Research

Functional characterization of the human dendritic cell immunodeficiency associated with the IRF8K108E mutation.

Blood. 2014 Aug 13;

Authors: Salem S, Langlais D, Lefebvre F, Bourque G, Bigley V, Haniffa M, Casanova JL, Burk D, Berghuis A, Butler KM, Leahy TR, Hambleton S, Gros P

Abstract
We have previously reported on a unique patient in whom homozygosity for a mutation at IRF8 (IRF8(K108E)) causes a severe immunodeficiency. Laboratory evaluation revealed a highly unusual myeloid compartment, remarkable for the complete absence of CD14(+) and CD16(+) monocytes, absence of CD11c(+) conventional dendritic cells (DCs) and of CD11c(+)/CD123(+) plasmacytoid DCs (pDCs), and striking granulocytic hyperplasia. The patient initially presented with severe disseminated mycobacterial and mucocutaneous fungal infections and was ultimately cured by cord blood transplant. Sequencing RNA from the IRF8(K108E) patient’s primary blood cells prior to transplant shows not only depletion of IRF8-bound and -regulated transcriptional targets, in keeping with the distorted composition of the myeloid compartment, but also a paucity of transcripts associated with activated CD4(+) and CD8(+) T lymphocytes. This suggests that T cells reared in the absence of a functional antigen-presenting compartment in IRF8(K108E) are anergic. Biochemical characterization of the IRF8(K108E) mutant in vitro shows that loss of the positively charged side chain at K108 causes loss of nuclear localization and loss of transcriptional activity, which is concomitant with decreased protein stability, increased ubiquitination, increased SUMOylation, and enhanced proteasomal degradation. These findings provide functional insight into the molecular basis of immunodeficiency associated with loss of IRF8.

PMID: 25122610 [PubMed – as supplied by publisher]

Powered by WPeMatico

Hematopoietic stem cell transplantation of an adolescent with neurological manifestations of homozygous missense PRF1 mutation.

Pediatr Blood Cancer. 2014 Aug 11;

Authors: Hussein AA, Hamadah T, Qandeel M, Sughayer M, Amarin R, Mansour A, Chiang SC, Al-Zaben A, Meeths M, Bryceson YT

Abstract
Individuals with biallelic truncating PRF1 mutations typically present with fulminant early-onset familial hemophagocytic lymphohistiocytosis (FHL). We report a 19-year-old male with a 5-year history of recurrent fever and headaches progressing to refractory seizures. Brain imaging revealed multiple ring enhancing lesions. Laboratory investigations demonstrated that the patient displayed defective lymphocyte cytotoxicity and carried a homozygous missense PRF1 mutation, c.394G > A (p.Gly132Arg). The patient was successfully treated with chemo-immunotherapy followed by matched related allogeneic hematopoietic stem cell transplantation (HSCT). Our findings demonstrate that prompt HSCT of late-onset FHL with primarily neurological manifestation can reverse central nervous system symptoms and improve long-term outcome. Pediatr Blood Cancer © 2014 Wiley Periodicals, Inc.

PMID: 25110876 [PubMed – as supplied by publisher]

Powered by WPeMatico

Identification of copy number variants from exome sequence data.

BMC Genomics. 2014 Aug 7;15(1):661

Authors: Samarakoon PS, Sorte HS, Kristiansen BE, Skodje T, Sheng Y, Tjønnfjord GE, Stadheim B, Stray-Pedersen A, Rødningen OK, Lyle R

