Serum and cerebrospinal fluid cytokine profile of patients with 2009 pandemic H1N1 influenza virus-associated encephalopathy

Purpose: Since April 2009, the number of patients with 2009 pandemic H1N1 influenza virus infection has been increasing in Japan just as in the rest of the world. Patients with 2009 pandemic H1N1 influenza-associated encephalopathy (pIE) have also been reported. The common clinical symptoms of this condition are seizures and progressive coma with high-grade fever. We previously reported the possible association between seasonal influenza-associated encephalopathy (sIE) and proinflammatory cytokines. However, the pathogenesis of pIE remains to be elucidated. Results: In PIE patients with a poor outcome, the serum levels of interleukin (IL)-6, IL-10, and soluble tumor necrosis factor (TNF) receptor (sTNFR1) were significantly higher than those in pIE patients without neurological sequelae. Similarly, the cerebrospinal fluid (CSF) IL-6 levels in pIE patients with a poor outcome were significantly higher than those in pIE patients without neurological sequelae. Conclusion: Our results suggest that IL-6, TNF-alpha, and IL-10 play important roles in PIE, and that the serum levels of IL-6, IL-10, and sTNFR1 and the CSF levels of IL-6 are related to neurological complications. (C) 2011 Elsevier Ltd All rights reserved.