The significance of Cerebrospinal fluid/Serum ratios of interleukins-6, -8, -10 in the differential diagnosis of meningitis in children

Meningitis is a devastating disease for which appropriate initial treatment improves outcome. Management strategies are based on the etiology, which is most commonly bacterial or viral. However, prompt detection of the etiologic agent is not possible in all cases; therefore, the investigation of additional early differential diagnostic markers, such as interleukins, remains relevant.

The aim of the study. To determine the differential diagnostic value of cerebrospinal fluid/serum ratios of interleukins 6, 8, 10 in purulent bacterial and viral meningitis in children.

Materials and Methods. This prospective study enrolled 63 children, divided into three groups: bacterial meningitis (n=20), viral meningitis (n=17), and a control group (n=26). Concentrations of albumin, interleukins 6, 8, 10 were evaluated in cerebrospinal fluid and serum samples obtained in parallel on the day of admission. Cerebrospinal fluid/serum ratios (QAlb and QIL) were calculated. Receiver operating characteristic (ROC) curve analysis was performed with estimation of the area under the curve (AUC) and determination of optimal cut-off values. A predictive model was developed with binary logistic regression.

Results. Interleukin 6 concentrations in cerebrospinal fluid (AUC = 0.982) and serum (AUC = 0.991), serum interleukin 10 (AUC = 0.965), and QIL10 (AUC = 0.953; sensitivity = 95.0%, specificity = 76.5%) demonstrated high diagnostic accuracy in differentiating bacterial from viral meningitis. Combining QAlb and QIL10 in the predictive model equation increased sensitivity (100%) and specificity (88.2%). A possible mechanism of intrathecal regulation of inflammation in the early stages of meningitis is proposed. In bacterial meningitis, only pro-inflammatory interleukins 6 and 8 are synthesized intrathecally, resulting in neutrophilic pleocytosis. In viral meningitis, intrathecal production of interleukins 6 and 8 and anti-inflammatory interleukin 10 inhibiting neutrophil recruitment into the cerebrospinal fluid leads to mixed or lymphocytic pleocytosis.

Conclusion. Evaluation of interleukin 6 concentration in cerebrospinal fluid and application of the predictive formula incorporating QAlb and QIL10 enables differentiation between bacterial and viral meningitis at the early stages of the disease.

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