Flu in your Genes

It's the time of year for sniffles, and many of us tell the boss we're laid up with flu when we've just got a bad cold. But flu can kill, though it usually targets the very young and very old. Every so often we get an epidemic of flu, such as the one in 1918, that kills millions of people of all ages around the world. And doom-mongers are predicting another flu epidemic, which could be the dreaded bird flu. But why does flu kill some people and not others? Researchers at the Southern Illinois University School of Medicine in the States are trying to find out, by studying genes involved in making the immune system respond to flu attacks. The team studied two different genetic strains of mice who had been given a dose of flu, and found that the immune response in the two types of mice was different, and they activated different genes in their lung cells. The mice that mounted a bigger immune response were more likely to die from flu than the hardier strain. So this suggests that it's crucial genetic differences between the two strains that are responsible for determining whether the mice are likely to die from the flu. And because we're very similar to mice (some of us more so than others), it's likely that similar genes will be at work in us too.