[Cytology and histochemistry of synovial cells in various forms of arthritis]

Synovial effusions from various kinds of arthritis have been examined both morphologically and histochemically. These two methods give complementary evidence, and show (i) that there are two fundamentally different types of cell present in rheumatoid arthritis (ii) that the synovial fluid from septic arthritis can clearly be separated from that of all other forms of arthritis and (iii) that intracellular crystals can be demonstrated in gout. Laboratory methods also give information on the polysaccharide and fat content of synovial fluid, in particular on the lipid material in the cell free supernatant. Large mononuclears in the fluid are probably generated in the local tissue and reflect minimal differentiation from a basic cell type.