title: Experiences in the measurement of RBC-bound IgG as markers of cell age.
abstract: An immunologically mediated pathway has been largely accepted to be one of the mechanisms involved in the clearance of senescent or prematurely damaged RBC. According to this pathway, RBC removal is mediated by binding of naturally occurring IgG to clustered integral membrane proteins, followed by complement deposition. The validation of an immunoenzymatic method for the detection of RBC-bound autologous IgG is presented. The use of RBC-bound IgG as an index related to red cell age was evaluated by measuring IgG binding in RBC treated with the clustering agent ZnCl2, in density fractionated RBC and in a selected group of patients expected to have an altered RBC life span. The immunoenzymatic method for IgG detection resulted to be reproducible (CV = 3.4%). IgG binding to in vitro clustered RBC was found to be enhanced to a very great extent, about 20 times higher with respect to untreated RBC. A slight but significant increase (about 1.8-fold) in membrane-bound IgG was observed in the highest density fraction of normal RBC, which constituted 1% of the total cells. A significantly greater number of RBC-bound IgG was measured in splenectomized beta-thalassemia intermedia patients and in subjects with secondary decreases in the C3 complement fraction concentration.
authors.affiliation: Dipartimento di Scienze e Tecnologie Biomediche, Università degli Studi di Milano, Via Fratelli Cervi 93, 20090 Segrate, Milan, Italy.
authors.forename: Renata
authors.initials: R
authors.lastname: Paleari
authors.forename: Ferruccio
authors.initials: F
authors.lastname: Ceriotti
authors.forename: Franco
authors.initials: F
authors.lastname: Azzario
authors.forename: Liliana
authors.initials: L
authors.lastname: Maccioni
authors.forename: Renzo
authors.initials: R
authors.lastname: Galanello
authors.forename: Andrea
authors.initials: A
authors.lastname: Mosca
mesh_terms: D015415:Biomarkers / Q000032:analysis; D016022:Case-Control Studies; D004905:Erythrocyte Aging; D004910:Erythrocyte Membrane / Q000276:immunology; D004912:Erythrocytes / Q000276:immunology* / Q000502:physiology; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D008722:Methods; D015203:Reproducibility of Results; D017086:beta-Thalassemia / Q000097:blood
chemical_list: D015415:Biomarkers; D007074:Immunoglobulin G