QUINOLINIC ACID IN PATIENTS WITH SYSTEMIC LUPUS-ERYTHEMATOSUS AND NEUROPSYCHIATRIC MANIFESTATIONS

Objective. To evaluate the relationship between quinolinic acid, a neu roactive metabolite of L-tryptophan, and neuropsychiatric manifestatio ns of systemic lupus erythematosus (SLE). Methods. Forty specimens of cerebrospinal fluid (CSF) were obtained from 39 patients with SLE who were evaluated for 40 episodes of neuropsychiatric dysfunction. The di agnosis of the neuropsychiatric dysfunction was determined clinically. CSF and serum specimens were analyzed for levels of quinolinic acid w ithout knowledge of the clinical diagnosis. Results. Neuropsychiatric dysfunction attributed to SLE (NPSLE) was confirmed in 30 patient-epis odes (Group 1), whereas in the other 10 (Group 2) other etiologies wer e felt to explain their CNS dysfunction. The median levels of CSF quin olinic acid for Group 1 (232.5 nmol/l) were significantly higher than those for Group 2 (median 38.2 nmol/l) (p < 0.014). CSF and serum quin olinic acid levels correlated significantly (p < 0.003) but there was no correlation between CSF quinolinic acid and CSF protein concentrati ons or white blood cell counts. Conclusion. We conclude that elevated quinolinic acid levels in the CSF and serum may be associated with NPS LE and could possibly play a role in its pathogenesis.