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Researchers Find That Immune B Cells from People with MS May Harm Nerve Cells

SUMMARY:

  • Researchers co-funded by the National MS Society have found that immune B cells obtained from the blood of people with relapsing-remitting MS secrete products that can be toxic to nerve cells grown in lab dishes.
  • This study offers new insight into how B cells may contribute to nervous system damage in MS.
  • The team is now conducting further studies to identify the toxic factor or factors secreted by the B cells, and when and how they may act in people with MS, and to answer questions such as whether they are unique to MS, whether they are also evident in people with progressive MS.
  • Drs Robert P Lisak, Joyce Benjamins (Wayne State University), Amit Bar-Or (McGill University and currently at University of Pennsylvania) and colleagues published their findings in the Journal of Neuroimmunology (2017 Aug 15;309:88-99, published online May 17)

DETAILS
Background: While scientists still don’t know what causes multiple sclerosis, they do know that immune-system attacks are involved, resulting in damage to the myelin that insulates nerve fibers and to nerve cells and fibers themselves. Immune T cells have typically been named as culprits, but it has become clear that immune B cells, another type of white blood cell, are also involved in MS. Research and studies on B cells, including early studies supported by the National MS Society, eventually led to successful clinical trials and approval of Ocrevus™ (ocrelizumab – Genentech, a member of the Roche Group) to treat people with primary progressive and relapsing-remitting MS. Ocrevus depletes certain B cells.

The Study: The current study builds on the researchers’ earlier findings that B cells from the blood of people with relapsing-remitting MS – but not blood from healthy individuals – are toxic to certain cells that build myelin. In this study, the team isolated B cells in the laboratory from the blood of 13 women and men with relapsing-remitting MS who were not receiving disease-modifying treatment or recent steroids, and 13 controls without MS.

The researchers found that products released by B cells from the people with MS were toxic to both rat and human nerve cells grown in lab dishes, while cells from the controls did not incur the same damage. The nerve cells died from apoptosis – a type of self-destruct program – and not, as might be expected, from cell disintegration, or from immunoglobulins (antibodies) that have been identified as culprits in the MS attack.

Drs Robert P Lisak, Joyce Benjamins (Wayne State University), Amit Bar-Or (McGill University and currently at University of Pennsylvania) and colleagues published their findings in the Journal of Neuroimmunology (2017 Aug 15;309:88-99, published online May 17). This study was supported by the National MS Society (USA), the Research Foundation of the MS Society of Canada, and others.

Next Steps: This study offers new insight into how B cells may contribute to nervous system damage in MS. The team is now conducting further studies to identify the toxic factor or factors secreted by the B cells, and when and how they may act in people with MS. They are using “proteomics” for this work, advanced technologies the can identify and quantify numerous molecules simultaneously, along with other approaches. They also plan to answer questions such as whether the toxic B cells are unique to MS or are found in other immune mediated disease, which subsets of B cells produce the toxic effects and whether they are also evident in people with progressive MS.

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Learn more about research on the immune system in MS

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Dawson’s Fingers ???

“Dawson’s fingers” is the name for the lesions around the ventricle-based brain veins of patients with multiple sclerosis. The condition is thought to be the result of inflammation or mechanical damage by blood pressure around long axis of medular veins.

Dawson’s fingers spread along, and from, large periventricular collecting veins, and are attributed to perivenular inflammation.

Lesions far away from these veins are known as Steiner’s splashes.

Sometimes experimental autoimmune encephalomyelitis has been triggered in humans by accident or medical mistake. The damage in these cases fulfils all the pathological diagnostic criteria of MS and can therefore be classified as MS in its own right. The lesions were classified as pattern II in the Lucchinetti system. This case of human EAE also showed Dawson fingers.

Study suggests possible inside-out origin for MS

A new study suggests an inside-out theory of multiple sclerosis in which the disease may be triggered by the death of brain cells that make the insulation around nerve fibers, according to a new study from Northwestern Medicine and the University of Chicago researchers. Creating a mouse-model of progressive MS, scientists also used a specially developed nanoparticle that prevented MS even after the death of those brain cells.
The new study shows the possibility that MS can begin from the inside out, in which damage to oligodendrocytes in the central nervous system can trigger an immune response directly. Oligodendrocytes can possibly be destroyed by developmental abnormalities, viruses, bacterial toxins or environmental pollutants. Oligodendrocytes are responsible for the maintenance of myelin. If they die, the myelin sheath falls apart. The death of these cells can activate the autoimmune response against myelin, which is the main feature of MS. The inside-out hypothesis suggests that when myelin falls apart, the immune system interprets the products of its degradation as foreign bodies or antigens, erroneously viewing them as invaders and beginning a full-scale attack on myelin, initiating MS.
“Protecting oligodendrocytes in susceptible individuals might help delay or prevent MS from initiating. It’s likely that therapeutic strategies that intervene early in the disease process will have greater impact,” said Brian Popko, the Jack Miller Professor of Neurological Disorders at the University of Chicago and one of the lead investigators in the study.
The scientists also developed the first mouse model of the progressive form of the autoimmune disease, which will enable the testing of new drugs against progressive MS. In the study, nanoparticles creating tolerance to the myelin antigen were administered and prevented progressive MS from developing. The nanoparticles are being developed for clinical trials that could lead to new treatments – without the side effects of current therapies – in adults.
The study was published in Nature Neuroscience.

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