Cervical lymph nodes give new information on the mechanisms of MS

Researchers at HUS Helsinki University Hospital and the University of Helsinki are the first in the world to publish research data in which cell samples from the cervical lymph nodes of MS patients were collected early in the diagnosis stage. The samples were examined by single-cell sequencing, in which the phenotype of individual cells is analyzed. Significant abnormalities were found in the subgroups of B cells of the patient samples, which also showed signs of alterations caused by an active Epstein Barr virus infection.

In 2022, it was found that an Epstein Barr virus infection is a prerequisite for the outbreak of MS. This common virus remains on the B lymphocytes for life, but only a small percentage of those who have contracted the virus develop MS. In particular, the risk of MS is related to being exposed to the virus only during puberty or as a young adult, in which case it causes mononucleosis.

MS has traditionally been studied by searching for immune defense cells in blood samples and cerebrospinal fluid samples, but these methods have so far not provided crucial information for understanding the disease mechanism.

New opportunities for developing pharmacotherapy from research data 

The autoimmune response of MS, meaning an attack on the brain and spinal cord, is believed to occur in the deep cervical lymph nodes. In this study, a subgroup of B cells was found in the deep cervical lymph nodes, which is larger in patients with MS than in healthy patients.

"The subgroup appears to be altered by the Epstein Barr virus infection. This is new knowledge. The key to recognizing it was studying the virus and immune defense in lymph nodes, where their interaction usually takes place in the body,” says Joona Sarkkinen, doctoral researcher at the University of Helsinki.

The glymphatic circulation of the brain transports the broken-down structures of the central nervous system to the deep cervical lymph nodes, where they are presented to the immune system.

"Based on our results, it would be interesting to plan pharmacotherapy that only targets this subgroup of B cells. Pharmacotherapies that destroy B cells are very effective in MS, but they also expose the patient to infections. Precise treatment that saves the normally functioning immune system and focuses only on the abnormal part of the immune system would be useful for patients, since MS often emerges in young adulthood and patients need treatment for decades," says Associate Professor, Neurologist Sini Laakso, who led the study, from HUS Neurocenter and the University of Helsinki.

Moving forward, the aim is to verify the results in a larger patient group and find out how the medication for MS affects the findings. 

"Our research encourages the application of well-known research methods to new fields. Examining MS from cervical lymph nodes using fine needle aspirations provides a new perspective on understanding the mechanisms of this complex disease. Previously, MS was mainly studied using animal models, in which the central link between the disease and B cells was not observed, for example,” Laakso says. 
 
Research article reference:  Altered Immune Landscape of Cervical Lymph Nodes Reveals Epstein-Barr Virus Signature in Multiple Sclerosis. Science Immunology, published on 21 February 2025.

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