Acute cytomegalovirus infections in blood donors are indicated by increased serum neopterin concentrations

In Austria serum neopterin measurement was introduced as an additional unspecific screening marker for the detection of routinely unscreened viral infections in blood donations in 1994. This study was performed to test for associations between serum neopterin concentrations in blood donations and cytomegalovirus infections of the donors. All consecutive blood donations from volunteer blood donors collected during 1 year were incorporated into the study. Serum neopterin concentrations were measured by enzyme-linked immunosorbent assay (ELISA), and each donation of donors with CMV seronegativity or unknown CMV status was also screened for CMV antibodies by CMV IgG/IgM antibody ELISA. Data of donors who had two or more donations within this period were retrospectively analyzed for CMV seroconversions. CMV seroconversion was defined as a change in the donor's CMV status from antibody negative to positive. Frozen, stored plasma samples of the matching donors were tested for CMV IgM antibodies to confirm seroconversion. CMV seroconversions were classified by antibody patterns. In total, 56,068 consecutive blood donations were given by 44,427 volunteer donors. Among these, 9,105 had more than one donation during the observation period, and 4,329 (47.5%) out of these repeated donors were initially CMV antibody negative, of whom 36 were recruited as candidates for CMV seroconversion; 20 conversions were confirmed. All early infections (n = 8) were associated with neopterin concentrations of more than 13 nmol/l (98th percentile of all donations = 12.1 nmol/l) and all donations were excluded from transfusion solely on the basis of their elevated neopterin level. In addition, 17% of late and carrier states (n = 12) showed elevated neopterin concentrations. Acute CMV infections among blood donors presented with elevated serum neopterin concentrations even before CMV IgG/IgM antibodies were detectable.