Failure to detect brain reactivity of lymphocytotoxins in cerebral lupus.

Lymphocytotoxic activity (LCA) was examined in the sera of 29 patients with systemic lupus erythematosus (SLE), including eight with cerebral involvement. LCA was elevated in 80% of samples and was significantly higher in the group with cerebral disease (P less than 0.001). No correlations were observed between LCA and immune complexes or complement components. Sera from 10 patients (six with cerebral SLE) were absorbed with homogenates of normal human frontal cortex and liver using protein standards to control for dilutional effects. No serum sample showed selective depletion of LCA following incubation with brain homogenate. It is concluded that no single parameter, including brain absorption of LCA, is effective in monitoring disease activity in cerebral lupus.