INTRODUCTION The local production of pathogenic autoantibodies by plasma cells in synovium is one of the hallmarks of rheumatoid arthritis (RA). There may be a potential link between ectopic lymphoid neogenesis and the local autoimmunity in rheumatoid synovium. The unfolded protein response (UPR) has key roles in the development and maintenance of plasma cells secreting immunoglobulin. This stu...

Electron microscopic study of synovial membranes of many animal species has added materially to our understanding of the structure and function of this organ. The fine structure of the synovium of man (Barland, Novikoff, and Hamerman, 1962; Roy, Ghadially, and Crane, 1966), guinea-pig (Wyllie, More, and Haust, 1964), rabbit (Ghadially and Roy, 1966), calf and dog (Langer and Huth, 1960), and ca...

Type VI collagen has recently been shown to be an important component of connective tissue. Double label immunofluorescence procedures were used to immunolocalize type VI collagen in normal and rheumatoid synovium and its distribution was compared with that of fibronectin. In normal synovium type VI collagen is expressed in the synovial membrane but not in the interstitium of the villus. In rhe...

The distribution and density of mast cells in the normal and diseased synovial membranes were investigated. The mast cell count (MCC) in the osteoarthritic (OA) synovium (36.9 +/- 26.9 cells/mm2) was significantly higher than that in the rheumatoid arthritic (RA) synovium (18 +/- 12.3 cells/mm2). There was a marked positive correlation between the MCC and the volume of joint fluid in OA (r = 0....

Rheumatoid arthritis (RA) is characterized by the accumulation of CD4(+) memory T cells in the inflamed synovium. To address the mechanism, we analyzed chemokine receptor expression and found that the frequency of CXC chemokine receptor (CXCR)4 expressing synovial tissue CD4(+) memory T cells was significantly elevated. CXCR4 expression could be enhanced by IL-15, whereas stromal cell-derived f...

The ultrastructural aspects of the lymphoid and plasma cell infiltrate in rheumatoid synovium have received little attention. We have therefore undertaken a study of the germinal follicles in rheumatoid synovium, and here draw attention to: (a) Cytoplasmic bridging between lymphocytes, plasma cells, and phagocytes; (b) Cytoplasmic and nuclear inclusions in lymphocytes; (c) Detachment of cytopla...

A 45-year-old Chinese man presented with recurrent bilateral knee swelling and pain. He was initially diagnosed with gouty arthritis, but later found to have lipoma arborescens. Magnetic resonance imaging demonstrated frond-like proliferations of fatty synovium. Arthroscopic synovectomy was performed. Histological examination of the specimen revealed villiform fatty tissue covered by slightly t...

INTRODUCTION: The clinical outcomes of rotator cuff repair vary among patients and are affected by multiple factors including chronic inflammation. Although inflamed synovium is a common clinical observation at the time of surgery, the role of this inflammation plays on clinical outcomes is not well elucidated. Several recent studies have shown that there is elevation of pro-inflammatory cytoki...

A major question concerning the immunopathology of rheumatoid arthritis is why the disease is localized to particular joints. A possible explanation could be the presence within the synovium of cells that foster inflammation or easy accessibility of the synovium to migratory disease enhancing cells. Within both the bone marrow and the synovium, fibroblastic stromal cells play an important role ...

In order to investigate the relationship between the synovial inflammatory response and lysosomal enzyme activity in osteoarthritis, synovial specimens obtained from 19 osteoarthritic patients and control specimens from 10 normal joints were analysed for cathepsin D and acid phosphatase enzyme levels. In estimating enzyme activities methods previously developed for quantitative enzyme determina...