Serum Neurofilament Light Chain Levels in Small Fiber Neuropathy Patients with Skin Denervation and Ongoing Neuropathic Symptoms (P14-8.004)

Abstract

<h3>Objective:</h3> To identify active axonal damage by measurement of serum neurofilament light chain (sNfL) levels in patients with small fiber neuropathy (SFN) and ongoing neuropathy symptoms. <h3>Background:</h3> SFN is associated with sensory symptoms and is evident by skin biopsy which show a reduction of the intraepidermal nerve fiber density (IENFD) indicating skin denervation. SFN patients may complain of prolonged/worsening symptoms, but it is not clear if this is associated with continuous axonal damage. <h3>Design/Methods:</h3> Blood samples were collected from 95 consecutive patients that were referred for a skin biopsy due to suspected SFN. All patients had symptoms that were consistent with a clinical diagnosis of SFN. Patients were excluded if they had clinical or imaging evidence for a central nervous system disorder, electrodiagnostic abnormalities or absence of electrodiagnostic evaluation. Following these exclusions, 34 patients were included for analysis. Skin biopsy was performed 2–3 months from symptoms onset by 4 patients, 4–12 months by 7, and after more than 12 months by 23. Severe skin denervation was defined by an intraepidermal nerve fiber density (IENFD) below the 5^th percentile per age, mild denervation when the IENFD was at the 5–20^th percentiles, and above the 20^th percentile was considered normal. <h3>Results:</h3> The majority of patients (29/34; 85%) showed normal sNfL levels and almost half of the patients showed skin denervation (15/34; 44%). Two patients with skin denervation (2/15; 13.3%) showed elevated sNfL, after 7 and more than 12 months from symptoms onset. The skin biopsy was normal in the other 3 patients with elevated sNfL, obtained 2, 8 and more than 12 months from symptoms onset. All patients with elevated sNfL had a history of chemotherapy treatment or immune-mediated disorders. <h3>Conclusions:</h3> In this cohort, a small portion of patients with SFN and skin denervation showed increased sNfL which indicated ongoing axonal damage. <b>Disclosure:</b> Dr. Zohar has nothing to disclose. Miss Qassim has nothing to disclose. Dr. Eltity has nothing to disclose. Dr. Keren has nothing to disclose. Efrat Shavit has nothing to disclose. Dr. Chapman has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Mapi Pharma. Dr. Chapman has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sanofi Genzyme. Dr. Chapman has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Merk Serono. The institution of Dr. Chapman has received research support from Ministry Of Industry. Dr. Dori has received personal compensation in the range of $500-$4,999 for serving as a Consultant for TEVA. Dr. Dori has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Takeda . Dr. Dori has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Sanofi. Dr. Dori has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Medison Pharma. Dr. Dori has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Medison Pharma. The institution of Dr. Dori has received research support from Biogen. The institution of Dr. Dori has received research support from Pfizer. The institution of Dr. Dori has received research support from Alnylam therapeutics. Dr. Dori has received intellectual property interests from a discovery or technology relating to health care.