RHEUMATOID arthritis (RA) is an autoimmune disease which progressively and systematicallyinvades the joints of bones. A severe chronic situation may lead to the damage of cartilages,bones and tendons and eventually handicap the patients. One of the main histopathological fea-tures of rheumatoid synovium is a marked increase of the thickness and the number of cells inthe synovial lining layer. It is well known that the synovial lining cells secrete many cell fac- RHEUMATOID arthritis (RA) is an autoimmune disease which progressively and systematically invades the joints of bones. A severe chronic situation may lead to the damage of cartilages, bones and tendons and eventually handicap the patients. One of the major histopathological fea- tures of rheumatoid synovium is a marked increase of the thickness and the number of cells inthe synovial lining layer. It is well known that the synovial lining cells secrete many cell fac-