Cerebrospinal fluid levels of cytokines in non-herpetic acute limbic encephalitis: Comparison with herpes simplex encephalitis

Background: Recently, non-herpetic acute limbic encephalitis (NHALE) was identified as a new subgroup of limbic encephalitis. The immunological pathophysiology of NHALE is still unclear. Methods: We measured the concentrations of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-2 (IL-2), IL-4, IL-6, IL-10, and soluble TNF receptor 1 (sTNFR1) in the cerebrospinal fluid (CSF) of 15 patients with NHALE and 13 with herpes simplex encephalitis (HSE) by cytometric bead array or ELISA. Results: The CSF concentrations of IL-6 in patients with NHALE and IFN-γ, IL-6, IL-10, and sTNFR1 in HSE patients were significantly higher than those of controls (p < 0.001, p = 0.004, p < 0.001, p = 0.018, and p < 0.001, respectively). There were significant correlations among CSF IL-6, IL-10, and sTNFR1 levels in HSE patients. The CSF concentrations of IFN-γ and sTNFR1 levels of patients with HSE were significantly higher than those with NHALE (p = 0.001 and p = 0.002, respectively). Conclusions: CSF cytokine levels in NHALE were relatively low compared with those in HSE. These results may be related to the favorable prognosis of NHALE.