Increased amounts of
neopterin are produced by human monocytes/macrophages upon stimulation with the
cytokine interferon-y. Therefore, measurement of
neopterin concentrations in body fluids like serum, cerebrospinal fluid or urine provides information about activation of T helper cell 1 derived cellular immune activation. 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 neurological and in
cardiovascular diseases cellular immune activation indicated by increased
neopterin production, is found. Major diagnostic applications of
neopterin measurements are, e.g. monitoring of allograft recipients to recognize immunological complications early.
Neopterin production provides prognostic information in patients with malignant
tumor diseases and in HIV-infected individuals, high levels being associated with poorer survival expectations.
Neopterin measurements are also useful to monitor
therapy in patients with autoimmune disorders and in individuals with
HIV infection. Screening of
neopterin concentrations in blood donations allows to detect acute
infections in a non-specific way and improves safety of
blood transfusions. As high
neopterin production is associated with increased production of
reactive oxygen species and with low serum concentrations of
antioxidants like
alpha-tocopherol,
neopterin can also be regarded as a marker of
reactive oxygen species formed by the activated cellular immune system. Therefore, by
neopterin measurements not only the extent of cellular immune activation but also the extent of oxidative stress can be estimated.