Figure 3

Location and frequency of lesions with AQP4 loss and neutrophil infiltrates outside the needle tract, after intrastriatal injection of IL-1β and intraperitoneal application of NMO-IgG. The location (red dots in the schemes of [6]; a,b) and histology (c,d) of perivascular lesions with AQP4 loss and neutrophil infiltration in adult animals seropositive for the NMO-IgGs, J0 (a,c) and I GF (b,d), that received intrastriatal injection of IL-1β (gray area represents the injection site). Similar lesions were not observed after transfer of IgGs from a NMO-IgG negative NMO patient (e), or three NMO-IgG negative MS patients (f-h). The number of those lesions was significantly higher in IL-1β/NMO-IgG injected animals (n=29) than in the controls (n=47), according to Mann Whitney U test with Bonferroni Holm correction (i). The following NMO-IgG or control IgG preparations were used: NMO-IgG J0 (1, 2, 7-14), NMO- IgG I GF (3, 4), NMO-IgG7 (5) and NMO-IgG8 (6). As controls, IgG preparations of two AQP4 antibody negative NMO patients (J3 and J4; 15), three NMO-IgG negative MS patients (J5, J6, J7; 16 and 17), and subcuvia (18, 19) were used. Experiments 1, 3, 7, 9, 11, 12, 13, 15 and 18 were performed using juvenile animals, and experiments 2, 4, 5, 6, 8, 10, 14, 16, 17 and 19 using adult rats. Cytokines were injected as indicated. The AQP4-specific antibodies found in the NMO-IgG preparations are responsible for the formation of lesions, as revealed by absorption studies using two different NMO-IgG preparations (j-l). Lesions were present (j, l; white circles) when NMO-IgG had been exposed to emGFP transfected HEK 293 cells, but were absent (k, l; black circles) when NMO-IgG had been exposed to AQP4-emGFP transfected HEK 293 cells. Bar=25 µm.