Circulating MAIT cells in multiple sclerosis and amyotrophic lateral sclerosis.

Area of Science:

• Immunology
• Neuroimmunology
• Cellular Biology

Background:

• Neurological disorders like multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS) can involve changes in blood cell composition.
• Mucosal-associated invariant T (MAIT) cells are a subset of CD8+ T cells with specific T cell receptor and marker expression.

Purpose of the Study:

• To investigate alterations in circulating MAIT cells in different courses of MS and ALS.
• To determine if MAIT cell changes correlate with specific neurological disease phenotypes.

Main Methods:

• Transcriptomic analysis of peripheral blood mononuclear cells (PBMC) from MS patients and healthy controls.
• Multiparametric flow cytometry to quantify CD8+ MAIT cells in PBMC from patients with relapsing-remitting MS (RR-MS), progressive MS (PP-MS, SP-MS), ALS, and healthy controls.

Main Results:

• Transcriptomics showed downregulation of MAIT cell markers in progressive MS compared to healthy controls.
• Flow cytometry revealed a significant loss of circulating CD8+ MAIT cells specifically in primary progressive MS (PP-MS).
• No significant changes in MAIT cells were observed in RR-MS, SP-MS, or ALS patients compared to controls.

Conclusions:

• A specific reduction in circulating CD8+ MAIT cells is associated with the primary progressive course of multiple sclerosis.
• These immunological findings in blood may contribute to the clinical definition and understanding of PP-MS.
• MAIT cell analysis could serve as a potential biomarker for distinct MS disease trajectories.