Clues provided by animal models of arthritis

All the findings discussed support the premise that animal experimentation is a pertinent endeavor for understanding chronic inflammatory synovitis in humans. Whether any of these data actually identify processes operative in RA or can be used to predict outcomes in the human disease is currently unclear. The review closes with an illustration of an area of controversy existing, in part, because of an absence of animal model research. The rationale for the use of gamma-interferon (IFN) in RA has been aptly described by S. H. Pincus as "curious". Evidence of deficient gamma-IFN production within the rheumatoid synovium has been acquired by several laboratories, suggesting that administration of this lymphokine might be helpful. This conclusion has been supported by news of short-term success in uncontrolled pilot trials. However, gamma-IFN is perhaps the most vigorous of the interleukins in terms of diversely activating the immune system. Thus, it would seem logical to envision that gamma-IFN would accelerate any process attributable to autoimmunity. The use of animal models to probe this dilemma, and others arising in the future, could provide a more convincing scientific cornerstone for clinical trials in RA. One caveat, however--animal models provide only clues or potential insights, not final answers, for human disease.