Publications by authors named "Ulrich Pannicke"

48 Publications

A Novel Non-Coding Variant in DCLRE1C Results in Deregulated Splicing and Induces SCID Through the Generation of a Truncated ARTEMIS Protein That Fails to Support V(D)J Recombination and DNA Damage Repair.

Front Immunol 2021 17;12:674226. Epub 2021 Jun 17.

Department of Diagnostic Sciences, Ghent University, Ghent, Belgium.

Severe Combined Immune Deficiency (SCID) is a primary deficiency of the immune system in which opportunistic and recurring infections are often fatal during neonatal or infant life. SCID is caused by an increasing number of genetic defects that induce an abrogation of T lymphocyte development or function in which B and NK cells might be affected as well. Because of the increased availability and usage of next-generation sequencing (NGS), many novel variants in SCID genes are being identified and cause a heterogeneous disease spectrum. However, the molecular and functional implications of these new variants, of which some are non-coding, are often not characterized in detail. Using targeted NGS, we identified a novel homozygous c.465-1G>C splice acceptor site variant in the gene in a TBNK SCID patient and fully characterized the molecular and functional impact. By performing a minigene splicing reporter assay, we revealed deregulated splicing of the transcript since a cryptic splice acceptor in exon 7 was employed. This induced a frameshift and the generation of a p.Arg155Serfs*15 premature termination codon (PTC) within all splice variants, resulting in the absence of full-length ARTEMIS protein. Consistently, a V(D)J recombination assay and a G0 micronucleus assay demonstrated the inability of the predicted mutant ARTEMIS protein to perform V(D)J recombination and DNA damage repair, respectively. Together, these experiments molecularly and functionally clarify how a newly identified c.465-1G>C variant in the gene is responsible for inducing SCID. In a clinical context, this demonstrates how the experimental validation of new gene variants, that are identified by NGS, can facilitate the diagnosis of SCID which can be vital for implementing appropriate therapies.
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http://dx.doi.org/10.3389/fimmu.2021.674226DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8248492PMC
October 2021

Mutations of the gene FNIP1 associated with a syndromic autosomal recessive immunodeficiency with cardiomyopathy and pre-excitation syndrome.

Eur J Immunol 2020 07 20;50(7):1078-1080. Epub 2020 Apr 20.

Department of Pediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany.

AMPK (adenosine monophosphate-activated protein kinase) is phosphorylated (AMPK-P) in response to low energy through allosteric activation by Adenosine mono- or diphosphate (AMP/ADP). Folliculin (FLCN) and the FLCN-interacting proteins 1 and 2 (FNIP1, 2) modulate AMPK. FNIP1 deficiency patients have a AMPK-P gain of function phenotype with hypertrophic cardiomyopathy, Wolff-Parkinson-White pre-excitation syndrome, myopathy of skeletal muscles and combined immunodeficiency.
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http://dx.doi.org/10.1002/eji.201948504DOI Listing
July 2020

Human FCHO1 deficiency reveals role for clathrin-mediated endocytosis in development and function of T cells.

Nat Commun 2020 02 25;11(1):1031. Epub 2020 Feb 25.

Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany.

Clathrin-mediated endocytosis (CME) is critical for internalisation of molecules across cell membranes. The FCH domain only 1 (FCHO1) protein is key molecule involved in the early stages of CME formation. The consequences of mutations in FCHO1 in humans were unknown. We identify ten unrelated patients with variable T and B cell lymphopenia, who are homozygous for six distinct mutations in FCHO1. We demonstrate that these mutations either lead to mislocalisation of the protein or prevent its interaction with binding partners. Live-cell imaging of cells expressing mutant variants of FCHO1 provide evidence of impaired formation of clathrin coated pits (CCP). Patient T cells are unresponsive to T cell receptor (TCR) triggering. Internalisation of the TCR receptor is severely perturbed in FCHO1-deficient Jurkat T cells but can be rescued by expression of wild-type FCHO1. Thus, we discovered a previously unrecognised critical role of FCHO1 and CME during T-cell development and function in humans.
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http://dx.doi.org/10.1038/s41467-020-14809-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7042371PMC
February 2020

Human RIPK1 deficiency causes combined immunodeficiency and inflammatory bowel diseases.

Proc Natl Acad Sci U S A 2019 01 27;116(3):970-975. Epub 2018 Dec 27.

Department of Pediatrics, University Medical Center Ulm, 89081 Ulm, Germany.

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) is a critical regulator of cell death and inflammation, but its relevance for human disease pathogenesis remains elusive. Studies of monogenic disorders might provide critical insights into disease mechanisms and therapeutic targeting of RIPK1 for common diseases. Here, we report on eight patients from six unrelated pedigrees with biallelic loss-of-function mutations in presenting with primary immunodeficiency and/or intestinal inflammation. Mutations in were associated with reduced NF-κB activity, defective differentiation of T and B cells, increased inflammasome activity, and impaired response to TNFR1-mediated cell death in intestinal epithelial cells. The characterization of RIPK1-deficient patients highlights the essential role of RIPK1 in controlling human immune and intestinal homeostasis, and might have critical implications for therapies targeting RIPK1.
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http://dx.doi.org/10.1073/pnas.1813582116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6338855PMC
January 2019

Late thymic deficiency after HLA-haploidentical hematopoietic stem cell transplantation for severe combined immunodeficiency.

