A longitudinal study of anticardiolipin antibody levels and cognitive functioning in systemic lupus erythematosus

To determine the relationship between persistently raised anticardiolipin antibody (aCL) levels and neuropsychological performance in patients with systemic lupus erythematosus (SLE).

Forty-five patients with SLE underwent a detailed neuropsychological assessment on 2 occasions 12-18 months apart. Serum samples stored since the time of previous assessments as well as samples obtained 6 months to 2 years before the first neuropsychological assessment were tested for IgG aCL levels. Patients were divided into 4 groups according to the number of times their aCL levels were elevated (never, once, twice, 3 times). A wide-ranging battery of new neuropsychological tests was utilized, and the results were compared with double-stranded DNA (dsDNA) antibody levels, C3 levels, and results of magnetic resonance imaging (MRI).

Analysis of variance revealed that the group with persistently elevated aCL levels performed less well than the other groups. At the first neuropsychological assessment, poorer performance by this group was noted for letter cancellation (P = 0.02), trail making task B (P = 0.04), and digit span (P = 0.03). At the second assessment, letter cancellation (P = 0.01), trail making task A (P = 0.03), trail making task B (P = 0.01), word fluency (P = 0.01), and reaction time (P = 0.05) were impaired. In contrast, no significant differences in neuropsychological test results were identified with respect to DNA antibody or C3 levels. MRI abnormalities were associated with both persistent elevation of aCL levels and low C3 levels.

Levels of IgG aCL that were persistently elevated over a 2-3-year period (as opposed to never or occasionally elevated) were associated with significantly poorer performance in cognitive function by patients with SLE. Tasks requiring speed of attention and concentration appear to be particularly affected.