[Central nervous system involvement in connective tissue diseases]

Neuropsychiatric manifestations are relatively common and serious complications in systemic lupus erythematosus (CNS lupus). Overall, in patients with CNS lupus, CSF IgM, IgA, IgG indexes (indicators of intrathecal Ig synthesis) as well as CSF IL-6 activities were significantly elevated. Of note, especially in patients lupus psychosis, but not in those with focal CNS lesions, anti-ribosomal P antibody (anti-P) in the sera as well as anti-neuronal antibody (anti-N) in the CSF was significantly elevated in relation to their CNS disease activities. These data indicate that the immune system activation within the CNS, possibly resulting in the elevation of CSF anti-N, plays an important role in the pathogenesis of CNS lupus, including lupus psychosis. CNS involvement in Behçet's disease, usually called neuro-Behçet's syndrome (NB), includes acute type and chronic progressive type. Acute NB is characterized by acute meningoencephalitis with focal lesions, presenting high intensity areas in T2-weightened images or Flare images on MRI scans, whereas chronic progressive NB is characterized by intractable slowly progressive dementia, ataxia and dysarthria with persistent elevation of CSF IL-6 activity. Chronic progressive NB is resistant to conventional treatment with steroid, cyclophosphamide, or azathioprine, but responds to low dose methotrexate. As for ANCA-related vasculitis, pachymeningitis has been found to be associated with P-ANCA as well as C-ANCA.