Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Oct 1;105(10):e488.
doi: 10.3324/haematol.2019.231399.

Germline biallelic PIK3CG mutations in a multifaceted immunodeficiency with immune dysregulation

Marini Thian  1 , Birgit Hoeger  1 , Anton Kamnev  1 , Fiona Poyer  2 , Sevgi Köstel Bal  1 , Michael Caldera  3 , Raúl Jiménez-Heredia  1 , Jakob Huemer  1 , Winfried F Pickl  4 , Miriam Groß  5 , Stephan Ehl  5 , Carrie L Lucas  6 , Jörg Menche  3 , Caroline Hutter  7 , Andishe Attarbaschi  2 , Loïc Dupré  1 , Kaan Boztug  1
Affiliations

Germline biallelic PIK3CG mutations in a multifaceted immunodeficiency with immune dysregulation

Marini Thian et al. Haematologica. .
No abstract available

PubMed Disclaimer

Figures

Figure 1.
Figure 1.
Compound-heterozygous PIK3CG mutations in a patient with systemic inflammation. (A) Patient response to dexamethasone treatment (purple) as evidenced by the decrease of ferritin in the patient’s peripheral blood. Disease relapsed upon initial withdrawal of dexamathasone, as evidenced by increased ferritin levels. Reinitiation of dexamethasone normalized ferritin levels, and treatment with Anakinra (blue) was initiated and well-tolerated. Treatment was initiated at 14 years of age, and ferritin was monitored over seven months. Colored bars indicate drug dosage. (B) Patient bone marrow biopsy showing engulfment of erythroblast (black asterisk) and mature erythrocyte (white arrow) by a macrophage. The nucleus is indicated by the black arrow. Scale bar: 25 mm. (C) Compound-heterozygous PIK3CG base pair substitutions in the index patient (filled symbol) segregate with parents. Sanger sequencing confirmed presence of a heterozygous variant in each parent (half-filled symbols). (D) Schematic representation of chromosomal position (top) and protein domains (bottom) of the identified PIK3CG/p110γ mutations, introducing two distinct missense mutations within the adaptor-binding domain (ABD) and near the kinase domain of the protein (bottom). RBD: Ras-binding domain; het: heterozygous. (E) Expression of p110γ protein in expanded T cells of the patient, compared with cells of mother and two healthy donors (HD). HSP90 was used as a housekeeping loading control.
Figure 2.
Figure 2.
PIK3CG mutations affect adaptive and innate immune functions. (A) Reduced proliferative capacity of patient-derived T cells upon stimulation with anti-CD3 antibody or combined anti-CD3/CD28 antibody. Phytohemagglutinin P (PHA) stimulation was not impaired, in agreement with TCR/PI3K-independent T-cell activation. Cells were stained with violet proliferation dye (VPD450), and dye dilutions were monitored three days post stimulation. (B) Impaired activation of patient T cells. Peripheral blood mononuclear cells (PBMC) were isolated and stained for the appearance of activation markers, one day (left, CD69 upregulation) or three days (right, CD25 upregulation) after stimulation with anti-CD3/CD28. Cells were gated on lymphocytes and CD8–CD4+ (left) or CD4–CD8+ (right) populations. (C) Rescue of T-cell activation via CD69 expression on day 2 post stimulation with anti-CD3 in patient cells by exogenous expression of wild-type (WT) PIK3CG or empty vector (EV). Gated on GFP+ transfected cells (left). Mean fluorescence intensity (MFI) of CD69 expression on GFP+ transfected cells (right). (D) PI3Kγ inhibition with IPI-549 phenocopies T-cell proliferation defects. Cells were stimulated with anti-CD3/CD28 and monitored for VPD450 dye dilution as in (A). (E) Addition of PI3Kγ inhibitor IPI-549 (1 mM) phenocopies the T-cell activation defect, compared to DMSO control. Cells were stimulated as in (B) and gated on CD4–CD8+ (left) or CD8–CD4+ (right) lymphocytes. (F) Impaired activation of AKT signaling in PIK3CG-mutated patient PBMC, gated on CD4+CD8– T cells. PBMC were stimulated with anti-CD3/CD28 for 15 minutes. (Left) Phospho-AKT signal was reduced in patient cells compared to healthy donors (HD). (Right) Normalization to unstimulated control. (G) Decreased activation of PIK3CG knockout (KO) Jurkat cells compared to Renilla KO control upon anti-CD3 stimulation. ****P<0.0001, two-way ANOVA. (H) Reduced MFI of AKT Ser473 phosphorylation in PIK3CG KO Jurkat cells compared to Renilla KO control and unstained control. (I) Representative immunostaining images of 40x magnification after 5 hours incubation with PMA/ionomycin in HD, mother and patient monocyte-derived macrophages. Images show reduced cell spreading and total F-actin intensity in patient macrophages upon stimulation. Scale bars: 100 mm (top), 20 mm (middle, bottom). The lookup table (bottom right) indicates a color code for pixel values. (J) Patient macrophages show lack of cell spreading as indicated by significantly smaller cell area compared to mother and HD cells. ****P<0.0001, Mann-Whitney U test. (K) Reduced total F-actin intensity of patient macrophages compared to mother and HD cells. ****P<0.0001, Mann-Whitney U test. (L) Reduced phagocytosis ability of patient-derived monocytes (left) and neutrophils (right). Whole-blood samples were incubated with pHrodo Red E. coli and phagocytosed bacteria were evaluated by flow cytometry. Populations were gated based on forward/side scatter characteristics of monocytes and neutrophils, respectively. All error bars indicate ± standard error of mean.
See this image and copyright information in PMC

References

    1. Fruman DA, Chiu H, Hopkins BD, et al. . The PI3K Pathway in Human Disease. Cell. 2017;170(4):605-635. - PMC - PubMed
    1. Janku F, Yap TA, Meric-Bernstam F. Targeting the PI3K pathway in cancer: are we making headway? Nat Rev Clin Oncol. 2018;15:273-291. - PubMed
    1. Tassi I, Cella M, Gilfillan S, et al. . p110γ and p110d Phosphoinositide 3-Kinase Signaling Pathways Synergize to Control Development and Functions of Murine NK Cells. Immunity. 2007;27(2):214-227. - PubMed
    1. Kaneda MM, Messer KS, Ralainirina N, et al. . PI3Kγ is a molecular switch that controls immune suppression. Nature. 2016; 539(7629):437-442. - PMC - PubMed
    1. Sasaki T, Irie-Sasaki J, Jones RG, et al. . Function of PI3Kγ in Thymocyte Development, T Cell Activation, and Neutrophil Migration. Science. 2000;287(5455):1040-1046. - PubMed

Publication types

Substances