Urinary neopterin index as a measure of rheumatoid activity.

The urinary neopterin index (U-NEOPT-I), expressed as micro-moles of neopterin/moles of creatinine) of 67 patients with definite or classical rheumatoid arthritis was significantly higher than that of sex- and age-matched persons or of 24 non-matched patients suffering from osteoarthrosis or arthralgia (2p less than 0.001). Furthermore, the patients with active disease had statistically significantly increased U-NEOPT-I when compared with patients with a clinically less active disease. In this study, the U-NEOPT-I value was the equal of CRP as a measure of rheumatoid activity. We suggest that neopterin might be involved in the pathogenesis of rheumatoid arthritis.