title: High-density expression of CD95 on B cells and underrepresentation of the B-1 cell subset in human lupus.
abstract: Recent evidence indicates that B cell receptor signaling plays a role in the generation of the B-1 cell lineage that expresses the CD5 marker, and the CD95-mediated death plays an essential role in maintaining B cell tolerance. We therefore probed CD5 and CD95 expression on B cells from systemic lupus erythematosos (SLE) patients and control subjects. Firstly, in agreement with previous studies, we found that CD5 expression (11%) was relatively constant among control individuals. We also noted that the activation of B cells up-regulates this marker. Unexpectedly, we found that the B-1 cell subset is under-represented (3.9+/-0.3%) in SLE patients in an inactive stage of the disease. Together with related studies, these findings suggest that there is a correlation between CD5 expression and disease activity. Secondly, we found that CD95(+) B cells can be divided into two subsets expressing a high- (CD95(high)) and a low-density (CD95(low)) of CD95. There was no difference in the proportion of total CD95(+) B cells (23.5+/-2.8) in the two groups, but SLE patients in an inactive phase of the disease characteristically expressed a relatively high proportion (50%) of CD95(high) B cells. This finding would mean that a large fraction of B lymphocytes are sensitive to apoptosis, implying that autoantibody-producing B cells are derived from CD95(low) B cells and are relatively resistant to apoptosis.
authors.affiliation: Département d'Immunologie, Institut Pasteur, 28, rue du Dr Roux, Paris, 75015, France.
authors.forename: S
authors.initials: S
authors.lastname: Huck
authors.forename: C
authors.initials: C
authors.lastname: Jamin
authors.forename: P
authors.initials: P
authors.lastname: Youinou
authors.forename: M
authors.initials: M
authors.lastname: Zouali
mesh_terms: D000328:Adult; D000368:Aged; D017209:Apoptosis / Q000276:immunology; D001323:Autoantibodies / Q000096:biosynthesis; D016175:B-Lymphocyte Subsets / Q000276:immunology / Q000473:pathology; D001402:B-Lymphocytes / Q000276:immunology* / Q000473:pathology; D018956:CD5 Antigens / Q000378:metabolism; D016022:Case-Control Studies; D005260:Female; D015870:Gene Expression; D006801:Humans; D066298:In Vitro Techniques; D008180:Lupus Erythematosus, Systemic / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D019014:fas Receptor / Q000235:genetics / Q000378:metabolism*
chemical_list: D001323:Autoantibodies; D018956:CD5 Antigens; D019014:fas Receptor