J Allergy Clin Immunol 2019 04 7;143(4):1623-1626.e13. Epub 2018 Dec 7.

Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm, Germany. Electronic address:

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http://dx.doi.org/10.1016/j.jaci.2018.11.027DOI Listing
April 2019

Recent advances in understanding the pathogenesis and management of reticular dysgenesis.

Br J Haematol 2018 03 21;180(5):644-653. Epub 2017 Dec 21.

Institute for Transfusion Medicine, University of Ulm, Ulm, Germany.

Reticular Dysgenesis is a rare immunodeficiency which is clinically characterized by the combination of Severe Combined Immunodeficiency (SCID) with agranulocytosis and sensorineural deafness. Mutations in the gene encoding adenylate kinase 2 (AK2) were identified to cause this phenotype. In this review, we will demonstrate important clinical differences between reticular dysgenesis and other SCID entities and summarize recent concepts in the understanding of the pathophysiology of the disease and the management strategies for this difficult condition.
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http://dx.doi.org/10.1111/bjh.15045DOI Listing
March 2018

Bone marrow failure unresponsive to bone marrow transplant is caused by mutations in .

Blood 2017 08 30;130(7):875-880. Epub 2017 May 30.

Department of Pediatric Hematology/Oncology, Boston Children's Hospital/Dana-Farber Cancer Institute/Harvard Medical School, Boston, MA; and.

We report 5 individuals in 3 unrelated families with severe thrombocytopenia progressing to trilineage bone marrow failure (BMF). Four of the children received hematopoietic stem cell transplants and all showed poor graft function with persistent severe cytopenias even after repeated transplants with different donors. Exome and targeted sequencing identified mutations in the gene encoding thrombopoietin (): THPO R99W, homozygous in affected children in 2 families, and THPO R157X, homozygous in the affected child in the third family. Both mutations result in a lack of THPO in the patients' serum. For the 2 surviving patients, improvement in trilineage hematopoiesis was achieved following treatment with a THPO receptor agonist. These studies demonstrate that biallelic loss-of-function mutations in cause BMF, which is unresponsive to transplant due to a hematopoietic cell-extrinsic mechanism. These studies provide further support for the critical role of the MPL-THPO pathway in hematopoiesis and highlight the importance of accurate genetic diagnosis to inform treatment decisions for BMF.
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http://dx.doi.org/10.1182/blood-2017-02-768036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5561901PMC
August 2017

Clinical and Molecular Heterogeneity of RTEL1 Deficiency.

Front Immunol 2017 1;8:449. Epub 2017 May 1.

Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, Medical Centre, Faculty of Medicine, University of Freiburg, Freiburg, Germany.

Typical features of dyskeratosis congenita (DC) resulting from excessive telomere shortening include bone marrow failure (BMF), mucosal fragility, and pulmonary or liver fibrosis. In more severe cases, immune deficiency and recurring infections can add to disease severity. RTEL1 deficiency has recently been described as a major genetic etiology, but the molecular basis and clinical consequences of RTEL1-associated DC are incompletely characterized. We report our observations in a cohort of six patients: five with novel biallelic mutations p.Trp456Cys, p.Ile425Thr, p.Cys1244ProfsX17, p.Pro884_Gln885ins53X13, and one with novel heterozygous mutation p.Val796AlafsX4. The most unifying features were hypocellular BMF in 6/6 and B-/NK-cell lymphopenia in 5/6 patients. In addition, three patients with homozygous mutations p.Trp456Cys or p.Ile425Thr also suffered from immunodeficiency, cerebellar hypoplasia, and enteropathy, consistent with Hoyeraal-Hreidarsson syndrome. Chromosomal breakage resembling a homologous recombination defect was detected in patient-derived fibroblasts but not in hematopoietic compartment. Notably, in both cellular compartments, differential expression of 1243aa and 1219/1300aa RTEL1 isoforms was observed. In fibroblasts, response to ionizing irradiation and non-homologous end joining were not impaired. Telomeric circles did not accumulate in patient-derived primary cells and lymphoblastoid cell lines, implying alternative pathomechanisms for telomeric loss. Overall, RTEL1-deficient cells exhibited a phenotype of replicative exhaustion, spontaneous apoptosis and senescence. Specifically, CD34 cells failed to expand , B-cell development was compromised, and T-cells did not proliferate in long-term culture. Finally, we report on the natural history and outcome of our patients. While two patients died from infections, hematopoietic stem cell transplantation (HSCT) resulted in sustained engraftment in two patients. Whether chemotherapy negatively impacts on the course and onset of other DC-related symptoms remains open at present. Early-onset lung disease occurred in one of our patients after HSCT. In conclusion, RTEL deficiency can show a heterogeneous clinical picture ranging from mild hypocellular BMF with B/NK cell lymphopenia to early-onset, very severe, and rapidly progressing cellular deficiency.
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http://dx.doi.org/10.3389/fimmu.2017.00449DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5410638PMC
May 2017

Reticular dysgenesis: international survey on clinical presentation, transplantation, and outcome.

