New research may one day lead to diagnosis of MS through a simple blood test
December 2, 2003
D M Pizzi
Real Living with Multiple Sclerosis
CAN A ROUTINE BLOOD TEST allow clinicians to positively diagnose individuals with MS in the near future? The short answer, based on newly published research, is "quite possibly."
Austrian researchers believe they may have found a clinical predictor of MS in the form of two antibodies that can be easily detected in the blood. Published in the july 9 issue of The New England Journal of Medicine, results of this research are preliminary but offer hope that a much quicker diagnostic technique for MS may some day be available.
"Speeding the diagnosis of MS is an important and necessary goal," according to the National Multiple Sclerosis Society (NMSS), which issued a research bulletin describing the study results. The bulletin stressed that the study's findings have yet to be confirmed, adding that "the practical implications of this study and the potential for influencing early diagnosis or treatment remain to be determined."
Why Early Diagnosis Is Important
Presently, an MS diagnosis requires proof that two neurologic events (an initial event and a relapse) occur in which "inflammation and loss of myelin in the brain and/or spinal cord" is evidenced, according to the NMSS. These events must be separated "in time and location." The majority of individuals who develop MS (about 90%) initially show signs of a "clinically isolated syndrome," characterized by symptoms typical of MS related to pathology in one area of the central nervous system (brain, spinal cord, or optic nerves). Many of these patients also show multiple brain lesions on a magnetic resonance imaging scan performed at that time, increasing the likelihood of the subsequent diagnosis of MS. Not all individuals experiencing this isolated event, however, will go on to develop MS.
The problem is that it's hard to predict who in this group will develop full-blown MS and who won't. The ability to make such a prediction accurately would allow persons who are most susceptible to developing definitive MS to begin early disease-modifying drug treatment, participate in counseling, and better adjust to living the rest of their lives with a chronic disease. In contrast, knowing those who are less likely to develop the disease would permit the avoidance of pharmacotherapy, which is costly and may cause side effects.
The actual mechanisms that cause a clinically isolated syndrome to develop definitive MS aren't known, but it's understood that in MS, myelin, a protective tissue covering nerve fibers, is damaged. Researchers in the current study decided to determine if the presence of two antibodies that attach to components of myelin-myelin basic protein and myelin oligodendrocyte glycoprotein-in persons experiencing the clinically isolated syndrome was a risk factor for the development of subsequent MS.
The study included 103 individuals (70 of whom were female) diagnosed with a clinically isolated syndrome. Blood samples were drawn and neurologic examinations were performed on each subject at baseline. Then, neurologic examinations were performed on each subject every 3 months to determine if individuals progressed to clinically definitive MS. Each study participant was followed for at least 12 months and didn't receive any disease-modifying MS drug treatments from the start of the study to the diagnosis of definite MS. all of the 103 subjects were included in the final analysis of the trial.
A total of 22 patients tested positive for both antibodies. Of those individuals, 21 (95%) experienced the second clinical event needed to definitively diagnose MS, whereas only 9 of 39 patients who did not have either of the proteins (38%) did so. A total of 42 patients tested positive for one antibody and of those, 35 (82%) suffered a relapse. Moreover, those individuals who tested negative for both antibodies but eventually experienced a second clinical event that led to an MS diagnosis did so after a much longer time frame (a mean of 45 months) than did individuals with both antibodies (a mean of 7.5 months). "Antibody status," the researchers concluded, "may therefore identify, at the onset of disease, the patients who are likely to have a relatively benign course of disease."
Cause for Hope
In an accompanying editorial, Jack P. Antel, MD, and Amit Bar-Or, MD, of the McGiIl University in Montreal, Canada, applauded the researchers' efforts. "The findings of the study," they wrote, "once confirmed, will improve the quality of the diagnostic and prognostic information that can be used to guide treatment." Like the researchers, they stressed that treatment with MS disease-modifying drugs has "a greater, albeit limited, efficacy if begun early."
Advisory Board note: These results, if confirmed, might lead to the development of commercially available tests that would identify those at-risk patients with clinically isolated syndromes who are especially likely to develop clinically definite MS in the near future. The study does not, however, have any direct implications for people with established MS. Further studies about antibody status might explore issues such as the ability to predict or monitor treatment response in such patients.
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Berger T, Rubner P, Schautzer F, et al. Antimyelin antibodies as a predictor of clinically definite multiple sclerosis after a first demyelinating event. N Engl J Med. 2003;349:139-145.
Egg R, Reindl M, Deisenhammer F, Linington C, Berger T. Anti-MOG and antiMBP antibody subclasses in multiple sclerosis. Mult Scler. 2001;7:285-289.
National Multiple Sclerosis Society, www.nationalmssociety.org
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