Research RoundUp 41

as at 30 November 2007

T-cell clones in MS

In MS, T-cells attack the brain and the spinal cord. It is known that often particular T-cell clones are expanded in the target tissue, but it is still not known whether identical T-cell clones are present at distinct anatomical sites, or whether the T-cell spectrum is locally diverse.

This study compared the T-cell receptor repertoire in distinct lesions and normal-appearing white matter from post-mortem brains of four MS patients. Each of the four patients had distinct T-cell clones that were present in more than two anatomically distinct regions. These clones were not restricted to lesions, but were also present in white matter. Some clones were present in all investigated lesions, and additionally, in white matter. A single T-cell clone was detected in nine different sites in one patient.

They found that pervasive T-cell clones exist in distinct regions of an MS affected brain, and that they are unique to individual patients.

Reference: Junker, A. et al. (2007) Multiple sclerosis: T-cell receptor expression in distinct brain regions Brain. 2007; 130(11): p. 2789-2799

Source full text of article: http://brain.oxfordjournals.org/cgi/content/abstract/130/11/2789?ct

Eye properties of those with MS examined

Researchers in this study used optical coherence tomography (OCT) to examine the retinal nerve fibre layer thickness, macular* volumes and visual acuity in the eyes of people with MS, with and without history of acute optic neuritis (ON).

They found that retinal nerve fibre layer and macular volumes were decreased in the eyes of those with and without ON from MS, and also that progressive MS cases showed more marked decreases in both measures than relapsing-remitting MS.

* The macula is part of the human eye that regulates clarity of vision

Reference: Pulicken, M. et al. (2007) Optical coherence tomography and disease subtype in multiple sclerosis. Neurology 27 Nov 2007 69(22): p. 2085.

Source full text of article: http://highwire.stanford.edu/cgi/medline/pmid;18040015

Reliability of reported MS prevalence rates

These researchers suggest that the review of recent medical literature raises doubts about the reliability of reported MS prevalence rates.

“Many published prevalence rates are inflated. Some studies have shown that relying on clinical information and MRI interpretation leads to one third of incorrect MS diagnoses.”

They suggest that “the most important error is failing to distinguish between the clinical and MRI characteristics of MS and of disseminated encephalomyelitis (DEM) in both their acute and relapsing forms.”

“The diagnostic criteria in current usage, including those relating to imaging, do not differentiate between MS and other recurrent inflammatory demyelinating diseases of the central nervous system.”

“Considering a second demyelinating episode following a clinically isolated symptom or acute DEM, as confirming MS, is another major source of error. Another is including cases with onset before they entered the study group or moved to the geographic area.”

Neuromyelitis optica (NMO) has long been considered an MS variant and in Far Eastern countries it is counted as the 'oriental' form of MS, falsely inflating prevalence rates of MS in those areas. Recent immunologic and radiologic evidence shows that at least some NMO cases represent instances of DEM.

Reference: Poser C. and Brinar V. (2007) The Accuracy of Prevalence Rates of Multiple Sclerosis: A Critical Review. Neuroepidemiology 27 Nov 2007 29(3-4): p. 150.

Source full text of article: http://highwire.stanford.edu/cgi/medline/pmid;18042998