Blood 2017 05 22;129(21):2928-2938. Epub 2017 Mar 22.

Institute for Transfusion Medicine, University of Ulm, Ulm, Germany.

Reticular dysgenesis (RD) is a rare congenital disorder defined clinically by the combination of severe combined immunodeficiency (SCID), agranulocytosis, and sensorineural deafness. Mutations in the gene encoding adenylate kinase 2 were identified to cause the disorder. Hematopoietic stem cell transplantation (HSCT) is the only option to cure this otherwise fatal disease. Retrospective data on clinical presentation, genetics, and outcome of HSCT were collected from centers in Europe, Asia, and North America for a total of 32 patients born between 1982 and 2011. Age at presentation was <4 weeks in 30 of 32 patients (94%). Grafts originated from mismatched family donors in 17 patients (55%), from matched family donors in 6 patients (19%), and from unrelated marrow or umbilical cord blood donors in 8 patients (26%). Thirteen patients received secondary or tertiary transplants. After transplantation, 21 of 31 patients were reported alive at a mean follow-up of 7.9 years (range: 0.6-23.6 years). All patients who died beyond 6 months after HSCT had persistent or recurrent agranulocytosis due to failure of donor myeloid engraftment. In the absence of conditioning, HSCT was ineffective to overcome agranulocytosis, and inclusion of myeloablative components in the conditioning regimens was required to achieve stable lymphomyeloid engraftment. In comparison with other SCID entities, considerable differences were noted regarding age at presentation, onset, and type of infectious complications, as well as the requirement of conditioning prior to HSCT. Although long-term survival is possible in the presence of mixed chimerism, high-level donor myeloid engraftment should be targeted to avoid posttransplant neutropenia.
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http://dx.doi.org/10.1182/blood-2016-11-745638DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5445572PMC
May 2017

Evaluation of RAG1 mutations in an adult with combined immunodeficiency and progressive multifocal leukoencephalopathy.

Clin Immunol 2017 06 20;179:1-7. Epub 2017 Feb 20.

Department for Clinical Immunology and Rheumatology, Hannover Medical School, Germany. Electronic address:

Here we describe novel mutations in recombination activation gene 1 (RAG1) in a compound heterozygous male patient with combined T and B cell immunodeficiency (CID). Clinical manifestations besides antibody deficiency included airway infections, granulomatosis and autoimmune features. He died at the age of 37 due to PML caused by JC virus infection. By targeted next-generation sequencing we detected post mortem in this patient three mutations in RAG1. One allele harbored two novel mutations (c.1123C>G, p.H375D and c.1430delC, p.F478Sfs*14), namely a missense variant and a frameshift deletion, of which the latter leads to a truncated RAG1 protein. The other allele revealed a previously described missense mutation (c.1420C>T, p.R474C, rs199474678). Functional analysis of the p.R474C variant in an in vitro V(D)J recombination assay exhibited reduced recombination activity compared to a wild-type control. Our findings suggest that mutations in RAG1, specifically the p.R474C variant, can be associated with relatively mild clinical symptoms or delayed occurrence of T cell and B cell deficiencies but may predispose to PML.
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http://dx.doi.org/10.1016/j.clim.2016.12.013DOI Listing
June 2017

Transplantation from a symptomatic carrier sister restores host defenses but does not prevent colitis in NEMO deficiency.

Clin Immunol 2016 Mar 23;164:52-6. Epub 2016 Jan 23.

Center of Chronic Immunodeficiency, University Medical Center Freiburg, Germany; Center for Pediatrics and Adolescent Medicine, University Medical Center Freiburg, Germany. Electronic address:

NF-κB essential modulator (NEMO) deficiency causes ectodermal dysplasia with immunodeficiency in males, while manifesting as incontinentia pigmenti in heterozygous females. We report a family with NEMO deficiency, in which a female carrier displayed skewed X-inactivation favoring the mutant NEMO allele associated with symptoms of Behçet's disease. Hematopoietic stem cell transplantation of an affected boy from this donor reconstituted an immune system with retained skewed X-inactivation. After transplantation no more severe infections occurred, indicating that an active wild-type NEMO allele in only 10% of immune cells restores host defense. Yet he developed inflammatory bowel disease (IBD). While gut infiltrating immune cells stained strongly for nuclear p65 indicating restored NEMO function, this was not the case in intestinal epithelial cells - in contrast to cells from conventional IBD patients. These results extend murine observations that epithelial NEMO-deficiency suffices to cause IBD. High anti-TNF doses controlled the intestinal inflammation and symptoms of Behçet's disease.
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http://dx.doi.org/10.1016/j.clim.2016.01.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6101191PMC
March 2016

MCM3AP and POMP Mutations Cause a DNA-Repair and DNA-Damage-Signaling Defect in an Immunodeficient Child.

