Manish Butte

Impaired RASGRF1/ERK-mediated GM-CSF response characterizes CARD9 deficiency in French-Canadians.

J Allergy Clin Immunol. 2015 Oct 29;

Authors: Gavino C, Hamel N, Zeng JB, Legault C, Guiot MC, Chankowsky J, Lejtenyi D, Lemire M, Alarie I, Dufresne S, Boursiquot JN, McIntosh F, Langelier M, Behr MA, Sheppard DC, Foulkes WD, Vinh DC

Abstract
BACKGROUND: Caspase recruitment domain-containing protein 9 (CARD9) deficiency is an autosomal recessive primary immunodeficiency conferring human susceptibility to invasive fungal disease, including spontaneous central nervous system candidiasis (sCNSc). However, clinical characterization of sCNSc is variable, hindering its recognition. Furthermore, an in-depth understanding of the bases for this susceptibility has remained elusive.
OBJECTIVES: We sought to comprehensively characterize sCNSc and to dissect the mechanisms by which a hypomorphic CARD9 mutation causes susceptibility to Candida species.
METHODS: We describe the clinical and radiologic findings of sCNSc caused by CARD9 deficiency in a French-Canadian cohort. We performed genetic, cellular, and molecular analyses to further decipher its pathophysiology.
RESULTS: In our French-Canadian series (n = 4) sCNSc had onset in adulthood (median, 38 years) and was often misinterpreted radiologically as brain malignancies; 1 patient had additional novel features (eg, endophthalmitis and osteomyelitis). CARD9 deficiency resulted from a hypomorphic p.Y91H mutation and allelic imbalance established in this population through founder effects. We demonstrate a consistent cellular phenotype of impaired GM-CSF responses. The ability of CARD9 to complex with B-cell CLL/lymphoma 10 (BCL10) and mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) is intact in our series, arguing against its involvement in susceptibility to fungi. Instead, we show that the p.Y91H mutation impairs the ability of CARD9 to complex with Ras protein-specific guanine nucleotide-releasing factor 1 (RASGRF1), leading to impaired activation of nuclear factor κB and extracellular signal-regulated kinase (ERK) in monocytes and subsequent GM-CSF responses. Successful treatment of a second patient with adjunctive GM-CSF bolsters the clinical relevance of these findings.
CONCLUSIONS: Hypomorphic CARD9 deficiency caused by p.Y91H results in adult-onset disease with variable penetrance and expressivity. Our findings establish the CARD9/RASGRF1/ERK/GM-CSF axis as critical to the pathophysiology of sCNSc.

PMID: 26521038 [PubMed – as supplied by publisher]

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Generation of switched memory B cells in response to vaccination in Down syndrome children and their siblings.

Vaccine. 2015 Oct 27;

Authors: Valentini D, Marcellini V, Bianchi S, Villani A, Facchini M, Donatelli I, Castrucci MR, Marasco E, Farroni C, Carsetti R

Abstract
BACKGROUND: Immunodeficiency is an integral aspect of Down syndrome, as demonstrated by the increased susceptibility to infection of affected. Mortality is still higher than in general population, with respiratory infections among the major causes of death. As more people with Down syndrome are living today than ever before, it is indispensable to develop strategies to prevent and cure the associated disorders. Vaccination is the most successful instrument of preventive medicine. Special seasonal influenza and pneumococcal vaccination strategies have been designed for individuals with risk conditions of all ages. Down syndrome individuals are not included in the high-risk categories.
METHODS: We enrolled in our study 15 children with Down syndrome and their siblings, vaccinated for the first time with seasonal influenza vaccine and receiving a booster dose of a glyco-conjugated pneumococcal vaccine. We compared the immunological features and response to vaccination measuring serum antibody titers and frequency of specific memory B cells.
RESULTS: We confirm that a severe reduction of switched memory B cells is always associated to Down syndrome. After primary vaccination Down syndrome children generate significantly less specific switched memory B cells than their siblings. The response to a booster dose of vaccine is instead comparable in both groups. The production of specific antibodies was equally effective in Down syndrome and controls both after primary and secondary immunization.
CONCLUSIONS: Down syndrome individuals should be considered a high risk group, because of their increased susceptibility to infection and reduced number of switched memory B cells. Tailored vaccination protocols are needed in order to reduce their burden of infections throughout life.

PMID: 26518399 [PubMed – as supplied by publisher]

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Decline of FOXN1 gene expression in human thymus correlates with age: possible epigenetic regulation.

