Follow-up of Urinary Neopterin Concentrations in two Healthy Children until Adolescence

Neopterin is a sensitive marker of the activated cellular (= Thl-type) immune response. Neopterin concentrations in healthy children are higher compared with those of adults and are declining with increasing age. In this study, we present a follow-up of urinary neopterin to creatinine concentrations in two healthy children until adolescence. Data were available from one female (7 - 23 years) and her brother (0 - 18 years), of whom early morning urine specimens were collected on an irregular basis throughout 18 years. In total, neopterin and creatinine concentrations were measured by high pressure liquid chromatography (HPLC) in 343 urinary specimens. In both children, concentrations of urinary neopterin were highest at study entry. With increasing age neopterin concentrations decreased continuously to reach rather constant levels around the age of fifteen years. On several occasions at which individuals presented with common sickness, mostly of infectious origin, neopterin concentrations were found highly increased. In the absence of such infectious episodes, neopterin/creatinine measurements of both individuals fit well to previously established normal ranges. However this was true only for specimens collcctcd when children were older than 10 years, before that age concentrations of neopterin were frequently found to be higher than the established upper limits of the normal range.