Long-Term Follow Up in Anti-Contactin-1 Autoimmune Nodopathy

To analyze long-term clinical and biomarker features of anti-contactin-1 (CNTN1) autoimmune nodopathy (AN). Patients with anti-CNTN1 autoimmune nodopathy detected in our laboratory from which clinical information was available were included. Clinical features and treatment response were retrospectively collected. Autoantibody, serum neurofilament light chain (sNfL), and serum CNTN1 levels (sCNTN1) were analyzed at baseline and follow up. A total of 31 patients were included. Patients presented with progressive sensory motor neuropathy (76.7%) with proximal (74.2%) and distal involvement (87.1%), ataxia (71.4%), and severe disability (median INCAT at nadir of 8). A total of 11 patients (35%) showed kidney involvement. Most patients (97%) received intravenous immunoglobulin, but only 1 achieved remission with intravenous immunoglobulin. A total of 22 patients (71%) received corticosteroids, and 3 of them (14%) did not need further treatments. Rituximab was effective in 21 of 22 patients (95.5%), with most of them (72%) receiving a single course. Four patients (12.9%) relapsed after a median follow up of 25 months after effective treatment (12-48 months). Anti-CNTN1 titers correlated with clinical scales at sampling and were negative after treatment in all patients, but 1 (20/21). sNfL levels were significantly higher and sCNTN1 significantly lower in anti-CNTN1 patients than in healthy controls (sNfL: 135.9 pg/ml vs 7.48 pg/ml, sCNTN1: 25.03 pg/ml vs 22,186 pg/ml, p