Clinical significance of serum and urinary neopterins in patients with chronic renal disease.

To determine the clinical significance of serum and urinary neopterins in patients with chronic renal disease, we measured these values using IMMUtest Neopterin RIA kits. Serum neopterin levels in patients with chronic glomerulonephritis (CGN) (10.2 +/- 8.1 nmol/l) and in those with chronic renal failure (CRF) (109 +/- 90) were significantly increased compared with the control subjects (C) (4.2 +/- 2.4) (p less than 0.001). The levels of serum neopterins in patients on chronic hemodialysis (HD) (212 +/- 106) were increased almost twofold compared with CRF (p less than 0.001). In CGN and CRF, a strong positive correlation was demonstrated between serum neopterin levels and serum creatinine concentrations (r = 0.95, p less than 0.001). In HD patients, neopterin levels and serum were not correlated with the length of time on dialysis. The urinary neopterin excretion ratios (urinary neopterin/urinary creatinine level) in CRF (227 +/- 114 mumols/molCr) were significantly increased compared with C (116 +/- 43) (p less than 0.01). A significantly negative correlation was observed between the urinary neopterin levels and the creatinine clearance in CGN and CRF (p less than 0.01). These data suggest that, in patients with chronic renal disease, the neopterin levels in serum are closely linked with glomerular filtration rate and yet the urinary neopterin/creatinine ratios may reflect the predominance of increased tubular secretion of neopterin over the renal injury per se.