Research

Proven and novel strategies for efficient editing of the human genome.

Curr Opin Pharmacol. 2015 Sep 3;24:105-112

Authors: Mussolino C, Mlambo T, Cathomen T

Abstract
Targeted gene editing with designer nucleases has become increasingly popular. The most commonly used designer nuclease platforms are engineered meganucleases, zinc-finger nucleases, transcription activator-like effector nucleases and the clustered regularly interspaced short palindromic repeat/Cas9 system. These powerful tools have greatly facilitated the generation of plant and animal models for basic research, and harbor an enormous potential for applications in biotechnology and gene therapy. This review recapitulates proven concepts of targeted genome engineering in primary human cells and elaborates on novel concepts that became possible with the dawn of RNA-guided nucleases and RNA-guided transcription factors.

PMID: 26342909 [PubMed – as supplied by publisher]

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Altered B-cell subsets and functional B-cell defects in selective IgM deficiency.

Clin Immunol. 2015 Sep 2;

Authors: Mensen A, Krause T, Hanitsch LG, Meisel C, Kleint ME, Volk HD, Na IK, Scheibenbogen C

PMID: 26342539 [PubMed – as supplied by publisher]

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BTK Signaling in B Cell Differentiation and Autoimmunity.

Curr Top Microbiol Immunol. 2015 Sep 5;

Authors: Corneth OB, Klein Wolterink RG, Hendriks RW

Abstract
Since the original identification of Bruton’s tyrosine kinase (BTK) as the gene defective in the primary immunodeficiency X-linked agammaglobulinemia (XLA) in 1993, our knowledge on the physiological function of BTK has expanded impressively. In this review, we focus on the role of BTK during B cell differentiation in vivo, both in the regulation of expansion and in the developmental progression of pre-B cells in the bone marrow and as a crucial signal transducer of signals downstream of the IgM or IgG B cell antigen receptor (BCR) in mature B cells governing proliferation, survival, and differentiation. In particular, we highlight BTK function in B cells in the context of host defense and autoimmunity. Small-molecule inhibitors of BTK have very recently shown impressive anti-tumor activity in clinical studies in patients with various B cell malignancies. Since promising effects of BTK inhibition were also seen in experimental animal models for lupus and rheumatoid arthritis, BTK may be a good target for controlling autoreactive B cells in patients with systemic autoimmune disease.

PMID: 26341110 [PubMed – as supplied by publisher]

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Subcutaneous Immunoglobulin Replacement Therapy with Hizentra® is Safe and Effective in Children Less Than 5 Years of Age.

J Clin Immunol. 2015 Sep 4;

Authors: Patel NC, Gallagher JL, Ochs HD, Prescott Atkinson T, Wahlstrom J, Dorsey M, Bonilla FA, Heimall J, Kobrynski L, Morris D, Haddad E

Abstract
BACKGROUND: Hizentra® (IGSC 20 %) is a 20 % liquid IgG product approved for subcutaneous administration in adults and children 2 years of age and older who have primary immunodeficiency disease (PIDD). There is limited information about the use of IGSC 20 % in very young children including those less than 5 years of age.
METHODS: A retrospective chart review involved 88 PIDD infants and children less than 5 years of age who received Hizentra®.
RESULTS: The mean age at the start of Hizentra® was 34 months (range 2 to 59 months). IGSC 20 % was administered weekly to 86 infants (two additional infants received twice weekly and three times weekly infusions, respectively) and included an average of 63 infusions (range 6-182) for an observation period up to 45.5 months. Infusion by manual delivery occurred in 15 patients. The mean dose was 674 mg/kg/4 weeks. The mean IgG level was 942 mg/dL while on IGSC 20 %, compared to a mean trough IgG level of 794 mg/dL (p < 0.0001) during intravenous or subcutaneous IgG administration prior to IGSC 20 %. Average infusion time was 47 (range 5-120) minutes, and the median number of infusion sites was 2 (range 1-4). Local reactions were mostly mild and observed in 36/88 (41 %) children. No serious adverse events were reported. A significant increase in weight percentile (7 % ± 19.2, p = 0.0012) among subjects was observed during IGSC 20 % administration. The rate of serious bacterial infections was 0.067 per patient-year while receiving IGSC 20 %, similar to previously reported efficacy studies.
CONCLUSIONS: Hizentra® is effective in preventing infections, and is well tolerated in children less than age 5 years.

PMID: 26336818 [PubMed – as supplied by publisher]

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Decreased activation-induced cell death by EBV-transformed B cells from a patient with autoimmune lymphoproliferative syndrome caused by a novel FASLG mutation.

