Fig. 1.

Kynurenine pathway metabolites in plasma from PASC patients, and recovered but prior hospitalized COVID-19 patients. For comparison we included values of plasma from patients with fatal/severe COVID-19 (reference⁶; these separate data have not been published before). Statistical analysis of parametric variables were performed using analysis of variance and post hoc tests with Tukey HSD. Non-parametric data were analysed using the Kruskal–Wallis H test with post hoc pairwise Kruskal–Wallis test with Benjamini-Hochberg correction. The area between the dotted lines represent the normal reference values as determined in reference 22 for plasma and reference 23 for serum. Metabolites in the fatal/severe group had several measurements at the lower limit of quantification for quinolinic acid, 3OH-anthranilic acid, kynurenic acid and xanthurenic acid, which were set at 1/10 of the lower limit of quantification. ns: not significant, ∗: p-value <0.05, ∗∗: p-value <0.001. Recov: Prior hospitalized COVID-19 patients PASC: Post-acute sequelae of COVID-19.