Virus specific memory T cell responses in H5N1 avian influenza virus infected patients

The aim of this study is to study how the human body can respond to avian influenza virus infection, focusing specifically on white blood cells (called killer T-cells) that kill influenza-virus-infected cells. We will ask how big are these T cell responses and do they react only to avian virus or will people whose T-cells recognise the common flu strains have some protection against avian flu? Do these T-cell responses play a part in protecting people who have been exposed to avian flu but who did not become sick? Or is there a possibility that having T-cell immunity to the more common influenza virus strains could actually cause disease in people who are exposed to avian strains of influenza A virus?

The threat of H5N1 avian influenza infection in humans has become a serious concern. In this study we intend to measure the H5N1 avian influenza virus specific T cell responses and cross reactive T memory cell responses in both acute and convalescent patients in Vietnam. We will monitor the functional changes in T cell memory pools longitudinally, and to study if the quality of the dominant T cell responses has an impact in clinical outcome of H5N1 human infection. We will also examine T cell responses in people who have been exposed to avian influenza virus but who have apparently been not ill, looking for evidence of subclinical infection.