Submitted by: Clark Pinyan, MD, MPH
Edited by: Bryan DeSouza, MD
Fulii T, Yamasaki R, Iinuma K, et al. A novel autoantibody against plexin D1 in patients with neuropathic pain
. Annals of Neurology
The authors actively sought novel autoantibodies in patients with neuropathic pain. Among 110 patients with neuropathic pain tested by tissue based IFA, 11 patients had a characteristic pattern of binding to mouse unmyelinated C‐fiber type dorsal root ganglion (DRG) neurons. Mass spectrometry analysis of the immunoprecipitant yielded a partial sequence identical to plexin D1 amino acids. Most of these patients had other identified immune conditions including Sjogren’s syndrome, asthma, and allergic rhinitis. The majority were young (26.3 ± 13.3), female (81.8%) and had relapsing or fluctuating clinical courses (100%). Seven patients underwent immunotherapy for related conditions, and all 7 reported improvement in neuropathic pain.
This paper is an important first step in identifying biomarkers for neuropathic pain in a cohort of Japanese patients. 10% of the neuropathic pain patients were found to have anti-unmyelinated C‐fiber type DRG neuronal antibodies directed against the plexin D1 antigen. Although this is an important finding, the majority – 90% of the neuropathic patients screened – did not have these autoantibodies. A majority were candidates for immunotherapy based on other systemic diagnoses (most commonly Sjogren’s syndrome), and all noted improvement in pain with treatment. This article highlights the growing importance of autoantibodies in neuropathic processes including pain.