Kynurenine production by Normal and CGD monocytes and PMN. Tryptophan and kynurenine concentrations were measured in culture supernatants after 24 (PMNs) or 48 hours (monocytes) of treatment with 1000 IU IFNγ/mL. Data shown represent mean kynurenine or tryptophan concentration (micromolar) ± SE from normal (circles) monocytes (n = 16) or PMNs (n = 14), A-CGD (squares) monocytes (n = 7) or A-CGD PMNs (n = 6), or X-CGD (triangles) monocytes (n = 7) or PMNs (n = 6).