Hum Mutat 2016 Mar 30;37(3):257-68. Epub 2015 Dec 30.

Department of Obstetrics and Gynecology, Ulm University, Ulm, D-89075, Germany.

Immunodeficiency patients with DNA repair defects exhibit radiosensitivity and proneness to leukemia/lymphoma formation. Though progress has been made in identifying the underlying mutations, in most patients the genetic basis is unknown. Two de novo mutated candidate genes, MCM3AP encoding germinal center-associated nuclear protein (GANP) and POMP encoding proteasome maturation protein (POMP), were identified by whole-exome sequencing (WES) and confirmed by Sanger sequencing in a child with complex phenotype displaying immunodeficiency, genomic instability, skin changes, and myelodysplasia. GANP was previously described to promote B-cell maturation by nuclear targeting of activation-induced cytidine deaminase (AID) and to control AID-dependent hyperrecombination. POMP is required for 20S proteasome assembly and, thus, for efficient NF-κB signaling. Patient-derived cells were characterized by impaired homologous recombination, moderate radio- and cross-linker sensitivity associated with accumulation of damage, impaired DNA damage-induced NF-κB signaling, and reduced nuclear AID levels. Complementation by wild-type (WT)-GANP normalized DNA repair and WT-POMP rescued defective NF-κB signaling. In conclusion, we identified for the first time mutations in MCM3AP and POMP in an immunodeficiency patient. These mutations lead to cooperative effects on DNA recombination and damage signaling. Digenic/polygenic mutations may constitute a novel genetic basis in immunodeficiency patients with DNA repair defects.
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http://dx.doi.org/10.1002/humu.22939DOI Listing
March 2016

DCLRE1C (ARTEMIS) mutations causing phenotypes ranging from atypical severe combined immunodeficiency to mere antibody deficiency.

Hum Mol Genet 2015 Dec 16;24(25):7361-72. Epub 2015 Oct 16.

Center for Chronic Immunodeficiency (CCI), University Medical Center Freiburg and University of Freiburg, Freiburg, Germany, Institute of Immunity and Transplantation, University College London, Royal Free Campus, London, UK

Null mutations in genes involved in V(D)J recombination cause a block in B- and T-cell development, clinically presenting as severe combined immunodeficiency (SCID). Hypomorphic mutations in the non-homologous end-joining gene DCLRE1C (encoding ARTEMIS) have been described to cause atypical SCID, Omenn syndrome, Hyper IgM syndrome and inflammatory bowel disease-all with severely impaired T-cell immunity. By whole-exome sequencing, we investigated the molecular defect in a consanguineous family with three children clinically diagnosed with antibody deficiency. We identified perfectly segregating homozygous variants in DCLRE1C in three index patients with recurrent respiratory tract infections, very low B-cell numbers and serum IgA levels. In patients, decreased colony survival after irradiation, impaired proliferative response and reduced counts of naïve T cells were observed in addition to a restricted T-cell receptor repertoire, increased palindromic nucleotides in the complementarity determining regions 3 and long stretches of microhomology at switch junctions. Defective V(D)J recombination was complemented by wild-type ARTEMIS protein in vitro. Subsequently, homozygous or compound heterozygous DCLRE1C mutations were identified in nine patients from the same geographic region. We demonstrate that DCLRE1C mutations can cause a phenotype presenting as only antibody deficiency. This novel association broadens the clinical spectrum associated with ARTEMIS mutations. Clinicians should consider the possibility that an immunodeficiency with a clinically mild initial presentation could be a combined immunodeficiency, so as to provide appropriate care for affected patients.
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http://dx.doi.org/10.1093/hmg/ddv437DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4664172PMC
December 2015

Omenn syndrome associated with a functional reversion due to a somatic second-site mutation in CARD11 deficiency.

Blood 2015 Oct 19;126(14):1658-69. Epub 2015 Aug 19.

