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Case Reports
. 2018 Jan;141(1):432-435.e7.
doi: 10.1016/j.jaci.2017.08.019. Epub 2017 Sep 18.

A novel IKAROS haploinsufficiency kindred with unexpectedly late and variable B-cell maturation defects

Delfien J Bogaert  1 , Hye Sun Kuehn  2 , Carolien Bonroy  3 , Katherine R Calvo  4 , Joke Dehoorne  5 , Arnaud V Vanlander  6 , Marieke De Bruyne  7 , Urszula Cytlak  8 , Venetia Bigley  8 , Frans De Baets  9 , Elfride De Baere  10 , Sergio D Rosenzweig  2 , Filomeen Haerynck  11 , Melissa Dullaers  12
Affiliations
Case Reports

A novel IKAROS haploinsufficiency kindred with unexpectedly late and variable B-cell maturation defects

Delfien J Bogaert et al. J Allergy Clin Immunol. 2018 Jan.
No abstract available

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Conflict of interest statement

Disclosure of potential conflict of interest: D. J. Bogaert received a PhD fellowship grant from Research Foundation Flanders (FWO) for this work. U. Cytlak’s and V. Bigley’s institutions received grant 101155/Z/13/Z from the Wellcome Trust for this work. E. De Baere personally received grants from Research Foundation Flanders (FWO, Senior Clinical Investigator), grant number BOF15/GOA/011 from the Ghent University Special Research Fund, and grant number AUGE/13/023 from the Hercules Foundation for this work. F. Haerynck personally received a grant from the Jeffrey Modell Foundation (JMF) for this work. The rest of the authors declare that they have no relevant conflicts of interest.

