Factors Influencing Serum Neopterin Concentrations in a Population of Blood Donors

Neopterin, a product of interferon-γ-activated monocytes/macrophages is a sensitive indicator of cell-mediated immune activation (1). In humans, increased concentrations of neopterin in serum and urine have been found during allograft rejection episodes and in various malignant disorders, autoimmune diseases, and viral infections, including HIV type 1 (HIV-1) (2)(3)(4)(5)(6)(7)(8). To improve the safety of blood donations, additional neopterin testing of blood donations became mandatory for all Austrian blood-transfusion services in addition to testing for HIV-1 and -2 antibodies, hepatitis C virus (HCV) antibodies, hepatitis B virus (HBV) surface antigen, alanine aminotransferase (ALT), and Treponema pallidum antibodies (9). In the Austrian Tyrol, ∼900 000 voluntary blood donations have been routinely screened for increased neopterin concentrations since 1986. According to the results of previous studies, the cutoff for neopterin concentrations was set to the 98th percentile, thus tolerating a donation loss of 2% (9). Although the behavior of neopterin concentrations during the course of acute viral infections, for example, is well known, there are fewer data regarding the association of neopterin concentrations and physiologic findings in a healthy population. In this study, we looked for associations between neopterin concentrations and other laboratory tests that are routinely performed on blood donations at our institute. Associations between neopterin concentrations and physiologic conditions of blood donors obtained during the blood-donation procedure were also investigated.