The test is based on the widely held theory that multiple sclerosis is an autoimmune disease. Somehow, the theory goes, the body starts to consider nerve cells to be dangerous enemies. It then attacks, destroying nerve cells' insulating myelin sheaths and, eventually, the nerves themselves.
Aristo Vojdani, PhD, of ImmunoSciences Lab Inc., in Beverly Hills, Calif., suggests that something happens in the earliest stages of multiple sclerosis. Broken-up pieces of nerve cells -- neural antigens -- enter the blood stream. The immune system sees these antigens as foreign material and attacks them. Unfortunately, this teaches them to attack healthy nerve cells as well.
The idea is to collect immune cells from people who might have MS. If these immune cells get ready for an attack when they are exposed to neural antigens, the chances are good that this person has MS.
His team tested this idea in 20 multiple sclerosis patients and in 20 healthy people for comparison. Blood cells from 30% of the comparison group and from 80% of the multiple sclerosis patients reacted to the neural antigens. The researchers report their findings in the October issue of the Journal of Internal Medicine.
Calculations showed that the test -- a combination of three kinds of neural antibodies -- has a sensitivity range of 60% to 80% and a specificity range of 65% to 70%. This means that if the test were given to 10 patients with multiple sclerosis, it would diagnose the disease in six to eight of the patients. If the test were given to 10 people who did not have multiple sclerosis, it would incorrectly say that three or four of them had the disease.
That's not good enough for a stand-alone diagnosis. But multiple sclerosis diagnosis is quite difficult. It depends on clinical indications, a costly MRI brain scan, analysis of cerebrospinal fluid, and a test of nerve responses. Not all patients show abnormalities on all these tests. The new blood test, it's hoped, will help doctors make this diagnosis more quickly.