TREATMENT WITH AN ANTI-CD4 MONOCLONAL-ANTIBODY STRONGLY AMELIORATES ESTABLISHED RAT ADJUVANT ARTHRITIS

Some experimental arthritic diseases can be prevented by treatment wit h anti-CD4 MoAbs. Trials with ongoing disease have not been successful so far. The aim of this study was to ascertain whether W3/25 could re verse adjuvant arthritis (AA), when beginning treatment on day 14, i.e . when the disease was established. Moreover, one group of animals tre ated with the anti-CD4 MoAb received OX8 MoAb at the same time, thus d epleting CD8(+) cells from circulation. During treatment with W3/25, a strong amelioration of inflammatory signals was observed, as assessed by means of paw volume increase and arthritic score. However, when tr eatment stopped, a rebound to arthritis signals occurred. The parallel depletion of CD8(+) cells did not modify these effects, thus the comb ined treatment W3/25 + OX8 gave the same amelioration as treatment wit h W3/25 alone. These findings indicate that CD4(+) cells play an impor tant role in perpetuating rat AA. Moreover, CD8(+) cells do not seem t o have a regulatory role in the CD4(+) cells responsible for the infla mmatory response.