In-Depth Characterization of L1CAM⁺ Extracellular Vesicles as Potential Biomarkers for Anti-CD20 Therapy Response in...

Area of Science:

• Neuroimmunology
• Biomarker Discovery
• Extracellular Vesicles

Background:

• Effective inflammation suppression is crucial for multiple sclerosis (MS) management.
• Current disease-modifying therapies, like anti-CD20 antibodies, lack reliable biomarkers for dosing and response evaluation.
• Prolonged therapy increases infection and side effect risks, necessitating personalized treatment strategies.

Purpose of the Study:

• To investigate the potential of blood-derived L1CAM+ extracellular vesicles (EVs) as biomarkers for treatment response to rituximab (RTX) in relapsing-remitting MS (RRMS).
• To assess changes in L1CAM+ EV profiles before and after RTX therapy compared to healthy controls.

Main Methods:

• Serum and cerebrospinal fluid (CSF) samples from RRMS patients treated with RTX and healthy controls were analyzed.
• Extracellular vesicles (EVs) were characterized using transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA).
• EV surface markers and protein cargo were analyzed via flow cytometry and proximity extension assay (PEA).

Main Results:

• Significantly higher concentrations of L1CAM+ EVs were found in untreated RRMS patients compared to healthy controls.
• Rituximab (RTX) therapy led to a significant reduction in L1CAM+ EV concentration in serum.
• TNFRSF13B levels were significantly downregulated in serum EVs after six months of RTX treatment.

Conclusions:

• L1CAM+ EVs in serum exhibit distinct immunological profiles that change with rituximab treatment.
• These findings highlight the potential of L1CAM+ EVs as dynamic biomarkers for optimizing anti-CD20 therapy in MS.
• Further research can explore using L1CAM+ EVs for personalized treatment strategies in multiple sclerosis.