Center for Chronic Immunodeficiency (CCI), University Medical Center and University of Freiburg, Freiburg, Germany; Center of Pediatric and Adolescent Medicine, University Medical Center and University of Freiburg, Freiburg, Germany;

Omenn syndrome (OS) is a severe immunodeficiency associated with erythroderma, lymphoproliferation, elevated IgE, and hyperactive oligoclonal T cells. A restricted T-cell repertoire caused by defective thymic T-cell development and selection, lymphopenia with homeostatic proliferation, and lack of regulatory T cells are considered key factors in OS pathogenesis. We report 2 siblings presenting with cytomegalovirus (CMV) and Pneumocystis jirovecii infections and recurrent sepsis; one developed all clinical features of OS. Both carried homozygous germline mutations in CARD11 (p.Cys150*), impairing NF-κB signaling and IL-2 production. A somatic second-site mutation reverting the stop codon to a missense mutation (p.Cys150Leu) was detected in tissue-infiltrating T cells of the OS patient. Expression of p.Cys150Leu in CARD11-deficient T cells largely reconstituted NF-κB signaling. The reversion likely occurred in a prethymic T-cell precursor, leading to a chimeric T-cell repertoire. We speculate that in our patient the functional advantage of the revertant T cells in the context of persistent CMV infection, combined with lack of regulatory T cells, may have been sufficient to favor OS. This first observation of OS in a patient with a T-cell activation defect suggests that severely defective T-cell development or homeostatic proliferation in a lymphopenic environment are not required for this severe immunopathology.
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http://dx.doi.org/10.1182/blood-2015-03-631374DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4654427PMC
October 2015

Targeted therapy with eculizumab for inherited CD59 deficiency.

N Engl J Med 2014 Jan;370(1):90-2

German Red Cross Blood Transfusion Service Baden-Württemberg-Hessen, Ulm, Germany

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http://dx.doi.org/10.1056/NEJMc1308104DOI Listing
January 2014

Deficiency of innate and acquired immunity caused by an IKBKB mutation.

N Engl J Med 2013 Dec;369(26):2504-14

From the Institute for Transfusion Medicine, University Hospital Ulm (U.P., C.L., H.S., K.S.), the Institute of Physiological Chemistry (B.B., T.W.), the Center for Biomedical Research, Genomics Core Facility (K. Holzmann), University of Ulm, and the Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Service Baden-Wuerttemberg-Hessen (E.-M.R., H.S., K.S.), Ulm; the Center of Chronic Immunodeficiency, University Medical Center Freiburg (S.F., P.H., A.R.-E., K. Hese, M.R., A.J., M.S., S.E.), the Faculty of Biology, University of Freiburg (S.F.), the Center for Pediatrics and Adolescent Medicine (P.H., S.E.), and the Department of Rheumatology and Clinical Immunology (M.S.), University Hospital Freiburg, Freiburg; and the Translational Center for Regenerative Medicine, University of Leipzig, Leipzig (S.B.) - all in Germany; the Division of Clinical Immunology and Transfusion Medicine, Department of Laboratory Medicine, Karolinska Institute, Karolinska University Hospital Huddinge, Stockholm (S.B.); and the Department of Pediatrics, University of Saskatchewan, Saskatoon (A.R.), and the Departments of Biochemistry and Medical Genetics (T.Z.) and Pediatrics and Child Health (T.Z., M.L.S.), University of Manitoba, Winnipeg - both in Canada.

Background: Severe combined immunodeficiency (SCID) comprises a heterogeneous group of heritable deficiencies of humoral and cell-mediated immunity. Many patients with SCID have lymphocyte-activation defects that remain uncharacterized.

Methods: We performed genetic studies in four patients, from four families of Northern Cree ancestry, who had clinical characteristics of SCID, including early onset of severe viral, bacterial, and fungal infections despite normal B-cell and T-cell counts. Genomewide homozygosity mapping was used to identify a candidate region, which was found on chromosome 8; all genes within this interval were sequenced. Immune-cell populations, signal transduction on activation, and effector functions were studied.

Results: The patients had hypogammaglobulinemia or agammaglobulinemia, and their peripheral-blood B cells and T cells were almost exclusively of naive phenotype. Regulatory T cells and γδ T cells were absent. All patients carried a homozygous duplication--c.1292dupG in exon 13 of IKBKB, which encodes IκB kinase 2 (IKK2, also known as IKKβ)--leading to loss of expression of IKK2, a component of the IKK-nuclear factor κB (NF-κB) pathway. Immune cells from the patients had impaired responses to stimulation through T-cell receptors, B-cell receptors, toll-like receptors, inflammatory cytokine receptors, and mitogens.

Conclusions: A form of human SCID is characterized by normal lymphocyte development despite a loss of IKK2 function. IKK2 deficiency results in an impaired response to activation stimuli in a variety of immune cells, leading to clinically relevant impairment of adaptive and innate immunity. Although Ikk2 deficiency is lethal in mouse embryos, our observations suggest a more restricted, unique role of IKK2-NF-κB signaling in humans. (Funded by the German Federal Ministry of Education and Research and others.).
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http://dx.doi.org/10.1056/NEJMoa1309199DOI Listing
December 2013

Lesson from hypomorphic recombination-activating gene (RAG) mutations: Why asymptomatic siblings should also be tested.

J Allergy Clin Immunol 2014 Apr 10;133(4):1211-5. Epub 2013 Dec 10.

Institute for Transfusion Medicine, University of Ulm, Ulm, Germany; Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Service, Baden-Württemberg-Hessen, Germany.

