Neuronal Autoantibodies and Clinical Significance in Stiff-Person Spectrum Disorder (P1.7-002)

Objective: To report the clinical features of stiff-person spectrum disorder (SPSD). Background: SPSD is a collective term encompassing classic stiff-person syndrome (SPS), stiff-limb syndrome (SLS), SPS-plus including progressive encephalomyelitis with rigidity and myoclonus (PERM), and overlapping syndromes. A large cohort study reported that 66.9% of patients with SPSD had neuronal antibodies (GAD65 [43.0%], glycine receptor (GlyR) [19.8%], and others [4.1%]), and patients with GAD65-antibodies had worse outcome than those with GlyR-antibodies or those without neuronal antibodies. Design/Methods: We reviewed the clinical information of 20 patients with clinical feaures of SPSD (median age 48 years [15–80 years], 10 female), who underwent testing for antibodies against neuronal cell-surface antigens (NSAs) in serum and CSF as well as GAD65 and amphiphysin in serum between July 2008 and August 2018. Results: The median long-term follow-up was 28.5 months (3.9 to 150 months). Clinical phenotypes included SPS-plus (n=11), SLS (n=5), overlapping syndrome (n=2), and classic SPS (n=2). Only 7 patients (35%) had neuronal antibodies: 5 GlyR (2 with GAD65), 1 AMPAR, GABA(B)R and CV2 associated with thymoma, and 1 GAD65. Three patients had an associated tumor (thymoma, follicular lymphoma, renal cancer), and 1 had a past history of breast cancer. GlyR-antibodies were detected in 3 of 11 patients (27.2%) with SPS-plus, and 2 of 5 patients (40.0%) with SLS. Compared with antibody-negative cases, antibody-positive cases had more frequently CSF oligoclonal bands (3/7 vs 0/11, p=0.0429), but no difference in age of onset, gender, CSF pleocytosis, IgG index, or tumor association. All patients received immunotherapy, but the long-term outcome (defined as modified Rankin Scale ≤ 2) was better in patients with NSA-antibodies than those without (6/6 vs 4/14, p=0.0108). Conclusions: Patients with SPSD and NSA antibodies have better prognosis than those without antibodies. Disclosure: Dr. Kaneko has nothing to disclose. Dr. Iizuka has nothing to disclose. Dr. Kondo has nothing to disclose. Dr. Abe has nothing to disclose. Dr. Kaneko has nothing to disclose. Dr. Hattori has nothing to disclose. Dr. Kobayashi has nothing to disclose. Dr. Ugawa has nothing to disclose. Dr. Sekiguchi has nothing to disclose. Dr. Maeda has nothing to disclose. Dr. Matsumoto has nothing to disclose. Dr. Kanazawa has nothing to disclose. Dr. Kitamura has nothing to disclose. Dr. Dalmau has received personal compensation in an editorial capacity for Editor: Neurology, Neuroimmunology, Neuroinflammation; and UpToDate. Dr. Dalmau has received royalty, license fees, or contractual rights payments from Euroimmune. Dr. Dalmau has received research support from Euroimmune. Dr. Nishiyama has nothing to disclose.