Neopterin concentrations in blood donors differ between AB0 blood group phenotypes

Objectives: Neopterin is produced by human monocyte-derived macrophages upon stimulation with interferon-γ and is therefore a sensitive indicator for cellular immune activation. Common factors like age, diastolic blood pressure, body mass index, or smoking habits were found to be associated with neopterin concentrations in humans. Design and methods: In order to find possible genetic determinants which might influence neopterin production, we investigated 8288 consecutive blood donors after exclusion of samples suspicious of infections. Results: Donors with blood group phenotype 0 had moderately, but significantly (P < 0.0001) higher neopterin concentrations (mean ± SD: 6.94 ± 1.52 nmol/L) than those with phenotype A (6.75 ± 1.50 nmol/L), phenotype B (6.73 ± 1.48 nmol/L), and phenotype AB (6.68 ± 1.57 nmol/L). Conclusions: Neopterin levels are higher in donors with blood group phenotype 0 than in other phenotypes. Data point to a genetic background of different neopterin concentrations. However, alterations of neopterin levels were much less expressed than the changes known to occur during diseases with an activated immune response.