Association of increased neopterin production with decreased humoral immunity in the elderly

Abstract Tetanus toxoid (TT) antibodies of 447 adult persons aged 27–69 years were investigated and analyzed in relationship with the time span since the last vaccination against tetanus as well as the serum concentration of neopterin. Neopterin is a pteridine, which is produced by monocytes/macrophages upon stimulation with the type 1 T cell-derived cytokine interferon-γ. There was an inverse correlation between serum neopterin and TT antibody concentrations (Spearman's rank correlation coefficient: r s =−0.259; p n =210; r s =−0.718; p The study demonstrates that an immunoregulatory shift towards type 1 immunity as indicated by higher neopterin concentrations coincides with lower TT antibody concentrations in the elderly.