Abstract
BACKGROUND: With advances in next generation sequencing technologies and genomic capture techniques, exome sequencing has become a cost-effective approach for mutation detection in genetic diseases. However, computational prediction of copy number variants (CNVs) from exome sequence data is a challenging task. Whilst numerous programs are available, they have different sensitivities, and have low sensitivity to detect smaller CNVs (1-4 exons). Additionally, exonic CNV discovery using standard aCGH has limitations due to the low probe density over exonic regions. The goal of our study was to develop a protocol to detect exonic CNVs (including shorter CNVs that cover 1-4 exons), combining computational prediction algorithms and a high-resolution custom CGH array.
RESULTS: We used six published CNV prediction programs (ExomeCNV, CONTRA, ExomeCopy, ExomeDepth, CoNIFER, XHMM) and an in-house modification to ExomeCopy and ExomeDepth (ExCopyDepth) for computational CNV prediction on 30 exomes from the 1000 genomes project and 9 exomes from primary immunodeficiency patients. CNV predictions were tested using a custom CGH array designed to capture all exons (exaCGH). After this validation, we next evaluated the computational prediction of shorter CNVs. ExomeCopy and the in-house modified algorithm, ExCopyDepth, showed the highest capability in detecting shorter CNVs. Finally, the performance of each computational program was assessed by calculating the sensitivity and false positive rate.
CONCLUSIONS: In this paper, we assessed the ability of 6 computational programs to predict CNVs, focussing on short (1-4 exon) CNVs. We also tested these predictions using a custom array targeting exons. Based on these results, we propose a protocol to identify and confirm shorter exonic CNVs combining computational prediction algorithms and custom aCGH experiments.

PMID: 25102989 [PubMed – as supplied by publisher]

Powered by WPeMatico

Splice-correcting oligonucleotides restore BTK function in X-linked agammaglobulinemia model.

J Clin Invest. 2014 Aug 8;

Authors: Bestas B, Moreno PM, Blomberg KE, Mohammad DK, Saleh AF, Sutlu T, Nordin JZ, Guterstam P, Gustafsson MO, Kharazi S, Piątosa B, Roberts TC, Behlke MA, Wood MJ, Gait MJ, Lundin KE, El Andaloussi S, Månsson R, Berglöf A, Wengel J, Smith CI

Abstract
X-linked agammaglobulinemia (XLA) is an inherited immunodeficiency that results from mutations within the gene encoding Bruton’s tyrosine kinase (BTK). Many XLA-associated mutations affect splicing of BTK pre-mRNA and severely impair B cell development. Here, we assessed the potential of antisense, splice-correcting oligonucleotides (SCOs) targeting mutated BTK transcripts for treating XLA. Both the SCO structural design and chemical properties were optimized using 2′-O-methyl, locked nucleic acid, or phosphorodiamidate morpholino backbones. In order to have access to an animal model of XLA, we engineered a transgenic mouse that harbors a BAC with an authentic, mutated, splice-defective human BTK gene. BTK transgenic mice were bred onto a Btk knockout background to avoid interference of the orthologous mouse protein. Using this model, we determined that BTK-specific SCOs are able to correct aberrantly spliced BTK in B lymphocytes, including pro-B cells. Correction of BTK mRNA restored expression of functional protein, as shown both by enhanced lymphocyte survival and reestablished BTK activation upon B cell receptor stimulation. Furthermore, SCO treatment corrected splicing and restored BTK expression in primary cells from patients with XLA. Together, our data demonstrate that SCOs can restore BTK function and that BTK-targeting SCOs have potential as personalized medicine in patients with XLA.

PMID: 25105368 [PubMed – as supplied by publisher]

Powered by WPeMatico

CD18 deficiency evolving to megakaryocytic (M7) acute myeloid leukemia: Case report.

Blood Cells Mol Dis. 2014 Aug 5;

Authors: de Moraes Vasconcelos D, Beitler B, Martinez GA, Pereira J, Amigo Filho JU, Klautau GB, Lian YC, Della Negra M, Duarte AJ

Abstract
Leukocyte adhesion deficiency type 1 (LAD 1 – CD18 deficiency) is a rare disease characterized by disturbance of phagocyte function associated with less severe cellular and humoral dysfunction. The main features are bacterial and fungal infections predominantly in the skin and mucosal surfaces, impaired wound healing and delayed umbilical cord separation. The infections are indolent, necrotic and recurrent. In contrast to the striking difficulties in defense against bacterial and fungal microorganisms, LAD 1 patients do not exhibit susceptibility to viral infections and neoplasias. The severity of clinical manifestations is directly related to the degree of CD18 deficiency. Here, a 20year-old female presenting a partial CD18 deficiency that developed a megakaryocytic (M7) acute myeloid leukemia is described for the first time. The clinical features of the patient included relapsing oral thrush due to Candida, cutaneous infections and upper and lower respiratory tract infections, followed by a locally severe necrotic genital herpetic lesion. The patient’s clinical features improved for a period of approximately two years, followed by severe bacterial infections. At that time, the investigation showed a megakaryocytic acute myeloid leukemia, treated with MEC without clinical improvement. The highly aggressive evolution of the leukemia in this patient suggests that adhesion molecules could be involved in the protection against the spread of neoplastic cells.