Pediatr Res. 2015 Sep 3;

Authors: Ruiz-García R, Mora S, Lozano-Sánchez G, Martínez-Lostao L, Paz-Artal E, Ruiz-Contreras J, Anel A, González-Granado LI, Moreno D, Allende LM

Abstract
BACKGROUND: Autoimmune lymphoproliferative syndrome (ALPS) is a primary immunodeficiency characterized by chronic lymphoproliferation, autoimmune manifestations, expansion of double-negative T-cells and susceptibility to malignancies. Most cases of ALPS are caused by germline or somatic FAS mutations. We report the case of an ALPS patient due to a novel homozygous Fasligand gene mutation (ALPS-FASLG).
METHODS: ALPS biomarkers were measured and FASLG mutation was identified. Functional characterization was carried out based on activation-induced cell death (AICD) and cytotoxicity assays.
RESULTS: This report describes the cases of a patient who presented a severe form of ALPSFASLG, and his brother who had died due to complications related to ALPS. Moreover, in another family, we present the first case of lymphoma in a patient with ALPS-FASLG. Functional studies showed defective Fasligand-mediated apoptosis, cytotoxicity and AICD in Tcell blasts. Otherwise, expression of the FASLG gene and corresponding protein was normal, but the shedding of the Fasligand was impaired in T-cells. Additionally, analyzing EBV-transformed B-cells, our results indicate impaired AICD in ALPS-FASLG patients.
CONCLUSION: Patients with autosomal recessive inheritance of ALPS-FASLG have a severe phenotype and a partial defect in AICD in T- and B-cell lines. The Fasligand could play a key role in immune surveillance preventing malignancy.Pediatric Research (2015); doi:10.1038/pr.2015.170.

PMID: 26334989 [PubMed – as supplied by publisher]

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The WASP-WIP complex in the molecular pathogenesis of Wiskott-Aldrich syndrome.

Pediatr Int. 2015 Sep 2;

Authors: Sasahara Y

Abstract
Wiskott-Aldrich syndrome (WAS) is an X-linked primary immunodeficiency disease that is characterized by recurrent infections, thrombocytopenia, and eczema. The gene responsible for X-linked WAS encodes the Wiskott-Aldrich syndrome protein (WASP), which is expressed in hematopoietic cells and which regulates T cell activation and cytoskeletal reorganization in T cell receptor (TCR) signaling. Here, I review our recent research on WASP and the WASP-interacting protein (WIP) complex in T cells. We first established a diagnostic screening method using flow cytometry and genetic analysis, and elucidated the molecular pathogenesis in WAS patients with unique clinical manifestations. We investigated the mechanisms by which WASP is recruited to lipid rafts following TCR stimulation and to immunological synapses between antigen-presenting cells and T cells. Subsequently, we revealed the molecular mechanisms by which WASP is degraded by calpain and ubiquitinated by Cbl-family proteins, which terminate WASP activation. More importantly, we found that WIP plays a critical role in WASP stability in T cells. These results provided new insights into the molecular pathogenesis of X-linked WAS and facilitated the discovery of WIP deficiency as an autosomal recessive form of WAS. This article is protected by copyright. All rights reserved.

PMID: 26331277 [PubMed – as supplied by publisher]

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Suppression of a Natural Killer Cell Response by Simian Immunodeficiency Virus Peptides.

PLoS Pathog. 2015 Sep;11(9):e1005145

Authors: Schafer JL, Ries M, Guha N, Connole M, Colantonio AD, Wiertz EJ, Wilson NA, Kaur A, Evans DT

Abstract
Natural killer (NK) cell responses in primates are regulated in part through interactions between two highly polymorphic molecules, the killer-cell immunoglobulin-like receptors (KIRs) on NK cells and their major histocompatibility complex (MHC) class I ligands on target cells. We previously reported that the binding of a common MHC class I molecule in the rhesus macaque, Mamu-A1*002, to the inhibitory receptor Mamu-KIR3DL05 is stabilized by certain simian immunodeficiency virus (SIV) peptides, but not by others. Here we investigated the functional implications of these interactions by testing SIV peptides bound by Mamu-A1*002 for the ability to modulate Mamu-KIR3DL05+ NK cell responses. Twenty-eight of 75 SIV peptides bound by Mamu-A1*002 suppressed the cytolytic activity of primary Mamu-KIR3DL05+ NK cells, including three immunodominant CD8+ T cell epitopes previously shown to stabilize Mamu-A1*002 tetramer binding to Mamu-KIR3DL05. Substitutions at C-terminal positions changed inhibitory peptides into disinhibitory peptides, and vice versa, without altering binding to Mamu-A1*002. The functional effects of these peptide variants on NK cell responses also corresponded to their effects on Mamu-A1*002 tetramer binding to Mamu-KIR3DL05. In assays with mixtures of inhibitory and disinhibitory peptides, low concentrations of inhibitory peptides dominated to suppress NK cell responses. Consistent with the inhibition of Mamu-KIR3DL05+ NK cells by viral epitopes presented by Mamu-A1*002, SIV replication was significantly higher in Mamu-A1*002+ CD4+ lymphocytes co-cultured with Mamu-KIR3DL05+ NK cells than with Mamu-KIR3DL05- NK cells. These results demonstrate that viral peptides can differentially affect NK cell responses by modulating MHC class I interactions with inhibitory KIRs, and provide a mechanism by which immunodeficiency viruses may evade NK cell responses.

