title: A flow cytometric assay for measuring complement receptor 1 (CR1) and the complement fragments C3d and C4d on erythrocytes.
abstract: A flow cytometric assay (FCA) was developed to measure complement receptor 1 (CR1) and the complement fragments C3d and C4d on erythrocytes. It was possible to measure these parameters accurately with intra- and interassay coefficients of variation of 2.0% and 6.5% respectively. The method was able to discriminate between low and high levels of erythrocyte CR1, C3d and C4d. Comparison with a previously described RIA method gave excellent correlation coefficients with r2 values of 0.94, 0.93 and 0.91 for CR1, C3d and C4d respectively. The flow cytometric assay was used to measure CR1, C3d and C4d on the erythrocytes of 98 healthy individuals and the 95% upper limits for C3d and C4d were established. There was a wide distribution of CR1 levels amongst these individuals but their C3d and C4d levels were low and often not above background. The possible application of this method in clinical medicine is discussed.
authors.affiliation: Department of Immunology, National University Hospital, Landspitalinn, Reykjavik, Iceland.
authors.forename: J
authors.initials: J
authors.lastname: Freysdottir
authors.forename: A
authors.initials: A
authors.lastname: Sigfusson
mesh_terms: D015703:Antigens, CD / Q000032:analysis*; D002469:Cell Separation; D003179:Complement C3b / Q000032:analysis*; D015933:Complement C3d / Q000032:analysis*; D003181:Complement C4 / Q000032:analysis*; D015935:Complement C4b; D004912:Erythrocytes / Q000737:chemistry*; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D010446:Peptide Fragments / Q000032:analysis*; D011863:Radioimmunoassay / Q000379:methods; D011951:Receptors, Complement / Q000032:analysis*; D017463:Receptors, Complement 3b; D015203:Reproducibility of Results; D013223:Statistics as Topic
chemical_list: D015703:Antigens, CD; D003181:Complement C4; D010446:Peptide Fragments; D011951:Receptors, Complement; D017463:Receptors, Complement 3b; D003179:Complement C3b; D015933:Complement C3d; D015935:Complement C4b; C032261:complement C4d