Cytokine expression in synovial membranes of patients with rheumatoid arthritis and osteoarthritis.
OBJECTIVE
To compare, by immunohistochemistry, the cellular and cytokine profile in rheumatoid arthritis (RA) and osteoarthritis (OA) synovial membranes (SMs). Synovium was obtained at knee arthroplasty from 10 patients with RA and 10 with OA.


METHODS
Synovial membranes were stained with a panel of monoclonal antibodies (MAb) to assess cytokine expression (IL-1 alpha, IL-1 beta, IL-6, GM-CSF, TNF-alpha and EGF) and the intensity of the mononuclear cellular infiltrate (MNC).


RESULTS
Significantly greater percentages of IL-1 alpha, IL-1 beta, IL-6, TNF-alpha, GM-CSF and EGF cells were detected in all areas of the rheumatoid SMs when compared with osteoarthritic SMs. Five RA but only one OA SM demonstrated focal lymphoid aggregates. Lining layer thickening was noted in RA SMs only. The intensity of the MNC and number of blood vessels were greater in the RA group.


CONCLUSIONS
The results suggest that the differences in cytokine production by RA and OA SMs are quantitative but that the greater thickness of the synovial lining layer and higher vascularity may be specific to RA.
Farahat
M N
MN
Department of Medicine, UMDS, Guy's Hospital, London, United Kingdom.
Yanni
G
G
Poston
R
R
Panayi
G S
GS
D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000473:pathology; D016207:Cytokines / Q000032:analysis*; D004815:Epidermal Growth Factor / Q000032:analysis; D005260:Female; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000032:analysis; D006801:Humans; D007124:Immunoenzyme Techniques; D007378:Interleukins / Q000032:analysis; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000473:pathology; D013583:Synovial Membrane / Q000737:chemistry* / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
D016207:Cytokines; D007378:Interleukins; D014409:Tumor Necrosis Factor-alpha; D004815:Epidermal Growth Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor