The dose of worms that could cure MS
Published: March 25, 2008 | 6957th good news item since 2003
Could drinking a cocktail of worm eggs help patients with multiple sclerosis? It sounds like medieval witchcraft, but the Food and Drug Administration, which vets all drug trials in the U.S., has just sanctioned a study to see if the gruesome mixture can ease the symptoms of the disease.
Once the eggs are inside the body, they will hatch into worms that live in the gut. It is hoped they will then stimulate the release of a certain type of immune system cell that will allow the body to heal the damage done by MS.
The trial was given the go ahead after a study last year in Argentina revealed that MS patients who had parasitic worms living in their intestines suffered significantly fewer relapses in their condition than a separate group that was worm-free.
Multiple sclerosis affects an estimated 85,000 people in the UK and is incurable. The disease appears to be caused by a chemical found naturally in the body, called interferon gamma.
Under normal circumstances, this chemical helps to activate the immune system to attack foreign invaders, such as viruses and bacteria. But for reasons which remain unclear, in people with MS, the chemical can also cause the immune system to turn against the very body it is supposed to protect.
As a result, the immune system goes into overdrive, attacking nerves in the brain and spinal cord. Gradually, the protective coating which shields these nerves – called the myelin sheath – starts to break down and the transmission of signals between nerve cells slows down and becomes irregular.
As the nervous system begins to be destroyed, the first symptoms to appear are usually a loss of balance, blurred vision and bouts of paralysis. Eventually, most patients end up paralysed and in a wheelchair.
Drugs that suppress the immune system are often used to treat the condition. But these are not always successful and work only in certain forms of the disease.
The worm cocktail has already been tested in the U.S. for other ‘auto-immune’ conditions – diseases that arise when the immune system turns on itself.
Trials on patients with gut disorders such as Crohn’s have shown promising results.
The key is how the parasitic worms – called whipworms – trigger the release of T-cells, a vital part of the body’s defence mechanism.
When a healthy body is under attack, the immune system calls up a certain type of T-cell, known as Th2. This launches a targeted attack on the invading virus or bacteria, but leaves healthy tissue alone.
In MS, the immune system calls up a different type of Tcell, known as Th1. These cells attack and destroy healthy tissue, triggering the symptoms of MS.
Parasitic worms, such as whipworms, seem to trigger the relatively mild Th2 immune system response, stopping the release of Th1 cells. The response is also focused on the worms rather than the tissues – allowing the body gradually to repair some of the damage done by the previous Th1 cells.
As part of the trial, five MS patients will take a worm-egg cocktail every two weeks for three months. Each drink, which will be in the form of a flavoured sports drink to make it more palatable, will be packed with 2,500 whipworm eggs.
The eggs, which are taken from pigs and are not thought to harm humans, hatch into larvae that are no bigger than an eyelash.
They then stick to the inside of the gut. Because the worms are eventually destroyed by the immune system, the patient needs to take another dose.
If the worm trial succeeds, then a bigger study will take place next year.
This is not the only treatment using creepy-crawlies to be used in modern medicine. Last year a British lorry driver avoided losing his leg when leeches were used to help it heal after surgery.
Maggots, meanwhile, are being used to help wounds infected with the hospital superbug MRSA to heal in just three weeks – compared with 28 weeks with conventional treatment.
Dr Laura Bell, from the MS Society, warned that this treatment would not be a quick result: “There is some research to show parasites may offer protection in MS but this investigation is at a very early stage.”