As expected, the expression of other markers of immune activation was elevated during HIV infection and we observed a positive association between the concentrations of sCD14 and both systemic IDO activity (Figure S4D in Supplementary Material) and plasmatic CRP (Figure S4E in Supplementary Material) in HIV/HCMV co-infected patients; moreover, these relationships were absent in healthy donors. Here, IDO1 is linked to HIV infectious disease.