The pattern of CD55 expression in atorvastatin-treated mouse brain was similar to that of AQP4, the astrocyte target of NMO autoantibody (Fig. 6c, right) and that of an endothelia cell marker (FITC-Isolectin B4) (Fig. 6f); however, by light microscopy the relative increase in CD55 expression in astrocytes versus endothelia and other brain cells cannot be resolved. Here, AQP4 is linked to neuromyelitis optica.