Researchers analyse why lupus affects more girls than boys

Researchers at UCL are coming closer to understanding why lupus, a rare disease of the immune system, affects more girls than boys.

The disease, which is often diagnosed around puberty, affects approximately 9 times as many girls as boys, but the reasons for this gender difference are not fully understood.

Previously, researchers had suspected that lupus was linked to oestrogen, the main female sex hormone.

However, analysis now being done at the Arthritis Research UK Centre for Adolescent Rheumatology at UCL, which is directly supported by the BRC, suggests that the number of X chromosomes may be more important than hormones in explaining the difference.

Lead UCL researcher, Dr Kate Webb, who received funding for the work from Action Medical Research, said:

‘A key question we have asked is, does lupus develop more frequently in girls because they have higher levels of oestrogen – or because they have two X chromosomes? Before, the thinking was that lupus was linked to hormones, but hormone treatments didn’t affect lupus. Now, we’re also looking at chromosomes and the role they play.’

The researchers, who are working with 190 young people aged 6-18, are also looking at the immune system response of girls and boys in relation to lupus.

Researchers are looking specifically at a mechanism called the interferon response, triggered through the immune system when the body detects a virus.

In patients with lupus, this mechanism is triggered when it shouldn’t be, and as a result the immune system attacks parts of the body – such as the skin, blood, brain, joints, kidneys, lungs and heart – by mistake.

This is the first time that research has looked at the interferon response of children before they reach puberty in relation to lupus, and the UCL team are looking at whether this immune system response is higher in girls than boys. Dr Webb explained:

‘The assumption was that the interferon response of boys and girls was the same before puberty – but we are testing if this is true. If girls’ interferon response is higher than that of boys, we are hopeful that this may help explain why girls are more likely to develop lupus.’

Because of the number of parts of the body lupus can affect, symptoms of the disease vary, but they range from skin rashes, fever and fatigue to arthritis, low blood counts, kidney problems, headaches and seizures.

Whilst medication can help, they often cause side effects, such as weight gain, tiredness and susceptibility to infections. At present, there is no cure for the disease.

Researchers hope that their work will lead to more specific treatment options for lupus, as well as help explain why the disease develops. Dr Webb said:

‘No-one has ever been able to tell a teenage girl why she’s more likely to develop lupus, or why it may attack at puberty. That’s difficult for a young person to deal with. We urgently need to be better able to understand and ultimately treat lupus in young people.’