test

[Guest guest]

Non-Invasive MS Test Proposed

by C.

Article Date: 06-24-05

Doctors in a new preliminary study are proposing a non-invasive way to measure disease activity in people with multiple sclerosis.1 They contend that tests to determine the presence of MS can be just as effective by collecting samples of saliva as they are collecting samples of cerebrospinal fluid (as in a spinal tap).

Why Saliva Testing?

Saliva contains a substance known as human leukocyte antigen, or HLA. This substance, also found on the surfaces of blood cells, alerts the immune system to respond when foreign invaders (like viruses or bacteria) enter the body. The immune system subsequently fights off these disease-causing organisms.2 But HLA levels can also be found in urine, tears, and the sweat of healthy people.3

However, based on other research, the investigators in this study suggest that HLA activity is altered in people diagnosed with MS. Magnetic resonance imaging (MRI) scans have revealed fluctuations in blood and spinal fluid levels of HLA, they contend.

"Theoretically, we would expect that measurement of [levels of] HLA in cerebrospinal fluid would be most likely to reflect central nervous system disease activity, if indeed such measurement could serve as a monitor of a disorder such as MS," wrote Irena Adamashvili, PhD, in the department of Neurology at the Louisiana State University Health Sciences Center, and her colleagues. "However, cerebrospinal fluid exams are invasive and not without potential complications."Thus, the researchers wanted to determine if measuring levels of HLA in saliva would be just as effective as a test for MS by similarly demonstrating disease activity.

Comparing Saliva Testing to Spinal Tap

They enrolled 13 people who'd been diagnosed with relapsing-remitting multiple sclerosis for the research along with 53 healthy people whom they assigned to a comparison group. Saliva samples were then collected from each patient and stored for testing. As a comparison, spinal fluid was also collected from each patient via spinal tap. Each study participant also underwent MRI exams. Patients with MS were then assigned to two sub-groups of those with and without brain lesions as seen on MRI scans.

When the test results were analyzed, all healthy patients had measurable HLA levels, wrote Adamashvili and her team wrote. In five patients, HLA could not be measured. By comparison, in the 13 patients with MS, HLA levels in saliva could also be measured. Though the levels varied by individual, the researchers established that they were equivalent to those seen in cerebrospinal fluid samples taken.

The investigators then compared the test results of HLA taken from saliva and from spinal fluid in the two subgroups of patients with and without MS-related brain lesions. These "revealed no significant cerebrospinal fluid or saliva differences," they wrote.

Based on these findings and those of other studies, Adamashvili's group concludes that the presence of HLA likely has some connection to an associated disease, such as MS. But whether these levels are indicative of the presence of MS needs to be studied further. "It remains to be determined in which body fluids soluble HLA production reflects immunoreactivity, if indeed this is the case," they stressed.

One question to be answered is whether this substance is a marker of immune system activity related to MS, or may be linked to the activity of the disease itself, the study team emphasized.

In the meantime, testing for the presence of the marker in saliva "may be a potential noninvasive" way to help doctors diagnose diseases of the central nervous system like MS, they concluded.

Immune System Connection to MS?

Multiple sclerosis is thought to be an autoimmune disease. For unknown reasons, it's believed the cells of the immune system, which normally target disease-causing organisms in the body, instead go after areas of the central nervous system. A primary target is a fatty substance known as myelin, whose main function is to protect nerve endings and help them communicate. But when myelin is stripped away, the nerve endings are left bare and vulnerable. When this happens, the symptoms of MS, such as dizziness, pain, and spasticity, begin to appear.4

It's estimated that 400,000 Americans have been diagnosed with the disease. Each week, an additional 200 are added to that number, experts estimate.5

1. Adamashvili I, Minagar A, -Toledo E, Featherston L, Kelley RE. Soluble HLA measurement in saliva and cerebrospinal fluid in Caucasian patients with multiple sclerosis: a preliminary study. J Neuroinflammation 2005 Jun 2;2(1):13 [Epub ahead of print].

2. Merck Manual. Immune Disorders. Biology of the Immune System. Available at: http://www.merck.com/mmhe/sec16/ch183/ch183a.html?qt=human%20leukocyte%20antigen & alt=sh. Accessed Jun 17, 2005.

3. Aultman D, Adamashvili I, Yaturu K et al. Soluble HLA in human body fluids. Hum Immunol 1999 Mar;60(3):239-44.

4. National Multiple Sclerosis Society. What is MS? Available at: http://www.nationalmssociety.org/What%20is%20MS.asp. Accessed June 17, 2005.

5. National Multiple Sclerosis Society. Who Gets MS? Available at: http://www.nationalmssociety.org/Who%20gets%20MS.asp. Accessed June 17, 2005.

is a long-time health journalist and an editor for Priority Healthcare. His credits include overseeing health news coverage for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.