Characteristics of anti-contactin1 antibody positive autoimmune nodopathies combined with membranous nephropathy

Abstract

BackgroundAutoimmune nodopathy (AN) is a very rare new disease entity, especially when combined with membranous nephropathy (MN). MethodsAntibodies against nodal-paranodal cell adhesion molecules in the serum were detected using cell-based assays. Antibody subtypes against contactin-1 (CNTN1) were confirmed. Cases of anti-CNTN1 antibody-positive AN with and without MN were retrieved through a literature search to compare clinical and electrophysiological characteristics. ResultsA 65-year-old male patient with MN developed limb numbness and weakness, along with walking instability. Serum CNTN1 antibodies were positive, primarily those of the IgG4 subtype. Electromyography showed prominent demyelination patterns in both the proximal and distal segments of the nerves compared to the middle nerve trunk. Magnetic resonance imaging revealed enlargement of the bilateral brachial and lumbosacral plexuses and local hyperintensity of the right C5-C6 nerve roots. Twenty-three cases with anti-CNTN1 antibody-positive AN with MN and 51 cases with anti-CNTN1 antibody-positive AN without MN were compared. There were no statistical differences in the clinical and electrophysiological characteristics between the two groups, which were mainly elderly men, manifested as acute or subacute onset, sensory ataxia, IgG4 antibody subtype, electrophysiological demyelination, and a certain effect on immunotherapy. ConclusionIn cases of electrophysiological manifestation of demyelinating peripheral neuropathy, especially in distal and poximal segments of nerves, AN should be considered, and further screening for renal function should be performed. Concomitant MN does not aggravate or alleviate peripheral nerve symptoms.