title: Aberrant expression of CD6 on B-cell subsets from patients with Sjögren's syndrome.
abstract: CD6 is one of a pair of related genes encoding CD5-associated receptors on all T cells and a subset of B cells. The current availability of "T1h", a humanized anti-CD6 monoclonal antibody for B cell-mediated autoimmune disorders revives analysis of the B-cell subset expression of CD6, particularly in primary Sjögren's syndrome (SS). Refined phenotype of B-lymphocytes peripheral blood (PB), bone marrow and tonsils revealed that the overlap between the expression of CD6 is less close to that of CD5 than currently acknowledged. In contrast to CD5, CD6 is absent on transitional B cells, while present on mature and memory B cells. Interestingly, the PB proportion of CD6(+) B cells is decreased in patients with primary SS, as opposed to those with rheumatoid arthritis. The reduction in primary SS does not result from the shedding of CD6 from the membrane of B cells, but from the lowering of memory B lymphocytes. It may result from the ability of CD6 to make transmigration of CD27(+) memory B cells into the salivary glands (SGs) easier. Consistent with this view is our finding that CD166 (one of the ligands for CD6) is highly expressed on epithelial cells of patients' SGs. This study is relevant in that the humanized T1h anti-CD6 becomes an alternative to anti-CD20 for treatment of primary SS.
authors.affiliation: EA 2216 Immunology and Pathology, IFR 148 ScInBioS, European University of Brittany, Brest, France.
authors.forename: Ruby
authors.initials: R
authors.lastname: Alonso
authors.forename: Caroline
authors.initials: C
authors.lastname: Buors
authors.forename: Christelle
authors.initials: C
authors.lastname: Le Dantec
authors.forename: Sophie
authors.initials: S
authors.lastname: Hillion
authors.forename: Jacques-Olivier
authors.initials: JO
authors.lastname: Pers
authors.forename: Alain
authors.initials: A
authors.lastname: Saraux
authors.forename: Enrique
authors.initials: E
authors.lastname: Montero
authors.forename: Rémi
authors.initials: R
authors.lastname: Marianowski
authors.forename: Séverine
authors.initials: S
authors.lastname: Loisel
authors.forename: Valérie
authors.initials: V
authors.lastname: Devauchelle
authors.forename: Pierre
authors.initials: P
authors.lastname: Youinou
authors.forename: Yves
authors.initials: Y
authors.lastname: Renaudineau
mesh_terms: D000911:Antibodies, Monoclonal / Q000378:metabolism; D015703:Antigens, CD / Q000096:biosynthesis* / Q000097:blood / Q000235:genetics; D000945:Antigens, Differentiation, T-Lymphocyte / Q000096:biosynthesis* / Q000097:blood / Q000235:genetics; D016175:B-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D001853:Bone Marrow / Q000473:pathology; D018956:CD5 Antigens / Q000276:immunology; D002452:Cell Count; D002454:Cell Differentiation; D019070:Cell Lineage; D002465:Cell Movement; D004847:Epithelial Cells / Q000276:immunology; D006801:Humans; D007156:Immunologic Memory; D014066:Palatine Tonsil / Q000473:pathology; D012859:Sjogren's Syndrome / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D018956:CD5 Antigens; C062279:CD6 antigen