Study of interleukin-6 and interleukin-8 levels in patients with neurological manifestations of dengue.

CONTEXT

Pro-inflammatory markers play a key role in the pathogenesis of various Flavivirus infection.

AIM

In this study, we evaluated the role of these markers in neurological manifestations of dengue.

SETTINGS AND DESIGNS

Consecutive dengue cases with different neurological manifestations who presented between August 2012 and July 2014 were studied in hospital-based case-control study.

MATERIALS AND METHODS

Interleukin (IL-6) and IL-8 level were measured in serum and cerebrospinal fluid (CSF) of dengue cases with different neurological manifestations and also in age- and sex-matched controls. Level was analyzed with various parameters and outcomes.

STATISTICAL ANALYSIS

Statistical analysis was done using SPSS version 16.0 by applying appropriate statistical methods. P < 0.05 considered statistically significant.

RESULTS

Out of the 40 enrolled cases of dengue with neurological manifestations, 29 had central nervous system and 11 had peripheral nervous system (CNS/PNS) manifestations. In CNS group, both IL-6 and IL-8 (CSF and serum) were significantly elevated (P < 0.001), whereas CSF IL-6 (P = 0.008), serum IL-6 (P = 0.001), and serum IL-8 (P = 0.005) were significantly elevated in PNS group. CSF IL-6, serum IL-6, and IL-8 were significantly elevated in poor outcome patients in CNS group (P < 0.05). CSF IL-6 and IL-8 were significantly elevated in CSF dengue positive cases as compared to CSF negative patients (P < 0.05). Cytokine level was not significantly correlated with neuroimaging abnormality in CNS group. Nine patients died and the remainder recovered.

CONCLUSION

Elevated level of IL-6 and IL-8 is associated with different neurological manifestations and poor outcome, but whether they are contributing to neuropathogenesis or simply a correlate of severe disease remains to be determined.