Urinary neopterin in idiopathic retinal vasculitis

Aims-To determine whether urinary neopterin:creatinine (UNC) ratios relate to disease activity in idiopathic retinal vasculitis (RV). Methods-18 patients with RV were prospectively recruited into a year long l ongitudinal study. Patients collected first morning urine samples on a week ly basis and on the same day completed a diary which documented their subje ctive view of RV activity and any concurrent infection. They were examined in clinic on a 6-8 weekly basis and an objective assessment was made of RV disease activity. 14 healthy controls collected urine samples in the same w ay. Results-UNC ratios were significantly higher in patients than in controls ( p=0.004, Mann-Whitney U test). UNC ratios were significantly higher when, a ccording to their diaries, the patients had a subjective flare up of RV (p= 0.001, Mann-Whitney U test). Subjective increased RV activity occurred more often when the patients had a concurrent infection (p<0.0001, <chi>(2) tes t). There was no significant difference in the UNC ratio between objective clinical relapse and non-relapse of RV. There was moderate agreement betwee n the clinical assessment and patients' subjective impression of RV activit y (kappa =0.48). Conclusions-Higher neopterin levels reflect cell mediated disease that occu rs in RV, but UNC ratios are not recommended as a means of monitoring clini cal disease activity in RV.