Neopterin as a marker for activated cell-mediated immunity: application in malignant disease.

A review is presented on studies concerning neopterin determination in patients with malignant neoplastic diseases. Neopterin is produced chiefly by human macrophages through their activation by T-cell-derived interferon gamma. In vivo, determinationof neopterin in various body fluids provides a convenient way to monitor early events that are involved in cell-mediated immune responses. In malignant neoplasia, elevation of neopterin concentrations in body fluids depends on tumor type. Within a given type of tumor, more advanced stages are generally associated with higher levels than early disease. In a variety of different tumor types and sites, a significantly poorer prognosis was associated with high pretherapeutic neopterin concentrations. This predictive value is independent of several possible confounders such as stage or therapy. During follow-up malignant disease, neopterin elevations may predict deterioration of the clinical status of the patients and thereby provide a valuable additional marker for monitoring such patients. Possible immunobiological implications of the results are discussed.