title: Ro52- and Ro60-specific B cell pattern in the salivary glands of patients with primary Sjögren's syndrome.
abstract: Primary Sjögren's syndrome (pSS) is characterized by the presence of autoantibodies against the ribonucleoprotein (RNP) particles Ro/SSA and La/SSB, and mononuclear cell infiltration of exocrine tissues, especially salivary and lachrymal glands. Low numbers of autoantigen-specific memory B cells and elevated levels of plasma cells have been detected previously in the peripheral blood (PB) of pSS patients compared to controls. As both Ro52 and Ro60-specific cells have been detected in the salivary glands (SG) of pSS patients, we aimed to characterize the SSA-specific B cell pattern in SG biopsies. A series of double immunohistochemical stainings were performed on paraffin-embedded tissue from 10 well-characterized pSS patients for each Ro52 and Ro60 along with CD19, CD5, CD20 or CD27, respectively. Ro52 and Ro60-specific cells detected in SG tissue were found to be CD19(+) B cells located outside the CD19(+)/CD20(+) B cell zones (BCZ) and also interstitially. These SSA-specific cells were also quantified. No SSA-specific cells were CD5(+), indicating that they do not belong to the B-1 B cell subset. Furthermore, no SSA-specific cells were observed within the CD20(+) BCZ. Hence, no SSA-specific memory B cells were detected in these individuals. Contrary to this, SSA-specific cells were found to be CD19(+)/CD27(++), demonstrating that they are differentiating short or long-lived plasma cells. Taken together, our findings suggest that these lower levels of SSA-specific memory B cells in PB and absence of SSA-specific memory B cells in SG of pSS patients could result from activation of these cells into plasma cells at the site of inflammation.
authors.affiliation: Broegelmann Research Laboratory, The Gade Institute, Bergen, Norway. lara.aqrawi@gades.uib.no
authors.forename: L A
authors.initials: LA
authors.lastname: Aqrawi
authors.forename: K
authors.initials: K
authors.lastname: Skarstein
authors.forename: G
authors.initials: G
authors.lastname: Øijordsbakken
authors.forename: K A
authors.initials: KA
authors.lastname: Brokstad
mesh_terms: D000974:Antibodies, Antinuclear / Q000097:blood / Q000276:immunology; D018941:Antigens, CD19 / Q000032:analysis; D018951:Antigens, CD20 / Q000032:analysis; D001323:Autoantibodies / Q000097:blood / Q000276:immunology; D001324:Autoantigens / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D018956:CD5 Antigens / Q000032:analysis; D006801:Humans; D007156:Immunologic Memory / Q000276:immunology; D010950:Plasma Cells / Q000378:metabolism; D012261:Ribonucleoproteins / Q000276:immunology*; D012469:Salivary Glands / Q000276:immunology*; D012859:Sjogren's Syndrome / Q000097:blood* / Q000276:immunology*; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7 / Q000032:analysis; D000099207:SS-A Antigen
chemical_list: D000974:Antibodies, Antinuclear; D018941:Antigens, CD19; D018951:Antigens, CD20; D001323:Autoantibodies; D001324:Autoantigens; D018956:CD5 Antigens; D012261:Ribonucleoproteins; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; D000099207:SS-A Antigen