T cells from multiple sclerosis patients recognize immunoglobulin G from cerebrospinal fluid

Area of Science:

• Immunology
• Neuroscience
• Autoimmunity

Background:

• Immunoglobulin (Ig) molecules possess idiotypic sequences resulting from genetic recombination and somatic mutation.
• These idiotypic sequences can function as immunogenic epitopes, potentially eliciting T-cell responses.
• Oligoclonal immunoglobulin G (IgG) synthesis in the cerebrospinal fluid (CSF) is a hallmark of multiple sclerosis (MS), suggesting ongoing intrathecal immune activity.

Purpose of the Study:

• To investigate T-cell responses directed against cerebrospinal fluid (CSF) IgG in patients with multiple sclerosis (MS).
• To determine if CSF IgG acts as a T-cell immunogen contributing to the intrathecal immune response in MS.

Main Methods:

• Peripheral blood mononuclear cells (PBMC) from MS patients and controls were stimulated with autologous CSF IgG.
• T-cell proliferation assays were used to assess immune responses.
• Characterization of responding T cells included CD4+ marker and human leucocyte antigen (HLA)-DR restriction analysis.

Main Results:

• A significant proportion of MS patients (14/21) exhibited T-cell proliferation in response to autologous CSF IgG.
• Control patients with other neurological diseases showed a lower response rate (4/17) to CSF IgG.
• Responses to myelin basic protein were less frequent compared to CSF IgG stimulation in both groups.

Conclusions:

• Cerebrospinal fluid (CSF) IgG, or associated substances, can act as T-cell immunogens in multiple sclerosis (MS).
• These findings suggest a potential role for idiotope-specific T cells in sustaining the intrathecal IgG synthesis observed in MS.
• CSF IgG-reactive T cells may contribute to the chronic immune response within the central nervous system in MS.