IFNG and Arthritis: A second case example is the finding that arthritis development is independent of IFN-γ [24], [25], [44], [45] as verified in IFN-γ knockout mice [46], [47], yet neutralization of IL-12 in B. burgdorferi-infected C3H mice resulted in reduced IFN-γ expression and diminished severity of Lyme arthritis [48].