C-reactive protein and cognitive deficits in systemic lupus erythematosus

Recent studies have highlighted the role of serum C-reactive protein (CRP) as a marker for atherosclerosis, and a predictor for vascular disease and stroke. Systemic lupus erythematosus (SLE) has been associated with (1) higher levels of CRP, (2) cerebrovascular disease, and (3) a "subcortical" pattern of cognitive deficits (eg, lower processing speed, poor working memory). These findings suggest that microvascular changes affect cognition in SLE. To our knowledge, no studies have yet attempted to relate levels of CRP with cognitive deficits in SLE. In the present study, we investigated the relationship between CRP level and measures of working memory/processing speed in SLE.

The Paced Auditory Serial Addition Test (PASAT), a sensitive measure of processing speed and working memory, was administered as part of a full neuropsychologic battery. CRP levels were obtained from blood collected on the day of cognitive testing. SLE patients were divided into 2 groups: No detectable CRP (No-CRP) and detectable CRP levels (Elevated-CRP).

In comparison to the No-CRP group, the Elevated-CRP group performed more poorly on the PASAT. They had fewer correct responses, fewer consecutive correct responses (dyads), and a greater percentage of responses that were obtained by using a less demanding but incorrect "chunking" strategy to perform the PASAT.

Results suggest that CRP may be a sensitive marker for subtle executive dysfunction in SLE, possibly due to central nervous system microvascular autoimmune processes. Early treatment of vasculopathy in SLE may help prevent microvascular disease and associated cognitive dysfunction.