Neopterin: biochemistry and clinical usefulness.

Abstract

Neopterin is a marker for activation of the immune system. Serum or urine neopterin can increase in infection, transplant rejection, or in other disturbances of the immune system. Measurement of neopterin concentrations in body fluids offers a way to monitor the patient's immune system in some disorders. However, the nonspecificity of this biochemical marker for particular diseases raises problems in the interpretation of the results. This paper discusses the effects of disease and other factors on the levels of neopterin in biological fluids.