A rare, and potentially fatal condition, aHUS, mystified doctors for years. Today, thanks to patient support, the outlook for sufferers is much more hopeful.
With just 210 diagnosed cases in the UK, atypical haemolytic uraemic syndrome (aHUS) is an extremely rare condition that causes kidney failure. It is distinct from the more common form of haemolytic uraemic syndrome, which is caused by some types of E. coli.
If patients around the country hadn’t donated their DNA, we’d be none the wiser.
With symptoms including tiredness, headache and decreased urine output, aHUS is difficult to diagnose and, until recently, even harder to treat.
“The problem was, we didn’t know what caused the condition,” says Professor David Kavanagh, Consultant Nephrologist at the National Renal Complement Therapeutics Centre (NRCTC). “If patients around the country hadn’t donated their DNA, we’d be none the wiser.”
Genetic faults cause patients’ bodies to attack themselves
In 1998, after studying samples from aHUS patients, the team at the NRCTC discovered the condition was linked to the body’s complement system – part of the immune system that fights infection.
“Over 60 per cent of patients who had aHUS have a genetic fault that prevents them from producing the protector proteins,” explains Kavanagh. “As a result, the C3 attacks their own cells.” As complement attacks the body’s own cells, especially those that line the blood vessels, it leads to clots in the filters of the kidney, putting the patient at risk of kidney failure.
Until recently, the outlook for patients with aHUS was bleak. There was no cure and a kidney transplant wasn’t usually possible as the disease would attack and destroy the new kidney. A lifetime on dialysis was the only option.
A new drug overrides the body’s self-destructive gene
However, in 2011 fresh hope was given when a monoclonal antibody was licenced to treat aHUS patients. The drug works by blocking the complement system and therefore preventing it from damaging the body’s own cells.
Suppressing the immune system means the drug needs to go hand in hand with antibiotics.
“Initially patients receive it every week and then every two weeks,” says Kavanagh. “It has revolutionised the management of the condition. Eculizumab usually prevents patients developing kidney failure and allows patients already on dialysis to receive a kidney transplant without a recurrence of disease.”
Although very effective, Eculizumab does suppress the immune system leaving patients susceptible to infections, such as meningitis, and the patients therefore need vaccinations and life long antibiotics to prevent this.
aHUS is an inherited condition
As with many medical intervention – the sooner treatment can begin the better. “Because it is an inherited condition, relatives of aHUS patients with complement mutations may be at risk of disease. We can now see all relatives and perform tests to see if they are at risk of disease too. If they are we will give them an aHUS at-risk card” says Professor Kavanagh. “If they feel unwell they can go straight to their GP, who can give them a simple blood test and, if they are abnormal, they’ll give us a ring so we can treat them early, thus preventing kidney failure.
The same patients who played a critical role in the research which ultimately resulted in a treatment for aHUS are now playing a pivotal role in protecting their family members. By asking them to get tested and bringing them to aHUS roadshows to learn about the early symptoms of disease, treatment can be initiated early to prevent kidney failure when the disease strikes.
To learn more visit the NRCTC website
