9 were higher in splenectomized versus non‐splenectomized patients. The presence of C5b‐9 on circulating cells from five splenectomized patients was confirmed by an ELISA employing a monoclonal antibody specific for a C5b‐9 neoantigen. When C5b‐9 positive cells from two patients were solubilized with detergent and subjected to sucrose density gradient centrifugation, the terminal complexes sedimented as 25–40S macromolecules, thus behaving as membrane C5b‐9 complexes. The presence of C8 and C9 in these high molecular weight fractions was directly demonstrated by Western blotting. These results constitute the first demonstration that circulating diseased erythrocytes may carry low numbers of potentially cytolytic C5b‐9 complement complexes which may be partly responsible for the known ionic disturbances found in thalassaemic cells. Both bound C3 and C5b‐9 could promote removal of diseased cells in the reticuloendothelial system.