Blood cytokine levels in anti-NMDAR and viral encephalitis during the early stage of hospitalization: a small-sample exploratory pilot study

Objectives We aimed to perform a preliminary analysis of early cytokine profiles in blood between patients with anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis and viral encephalitis (VE), and to observe potential preliminary trends. Methods This study adopted a retrospective design. Following a standardized screening process, anti-NMDAR encephalitis (n = 15), VE (n = 15), and non-inflammatory central nervous system diseases as controls (n = 15) were retrospectively enrolled. Correlations between candidate biomarkers and clinical characteristics of two kinds of encephalitis patients were analyzed. Results This study identified significant alterations in the CSF/serum albumin ratio (QAlb), IL-4 and IL-17A levels across among the two patient groups and controls. These markers exhibited certain diagnostic potential for differentiating anti-NMDAR encephalitis from VE. In the anti-NMDAR encephalitis group, IL-17A and QAlb were positively correlated with the patients’ hospital stay duration and mRS score at admission (P<0.05). In the VE group, IL-4 and QAlb were associated with the patients’ hospital stay duration and disease severity (P<0.05), with IL-4 showing a negative correlation. However, the present findings should be regarded as preliminary and require further confirmation before clinical translation. Conclusions Elevated levels of specific inflammatory indicators showed potential as candidate biomarkers to aid in the early differential diagnosis between anti-NMDAR encephalitis and VE.