The synovium of transgenic arthritic mice expressing human tumor necrosis factor contains a high level of nerve growth factor.

We have recently reported that nerve growth factor (NGF) increases in the synovium of patients affected by rheumatoid arthritis and in the synovium of pharmacologically-induced arthritis in animal models. In the present study, we demonstrate that arthritic transgenic mice which carry and express the human TNF gene (Tg197) also express elevated levels of NGF, and that subcutaneous injection of NGF-antibodies attenuates the loss of body weight caused by the development of disease in these mice. Along with our previous findings, which show an increase in the level of NGF during the acute phase of other autoimmune diseases, these results suggest a role of NGF in these pathologies. The functional significance of NGF in rheumatoid arthritis (RA) is currently under study.