IL4 and Arthritis: Attenuates murine collagen-induced arthritis by augmenting IL-4, IL-10, and collagen-specific IgG1, distinctly reducing IFN-r and collagen-specific IgG2a, and decreasing IL-6, IL-17, TNF-α, and RANKL. Reduces severity of complete Freund’s adjuvant-induced arthritis in a rat model by increasing production of IL-10 and IL-4 and decreasing production of IL-12p70 and IFN-r.