First evidence of a pro-inflammatory response to severe infection with influenza virus H1N1

Abstract

The great majority of infections caused by the pandemic variant of the infl uenza virus (nvH1N1) are self-limited, but a small percentage of patients develop severe symptoms requiring hospitalization. Bermejo-Martin and colleagues have presented a pilot study describing the diff erences in the early immune response for patients both mildly and severely infected with nvH1N1. Patients who develop severe symptoms after nvH1N1 infection showed Th1 and Th17 'hypercytokinemia', compared to mildly infected patients and healthy controls. The mediators involved with the Th1 and Th17 profi les are known to be involved in antiviral, pro-infl ammatory and autoimmune responses. This is the fi rst work reporting the association of a pro-infl amatory immune response with a severe pandemic infection, although it is likely that more studies are needed to understand the detrimental or benefi cial roles these cytokines play in the evolution of mild and severe nvH1N1 infection. © 2010 BioMed Central Ltd.