Concomitant PIK3CD and TNFRSF9 deficiencies cause chronic active Epstein-Barr virus infection of T cells

J Exp Med. 2019 Dec 2;216(12):2800-2818. doi: 10.1084/jem.20190678. Epub 2019 Sep 19.

Abstract

Infection of T cells by Epstein-Barr virus (EBV) causes chronic active EBV infection (CAEBV) characterized by T cell lymphoproliferative disorders (T-LPD) of unclear etiology. Here, we identified two homozygous biallelic loss-of-function mutations in PIK3CD and TNFRSF9 in a patient who developed a fatal CAEBV. The mutation in TNFRSF9 gene coding CD137/4-1BB, a costimulatory molecule expressed by antigen-specific activated T cells, resulted in a complete loss of CD137 expression and impaired T cell expansion toward CD137 ligand-expressing cells. Isolated as observed in one sibling, CD137 deficiency resulted in persistent EBV-infected T cells but without clinical manifestations. The mutation in PIK3CD gene that encodes the catalytic subunit p110δ of the PI3K significantly reduced its kinase activity. Deficient T cells for PIK3CD exhibited reduced AKT signaling, while calcium flux, RAS-MAPK activation, and proliferation were increased, suggestive of an imbalance between the PLCγ1 and PI3K pathways. These skewed signals in T cells may sustain accumulation of EBV-infected T cells, a process controlled by the CD137-CD137L pathway, highlighting its critical role in immunity to EBV.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Class I Phosphatidylinositol 3-Kinases / chemistry
  • Class I Phosphatidylinositol 3-Kinases / deficiency*
  • Disease Susceptibility
  • Epstein-Barr Virus Infections / diagnosis
  • Epstein-Barr Virus Infections / etiology*
  • Germ-Line Mutation
  • Herpesvirus 4, Human / immunology*
  • Histocytochemistry
  • Homozygote
  • Humans
  • Immunophenotyping
  • Loss of Function Mutation
  • Lymphocyte Activation
  • Lymphoproliferative Disorders / diagnosis
  • Lymphoproliferative Disorders / etiology
  • Lymphoproliferative Disorders / metabolism
  • Models, Molecular
  • Pedigree
  • Phospholipase C gamma / metabolism
  • Protein Conformation
  • Proto-Oncogene Proteins c-akt
  • Ribosomal Protein S6 Kinases / metabolism
  • Sequence Analysis, DNA
  • Signal Transduction
  • Structure-Activity Relationship
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism*
  • T-Lymphocytes / virology
  • Tumor Necrosis Factor Receptor Superfamily, Member 9 / chemistry
  • Tumor Necrosis Factor Receptor Superfamily, Member 9 / deficiency*
  • Virus Activation / genetics*
  • Virus Activation / immunology*

Substances

  • TNFRSF9 protein, human
  • Tumor Necrosis Factor Receptor Superfamily, Member 9
  • Class I Phosphatidylinositol 3-Kinases
  • PIK3CD protein, human
  • Proto-Oncogene Proteins c-akt
  • Ribosomal Protein S6 Kinases
  • PLCG1 protein, human
  • Phospholipase C gamma

Associated data

  • PDB/5T8F
  • PDB/2RD0
  • SWISSPROT/O00329
  • SWISSPROT/P42338
  • SWISSPROT/P48736
  • SWISSPROT/P42336