A UCSF study finds that specific CD8+ killer T cells are more abundant in the cerebrospinal fluid of people with multiple sclerosis or early signs, suggesting these cells may drive the disease by targeting Epstein-Barr virus.

This clearer EBV–MS link supports ongoing antiviral and immune-based drug discovery, with broader implications for other EBV-associated autoimmune conditions such as lupus and rheumatoid arthritis.

Senior author Joe Sabatino, MD, PhD, notes that interfering with EBV could yield broad therapeutic benefits beyond MS and improve patients’ quality of life.

The study’s DOI is 10.1038/s41590-025-02412-3.

The article cites the full reference: Hayashi, F., et al. (2026). Antigen specificity of clonally enriched CD8+ T cells in multiple sclerosis, Nature Immunology, DOI: 10.1038/s41590-025-02412-3.

UCSF researchers conducted the study, published February 5, 2026 in Nature Immunology, with NIH funding support.

The Nature Immunology article is accessible at nature.com/articles/s41590-025-02412-3 and marks a 2026 publication.

The research was funded by multiple NIH grants and conducted by the UCSF MS-EPIC team and collaborators; the paper’s DOI is 10.1038/s41590-025-02412-3 and it was released on February 5, 2026.

MS is an autoimmune disease where the immune system attacks myelin in the brain and spinal cord, and historically CD4+ T cells were the main focus, while CD8+ T cells have been harder to study in patients.

Although EBV is carried by about 95% of adults, its role in MS has remained unclear; this work identifies a specific T cell subset and viral gene activity as potential drivers of MS pathology.