Currently, MS cannot be diagnosed with a simple blood sample or any other type of test, which can greatly delay its identification for a disorder that relies on early intervention.
Researchers from the Johns Hopkins University in Baltimore, analysed samples of cerebrospinal fluid (CSF) from 29 people with MS or pre-MS symptoms, and found the protein, 12.5 kDa, present in about two-thirds of the patients.
The investigators used SELDI-time-of-flight mass spectroscopy that can find one specific protein in a complex mixture based on its weight. CSF was analysed instead of blood samples because CSF better represents local events in the brain than does blood, according to Dr. Avindra Nath, the study's author.
"And the high concentrations of many proteins in the blood can mask proteins that might be biomarkers for MS," he added.
The scientists demonstrated that 12.5 kDa is a breakdown product of a larger protein called cystatin C, which blocks the activity of some enzymes, including cathepsin B.
Cathepsin B has been linked to the demyelination (nerve sheath destruction) that occurs in sufferers.
"There is the possibility now that the protein we identified can be used to diagnose MS, perhaps in its earliest stages, and also to monitor treatment by measuring its levels in cerebrospinal fluid," said Dr. Avindra Nath, the study's author.
About 10,000 Americans, mostly women, are diagnosed with MS each year. The disease causes muscle weakness, numbness, loss of muscle coordination, and problems with speech, vision and bladder control.
In people with MS, the immune system destroys myelin, the covering of the nerves that helps transmit signals.
Currently there is no cure for MS. However, there are treatments available that may slow its progression and alleviate associated symptoms.
Medications that target the body's immune system may decrease the frequency and duration of attacks. These medications can be used on a long-term basis and also to treat specific attacks. Additional medications may be prescribed for other symptoms such as pain or depression.
Interferon beta-1a (Avonex or Rebif) and interferon beta-1b (Betaferon) are used for some people who have the relapsing and remitting form of the disease. They are not effective for everybody, and some people experience side effects such as irritation at the injection sight, flu-like symptoms, diarrhoea and insomnia.
Glatiramer acetate (Copaxone) injections can reduce the frequency of attacks of MS. It can be prescribed for some people with relapsing-remitting MS or secondary progressive MS.
The research, reported in the February issue of the >Annals of Neurology.