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http://dx.doi.org/10.1016/j.jaci.2013.10.021DOI Listing
April 2014

SCID patients with ARTEMIS vs RAG deficiencies following HCT: increased risk of late toxicity in ARTEMIS-deficient SCID.

Blood 2014 Jan 21;123(2):281-9. Epub 2013 Oct 21.

Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm, Germany;

A subgroup of severe combined immunodeficiencies (SCID) is characterized by lack of T and B cells and is caused by defects in genes required for T- and B-cell receptor gene rearrangement. Several of these genes are also involved in nonhomologous end joining of DNA double-strand break repair, the largest subgroup consisting of patients with T(-)B(-)NK(+)SCID due to DCLRE1C/ARTEMIS defects. We postulated that in patients with ARTEMIS deficiency, early and late complications following hematopoietic cell transplantation might be more prominent compared with patients with T(-)B(-)NK(+)SCID caused by recombination activating gene 1/2 (RAG1/2) deficiencies. We analyzed 69 patients with ARTEMIS and 76 patients with RAG1/2 deficiencies who received transplants from either HLA-identical donors without conditioning or from HLA-nonidentical donors without or with conditioning. There was no difference in survival or in the incidence or severity of acute graft-versus-host disease regardless of exposure to alkylating agents. Secondary malignancies were not observed. Immune reconstitution was comparable in both groups, however, ARTEMIS-deficient patients had a significantly higher occurrence of infections in long-term follow-up. There is a highly significant association between poor growth in ARTEMIS deficiency and use of alkylating agents. Furthermore, abnormalities in dental development and endocrine late effects were associated with alkylation therapy in ARTEMIS deficiency.
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http://dx.doi.org/10.1182/blood-2013-01-476432DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3953035PMC
January 2014

Dihydrofolate reductase deficiency due to a homozygous DHFR mutation causes megaloblastic anemia and cerebral folate deficiency leading to severe neurologic disease.

Am J Hum Genet 2011 Feb;88(2):226-31

Department of Pediatrics and Adolescent Medicine, University Hospital, Ulm, Germany.

The importance of intracellular folate metabolism is illustrated by the severity of symptoms and complications caused by inborn disorders of folate metabolism or by folate deficiency. We examined three children of healthy, distantly related parents presenting with megaloblastic anemia and cerebral folate deficiency causing neurologic disease with atypical childhood absence epilepsy. Genome-wide homozygosity mapping revealed a candidate region on chromosome 5 including the dihydrofolate reductase (DHFR) locus. DHFR sequencing revealed a homozygous DHFR mutation, c.458A>T (p.Asp153Val), in all siblings. The patients' folate profile in red blood cells (RBC), plasma, and cerebrospinal fluid (CSF), analyzed by liquid chromatography tandem mass spectrometry, was compatible with DHFR deficiency. DHFR activity and fluorescein-labeled methotrexate (FMTX) binding were severely reduced in EBV-immortalized lymphoblastoid cells of all patients. Heterozygous cells displayed intermediate DHFR activity and FMTX binding. RT-PCR of DHFR mRNA revealed no differences between wild-type and DHFR mutation-carrying cells, whereas protein expression was reduced in cells with the DHFR mutation. Treatment with folinic acid resulted in the resolution of hematological abnormalities, normalization of CSF folate levels, and improvement of neurological symptoms. In conclusion, the homozygous DHFR mutation p.Asp153Val causes DHFR deficiency and leads to a complex hematological and neurological disease that can be successfully treated with folinic acid. DHFR is necessary for maintaining sufficient CSF and RBC folate levels, even in the presence of adequate nutritional folate supply and normal plasma folate.
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http://dx.doi.org/10.1016/j.ajhg.2011.01.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3035706PMC
February 2011

Regulated expression of nuclear receptor RORγt confers distinct functional fates to NK cell receptor-expressing RORγt(+) innate lymphocytes.

Immunity 2010 Nov;33(5):736-51

IMMH, Institute of Medical Microbiology & Hygiene, University of Freiburg, 79104 Freiburg, Germany.

Whether the recently identified innate lymphocyte population coexpressing natural killer cell receptors (NKRs) and the nuclear receptor RORγt is part of the NK or lymphoid tissue inducer (LTi) cell lineage remains unclear. By using adoptive transfer of genetically tagged LTi-like cells, we demonstrate that NKR⁻RORγt(+) innate lymphocytes but not NK cells were direct progenitors to NKR(+)RORγt(+) cells in vivo. Genetic lineage tracing revealed that the differentiation of LTi-like cells was characterized by the stable upregulation of NKRs and a progressive loss of RORγt expression. Whereas interleukin-7 (IL-7) and intestinal microbiota stabilized RORγt expression within such NKR-LTi cells, IL-12 and IL-15 accelerated RORγt loss. RORγt(+) NKR-LTi cells produced IL-22, whereas RORγt⁻ NKR-LTi cells released IFN-γ and were potent inducers of colitis. Thus, the RORγt gradient in NKR-LTi cells serves as a tunable rheostat for their functional program. Our data also define a previously unappreciated role of RORγt⁻ NKR-LTi cells for the onset or maintenance of inflammatory bowel diseases.
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http://dx.doi.org/10.1016/j.immuni.2010.10.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3042726PMC
November 2010

Chronic inflammatory bowel disease as key manifestation of atypical ARTEMIS deficiency.

