Spearman rank correlation between metabolites in the kynurenine pathway and selected cytokines
| Tryptophan (μM) | Kynurenine (nM) | Quinolinic acid (nM) | Kynurenine/tryptophan | |
| IP-10 | −0.09 | 0.39 | 0.43 | 0.43 |
| TNF-α | −0.13 | 0.45 | 0.49 | 0.48 |
| IL-16 | −0.08 | 0.43 | 0.40 | 0.40 |
| IL-6 | −0.12 | 0.15 | 0.07 | 0.19 |
| MIP-1β | −0.17 | 0.15 | 0.07 | 0.24 |
| IFN-γ | 0.03 | 0.17 | 0.29 | 0.12 |
Spearman’s correlation coefficients (rs ) above |0.2| are highlighted in bold.
IFN-γ, interferon gamma; IL, interleukin; IP-10, interferon gamma-induced protein 10; MIP-1β, macrophage inflammatory proteins 1 beta; TNF-α, tumour necrosis factor alpha.