Treatable, motor-sensory, axonal neuropathies with C5b-9 complement on endoneurial microvessels

Area of Science:

• Neurology
• Immunology
• Pathology

Background:

• Immune-mediated polyneuropathies can cause significant disability.
• Identifying specific immune markers can guide treatment and improve patient outcomes.

Purpose of the Study:

• To investigate the clinical features, laboratory findings, and treatment response in patients with motor-sensory axonal polyneuropathies associated with C5b-9 complement staining on endoneurial microvessels.

Main Methods:

• Retrospective review of 16 adult patients with motor-sensory axonal polyneuropathies and C5b-9 staining on nerve biopsy.
• Treatment with intravenous corticosteroids (methylprednisolone).
• Quantitative handheld dynamometry for strength assessment.

Main Results:

• Patients presented with progressive, asymmetric, distal weakness and sensory loss.
• Nerve pathology confirmed C5b-9 staining on endoneurial microvessels and axonal loss.
• Corticosteroid treatment led to significant improvement in distal strength (mean 34% increase).

Conclusions:

• Motor-sensory axonal polyneuropathies with C5b-9 staining of endoneurial microvessels (HIEM) represent a distinct, treatable entity.
• This condition often presents with progressive weakness and responds well to corticosteroid therapy.
• HIEM may be a new class of noninflammatory, vasculopathic, treatable axonal neuropathies.