NEOPTERIN CONCENTRATIONS IN CEREBROSPINAL-FLUID AND SERUM AS AN AID IN DIFFERENTIATING CENTRAL-NERVOUS-SYSTEM AND PERIPHERAL INFECTIONS IN CHILDREN

Neopterin is a sensitive indicator for cellular immune activation. Its concentrations were determined in cerebrospinal fluid (CSF) and serum specimens from 91 children with no evidence of central nervous system (CNS) or peripheral inflammations, 43 with definite neuroborreliosis, 51 with other CNS infections, and 33 with peripheral infections. The aim of our study was (a) to establish a range of normal CSF neopterin concentrations in control children, and (b) to inquire into the diagno stic potential of neopterin measurements in both body compartments for aiding in differential diagnosis of inflammatory vs noninflammatory d iseases, and CNS vs peripheral inflammations. CSF neopterin concentrat ions in controls were invariably low (up to 9.3 nmol/L), but in childr en with neuroborreliosis and, even more so, with other CNS infections neopterin concentrations were significantly (P <0.0001) increased. Chi ldren with peripheral infections, however, rarely showed raised CSF ne opterin concentrations. Serum concentrations of neopterin, on the othe r hand, were not significantly different between controls and children with neuroborreliosis. Although serum concentrations were significant ly different between controls and children with other CNS infections, diagnostic efficiency was poor for this comparison. Peripheral infecti ons, in contrast, were associated with significantly higher (P <0.0001 ) serum neopterin concentrations when compared with controls. A classi fication tree was constructed on the basis of CSF and serum neopterin concentrations, allowing with high accuracy the discrimination between controls, children with CNS infections, and children with peripheral infections. Thus, on the basis of a comparatively large control group, our data underline the diagnostic validity of neopterin as an aid in differential diagnosis of inflammatory vs noninflammatory diseases, an d confirm that CSF neopterin concentrations are not correlated with se rum neopterin concentrations, and, therefore, CSF neopterin appears to be produced intrathecally.