To determine the prevalence, characteristics and treatment course of patients with autoimmune nodopathies in the US.

Autoimmune nodopathies (AINs) are a rare group of disorders characterized by circulating autoantibodies targeting antigens at the node of Ranvier, usually of the immunoglobulin G4 (IgG4) subclass. About 5-10% of patients with electrodiagnostic features of a demyelinating neuropathy have autoimmune nodopathies. Patients with AINs may present with suggestive clinical features, demonstrate mixed responses to intravenous immunoglobulin (IVIg), but improve with B-cell-depleting therapy. 

This multi-center study, including over 12 centers in the US, is actively capturing the clinical features and therapeutic responses of patients with AINs.

To date, we have included 33 patients, with twenty-five (76%) positive for anti-neurofascin 155 (NF155), six (18%) positive for anti-Contactin IgG4 autoantibodies, and two (6%) positive for both autoantibodies. The average age of disease onset was 50.3 ± 19.6 years, and 18 (54.5%) patients were male. 55% had distal and proximal weakness, 36% predominant distal weakness, and 24% had facial weakness. Distal sensory loss, particularly loss of vibration sensation, and ataxia were common. Areflexia was noted in more than 80% of patients. Additional clinical details will be presented. Almost 40% of patients presented acutely or sub-acutely and were initially diagnosed as Guillain-Barré syndrome.   Over 90% of this cohort received IVIg, but only 33% had partial benefit. Steroids were used in 50% of cases, neonatal Fc receptor (FcRn) inhibitors in 16% of cases, and PLEX in 20% of cases. Over 70% of patients received rituximab, and most showed objective benefit on clinical examination. Additional treatment details, including extent and durability of response will be presented. 

This collaborative effort across the US is providing new insights into the clinical characteristics of AIN from a large US cohort, as well as critical information on management strategies.