PMID: 26333068 [PubMed – in process]

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Related Articles

IMMUNODEFICIENCIES. Impairment of immunity to Candida and Mycobacterium in humans with bi-allelic RORC mutations.

Science. 2015 Aug 7;349(6248):606-13

Authors: Okada S, Markle JG, Deenick EK, Mele F, Averbuch D, Lagos M, Alzahrani M, Al-Muhsen S, Halwani R, Ma CS, Wong N, Soudais C, Henderson LA, Marzouqa H, Shamma J, Gonzalez M, Martinez-Barricarte R, Okada C, Avery DT, Latorre D, Deswarte C, Jabot-Hanin F, Torrado E, Fountain J, Belkadi A, Itan Y, Boisson B, Migaud M, Arlehamn CS, Sette A, Breton S, McCluskey J, Rossjohn J, de Villartay JP, Moshous D, Hambleton S, Latour S, Arkwright PD, Picard C, Lantz O, Engelhard D, Kobayashi M, Abel L, Cooper AM, Notarangelo LD, Boisson-Dupuis S, Puel A, Sallusto F, Bustamante J, Tangye SG, Casanova JL

Abstract
Human inborn errors of immunity mediated by the cytokines interleukin-17A and interleukin-17F (IL-17A/F) underlie mucocutaneous candidiasis, whereas inborn errors of interferon-γ (IFN-γ) immunity underlie mycobacterial disease. We report the discovery of bi-allelic RORC loss-of-function mutations in seven individuals from three kindreds of different ethnic origins with both candidiasis and mycobacteriosis. The lack of functional RORγ and RORγT isoforms resulted in the absence of IL-17A/F-producing T cells in these individuals, probably accounting for their chronic candidiasis. Unexpectedly, leukocytes from RORγ- and RORγT-deficient individuals also displayed an impaired IFN-γ response to Mycobacterium. This principally reflected profoundly defective IFN-γ production by circulating γδ T cells and CD4(+)CCR6(+)CXCR3(+) αβ T cells. In humans, both mucocutaneous immunity to Candida and systemic immunity to Mycobacterium require RORγ, RORγT, or both.

PMID: 26160376 [PubMed – indexed for MEDLINE]

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Ulcerative colitis associated with chronic granulomatous disease: case report.

Gastroenterol Hepatol Bed Bench. 2015;8(3):233-5

Authors: Imanzade F, Sayarri A, Tajik P

Abstract
Chronic Granulomatous Disease (CGD) is an inherited primary immunodeficiency disease which increases the body’s susceptibility to infections caused by certain bacteria and fungi. CGD is a rare disease, caused by four genes, one type is 1X linked and the other three are “autosomal recessive”. Although clinical presentation is variable, but characteristic features are recurrent pneumonia, lymphadenitis, hepatic or other abscesses. Gastrointestinal tract symptoms are common in x-linked recessive form of CGD. These include gastric and esophageal obstruction and inflammatory bowel disease. GI involvement including small and large intestines, the findings of luminal narrowing and the presence of granuloma can make it difficult to distinguish from Crohn’s disease. On the other hands according to the literature ulcerative colitis is rarely reported in patients with CGD. Our case presented with ulcerative colitis with CGD.

PMID: 26328046 [PubMed]

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IgH sequences in common variable immune deficiency reveal altered B cell development and selection.

Sci Transl Med. 2015 Aug 26;7(302):302ra135

Authors: Roskin KM, Simchoni N, Liu Y, Lee JY, Seo K, Hoh RA, Pham T, Park JH, Furman D, Dekker CL, Davis MM, James JA, Nadeau KC, Cunningham-Rundles C, Boyd SD

Abstract
Common variable immune deficiency (CVID) is the most common symptomatic primary immune deficiency, affecting ~1 in 25,000 persons. These patients suffer from impaired antibody responses, autoimmunity, and susceptibility to lymphoid cancers. To explore the cellular basis for these clinical phenotypes, we conducted high-throughput DNA sequencing of immunoglobulin heavy chain gene rearrangements from 93 CVID patients and 105 control subjects and sorted naïve and memory B cells from 13 of the CVID patients and 10 of the control subjects. The CVID patients showed abnormal VDJ rearrangement and abnormal formation of complementarity-determining region 3 (CDR3). We observed a decreased selection against antibodies with long CDR3s in memory repertoires and decreased variable gene replacement, offering possible mechanisms for increased patient autoreactivity. Our data indicate that patient immunodeficiency might derive from both decreased diversity of the naïve B cell pool and decreased somatic hypermutation in memory repertoires. The CVID patients also exhibited an abnormal clonal expansion of unmutated B cells relative to the controls. Although impaired B cell germinal center activation is commonly viewed as causative in CVID, these data indicate that CVID B cells diverge from controls as early as the pro-B stage, cell and suggest possible explanations for the increased incidence of autoimmunity, immunodeficiency, and lymphoma CVID patients.

PMID: 26311730 [PubMed – as supplied by publisher]

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