Immun Ageing. 2015;12:18

Authors: Reis MD, Csomos K, Dias LP, Prodan Z, Szerafin T, Savino W, Takacs L

Abstract
BACKGROUND: Thymic involution is thought to be an important factor of age related immunodeficiency. Understanding the molecular mechanisms of human thymic senescence may lead to the discovery of novel therapeutic approaches aimed at the reestablishment of central and peripheral T cell repertoire.
RESULTS: As an initial approach, here we report that the decline of human thymic FOXN1 transcription correlates with age, while other genes, DLL1, DLL4 and WNT4, essential for thymopoiesis, are constitutively transcribed. Using a human thymic epithelial cell line (hTEC), we show that FOXN1 expression is refractory to signals that induce FOXN1 transcription in primary 3D culture conditions and by stimulation of the canonical WNT signaling pathway. Blockage of FOXN1 induceability in the hTEC line may be mediated by an epigenetic mechanism, the CpG methylation of the FOXN1 gene.
CONCLUSION: We showed a suppression of FOXN1 transcription both in cultured human thymic epithelial cells and in the aging thymus. We hypothesize that the underlying mechanism may be associated with changes of the DNA methylation state of the FOXN1 gene.

PMID: 26516334 [PubMed]

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Establishment and characterization of a novel MYC/BCL2 “double-hit” diffuse large B cell lymphoma cell line, RC.

J Hematol Oncol. 2015;8(1):121

Authors: Pham LV, Lu G, Tamayo AT, Chen J, Challagundla P, Jorgensen JL, Medeiros LJ, Ford RJ

Abstract
BACKGROUND: Diffuse large B cell lymphoma (DLBCL) is the most common type of lymphoid malignancy worldwide. Approximately 5 % of cases of DLBCL are so-called double-hit lymphomas (DHL), defined by a chromosomal translocation or rearrangement involving MYC/8q24.2 in combination with another recurrent breakpoint, usually BCL2/18q21.3. Patients with MYC/BCL2 DHL are resistant to standard front-line therapy, and currently, there is no consensus for a therapeutic strategy to treat these patients. Lack of clinically relevant or validated human experimental DHL models of any type that would improve our understanding of the biologic basis of MYC/BCL2 DHL pathophysiology continues to hamper identification of valid therapeutic targets. We describe a unique MYC/BCL2 DHL cell line with morphologic features of DLBCL that we have established, designated as RC.
METHODS: We used tissue culture techniques to establish the RC cell line from primary DLBCL cells. We also utilized molecular and cellular biological techniques including flow cytometry, polymerase chain reaction (PCR), DNA fingerprinting, reverse-phase protein array, conventional cytogenetics, and fluorescence in situ hybridization (FISH) analysis to characterize the RC cell line. NSG-severe combined immunodeficiency (SCID) mice were utilized as a model for xeno-transplantation of RC cells.
RESULTS: RC cells had the following immunophenotype: positive for CD10, CD19, CD20, CD22, CD38, CD43, CD44, and CD79b and negative for CD3, CD4, CD5, CD8, CD11c, CD14, CD30, CD56, and CD200, which was identical to the primary tumor cells. Conventional cytogenetic analysis showed a t(2;8)(p12;q24.2) and t(14;18)(q32;q21.3), corresponding to MYC and BCL2 gene rearrangements, respectively. DNA fingerprinting authenticated the RC cell line to be of the same clone as the primary tumor cells. In addition, RC cells were established in SCID mice as an in vivo model for translational therapeutics studies. Proteomic analysis showed activation of the mTOR signaling pathway in RC cells that can be targeted with an mTOR inhibitor.
CONCLUSION: The data presented confirm the validity of the RC cell line as a representative model of MYC/BCL2 DHL that will be useful for both in vitro and in vivo studies of DHL pathogenesis and therapeutics.

PMID: 26515759 [PubMed – in process]

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Intestinal decolonization of Enterobacteriaceae producing extended-spectrum β-lactamases (ESBL): a retrospective observational study in patients at risk for infection and a brief review of the literature.

