NITRIC-OXIDE SYNTHESIS IS INCREASED IN PATIENTS WITH SYSTEMIC LUPUS-ERYTHEMATOSUS

Nitric oxide (NO) is believed to have a role in the inflammatory proce ss. NO production was measured in 26 patients with systemic lupus eryt hematosus (SLE) and 20 healthy volunteers, using spectrophotometricall y determined serum nitrite and citrulline as surrogate markers. Both n itrite and citrulline levels were significantly higher in patients wit h SLE than in controls (P<0.001). Twelve and 10 patients, respectively , with SLE had nitrite and citrulline levels that were two standard de viations higher than the mean level of controls. These patients had a significantly higher measure of disease activity (SLE Disease Activity Index). These data show that there is increased NO production in SLE and that it may serve as a marker for disease activity.