Figures

Fig E1
Fig E1
Peripheral blood T-cell subsets. Flow cytometric immunophenotyping of T-cell subsets was performed on patients’ PBMCs in comparison with age-matched healthy control subjects (HC). At the time of analysis, subjects I:2, II:3 and II:4 were 40, 14, and 9.5 years old, respectively. Patient II:3 is indicated as a purple triangle, and patient II:4 is indicated as a blue star. Total T cells were gated as CD3+ in alive PBMCs. αβ T cells were gated as γδ T-cell receptor–negative in total T cells. CD4+ and CD8+ T cells were gated in αβ T cells. In CD4+ and CD8+ T cells naive cells were gated as CD45RO−CCR7+, central memory cells (TCM) as CD45RO+CCR7+, effector memory cells (TEM) as CD45RO+CCR7−, and terminally differentiated cells (TEMRA) as CD45RO−CCR7−. Regulatory T (Treg) cells were gated as CD25+Foxp3+ and circulating follicular helper T (cTfh) cells were gated as CXCR5+CD45RO+ in CD4+ T cells. Double-negative (DN) T cells were gated as CD4−CD8− in αβ T cells. Natural killer (NK) T cells were gated as CD56+ in total CD3+ T cells.
Fig E2
Fig E2. IKZF1 cDNA sequencing.
Representative IKZF1 cDNA sequences of a mutant (M/WT) and wild-type (WT/WT) family member. cDNA was derived from total PBMCs. The position of the nucleotide deletion (c.136) is shown at the top. The M/WT subject has both a mutant and a wild-type cDNA sequence, suggesting that the mutant transcripts escape nonsense-mediated mRNA decay.
Fig E3
Fig E3
Flow cytometric analysis of hematopoietic stem and early lineage progenitor cells in the bone marrow. The gating strategy was based on the method of Hoshino et al. Percentages are percentages of the parent population, indicated at the top of each plot. CLP, Common lymphoid progenitor; HSC, hematopoietic stem cell; MPP, multipotent progenitor.
Fig E4
Fig E4
Kaplan-Meier curve on symptom-free survival in germline IKZF1 mutation carriers. The curve was generated based on the presence and age of onset of clinical symptoms in the 42 previously published cases and the 3 reported cases with germline heterozygous IKZF1 mutations.,, Manifesting subjects first presented with symptoms up to the age of 57 years. Asymptomatic cases were 50 years or younger at time of publication (ie, censored subjects, as indicated on the curve as black tick marks). The Kaplan-Meier symptom-free survival curve estimates that all IKZF1 mutation carriers will have symptoms by 57 years of age.
Fig 1
Fig 1. Molecular and functional characterization.
A, Pedigree. Squares, circles, and diamonds indicate male, female, and sex unknown, respectively. Diagonal lines indicate deceased siblings. Corresponding electropherograms are shown on the right. lab abn., Laboratory abnormalities. B, Schematic structure of IKAROS isoform 1 (IKZF1 transcript NM_006060). Gray boxes represent exons. Zinc fingers (ZF) 1 to 4 constitute the DNA binding domain, and ZF5 and ZF6 constitute the protein dimerization domain. Previously published mutations are depicted in black; 1 family had a large chromosomal deletion (7p12.3-p12.1) encompassing the IKZF1 gene. The reported novel mutation is indicated in red. C, IKZF1 mRNA expression was determined by means of real-time quantitative PCR of 2 amplicons located upstream and downstream of the mutation site, respectively. The cDNA start and end position of each amplicon is shown between brackets (IKZF1 transcript NM_006060). The 2 studied patients (II:3 and II:4) had similar IKZF1 mRNA levels compared with healthy control subjects (HC), indicating that the mutant transcripts escape nonsense-mediated mRNA decay. The graph represents the mean ± SD of 1 experiment. ns, Not significant. D, IKAROS protein expression in mutant (M/WT) and wild-type (WT/WT) family members and 3 healthy control subjects (HC) analyzed in CD31+ T cells by use of flow cytometry. Histograms are depicted on the left. The graph on the right displays mean ± SDs of the corresponding mean fluorescence intensity (MFI) values. Data shown are representative of 2 replicate experiments. FMO, Fluorescence minus one.
Fig 2
Fig 2. B-cell phenotype.
A, Peripheral blood total B-cell counts. Measurements shown are from the first to the last immunologic laboratory evaluation performed in our hospital. Gray shading represents the age-based reference range. B, Peripheral blood B-cell subsets. The top row depicts total B cells gated as CD19+CD20+ in alive PBMCs. In the second and third rows, B-cell subsets were gated on total CD19+CD20+ B cells, as indicated. Note that samples shown here were taken at different time points than those in Table E1. C, Overview of different precursor stages of B-cell development in bone marrow shown as a proportion of total Lin−CD45+, CD45+, or CD19+CD5− cells, as indicated. D, Bone marrow B-cell subsets. The top row depicts total B-lineage cells gated as CD19+CD5− in CD451 cells. In the second and third rows, B-lineage subsets were gated within this CD19+CD5− population. The middle graphs allow discrimination of pro-B cells (CD34+CD19+) from more mature B-lineage cells (CD34−CD19+). The lower graphs show the development from pro- and pre-B cells (pro-/pre-B; CD10+CD20−) over immature and transitional B cells (immature/strans B; CD10+CD20+) to mature naive B cells (mature B; CD10−CD20+). CLP, Common lymphoid progenitors; HC, healthy control subject; HSC, hematopoietic stem cells; imm., immature B; MPP, multipotent progenitors; MZB, marginal zone B cells; NB, naive B cells; SMB, switched memory B cells; Trans B, transitional B cells.
See this image and copyright information in PMC

References

    1. John LB, Ward AC. The Ikaros gene family: transcriptional regulators of hematopoiesis and immunity. Mol Immunol. 2011;48:1272–8. - PubMed
    1. Kuehn HS, Boisson B, Cunningham-Rundles C, Reichenbach J, Stray-Pedersen A, Gelfand EW, et al. Loss of B cells in patients with heterozygous mutations in IKAROS. N Engl J Med. 2016;374:1032–43. - PMC - PubMed
    1. Hoshino A, Okada S, Yoshida K, Nishida N, Okuno Y, Ueno H, et al. Abnormal hematopoiesis and autoimmunity in human subjects with germline IKZF1 mutations. J Allergy Clin Immunol. 2017;140:223–31. - PubMed
    1. Goldman FD, Gurel Z, Al-Zubeidi D, Fried AJ, Icardi M, Song C, et al. Congenital pancytopenia and absence of B lymphocytes in a neonate with a mutation in the Ikaros gene. Pediatr Blood Cancer. 2012;58:591–7. - PMC - PubMed
    1. Kakinuma S, Kodama Y, Amasaki Y, Yi S, Tokairin Y, Arai M, et al. Ikaros is a mutational target for lymphomagenesis in Mlh1-deficient mice. Oncogene. 2007;26:2945–9. - PubMed