BMC Infect Dis. 2015;15(1):475

Authors: Rieg S, Küpper MF, de With K, Serr A, Bohnert JA, Kern WV

Abstract
BACKGROUND: Multidrug-resistant Escherichia coli and other enteric bacteria producing extended-spectrum β-lactamases (ESBL) have emerged as an important cause of invasive infection. Targeting the primary (intestinal) niche by decolonization may be a valuable approach to decrease the risk of relapsing infections and to reduce transmission of ESBL-producing enteric pathogens.
METHODS: In a retrospective observational study we evaluated the efficacy of intestinal decolonization treatment using orally administered colistin or other non-absorbable agents given for 2 to 4 weeks in adult patients with previous relapsing infection and persistent intestinal colonization with ESBL-positive Enterobacteriaceae (ESBL-E). Eradication success was defined as negative rectal swab or stool culture at the end of treatment and at follow up-2 weeks after treatment discontinuation.
RESULTS: First-line decolonization treatment led to eradication of ESBL-E in 19/45 patients (42 %, 7/18 low-dose [4 × 1 million units] colistin, 3/12 high-dose [4 × 2 million units] colistin, 9/15 rifaximin [2 × 400 mg]), and secondary/salvage treatment was successful in 8/13 patients (62 %, 20 treatment episodes). Late follow-up showed that 7/13 patients (54 %) with successful initial or salvage decolonization became recolonized within 3 months after post-treatment assessment while all eight of the patients failing initial or salvage decolonization treatment with late follow-up remained colonized. A narrative review of the literature confirms the limited efficacy of non-absorbable antibiotics including conventional selective digestive tract decolonization (SDD)-like combination regimens for eradicating multidrug-resistant enteric bacteria from the intestinal tract.
CONCLUSIONS: At present, there is no clear evidence of a significant decolonization efficacy using single-drug treatment with oral non-absorbable antibiotics. More effective regimens are needed and a better definition of at risk patients is required for planning meaningful randomized controlled studies in this field.

PMID: 26511929 [PubMed – in process]

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Adenovirus necrotizing hepatitis complicating atypical teratoid rhabdoid tumor.

Pediatr Int. 2015 Oct;57(5):974-7

Authors: McKillop SJ, Belletrutti MJ, Lee BE, Yap JY, Noga ML, Desai SJ, Sergi C

Abstract
Adenovirus-induced fulminant hepatitis is rare. It has been reported in children with primary immunodeficiency, following transplantation or while receiving chemotherapy for hematological malignancy. We present the case of an infant recovering from chemotherapy for atypical teratoid rhabdoid tumor (ATRT) in whom a diagnosis of hepatic necrosis due to adenovirus was made.

PMID: 26508178 [PubMed – in process]

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Immunoactivation induced by chronic viral infection inhibits viral replication and drives immunosuppression through sustained IFN-I responses.

Eur J Immunol. 2015 Oct 28;

Authors: Honke N, Shaabani N, Merches K, Gassa A, Kraft A, Ehrhardt K, Häussinger D, Löhning M, Dittmer U, Hengel H, Recher M, Lang PA, Lang KS

Abstract
Acute or chronic viral infections can lead to generalized immunosuppression. Several mechanisms, such as immunopathology of CD8(+) T cells, inhibitory receptors, or regulatory T (Treg) cells, contribute to immune dysfunction. Moreover, patients with chronic viral infections usually do not respond to vaccination, a finding that has not been previously explained. Recently, we reported that CD169(+) macrophages enforce viral replication, which is essential for guaranteeing antigen synthesis and efficient adaptive immune responses. In the present study we used a chronic lymphocytic choriomeningitis virus (LCMV) infection mouse model to determine whether this mechanism is affected by chronic viral infection, which may impair the activation of adaptive immunity. We found that enforced viral replication of a superinfecting virus is completely blunted in chronically infected mice. This absence of enforced viral replication in CD169(+) macrophages is not explained by CD8(+) T cell-mediated immunopathology but rather by prolonged IFN-I responses. Consequently, the absence of viral replication impairs both antigen production and the adaptive immune response against the superinfecting virus. These findings indicate that chronic infection leads to sustained IFN-I action, which is responsible for the absence of an antiviral immune response against a secondary viral infection. This article is protected by copyright. All rights reserved.

PMID: 26507703 [PubMed – as supplied by publisher]

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Is Whole Exome Sequencing Clinically Practical in the Management of Pediatric Crohn’s Disease?

Gut Liver. 2015 Nov 23;9(6):767-75

Authors: Oh SH, Baek J, Kim KM, Lee EJ, Jung Y, Lee YJ, Jin HS, Ye BD, Yang SK, Lee JK, Seo EJ, Lim HT, Lee I, Song K

Abstract
BACKGROUND/AIMS: The aim of this study was to identify the profile of rare variants associated with Crohn’s disease (CD) using whole exome sequencing (WES) analysis of Korean children with CD and to evaluate whether genetic profiles could provide information during medical decision making.
METHODS: DNA samples from 18 control individuals and 22 patients with infantile, very-early and early onset CD of severe phenotype were used for WES. Genes were filtered using panels of inflammatory bowel disease (IBD)-associated genes and genes of primary immunodeficiency (PID) and monogenic IBD.
RESULTS: Eighty-one IBD-associated variants and 35 variants in PID genes were revealed by WES. The most frequently occurring variants were carried by nine (41%) and four (18.2%) CD probands and were ATG16L2 (rs11235604) and IL17REL (rs142430606), respectively. Twenty-four IBD-associated variants and 10 PID variants were predicted to be deleterious and were identified in the heterozygous state. However, their functions were unknown with the exception of a novel p.Q111X variant in XIAP (X chromosome) of a male proband.
CONCLUSIONS: The presence of many rare variants of unknown significance limits the clinical applicability of WES for individual CD patients. However, WES in children may be beneficial for distinguishing CD secondary to PID.

