Proliferative lesion of arthritis: a target for therapy?

The term proliferative lesion refers to the increase in the amount of connective tissue and in the number of small blood vessels and mesenchymal cells with both phagocytic and synthetic functions, characterizing the rheumatoid synovium. This type of lesion is probably responsible for most of the joint destruction and synovial tissue fibrosis seen in this disease. In vitro data indicate that not only factors inducing bone resorption, for instance osteoclast activating factor and prostoglandins, but also connective tissue-degrading enzymes, can be produced locally in the joint, which suggests that these factors play a role in the destruction of articular structures. D-Penicillamine suppresses the immuno-inflammatory process of rheumatoid arthritis, which indirectly may lead to a depression of the stimuli perpetuating the proliferative lesion. As yet, there are no unequivocal clinical data indicating that D-Penicillamine has a direct suppressive effect on the proliferative lesion.