Dose dependent suppression of disease activity of collagen-inducedarthritis (CIA) by interleukin (IL)-4 and the combination of IL-4/prednisolone(Pred). Mice with established CIA were divided into separate groups of at least10 mice. Groups were treated intraperitoneally twice a day with vehicle, IL-4,prednisolone, or combined IL-4/prednisolone for 8 consecutive days. The datarepresent the mean arthritis score, expressed as percentage of initial value atday 28. Experiments were repeated once with approximately the same outcome.*P < 0.05, versus vehicle, by Mann-Whitney U test.