RT Journal Article SR Electronic T1 Plasma Cell Development in Synovial Germinal Centers in Patients with Rheumatoid and Reactive Arthritis JF The Journal of Immunology JO J. Immunol. FD American Association of Immunologists SP 3053 OP 3062 VO 162 IS 5 A1 Kim, Hye-Jung A1 Krenn, Veit A1 Steinhauser, Gudrun A1 Berek, Claudia YR 1999 UL http://www.jimmunol.org/content/162/5/3053.abstract AB Plasma cells are found surrounding the inflammatory infiltrates of macrophages, T, and B cells in the synovial tissue of patients with rheumatoid and reactive arthritis. This characteristic arrangement suggests that in the synovial tissue CD20+ B cells differentiate into plasma cells. To examine clonal relationships, we have used micromanipulation to separately isolate CD20+ B cells and plasma cells from single infiltrates. DNA was extracted, and from both populations the VH/VL gene repertoires was determined. The data show that in the inflamed synovial tissue activated B cells are clonally expanded. During proliferation in the network of follicular dendritic cells, V gene variants are generated by the hypermutation mechanism. Surprisingly, we do not find identical rearrangements between CD20+ B cells and plasma cells. Nevertheless, the finding of clonally related plasma cells within single infiltrates suggests that these cells underwent terminal differentiation in the synovial tissue. These results indicate that B cell differentiation in the synovial tissue is a dynamic process. Whereas CD20+ B cells may turnover rapidly, plasma cells may well be long lived and thus accumulate in the synovial tissue. The analysis of individual B cells recovered from synovial tissue opens a new way to determine the specificity of those cells that take part in the local immune reaction. This will provide new insights into the pathogenesis of chronic inflammatory diseases like rheumatoid or reactive arthritis.