PMID: 26503572 [PubMed – in process]

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Absence of WASp Enhances Hematopoietic And Megakaryocytic Differentiation In A Human Embryonic Stem Cell Model.

Mol Ther. 2015 Oct 27;

Authors: Toscano MG, Muñoz P, Sánchez-Gilabert A, Cobo M, Benabdellah K, Anderson P, Ramos-Mejía V, Real PJ, Neth O, Molinos A, Gregory PD, Holmes MC, Martin F

Abstract
The Wiskott-Aldrich syndrome (WAS) is an X-linked primary immunodeficiency caused by mutations in the WAS gene and characterized by severe thrombocytopenia. Although the role of WASp in terminally differentiated lymphocytes and myeloid cells is well characterized, its role in early hematopoietic differentiation and in platelets (Plts) biology is poorly understood. In the present manuscript we have used zinc finger nucleases targeted to the WAS locus for the development of two isogenic WAS knockout (WASKO) human embryonic stem cell lines (hESCs). Upon hematopoietic differentiation, hESCs-WASKO generated increased ratios of CD34(+)CD45(+) progenitors with altered responses to stem cell factor compared to hESCs-WT. When differentiated toward the megakaryocytic linage, hESCs-WASKO produced increased numbers of CD34(+)CD41(+) progenitors, megakaryocytes (MKs) and Plts. hESCs-WASKO derived MKs and Plts showed altered phenotype as well as defective responses to agonist, mimicking WAS patients MKs and Plts defects. Interestingly, the defects were more evident in WASp-deficient MKs than in WASp-deficient Plts. Importantly, ectopic WAS expression using lentiviral vectors restored normal Plts development and MKs responses. These data validate the AND-1_WASKO cell lines as a human cellular model for basic research and for preclinical studies for WAS.Molecular Therapy (2015); doi:10.1038/mt.2015.196.

PMID: 26502776 [PubMed – as supplied by publisher]

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Prospective neonatal screening for severe T- and B- lymphocyte deficiencies in Seville.

Pediatr Allergy Immunol. 2015 Oct 25;

Authors: de Felipe B, Olbrich P, Lucenas JM, Delgado-Pecellin C, Pavon-Delgado A, Marquez J, Salamanca C, Soler-Palacin P, Gonzalez-Granado LI, Antolin LF, Borte S, Neth O

Abstract
BACKGROUND: Early diagnosis of primary immunodeficiency such as severe combined immunodeficiency (SCID) and X-linked agammaglobulinemia (XLA) improves outcome of affected children. T-cell-receptor-excision circles (TRECs) and kappa-deleting-recombination-excision circles (KRECs) determination from dried blood spots (DBS) identify neonates with severe T- and/or B-lymphopenia. No prospective data exist of the impact of gestational age (GA) and birth weight (BW) on TRECs and KRECs values.
METHODS: TRECs and KRECs determination using triplex RT-PCR (TRECS-KRECS-β-actin-Assay) from prospectively collected DBS between 02/2014 and 02/2015 in three hospitals in Seville, Spain. Cut-off levels were TRECs<6/punch, KRECs<4/punch and -β-actin>700/punch. Internal (SCID, XLA, ataxia telangiectasia) and external controls (NBS quality assurance program, CDC) were included.
RESULTS: A total of 5160 DBS were tested. Re-punch was needed in 77 samples (1.5%) due to insufficient β-actin (<700 copies/punch). Preterm neonates (GA<37 weeks) and neonates with a BW<2500g showed significantly lower TRECs and KRECs levels (p<0.001). Due to repeat positive results five neonates were re-called (<0.1%): Fatal chromosomopathy (n=1; TRECs 1/KRECs 4); extreme prematurity (n=2; TRECs 0/KRECs 0 and TRECs 1/KRECs 20 copies/punch); neonates born to mothers receiving azathioprine during pregnancy (n=2; TRECs 92/KRECs 1 and TRECs 154/KRECs 3 copies/punch). All internal and external controls were correctly identified.
CONCLUSIONS: TRECS-KRECS-β-actin-Assay correctly identifies T- and B-cell lymphopenias. Prematurity and low BW is associated with lower TREC and KREC levels. Extreme prematurity and maternal immune suppressive therapy may be a cause for false positive results of TRECs and KRECs values, respectively. To reduce the rate of insufficient samples, DBS extraction and storage need to be improved. This article is protected by copyright. All rights reserved.

PMID: 26498110 [PubMed – as supplied by publisher]

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