Aberrant X chromosome skewing and acquired clonal hematopoiesis in adult-onset common variable immunodeficiency
Gabriel K. Wong, … , Alex Richter, Mark Cobbold
Gabriel K. Wong, … , Alex Richter, Mark Cobbold
Published July 25, 2019
Citation Information: JCI Insight. 2019;4(14):e127614. https://doi.org/10.1172/jci.insight.127614.
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Research Article Hematology Immunology

Aberrant X chromosome skewing and acquired clonal hematopoiesis in adult-onset common variable immunodeficiency

Abstract

Advances in genomic medicine have elucidated an increasing number of genetic etiologies for patients with common variable immunodeficiency (CVID). However, there is heterogeneity in clinical and immunophenotypic presentations and a limited understanding of the underlying pathophysiology of many cases. The primary defects in CVID may extend beyond the adaptive immune system, and the combined defect in both the myeloid and lymphoid compartments suggests the mechanism may involve bone marrow output and earlier progenitors. Using the methylation profile of the human androgen receptor (AR) gene as a surrogate epigenetic marker for bone marrow clonality, we examined the hematopoietic compartments of patients with CVID. Our data show that clonal hematopoiesis is common among patients with adult-onset CVID who do not have associated noninfectious complications. Nonblood tissues did not show a skewed AR methylation status, supporting a model of an acquired clonal hematopoietic event. Attenuation of memory B cell differentiation into long-lived plasma cells (CD20–CD27+CD38+CD138+) was associated with marked changes in the postdifferentiation methylation profile, demonstrating the functional consequence of clonal hematopoiesis on humoral immunity in these patients. This study sheds light on a potential etiology of a subset of patients with CVID, and the findings suggest that it is a stage of an acquired lymphocyte maturation disorder.

Authors

Gabriel K. Wong, Sara Barmettler, James M. Heather, David Millar, Sarah A. Penny, Aarnoud Huissoon, Alex Richter, Mark Cobbold

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Figure 3

Numerical deficit in long-lived plasma cell generation by patients with CVID.

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Numerical deficit in long-lived plasma cell generation by patients with ...
Naive (CD27–) and memory (CD27+) B cells were enriched by magnetic bead isolation and terminally differentiated into plasma cells using a 3-step culture system. B cells were initially activated by CD40L-expressing L cells supplemented with IL-2, IL-21, and anti–IgA/M/G F(ab′)2 and then transferred to a Transwell system supported by murine bone marrow fibroblasts (M2-10B4) on day 6. The wells were harvested on days 13 and 41 for flow cytometric analysis. Short-lived plasma cells (SLPCs: 7-AAD–CD20–CD27+CD38+CD138–) and long-lived plasma cells (LLPCs: 7-AAD–CD20–CD27+CD38+CD138+) were enumerated using counting beads. (A) Schematic diagram of LLPC culture. (B) The gating strategy is shown. A U266 myeloma cell line was used to optimize CD38 and CD138 gating. Events within the upper-left quadrant of the far-right gate were considered SLPCs, whereas events within the upper-right quadrant were considered LLPCs. Examples of both naive and memory B cell differentiation of a healthy donor at day 13. (C) SLPC and LLPC counts generated from naive and memory cultures at day 13 of healthy donors (n = 10) and patients with CVID (n = 14). Median and interquartile range are represented by the height and error bar, respectively. Mann-Whitney U test was used. Statistical significance is indicated as *P < 0.05. (D) The proportions of SLPCs (blue) and LLPCs (green) within naive and memory cultures at day 13 and day 41 are shown in a series of pie charts.