J Clin Immunol 2010 Mar 5;30(2):314-20. Epub 2009 Dec 5.

Centre of Pediatrics and Adolescent Medicine, University Medical Center, Freiburg, Germany.

Introduction: We describe a girl presenting at age 6 years with a history of chronic ulcerating intestinal inflammation since 9 months of age. She exhibited a severe, steroid-dependent clinical course of intestinal inflammation over several years in the absence of serious infections.

Results And Discussion: Immunodeficiency was first considered at 6 years of age due to chronic lymphopenia. Immunophenotyping revealed low B and T cell counts with few naïve T cells, a skewed TCR repertoire, and TCR gamma/delta T cell predominance, suggesting a defect of lymphocyte development. Genetic and functional analyses identified a hypomorphic mutation in the DCLRE1C (ARTEMIS) gene compromising V(D)J recombination efficiency, but allowing residual T and B cell development. Hematopoetic stem cell transplantation reconstituted the lymphocyte compartment and cured the inflammatory bowel disease.

Conclusion: This report illustrates that a genetic disorder of lymphocyte development can present with chronic inflammatory bowel disease as the dominant phenotype in the absence of severe infection susceptibility.
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http://dx.doi.org/10.1007/s10875-009-9349-xDOI Listing
March 2010

The most frequent DCLRE1C (ARTEMIS) mutations are based on homologous recombination events.

Hum Mutat 2010 Feb;31(2):197-207

Institute for Transfusion Medicine, University of Ulm, Ulm, Germany.

The nuclease ARTEMIS is an essential factor of V(D)J recombination during lymphocyte development and in the repair of DNA double-strand breaks (DSB) by the nonhomologous end joining (NHEJ) pathway. Patients with mutations in the DCLRE1C gene, which encodes ARTEMIS, suffer from radiosensitive B(-/low) T(-/low) severe combined immunodeficiency (SCID) or radiosensitive Omenn syndrome. To date, causative DCLRE1C mutations inherited as a recessive trait have been reported in 49 patients. In this study, molecular diagnoses of 29 novel patients presenting with the phenotype of B(-/low) SCID revealed mutations in the DCLRE1C gene. In total, 13 different mutated DCLRE1C alleles were detected, nine of which have not been described before. By far the most frequent mutations (59%) were gross deletions of exons 1-3 or exons 1-4 due to a homologous recombination of the wild-type DCLRE1C gene with a pseudo-DCLRE1C gene located 61.2 kb 5' to the DCLRE1C start codon. Fine mapping of the recombination intervals revealed private mutations in most cases. MEIG1, a gene encoding a protein that is essential for spermatogenesis in mice, is lost by the gross deletions. Functional analyses on patients' fibroblasts demonstrated that the corresponding alleles carry null mutations of the DCLRE1C gene.
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http://dx.doi.org/10.1002/humu.21168DOI Listing
February 2010

Mutations affecting the secretory COPII coat component SEC23B cause congenital dyserythropoietic anemia type II.

Nat Genet 2009 Aug 28;41(8):936-40. Epub 2009 Jun 28.

Institute for Transfusion Medicine, University of Ulm, Ulm, Germany.

Congenital dyserythropoietic anemias (CDAs) are phenotypically and genotypically heterogeneous diseases. CDA type II (CDAII) is the most frequent CDA. It is characterized by ineffective erythropoiesis and by the presence of bi- and multinucleated erythroblasts in bone marrow, with nuclei of equal size and DNA content, suggesting a cytokinesis disturbance. Other features of the peripheral red blood cells are protein and lipid dysglycosylation and endoplasmic reticulum double-membrane remnants. Development of other hematopoietic lineages is normal. Individuals with CDAII show progressive splenomegaly, gallstones and iron overload potentially with liver cirrhosis or cardiac failure. Here we show that the gene encoding the secretory COPII component SEC23B is mutated in CDAII. Short hairpin RNA (shRNA)-mediated suppression of SEC23B expression recapitulates the cytokinesis defect. Knockdown of zebrafish sec23b also leads to aberrant erythrocyte development. Our results provide in vivo evidence for SEC23B selectivity in erythroid differentiation and show that SEC23A and SEC23B, although highly related paralogous secretory COPII components, are nonredundant in erythrocyte maturation.
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http://dx.doi.org/10.1038/ng.405DOI Listing
August 2009

Reticular dysgenesis (aleukocytosis) is caused by mutations in the gene encoding mitochondrial adenylate kinase 2.

Nat Genet 2009 Jan 30;41(1):101-5. Epub 2008 Nov 30.

