URINE NEOPTERIN - A NEW PARAMETER FOR SERIAL MONITORING OF DISEASE-ACTIVITY IN PATIENTS WITH SYSTEMIC LUPUS-ERYTHEMATOSUS

Objective-To investigate the role of serial measurement of urine neopt erin concentration in monitoring the progression of systemic lupus ery thematosus (SLE) disease activity scored using the British Isles Lupus Assessment Group (BILAG) index. Methods-We followed prospectively 68 unselected SLE patients for a total of 464 patient months during which 233 separate assessments were carried out. At each assessment, urine neopterin, determined by high performance liquid chromatography, toget her with erythrocyte sedimentation rate (ESR) and plasma C3, C4, and C 3d were measured and the SLE disease activity scored by a single obser ver. Serial data sets were analysed using time series modelling techni ques. Results-Single time point analysis showed a significant increase in urine neopterin concentrations in 14 patients who suffered flares of their disease during the study period (p = 0.02). Thirty patients w ith active disease went into disease remission with significant decrea ses in their urine neopterin values (p = 0.02). In the time series ana lysis, a statistically significant association was found between seria l concentrations of urine neopterin and BILAG score (r = 0.6, p < 0.05 ); no other study parameter (ESR and serum C3, C4, and C3d) mirrored S LE disease activity as effectively. Conclusions-This study provides in itial evidence that changes in urine concentrations of neopterin are s ignificantly correlated with fluctuations in disease activity over tim e, scored using the BILAG index, amongst individual patients with SLE. Consequently, serial urine neopterin measurements appear to be clinic ally useful for monitoring disease activity and may contribute substan tially to therapeutic decision making in these patients.