The Importance of Neopterin as a Laboratory Diagnostic Marker of Immune Activation

Neopterin is produced and secreted in large amounts by interferon-g stimulated human monocytes/macrophages. Neopterin measurement in urine and semm provides a usefi.ll possibility to estimate the dcgree of ccllular (Thl-type) immune activation, which is directed against viral infections, intracellular bacteria, and certain parasites. Also in malignancy, autoimmw1e diseases and allograft rejection episodes neopterin sensitively reflects the extent of cellular immune activation. Determination of neoptcrin concentrations can be conveniently performed by immunoassay like ELISA or RIA, and HPLC. The major diagnostic applications of neopterin monitoring are: surveillancc of the immw1e status of organ recipients, therapy control and prognosis of diseasc progression in tumor diseascs and HIV infections and also detection of unknown infections in e.g. blood banks. High neopterin levels are strongly associated with oxidative stress, opening an additional application field of ncopterin monitoring to estimate the extent of tissue damagc in the course of immune activation.