Institute for Transfusion Medicine, University of Ulm, Ulm, Germany.

Human severe combined immunodeficiencies (SCID) are phenotypically and genotypically heterogeneous diseases. Reticular dysgenesis is the most severe form of inborn SCID. It is characterized by absence of granulocytes and almost complete deficiency of lymphocytes in peripheral blood, hypoplasia of the thymus and secondary lymphoid organs, and lack of innate and adaptive humoral and cellular immune functions, leading to fatal septicemia within days after birth. In bone marrow of individuals with reticular dysgenesis, myeloid differentiation is blocked at the promyelocytic stage, whereas erythro- and megakaryocytic maturation is generally normal. These features exclude a defect in hematopoietic stem cells but point to a unique aberration of the myelo-lymphoid lineages. The dramatic clinical course of reticular dysgenesis and its unique hematological phenotype have spurred interest in the unknown genetic basis of this syndrome. Here we show that the gene encoding the mitochondrial energy metabolism enzyme adenylate kinase 2 (AK2) is mutated in individuals with reticular dysgenesis. Knockdown of zebrafish ak2 also leads to aberrant leukocyte development, stressing the evolutionarily conserved role of AK2. Our results provide in vivo evidence for AK2 selectivity in leukocyte differentiation. These observations suggest that reticular dysgenesis is the first example of a human immunodeficiency syndrome that is causally linked to energy metabolism and that can therefore be classified as a mitochondriopathy.
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http://dx.doi.org/10.1038/ng.265DOI Listing
January 2009

Clinical and immunologic consequences of a somatic reversion in a patient with X-linked severe combined immunodeficiency.

Blood 2008 Nov 26;112(10):4090-7. Epub 2008 Aug 26.

Center for Paediatrics and Adolescent Medicine, University of Freiburg, Freiburg, Germany.

X-linked severe combined immunodeficiency is a life-threatening disorder caused by mutations in the gene encoding the interleukin-2 receptor gamma chain (IL2RG). Hypomorphic mutations and reversion of mutations in subpopulations of cells can result in variant clinical phenotypes, making diagnosis and treatment difficult. We describe a 5-year-old boy with mild susceptibility to infection who was investigated for a mutation in IL2RG due to persistent natural killer (NK)- and T-cell lymphopenia. A functionally relevant novel T466C point mutation was found in B, NK, and epithelial cells, whereas alpha/beta and gamma/delta T cells showed the normal gene sequence, suggesting reversion of the mutation in a common T-cell precursor. This genetic correction in T cells resulted in a diverse T-cell repertoire and significant immunity despite failure to produce specific antibodies linked to an intrinsic defect of mutant B cells. These observations confirm the potential of revertant T-cell precursors to reconstitute immune function, but questions remain on the longevity of revertant cells implicating the need for careful follow up and early consideration of hematopoietic stem cell transplantation (HSCT).
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http://dx.doi.org/10.1182/blood-2008-04-153361DOI Listing
November 2008

DNA-ligase IV and DNA-protein kinase play a critical role in deficient caspases activation in apoptosis-resistant cancer cells by using doxorubicin.

Mol Biol Cell 2008 Aug 28;19(8):3283-9. Epub 2008 May 28.

Institute of Legal Medicine, University of Ulm, 89075 Ulm, Germany.

Resistance toward cytotoxic drugs is one of the primary causes for therapeutic failure in cancer therapy. DNA repair mechanisms as well as deficient caspases activation play a critical role in apoptosis resistance of tumor cells toward anticancer drug treatment. Here, we discovered that deficient caspases activation in apoptosis-resistant cancer cells depends on DNA-ligase IV and DNA-protein kinase (DNA-PK), playing crucial roles in the nonhomologous end joining (NHEJ) pathway, which is the predominant pathway for DNA double-strand break repair (DNA-DSB-repair) in mammalian cells. DNA-PK(+/+) as well as DNA-ligase IV (+/+) cancer cells were apoptosis resistant and deficient in activation of caspase-3, caspase-9, and caspase-8 and in cleavage of poly(ADP-ribose) polymerase after doxorubicin treatment. Inhibition of NHEJ by knocking out DNA-PK or DNA-ligase IV restored caspases activation and apoptosis sensitivity after doxorubicin treatment. In addition, inhibition of caspases activation prevented doxorubicin-induced apoptosis but could not prevent doxorubicin-induced DNA damage, indicating that induction of DNA damage is independent of caspases activation. However, caspases activation depends on induction of DNA damage left unrepaired by NHEJ-DNA-DSB-repair. We conclude that DNA damage left unrepaired by DNA-ligase IV or DNA-PK might be the initiator for caspases activation by doxorubicin in cancer cells. Failure in caspases activation using doxorubicin depends on loss of DNA damage and is due to higher rates of NHEJ-DNA-DBS-repair.
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http://dx.doi.org/10.1091/mbc.e08-03-0306DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2488297PMC
August 2008
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