Neurofascin 155 IgG4 antibodies, a specific marker of chronic inflammatory demyelinating polyradiculoneuropathy
Clinical cases: Neurology
Background
A 34-year-old man notes tingling and numbness in the feet. Over several months, these sensory symptoms progress throughout his leg with noted weakness. Electrophysiological studies show prolonged distal latencies, reduced conduction velocities of the motor nerves in the upper and lower limbs, and temporal dispersion and reduction of CMAP amplitudes. Evaluation of CSF shows an elevated CSF protein of 348 mg/dL.
An immune-mediated demyelinating neuropathy with chronic progression is suspected, and the patient is referred for evaluation at a peripheral neurology clinic. IVIG and oral prednisone are initiated, but after several weeks of treatment, there is no response. Testing for neurofascin 155 (NF155) IgG4 antibodies in serum is performed, with positive results and a diagnosis of NF155 IgG4 chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). The patient subsequently receives five rounds of plasmapheresis and rituximab. During this treatment, the patient has subjective and objective neurological improvement on examination.
Teaching points
- NF155 IgG4 antibodies are a biomarker of a subset of patients with CIDP.
- Often, patients with NF155 IgG4 antibodies are refractory to IVIG treatment.
Key testing
CIDP | Chronic Inflammatory Demyelinating Polyradiculoneuropathy/Nodopathy Evaluation, Serum
- Turnaround time: 10 days
Find out how our testing uses neurofascin 155 IgG4 antibodies as a specific marker of chronic inflammatory demyelinating polyradiculoneuropathy.
