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.