This finding could help identify those at high risk of severe infection and help prioritise those in highest need of treatment. Results are published today in Nature Communications.
The study, led by Dr Tao Dong, showed that having this variant in your genetic make-up could increase your chances of severe infection by six times. The variation rs12252-C is occasionally found in Caucasian populations (in around 1 in 3,000 people) and was already known to be associated with more severe influenza. The teams in the UK and China focussed on this variation as it is 100 times more common in Han Chinese, the predominant ethnic group in China. The results showed that it was present in 69 per cent of Chinese patients with severe pandemic (swine) influenza in 2009 compared with 25 per cent who only had a mild version of the infection.
Lead author, Dr Tao Dong at the MRC Human Immunology Unit, Oxford University, says:
“Understanding why some people may be worse affected than others is crucial in improving our ability to manage flu epidemics and to prevent people dying from the virus. Previous studies had shown genetic variant was associated with severe influenza infection in Europeans, but this variant is extremely rare in Europeans. We became interested in this because we noticed it is 100 times more common in China. It’s vital that we continue to fund research that examines flu infection, from the smallest details of our genetic code and in the populations around the world that continue to be vulnerable to infection.”
Co-author, Professor Andrew McMichael at the MRC Human Immunology Unit, Oxford University, adds:
“The apparent effect of this gene variant on the severity of influenza is of great interest. It remains to be seen how this gene affects the whole picture of influenza in China and South East Asia but it might help explain why new influenza viruses often first appear in this region of the world.”
The original work on the genetic variation rs12252-C and flu severity was carried out by Professor Paul Kellam at the Wellcome Trust Sanger Centre in Cambridge and Professor Peter Openshaw at Imperial College London. The work was supported by the Medical Research Council, Wellcome Trust Sanger Institute, the Beijing Natural Science Foundation, Beijing Municipal Science and Technology Commission, National S&T Major Project for Infectious Diseases Control, Beijing Youan Hepatitis/AIDS Foundation and the National Natural Science Foundation of China.