RT Journal Article
SR Electronic
T1 Novel Cell-Based Assay for Alpha-3 Nicotinic Receptor Antibodies Detects Antibodies Exclusively in Autoimmune Autonomic Ganglionopathy
JF Neurology - Neuroimmunology Neuroinflammation
JO Neurol Neuroimmunol Neuroinflamm
FD Lippincott Williams & Wilkins
SP e1162
DO 10.1212/NXI.0000000000001162
VO 9
IS 3
A1 Katerina Karagiorgou
A1 Maria Dandoulaki
A1 Renato Mantegazza
A1 Francesca Andreetta
A1 Raffaello Furlan
A1 Jon Lindstrom
A1 Paraskevi Zisimopoulou
A1 Elisabeth Chroni
A1 Panagiotis Kokotis
A1 Evangelos Anagnostou
A1 Dimitrios Tzanetakos
A1 Marianthi Breza
A1 Zoe Katsarou
A1 Georgios Amoiridis
A1 Vasileios Mastorodemos
A1 Marianna Bregianni
A1 Anastasios Bonakis
A1 Georgios Tsivgoulis
A1 Konstantinos Voumvourakis
A1 Socrates Tzartos
A1 John Tzartos
YR 2022
UL http://nn.neurology.org/content/9/3/e1162.abstract
AB Background and Objectives Autoantibodies against α3-subunit–containing nicotinic acetylcholine receptors (α3-nAChRs), usually measured by radioimmunoprecipitation assay (RIPA), are detected in patients with autoimmune autonomic ganglionopathy (AAG). However, low α3-nAChR antibody levels are frequently detected in other neurologic diseases with questionable significance. Our objective was to develop a method for the selective detection of the potentially pathogenic α3-nAChR antibodies, seemingly present only in patients with AAG.Methods The study involved sera from 55 patients from Greece, suspected for autonomic failure, and 13 patients from Italy diagnosed with autonomic failure, positive for α3-nAChR antibodies by RIPA. In addition, sera from 52 patients with Ca2+ channel or Hu antibodies and from 2,628 controls with various neuroimmune diseases were included. A sensitive live cell-based assay (CBA) with α3-nAChR–transfected cells was developed to detect antibodies against the cell-exposed α3-nAChR domain.Results Twenty-five patients were found α3-nAChR antibody positive by RIPA. Fifteen of 25 patients were also CBA positive. Of interest, all 15 CBA-positive patients had AAG, whereas all 10 CBA-negative patients had other neurologic diseases. RIPA antibody levels of the CBA-negative sera were low, although our CBA could detect dilutions of AAG sera corresponding to equally low RIPA antibody levels. No serum bound to control-transfected cells, and none of the 2,628 controls was α3-CBA positive.Discussion This study showed that in contrast to the established RIPA for α3-nAChR antibodies, which at low levels is of moderate disease specificity, our CBA seems AAG specific, while at least equally sensitive with the RIPA. This study provides Class II evidence that α3-nAChR CBA is a specific assay for AAG.Classification of Evidence This study provides Class II evidence that an α3-nAChR cell-based assay is a more specific assay for AAG than the standard RIPA.AAG=autoimmune autonomic ganglionopathy; AQP4=aquaporin-4; CBA=cell-based assay; DMEM=Dulbecco's modified Eagle's medium; HEPES=0.46% w/v N-(2-hydroxyethyl) piperazine-N’-(2-ethanesulfonic acid); LIPS=luciferase immunoprecipitation system; mAb=monoclonal antibody; nAChR=nicotinic acetylcholine receptor; POTS=postural orthostatic tachycardia syndrome; RIPA=radioimmunoprecipitation assay; RT=room temperature; VGCC=voltage-gated Ca++ channels P/Q-type; α3-nAChR=α3-subunit–containing nAChR