MMP9 and systemic lupus erythematosus: Studies have reported that SLE patients with different NPSLE syndromes had alterations in the CSF or the serum levels of various analytes, including cytokines (IL-10, IL-6, IFN-γ, TNF-α, TWEAK, S100B, and S100A8/A9, amongst others) and proteases (NGAL and MMP-9) that can affect intrinsic brain components (e.g., blood-brain barrier [BBB], the neurovascular interface, and resident microglia) leading to neuroinflammation (11–17).