Table 2.
Comparison of pathology at CSF–brain and blood–CSF interfaces
| NMO | MS | Normal | |
|---|---|---|---|
| Pial surface | |||
| C9neo deposition | Yes (17/21) | Yes (2/5) | No |
| Microglial reaction | |||
| Localized to pia | Yes (18/22) | Yes | No |
| Extended into cortex | Rare | Yes | No |
| Associated with CDM | No | No | No |
| AQP4 loss | Yes (21/23) | No (increased) | No |
| Ependyma | |||
| C9neo deposition | Yes (6/16) | Yes (1/5) | No |
| Microglial reaction | Yes (16/16) | Scattered (2/5) | No |
| AQP4 loss | Yes (9/16) | No (increased) | No |
| Ependymal discontinuity | Yes (16/16) | Yes (5/5) | Rare |
| Choroid plexusa | |||
| C9neo deposition | |||
| On epithelial membrane | Yes (4/10) | No | No |
| In stroma | Yes | Yes | Yes (rare) |
| Microglial reaction | Moderate | Mild | Minimal |
| AQP4 loss | Yes (12/12) | No (increased) | No |
CDM cortical demyelination
aEpithelial cells in the normal choroid plexus of the fourth ventricle express AQP4. In NMO, AQP4 loss was reflected by a decrease in the number of positive cells and by reduced AQP4 staining intensity on positive cells