Monogenic mutations differentially affect the quantity and quality of T follicular helper cells in patients with human primary immunodeficiencies

J Allergy Clin Immunol. 2015 Oct;136(4):993-1006.e1. doi: 10.1016/j.jaci.2015.05.036. Epub 2015 Jul 7.

Abstract

Background: Follicular helper T (TFH) cells underpin T cell-dependent humoral immunity and the success of most vaccines. TFH cells also contribute to human immune disorders, such as autoimmunity, immunodeficiency, and malignancy. Understanding the molecular requirements for the generation and function of TFH cells will provide strategies for targeting these cells to modulate their behavior in the setting of these immunologic abnormalities.

Objective: We sought to determine the signaling pathways and cellular interactions required for the development and function of TFH cells in human subjects.

Methods: Human primary immunodeficiencies (PIDs) resulting from monogenic mutations provide a unique opportunity to assess the requirement for particular molecules in regulating human lymphocyte function. Circulating follicular helper T (cTFH) cell subsets, memory B cells, and serum immunoglobulin levels were quantified and functionally assessed in healthy control subjects, as well as in patients with PIDs resulting from mutations in STAT3, STAT1, TYK2, IL21, IL21R, IL10R, IFNGR1/2, IL12RB1, CD40LG, NEMO, ICOS, or BTK.

Results: Loss-of-function (LOF) mutations in STAT3, IL10R, CD40LG, NEMO, ICOS, or BTK reduced cTFH cell frequencies. STAT3 and IL21/R LOF and STAT1 gain-of-function mutations skewed cTFH cell differentiation toward a phenotype characterized by overexpression of IFN-γ and programmed death 1. IFN-γ inhibited cTFH cell function in vitro and in vivo, as corroborated by hypergammaglobulinemia in patients with IFNGR1/2, STAT1, and IL12RB1 LOF mutations.

Conclusion: Specific mutations affect the quantity and quality of cTFH cells, highlighting the need to assess TFH cells in patients by using multiple criteria, including phenotype and function. Furthermore, IFN-γ functions in vivo to restrain TFH cell-induced B-cell differentiation. These findings shed new light on TFH cell biology and the integrated signaling pathways required for their generation, maintenance, and effector function and explain the compromised humoral immunity seen in patients with some PIDs.

Keywords: Follicular helper T cells; cytokine signaling; humoral immunity; primary immunodeficiencies.

Publication types

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

MeSH terms

  • Agammaglobulinaemia Tyrosine Kinase
  • B-Lymphocytes / immunology
  • CD40 Ligand / genetics
  • Cell Differentiation / genetics
  • Cell Proliferation / genetics
  • Cells, Cultured
  • Humans
  • I-kappa B Kinase / genetics
  • Immunity, Humoral / genetics
  • Immunologic Deficiency Syndromes / genetics
  • Immunologic Deficiency Syndromes / immunology*
  • Immunologic Memory
  • Inducible T-Cell Co-Stimulator Protein / genetics
  • Interferon-gamma / genetics
  • Interferon-gamma / metabolism
  • Lymphocyte Activation
  • Mutation / genetics
  • Protein-Tyrosine Kinases / genetics
  • Receptors, Cytokine / genetics
  • STAT1 Transcription Factor / genetics
  • STAT3 Transcription Factor / genetics
  • Signal Transduction / genetics
  • Signal Transduction / immunology
  • T-Lymphocyte Subsets / immunology*
  • T-Lymphocytes, Helper-Inducer / immunology*

Substances

  • ICOS protein, human
  • IKBKG protein, human
  • Inducible T-Cell Co-Stimulator Protein
  • Receptors, Cytokine
  • STAT1 Transcription Factor
  • STAT1 protein, human
  • STAT3 Transcription Factor
  • STAT3 protein, human
  • CD40 Ligand
  • Interferon-gamma
  • Protein-Tyrosine Kinases
  • Agammaglobulinaemia Tyrosine Kinase
  • BTK protein, human
  • I-kappa B Kinase