Refining cell-based assay to detect MOG-IgG in patients with central nervous system inflammatory diseases

Mult Scler Relat Disord. 2020 May:40:101939. doi: 10.1016/j.msard.2020.101939. Epub 2020 Jan 9.

Abstract

Background: Given that the spectrum of myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG) associated disease is yet to be fully defined, development of sensitive and highly specific assays to identify MOG-IgG is crucial to precisely define the clinical phenotypes, disease courses and prognosis to describe the full spectrum of MOG-IgG associated diseases. Here, we aim to validate a new in-house live cell-based assay (CBA) for screening MOG-IgG in patients with central nervous system inflammatory diseases.

Methods: We generated a full length MOG transfected HEK293 stable cell line using pIRES2-eGFP vector. Sera from 355 patients with central nervous system inflammatory diseases and 25 healthy individuals were evaluated for MOG-IgG seropositivity using in-house cell-based immunofluorescence assay (CBA-IF). The specificity of IgG (H + L) and IgG1-Fc secondary antibodies as well as IgM binding were determined by cell-based flow cytometry (CBA-FACS). The optimal cut-offs for determining seropositivity in CBA-FACS were calculated and the concordance of CBA-IF score and CBA-FACS was studied. The results of our CBA-IF were compared with the Oxford CBA-IF.

Results: 11.5% (41/355) of patients were seropositive for MOG-IgG and had clinical phenotypes that were within the known clinical spectrum of MOG-IgG associated diseases. No typical multiple sclerosis patients, aquaporin-4-IgG positive neuromyelitis optica spectrum disorder or healthy individuals were MOG-IgG seropositive. Using CBA-FACS, the anti-human IgG (H + L) was found to be comparable to IgG1-Fc antibody. No IgM binding was observed in all the samples tested. CBA-IF score and CBA-FACS yielded high correlation. The concordance of the NCC CBA-IF with the Oxford CBA-IF was 98%.

Conclusion: We have developed MOG-IgG CBAs that have different characteristics and benefits but with high specificity and concordance. The complementary use of two methods and follow-up study with larger cohort will increase the clinical usefulness of MOG-IgG CBAs.

Keywords: MOG-IgG; MOG-IgG assay; MOG-IgG associated diseases; cell-based assay.

MeSH terms

  • Adolescent
  • Adult
  • Biological Assay / standards*
  • Child
  • Child, Preschool
  • Demyelinating Autoimmune Diseases, CNS / blood*
  • Demyelinating Autoimmune Diseases, CNS / immunology
  • Demyelinating Autoimmune Diseases, CNS / physiopathology
  • Female
  • Flow Cytometry
  • Fluorescent Antibody Technique
  • HEK293 Cells
  • Humans
  • Immunoglobulin G / blood*
  • Inflammation / blood*
  • Inflammation / immunology
  • Inflammation / physiopathology
  • Male
  • Middle Aged
  • Myelin-Oligodendrocyte Glycoprotein / immunology*
  • Retrospective Studies
  • Sensitivity and Specificity
  • Young Adult

Substances

  • Immunoglobulin G
  • MOG protein, human
  • Myelin-Oligodendrocyte Glycoprotein