Figure 1From: Aging-associated increase in indoleamine 2,3-dioxygenase (IDO) activity appears to be unrelated to the transcription of the IDO1 or IDO2 genes in peripheral blood mononuclear cellsIDO 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).Back to article page