Go to JCI Insight
  • About
  • Editors
  • Consulting Editors
  • For authors
  • Alerts
  • Advertising/recruitment
  • Subscribe
  • Contact
  • Current Issue
  • Past Issues
  • By specialty
    • COVID-19
    • Cardiology
    • Gastroenterology
    • Immunology
    • Metabolism
    • Nephrology
    • Neuroscience
    • Oncology
    • Pulmonology
    • Vascular biology
    • All ...
  • Videos
    • Conversations with Giants in Medicine
    • Author's Takes
  • Reviews
    • View all reviews ...
    • Tumor Microenvironment (Mar 2021)
    • 100th Anniversary of Insulin's Discovery (Jan 2021)
    • Hypoxia-inducible factors in disease pathophysiology and therapeutics (Oct 2020)
    • Latency in Infectious Disease (Jul 2020)
    • Immunotherapy in Hematological Cancers (Apr 2020)
    • Big Data's Future in Medicine (Feb 2020)
    • Mechanisms Underlying the Metabolic Syndrome (Oct 2019)
    • View all review series ...
  • Viewpoint
  • Collections
    • In-Press Preview
    • Commentaries
    • Concise Communication
    • Editorials
    • Viewpoint
    • Top read articles
  • Clinical Medicine
  • JCI This Month
    • Current issue
    • Past issues

  • Current issue
  • Past issues
  • Specialties
  • Reviews
  • Review series
  • Conversations with Giants in Medicine
  • Author's Takes
  • In-Press Preview
  • Commentaries
  • Concise Communication
  • Editorials
  • Viewpoint
  • Top read articles
  • About
  • Editors
  • Consulting Editors
  • For authors
  • Alerts
  • Advertising/recruitment
  • Subscribe
  • Contact
Loss of ARHGEF1 causes a human primary antibody deficiency
Amine Bouafia, … , Eric Oksenhendler, Sven Kracker
Amine Bouafia, … , Eric Oksenhendler, Sven Kracker
Published December 6, 2018
Citation Information: J Clin Invest. 2019;129(3):1047-1060. https://doi.org/10.1172/JCI120572.
View: Text | PDF
Research Article Immunology

Loss of ARHGEF1 causes a human primary antibody deficiency

  • Text
  • PDF
Abstract

ARHGEF1 is a RhoA-specific guanine nucleotide exchange factor expressed in hematopoietic cells. We used whole-exome sequencing to identify compound heterozygous mutations in ARHGEF1, resulting in the loss of ARHGEF1 protein expression in 2 primary antibody–deficient siblings presenting with recurrent severe respiratory tract infections and bronchiectasis. Both ARHGEF1-deficient patients showed an abnormal B cell immunophenotype, with a deficiency in marginal zone and memory B cells and an increased frequency of transitional B cells. Furthermore, the patients’ blood contained immature myeloid cells. Analysis of a mediastinal lymph node from one patient highlighted the small size of the germinal centers and an abnormally high plasma cell content. On the molecular level, T and B lymphocytes from both patients displayed low RhoA activity and low steady-state actin polymerization (even after stimulation of lysophospholipid receptors). As a consequence of disturbed regulation of the RhoA downstream target Rho-associated kinase I/II (ROCK), the patients’ lymphocytes failed to efficiently restrain AKT phosphorylation. Enforced ARHGEF1 expression or drug-induced activation of RhoA in the patients’ cells corrected the impaired actin polymerization and AKT regulation. Our results indicate that ARHGEF1 activity in human lymphocytes is involved in controlling actin cytoskeleton dynamics, restraining PI3K/AKT signaling, and confining B lymphocytes and myelocytes within their dedicated functional environment.

Authors

Amine Bouafia, Sébastien Lofek, Julie Bruneau, Loïc Chentout, Hicham Lamrini, Amélie Trinquand, Marie-Céline Deau, Lucie Heurtier, Véronique Meignin, Capucine Picard, Elizabeth Macintyre, Olivier Alibeu, Marc Bras, Thierry Jo Molina, Marina Cavazzana, Isabelle André-Schmutz, Anne Durandy, Alain Fischer, Eric Oksenhendler, Sven Kracker

×

Figure 1

Myelocytosis, an increase in transitional B cells, and the absence of marginal zone and memory B cells are hallmarks of the patients’ phenotype.

Options: View larger image (or click on image) Download as PowerPoint
Myelocytosis, an increase in transitional B cells, and the absence of ma...
(A) Pictures of blood smears from P1 and P2 after staining with May-Grunwald-Giemsa reagent, showing the abnormal presence of myelocytes. Original magnification, ×100. (B) Distribution of the different myeloid cell populations in the blood of both affected siblings. Each circle (P1) or square (P2) denotes an independent blood sample. n = 2. Pro., promyelocytes; My., myelocytes; Meta., metamyelocytes. (C and D) Representative FACS plots analyzing the frequency of transitional B lymphocytes (C), marginal zone, memory, and naive B lymphocytes (D) in the blood of 2 healthy donors (HD1, HD2) and both patients. These experiments were performed 3 times. transi, transitional; Me., memory; MZ, marginal zone; N, naive.

Copyright © 2021 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)

Sign up for email alerts