Fig 1: OPN expression in the cerebral cortex of NMO patients.(A) High OPN expression level in the white matter of NMO patients. Scale bar: 2.5 mm. OPN expression around the boundary area between white and gray matter in the patient with NMO (B), MS (C), and AD (D). Scale bars: 200 µm. The dashed lines indicate the boundary between white and gray matter. w, white matter; g, gray matter. OPN expression in astrocytes (E; arrows), neurons (E; white arrowheads), and oligodendroglias (F; arrowheads) of the cerebral sections of NMO patients. Scale bars: 50 µm. (G and H) Serial cerebral section from NMO patients demonstrating perivascular infiltration of numerous macrophages expressing OPN. The area in the rectangle in (G) is shown at higher magnification in (H). The arrowheads in (H) indicate macrophages. Scale bars: 200 µm (G), and 50 µm (H). OPN staining was performed using mAb against OPN (clone 53) on paraffin-embedded sections (n = 3) from two patients per disease. Photos in (B–H) are immunoperoxidase-stained with 3,3'-diaminobenzidine and hematoxylin counterstain. (I and J) Representative immunofluorescence staining of cerebral sections of an NMO patient. (I) Staining with OPN (green) and GFAP (red: astrocytes). (J) Staining with OPN (green) and CNPase (red: oligodendroglias). Nuclei were stained blue with Hoechst 33342. Scale bars: 50 µm.