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.
© 2019 Rodriguez et al.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Class I Phosphatidylinositol 3-Kinases / chemistry
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Class I Phosphatidylinositol 3-Kinases / deficiency*
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Disease Susceptibility
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Epstein-Barr Virus Infections / diagnosis
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Epstein-Barr Virus Infections / etiology*
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Germ-Line Mutation
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Herpesvirus 4, Human / immunology*
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Histocytochemistry
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Homozygote
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Humans
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Immunophenotyping
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Loss of Function Mutation
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Lymphocyte Activation
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Lymphoproliferative Disorders / diagnosis
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Lymphoproliferative Disorders / etiology
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Lymphoproliferative Disorders / metabolism
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Models, Molecular
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Pedigree
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Phospholipase C gamma / metabolism
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Protein Conformation
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Proto-Oncogene Proteins c-akt
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Ribosomal Protein S6 Kinases / metabolism
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Sequence Analysis, DNA
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Signal Transduction
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Structure-Activity Relationship
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T-Lymphocytes / immunology*
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T-Lymphocytes / metabolism*
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T-Lymphocytes / virology
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Tumor Necrosis Factor Receptor Superfamily, Member 9 / chemistry
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Tumor Necrosis Factor Receptor Superfamily, Member 9 / deficiency*
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Virus Activation / genetics*
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Virus Activation / immunology*
Substances
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TNFRSF9 protein, human
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Tumor Necrosis Factor Receptor Superfamily, Member 9
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Class I Phosphatidylinositol 3-Kinases
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PIK3CD protein, human
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Proto-Oncogene Proteins c-akt
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Ribosomal Protein S6 Kinases
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PLCG1 protein, human
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Phospholipase C gamma
Associated data
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PDB/5T8F
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PDB/2RD0
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SWISSPROT/O00329
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SWISSPROT/P42338
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SWISSPROT/P48736
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SWISSPROT/P42336