Secretion of the chemokine interleukin-8 during Japanese encephalitis virus infection

Japanese encephalitis (JE) virus infection induces infiltration of neutroph ils in neural as well as extraneural tissues in patients. As interleukin-8 (IL-8) has inflammatory properties, the present study was undertaken to inv estigate the IL-8 concentrations in cerebrospinal fluid (CSF) and serum fro m patients with JE and correlate them with neutrophil counts. IL-8 was meas ured in the CSF or serum of 30 patients with confirmed JE, The majority (92 %) of the acute CSF samples showed raised levels of IL-8 with raised number s of polymorphonuclear leucocytes. Similarly, significantly higher serum IL -8 concentrations were detected in the acute phase of illness than in conva lescent JE patients or normal healthy controls. Twenty-one of 25 patients w ith high concentrations of IL-8 showed significantly increased neutrophil c ounts in acute phase sera. A gradual decline in neutrophil counts was obser ved in the convalescent phase of patients who recovered. There was a signif icant correlation between IL-8 level and the severity of illness, as all se verely ill and fatal cases showed higher levels of IL-8 in acute CSF or ser um than the levels found in those who recovered. IL-8 concentrations remain ed high for a longer period in patients with prolonged severe illness than in those who made a complete recovery.