title: Increased Lymphocyte Infiltration in Rheumatoid Arthritis Is Correlated with an Increase in LTi-like Cells in Synovial Fluid.
abstract: In this study, we compared the immune cell populations in rheumatoid arthritis (RA) synovial fluid, which shows lymphoid tissue-like structure, with those in tonsils, which are normal secondary lymphoid tissues. Firstly, we found that CD4(-)CD11b(+) macrophages were the major population in RA synovial fluid and that B cells were the major population in tonsils. In addition, synovial fluid from patients with osteoarthritis, which is a degenerative joint disease, contained CD4(+)CD11b(+) monocytes as the major immune cell population. Secondly, we categorized three groups based on the proportion of macrophages found in RA synovial fluid: (1) the macrophage-high group, which contained more than 80% macrophages; (2) the macrophage-intermediate group, which contained between 40% and 80% macrophages; and (3) the macrophage-low group, which contained less than 40% macrophages. In the macrophage-low group, more lymphoid tissue inducer (LTi)-like cells were detected, and the expression of OX40L and TRANCE in these cells was higher than that in the other groups. In addition, in this group, the suppressive function of regulatory T cells was downregulated. Finally, CXCL13 expression was higher in RA synovial fluid than in tonsils, but CCL21 expression was comparable in synovial fluid from all groups and in tonsils. These data demonstrate that increased lymphocyte infiltration in RA synovial fluid is correlated with an increase in LTi-like cells and the elevation of the chemokine expression.
authors.affiliation: Department of Bioinformatics and Life Science, Soongsil University, Seoul 156-743, Korea.
authors.forename: Jihye
authors.initials: J
authors.lastname: Koo
authors.affiliation: Department of Bioinformatics and Life Science, Soongsil University, Seoul 156-743, Korea.
authors.forename: Soochan
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Bioinformatics and Life Science, Soongsil University, Seoul 156-743, Korea.
authors.forename: Woong Jae
authors.initials: WJ
authors.lastname: Jung
authors.affiliation: Department of Bioinformatics and Life Science, Soongsil University, Seoul 156-743, Korea.
authors.forename: Ye Eun
authors.initials: YE
authors.lastname: Lee
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Korea University Guro Hospital, Seoul 152-703, Korea.
authors.forename: Gwan Gyu
authors.initials: GG
authors.lastname: Song
authors.affiliation: Department of Otorhinolaryngology, Human Barrier Research Institute, Yonsei University College of Medicine, Seoul 135-720, Korea.
authors.forename: Kyung-Su
authors.initials: KS
authors.lastname: Kim
authors.affiliation: Department of Bioinformatics and Life Science, Soongsil University, Seoul 156-743, Korea.
authors.forename: Mi-Yeon
authors.initials: MY
authors.lastname: Kim
keywords: Lymphoid tissue inducer; Rheumatoid arthritis; Tonsil