Groundbreaking study reveals the cause of multiple sclerosis

Multiple sclerosis (MS) is a progressive disease that affects 2.8 million people worldwide and for which there is no definitive cure. (CREDIT: Creative Commons)

According to a study by the Harvard School of public health researchers.

“The hypothesis that EBV causes multiple sclerosis has been explored by our group and others for several years, but this is the first study to provide conclusive evidence for a causal relationship,” said Alberto Asquerio, professor of epidemiology and nutrition at the Harvard Chan School and Sr. author of the study. study. “This is a big step because it suggests that most MS cases can be prevented by stopping EBV infection, and that targeting EBV could lead to the discovery of a cure for MS.”

MS is a chronic inflammatory disease of the central nervous system that affects the myelin sheaths that protect neurons in the brain and spinal cord. Its cause is unknown, but one of the main suspects is EBV, a herpes virus that can cause infectious mononucleosis and causes a lifelong latent infection of the host.

Establishing a causal relationship between the virus and the disease is difficult because EBV affects approximately 95% of adults, multiple sclerosis is a relatively rare disease, and symptoms of multiple sclerosis begin approximately ten years after EBV infection.

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To determine the link between EBV and MS, researchers conducted a study of more than 10 million active-duty youths in the US military and identified 955 individuals who were diagnosed with MS during their service.

The team analyzed biennial serum samples taken by the military and determined the soldiers’ EBV status at the time the first sample was taken, as well as the relationship between EBV infection and the onset of multiple sclerosis during active service.

In this cohort, the risk of MS increased 32-fold after infection with EBV, but did not change after infection with other viruses. Serum levels of neurofilament light chain, a biomarker of nerve degeneration typical of MS, only increased after EBV infection. The findings cannot be explained by any known risk factor for multiple sclerosis and suggest that EBV is the underlying cause of multiple sclerosis.

Study results table: DoDSR residual serum samples were obtained from 810 MS patients and 1577 matched controls. We assessed whether people were EBV and CMV seropositive with three serum samples per person. We measured sNfL in those who were EBV negative in the first serum sample. VirScan has been used to profile the virome in a subset of MS cases with serum samples collected shortly before and after symptom onset. (CREDIT: Longitudinal analysis shows high prevalence of Epstein-Barr virus associated with multiple sclerosis research)

Ascherio says that the delay between EBV infection and the onset of multiple sclerosis may be partly due to the fact that symptoms of the disease are not detected at the earliest stages, and partly due to the developing connection between EBV and the host immune system, which is repeatedly stimulated whenever latent the virus is reactivated.

Serum levels of neurofilament light chain, a biomarker of nerve degeneration typical of MS, only increased after EBV infection. (TEACHER: Harvard University)

“Currently, there is no way to effectively prevent or treat EBV infection, but an EBV vaccine or exposure to the virus with EBV-specific antiviral drugs may eventually prevent or cure multiple sclerosis,” Ascherio said.

Recent developments or new treatments for multiple sclerosis

Bruton’s tyrosine kinase inhibitor (BTK) is a new therapy being studied in relapsing-remitting multiple sclerosis and secondary progressive multiple sclerosis. It works by predominantly modulating B cells and microglia, which are immune cells in the central nervous system.

Stem cell transplantation is a therapy that destroys the immune system of a person with multiple sclerosis and then replaces it with transplanted healthy stem cells. Researchers are still investigating whether this therapy can reduce inflammation in people with MS and help “reboot” the immune system. Possible side effects are fever and infections.

Researchers will learn more about how existing DMTs work to reduce relapses and reduce brain damage associated with multiple sclerosis. Further research will determine whether treatment can delay the disability caused by the disease.

Symptoms of multiple sclerosis

According to the Mayo Clinic, the signs and symptoms of multiple sclerosis can vary greatly from person to person and depending on the course of the disease depending on the location of the affected nerve fibers. Symptoms often affect movement, such as:

• Numbness or weakness in one or more limbs, which usually occurs on one side of the body at a time or in the legs and trunk.

• An electric shock sensation that occurs with certain movements of the neck, especially when the neck is tilted forward (Lhermitte’s sign).

• Tremor, incoordination, or unsteady gait

Vision problems are also common, including:

• Partial or complete loss of vision, usually in one eye, often with pain on eye movement

• Prolonged double vision

• blurred vision

Symptoms of multiple sclerosis may also include:

• Slurred speech

• Fatigue

• Dizziness

• Tingling or pain in body parts

• Problems with sexual function, intestines and bladder

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Note. Materials provided above by the Harvard T. H. Chan School of Public Health. Content can be edited for style and length.

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