AQP4 and neuromyelitis optica: MRI data show that the group of IL-15tg mice have markedly reduced NMO lesion size as compared to WT littermates (IL-15tg vs WT: 2.40 ± 0.58 vs 5.23 ± 0.45 mm3) (Figures 2A,B), corresponding to less loss of GFAP and AQP4 immunostaining in the region of injection site (IL-15tg vs WT: 9.00 ± 2.1% vs 17.24 ± 1.9%) (Figures 2C,D).