Neopterin to Monitor Clinical Pathologies Involving Interferon-γ Production

Abstract

Abstract Upon stimulation with the cytokine interferon-γ human monocytes/macrophages produce neopterin. Accordingly, measurement of neopterin concentrations in body fluids like blood, urine or cerebrospinal fluid provides information about activation of immune response involving type 1 Τ helper cells. Increased neopterin production is found in infections by viruses including human immunodeficiency virus (HIV), infections by intracellular living bacteria and parasites, autoimmune diseases, malignant tumor diseases and in allograft rejection episodes, but also in some neurodegenerative and in cardiovascular diseases. Major diagnostic applications of neopterin measurements are monitoring of the immune status of allograft recipients, detection of infectious diseases in blood donations and monitoring of therapy in HIV-infected individuals. Neopterin concentrations also provide prognostic information in HIV-infected individuals and in several malignant tumor diseases, high neopterin production at the moment of diagnosis is associated with poorer survival expectations. As high neopterin production is associated with increased production of reactive oxygen species and with low serum concentrations of antioxidants like α-tocopherol, neopterin can be regarded as a marker of oxidative stress caused by an activated immune system. Therefore, by neopterin measurements not only the extent of cellular immune activation, but also the extent of tissue damage caused by reactive oxygen specics may be estimated.