[Preponderant synthesis of rheumatoid factors by synovial plasma cells in rheumatoid polyarthritis].

Plasma cells synthesising rheumatoid factor have been identified by immunofluorescent studies of sections of cells eluted from synovial membranes poor in macrophages. More than 90% of the IgM plasma cells produce rheumatoid factor, while 50 to 60% of IgG plasma cells and only 10% of IgA plasma cells produce rheumatoid factor. The equivalent results obtained in patients with sero-positive and sero-negative rheumatoid arthritis suggest that auto-immunisation between the IgG plays the same determinant role in the pathophysiology of the two types of rheumatoid arthritis.