In patients with encephalitis there was a strong positive correlation between MCS and the putative neuroprotective/neurotoxic ratio of KYNA/ (3-HK + QA) (Rho 0.9, p = 0.014) and strong inverse correlation with neopterin, as a marker of Th1 cell activation (Rho −0.9, p = 0.007), and IDO (Rho −0.9, p = 0.014) (Table 5). Here, IDO1 is linked to viral encephalitis.