New study explains 'man flu' and why men can get sicker from viruses than women
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Most men have probably been accused of coming down with 'man flu' at one time or another, with even your (so-called) best of friends and loved ones not entirely convinced by the severity of the illness that you claim to be suffering from.
The judgement can be even worse if a wife, girlfriend or female mate has recently got over that same illness with fewer complaints, meaning that not only are you ill, but you're now being accused of being 'dramatic' every time you mention it.
Lads have put up with the accusations for years, but it turns out there might actually be some science on mens' side.
In a new study, researchers at the University of California, Los Angeles (UCLA) spotted a possible difference between men and women's immune systems which might explain why women react better to certain illness.
The findings stem from the fact women have two X chromosomes; a chromosome which contains the gene and protein UTX.
UTX is important for the function of natural killer (NK) cells, which form the first line of defence in the body against invading viruses or illnesses.
As women have two X chromosomes, the genes in one are mostly switched off - a process called X-chromosome inactivation. But they're not switched off entirely, and as women have two X chromosomes, they therefore have more UTX working for them in the NK cells.
Scientists have previously found that men often have more NK cells than women, but the new research indicates that strength may be more important than quantity.
Dr Maureen Su, who participated in the study, said: “It turns out that women have more UTX in their NK cells than men, which allows them to fight viral infections more efficiently."
The scientists used mice to help with their research, noting that male mice with more natural killer cells reacted more weakly to threats than female mice.
Researchers also edited the mice to remove UTX completely, and found that these mice died from viral infections.
“Just knocking out one gene was the difference between whether the mice survived or died in this model,” Erik Dissen, professor and immunologist at the University of Oslo, explained.
So, is man flu a real thing? Dissen suggested it just might be.
“The term ‘man flu’ is a slightly sarcastic term suggesting that men are more whiny when they get sick," he said. "However, it is actually possible to measure systematic differences if you look at enough women and men and how they respond to viral infection.
"Signalling substances in the blood are one way to do this. Then you can see differences. It looks like men produce a little more of the substances that cause fever and make you feel ill.”
However, that's not to say men will always get sicker than women, as Dissen noted: “Individual differences include a whole lot of genes that have nothing to do with gender - like environmental factors."
Dissen also said women appear to be more susceptible to autoimmune diseases than men.
It's too early at the moment to say whether the findings from the experiments with mice definitely translate to humans, or whether it could have an impact on treatment, but Dissen has noted that such research 'helps us understand the variation between men and women'.