In parallel, transcript levels for IDO1, the first and rate-limiting enzyme for NAD+ de novo synthesis, and of CD38, PARP9, and PARP10, which promote NAD+ breakdown and consumption, were concordantly upregulated in the inactive SLE cohort monocytes as compared with healthy volunteers (Supplemental Figure 5). The gene discussed is IDO1; the disease is systemic lupus erythematosus.