OPG serum levels were significantly increased during inflammation induced by a bacterial infection, compared to viral infection and controls (4.17 pmol/l (2.40–12.12) vs 3.2 (1.66–5.33) and 3 pmol/l (2.13–4.76), respectively, p < 0.001). The gene discussed is TNFRSF11B; the disease is bacterial infectious disease.