Hyper-reflective foci changes in RRMS under natalizumab therapy.

Area of Science:

• Neuro-immunology
• Ophthalmology
• Neuroscience

Background:

• Microglia (MG) activation is implicated in Multiple Sclerosis (MS) immunopathology.
• Hyper-reflective foci (HRF) observed via Optical Coherence Tomography (OCT) may indicate MG activation.
• Understanding drug mechanisms in MS is crucial for treatment optimization.

Purpose of the Study:

• To investigate the effect of Natalizumab (NTZ) on HRF in MS patients.
• To clarify the impact of NTZ on retinal layers indicative of microglial activity.
• To explore NTZ's mechanism of intrathecal action in MS.

Main Methods:

• Prospective, single-center study of 36 Relapsing-Remitting MS (RRMS) patients treated with NTZ.
• OCT imaging (peripapillary and macular scans) performed at multiple time points during NTZ therapy.
• Analysis of peripapillary retinal nerve fiber layer (RNFL) thickness, macular volumes, and HRF count in specific retinal layers (GCL, IPL, INL).

Main Results:

• HRF count significantly increased in the Ganglion Cell Layer (GCL) and Inner Plexiform Layer (IPL) under NTZ therapy.
• No significant changes in HRF count were observed in the Inner Nuclear Layer (INL).
• No significant modifications in RNFL thickness or macular volumes were detected; clinical outcomes (EDSS, relapses) remained stable.

Conclusions:

• NTZ therapy influences HRF count in the GCL and IPL of RRMS patients.
• The observed changes suggest NTZ may not affect all microglial-related immunopathological processes in MS.
• Further research is needed to fully elucidate the impact of NTZ on MS immunopathology.