Anti-CV2/CRMP5 antibodies-associated paraneoplastic peripheral neuropathy: analysis on two cases

Abstract

Background Anti-CV2/CRMP5 antibodies-associated paraneoplastic peripheral neuropathy (PPN) is a poorly understood disease due to its rarity. This study aimed to summarize the clinical manifestations, electrophysiological and pathological characteristics of anti-CV2/CRMP5 antibodies-associated PPN and reviewed related literatures, so as to improve the understandings on this disease. Methods The clinical data of 2 patients with anti-CV2/CRMP5 antibodies-associated PPN were retrospectively reviewed, including their clinical manifestations, electrophysiological and pathological characteristics, treatment and follow-up.  Results Case 1 was a 52-year-old woman who initially presented with a 3-year history of slowly progressive numbness of limbs, which presented from right leg and gradually spread to her left arm and right ring finger and little finger. Then she suffered from weakness of left leg, weakened muscle strength of left hand and had difficultly in lifting left arm. Serum anti-CV2/CRMP5 antibodies were weakly positive, and anti-Hu, Yo, Ri, amphiphysin antibodies were negative. EMG showed peripheral neurogenic damage. Nerve tissue biopsy showed chronic severe active axonal peripheral neuropathy. There was no improvement after two courses of intravenous immunoglobulin (IVIg) and then she received steroid pulse treatment and sequential therapy. The symptom was still not improved 2 months after discharge, and oral azathioprine was added. Follow-up in one year, the numbness and weakness were improved. Case 2 was an 18-year-old man who presented with one-month history of limbs weakness with fluctuating symptoms and positive results of fatigue test. Serum anti-CV2/CRMP5 antibodies were positive. Acetylcholine receptor antibodies (AchR-Ab) was 27.47 nmol/L, and cerebrospinal fluid (CSF) protein was 1360 mg/L. EMG showed symmetrical involvement of sensorimotor nerves of all limbs, mainly demyelination. Repetitive nerve stimulation (RNS) showed low-frequency amplitude decreased progressively. Needle biopsy of thymus showed type B3 thymoma. The patient was diagnosed as myasthenia gravis (MS), peripheral neuropathy and type B3 thymoma. He was treated by IVIg, oral pyridostigmine bromide and chemotherapy. EMG 10 months after discharge showed worsened neurogenic damage of four limbs. Serum anti-CV2/CRMP5 antibodies were still positive.  Conclusions Anti-CV2/CRMP5 antibodies-associated paraneoplastic peripheral neuropathy patients can present a symmetric or asymmetric sensorimotor peripheral neuropathy with either axonal or demyelinating damage. Immunotherapy maybe effective.

DOI: 10.3969/j.issn.1672-6731.2018.09.011