Figure 1

IDO enzyme activity in nonagenarians and young controls. The ratio of kyn to trp, indicating IDO enzyme activity, is elevated in the plasma of nonagenarians compared to young controls (p = 0.011, Mann-Whitney U-test).
IDO enzyme activity in nonagenarians and young controls. The ratio of kyn to trp, indicating IDO enzyme activity, is elevated in the plasma of nonagenarians compared to young controls (p = 0.011, Mann-Whitney U-test).