Protection or susceptibility to devastating childhood epilepsy: Nodding Syndrome associates with immunogenetic fingerprints in the HLA binding groove

PLoS Negl Trop Dis. 2020 Jul 8;14(7):e0008436. doi: 10.1371/journal.pntd.0008436. eCollection 2020 Jul.

Abstract

Nodding syndrome (NS) is a devastating and enigmatic childhood epilepsy. NS is accompanied by multiple neurological impairments and neuroinflammation, and associated with the parasite Onchocerca volvulus (Ov) and other environmental factors. Moreover, NS seems to be an 'Autoimmune Epilepsy' since: 1. ~50% of NS patients have neurotoxic cross-reactive Ov/Leimodin-I autoimmune antibodies. 2. Our recently published findings: Most (~86%) of NS patients have glutamate-receptor AMPA-GluR3B peptide autoimmune antibodies that bind, induce Reactive Oxygen Species, and kill both neural cells and T cells. Furthermore, NS patient's IgG induce seizures, brain multiple damage alike occurring in brains of NS patients, and elevation of T cells and activated microglia and astrocytes, in brains of normal mice. Human Leukocyte antigen (HLA) class I and II molecules are critical for initiating effective beneficial immunity against foreign microorganisms and contributing to proper brain function, but also predispose to detrimental autoimmunity against self-peptides. We analyzed seven HLA loci, either by next-generation-sequencing or Sequence-Specific-Oligonucleotide-Probe, in 48 NS patients and 51 healthy controls from South Sudan. We discovered that NS associates significantly with both protective HLA haplotype: HLA-B*42:01, C*17:01, DRB1*03:02, DQB1*04:02 and DQA1*04:01, and susceptible motif: Ala24, Glu63 and Phe67, in the HLA-B peptide-binding groove. These amino acids create a hydrophobic and sterically closed peptide-binding HLA pocket, favoring proline residue. Our findings suggest that immunogenetic fingerprints in HLA peptide-binding grooves tentatively associate with protection or susceptibility to NS. Accordingly, different HLA molecules may explain why under similar environmental factors, only some children, within the same families, tribes and districts, develop NS, while others do not.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Amino Acid Motifs
  • Autoantibodies / immunology
  • Case-Control Studies
  • Child
  • Child, Preschool
  • Disease Susceptibility
  • Female
  • HLA Antigens / chemistry*
  • HLA Antigens / genetics
  • HLA Antigens / immunology*
  • Humans
  • Male
  • Nodding Syndrome / genetics
  • Nodding Syndrome / immunology*
  • Nodding Syndrome / prevention & control
  • Receptors, AMPA / genetics
  • Receptors, AMPA / immunology
  • South Sudan
  • Young Adult

Substances

  • Autoantibodies
  • HLA Antigens
  • Receptors, AMPA
  • glutamate receptor ionotropic, AMPA 3

Grants and funding

Financial support to the studies described in this paper were provided by all the following organizations: European Research council (ERC) advance - GA No. 786575 – RxmiRcanceR (EG); Deutsche Forschungsgemeinschaft (DFG) SFB841 project C3 (EG); The National Institute of Health (NIH) CA197081-02 (EG); The Ministry of Science and Technology (MOST) (EG); The Israeli Science Foundation (ISF) collaboration with Canada (2473/2017) (EG); The personal ISF (486/2017) (EG); The ICORE–ISF (41/2011) (EG), by the German Cancer Research Center (DKFZ)-MOST (EG); Robert H. Benson Living Trust; The Selma Kron Foundation to student fellowships. This work was also supported by The Medina Family, and by Dr. Shmuel Cabily, and the authors are grateful for this support. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.