What tests are used to evaluate B cells and T cells in Multiple Sclerosis (MS)?

From the Guidelines

Testing B and T cells in multiple sclerosis (MS) is not a routine practice in clinical settings, but rather used in research to understand disease mechanisms and develop new treatments. The diagnosis and management of MS rely on a combination of clinical evaluation, MRI findings, cerebrospinal fluid analysis, and evoked potential tests, as outlined in guidelines such as those for the diagnosis and management of primary immunodeficiency 1. While B and T cells play significant roles in MS pathology, with T cells mediating inflammation and B cells producing antibodies and presenting antigens, their measurement is not typically used to guide treatment decisions.

Some disease-modifying therapies for MS, such as ocrelizumab and rituximab, target B cells, and others like natalizumab and fingolimod affect T cell trafficking, but their effectiveness is monitored through clinical outcomes and MRI changes rather than direct immune cell testing 1. The complex interplay between these immune cells in MS makes single cell-type measurements less useful than comprehensive clinical assessment for managing the disease.

Key points to consider in the management of MS include:

• The use of MRI in monitoring disease prognosis and patient management, as discussed in evidence-based guidelines 1
• The importance of clinical evaluation and comprehensive assessment in guiding treatment decisions
• The role of B and T cells in MS pathology, although their measurement is not routine in clinical practice
• The focus on developing new treatments and understanding disease mechanisms through research on immune cells and other aspects of MS pathology.

From the Research

Testing B and T Cells in MS

• B cells and T cells play a crucial role in the pathogenesis of multiple sclerosis (MS) 2, 3.
• Studies have shown that MS patients have a significantly lower proportion of CD3+ T cells, CD4+ T cells, and a higher proportion of NK T cells compared to healthy subjects 4.
• The CD4+/CD8+ T cell ratio is also lowered in MS patients, indicating a complex and heterogeneous disease 4.
• Fingolimod treatment has been shown to reduce CD3+ T cell, CD4+ T cell, and CD19+ B cell frequencies, while increasing CD8+ T cell frequencies 5.
• CD4+ CD8+ double-positive T cells are present in small numbers in the peripheral blood of healthy humans and may have anti-viral capacities, but their frequencies are comparable to healthy controls in treatment-naive and natalizumab-treated MS patients 6.

B Cell Involvement in MS

• B cells contribute to MS pathogenesis by producing autoantibodies, presenting antigens, producing proinflammatory cytokines, and potentially involving EBV 3.
• B-cell-targeted therapies, such as rituximab, ocrelizumab, and ofatumumab, have shown promise in treating MS by targeting surface molecules like CD20 and CD19 3.
• Other therapeutic strategies, including targeting B cell activating factor (BAFF) and Bruton's Tyrosine Kinase (BTK), are also being explored 3.

T Cell Involvement in MS

• T cells, particularly CD4+ T cells, play a key role in the immune response and have been implicated in MS pathogenesis 4, 5.
• Activated CD4+ T cells are reduced in MS patients, and fingolimod treatment has been shown to decrease CD4+ T cell frequencies 4, 5.
• CD8+ T cells are increased in MS patients treated with fingolimod, suggesting a potential shift in the immune response 5.