September 8th, 2003
Boston Cure Project
A recent development in MRI technology1 may soon allow doctors and scientists to monitor the infiltration of T cells into the brain in MS and other diseases. Although MRI technology is already very useful in identifying lesions, inflammation, and other features of MS, being able to monitor the presence of individual actors such as different types of cells and molecules would greatly illuminate such important but poorly understood subjects such as the sequence of events in MS and the mechanisms of action of disease-modifying drugs. Using MRI to detect cells would also allow the sequential monitoring of cells in an individual brain at different points in the disease progression -- currently cells can only be identified by removing brain tissue (via biopsy or autopsy in the case of humans), and this process of removal cuts off any possibility for ongoing study.
In this new technique, antibodies specific for an antigen present on the surface of T cells (CD4) are labeled with ultrasmall paramagnetic iron oxide particles, or USPIOs. When these are injected into a subject, the antibodies attach to T cells present in the body. If these T cells subsequently pass through the blood-brain barrier, they can then be detected via MRI because the iron particles affect the magnetic characteristics of their environment.
While this technique so far has only been used in animals, its creators
feel that it should be safe to use in humans because the USPIOs are biodegradable
and indeed are already approved for human use. If you're interested in
learning more, you can read the full-text of the article describing this
method by going to the publisher's web site, http://www.cmj.hr/index.php?D=/44/4/463,
and registering for free.
1. "Magnetic resonance imaging of immune cells in inflammation of central nervous system"
Pirko I, Ciric B, Johnson AJ, Gamez J, Rodriguez M, Macura S.
Croat Med J. 2003 Aug;44(4):463-8
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