PMID: 25106692 [PubMed – as supplied by publisher]

Powered by WPeMatico

Applying T-cell receptor excision circles and immunoglobulin κ-deleting recombination excision circles to patients with primary immunodeficiency diseases.

Ann Med. 2014 Aug 11;:1-11

Authors: Lee WI, Huang JL, Lin SJ, Yeh KW, Chen LC, Ou LS, Yao TC, Jaing TH, Shih YF, Tseng TY, Lin YL

Abstract
Background. Biomarkers of T-cell receptor excision circles (TRECs) and immunoglobulin κ-deleting recombination excision circles (KRECs) reflect naïve T and B cell emigrants. This study assessed the biomarkers in patients with primary immunodeficiency diseases (PIDs) to determine the lymphocyte output disturbance and the correlation to lymphocytes. Methods. A standard plasmid was constructed to calculate TRECs and KRECs in 250 ng genomic DNA from whole blood of PIDs patients. These were correlated to naïve and memory lymphocytes for further classification and adequate treatment. Results. In 69 studied patients, the low TRECs mainly included those with severe combined T and B immunodeficiency (SCID, 7/8), combined immunodeficiency (CID, 4/4), and common variable immunodeficiency (CVID, 6/7). The diminished KRECs was in SCID (4/8), CID (4/4), CVID (7/7), Bruton’s tyrosine kinase mutation (Btk, 3/4), anti-B cell deletion (by anti-CD20 antibody in 1), and Behçet syndrome under steroid treatment (1). The TRECs and KRECs positively correlated to absolute naïve T (CD4 + CD45RA+) and naïve B (CD19 + CD27-), and to memory B (CD19 + CD27+) numbers, respectively. Conclusion. This study validates that low TRECs and KRECs values reflect low naïve T and B lymphocytes in ‘combined immunodeficiencies’ and in some CVID patients with the potential to develop the CID phenotype.

PMID: 25109505 [PubMed – as supplied by publisher]

Powered by WPeMatico

Comparison of outcomes of hematopoietic stem cell transplantation without chemotherapy conditioning by using matched sibling and unrelated donors for treatment of severe combined immunodeficiency.

J Allergy Clin Immunol. 2014 Aug 7;

Authors: Dvorak CC, Hassan A, Slatter MA, Hönig M, Lankester AC, Buckley RH, Pulsipher MA, Davis JH, Güngör T, Gabriel M, Bleesing JH, Bunin N, Sedlacek P, Connelly JA, Crawford DF, Notarangelo LD, Pai SY, Hassid J, Veys P, Gennery AR, Cowan MJ

Abstract
BACKGROUND: Patients with severe combined immunodeficiency disease who have matched sibling donors (MSDs) can proceed to hematopoietic cell transplantation (HCT) without conditioning chemotherapy.
OBJECTIVE: We sought to determine whether the results of HCT without chemotherapy-based conditioning from matched unrelated donors (URDs), either from volunteer adults or umbilical cord blood, are comparable with those from MSDs.
METHODS: We performed a multicenter survey of severe combined immunodeficiency transplantation centers in North America, Europe, and Australia to compile retrospective data on patients who have undergone unconditioned HCT from either URDs (n = 37) or MSDs (n = 66).
RESULTS: Most patients undergoing URD HCT (92%) achieved donor T-cell engraftment compared with 97% for those with MSDs; however, estimated 5-year overall and event-free survival were worse for URD recipients (71% and 60%, respectively) compared with MSD recipients (92% and 89%, respectively; P < .01 for both). URD recipients who received pre-HCT serotherapy had similar 5-year overall survival (100%) to MSD recipients. The incidences of grade II to IV acute and chronic graft-versus-host disease were higher in URD (50% and 39%, respectively) compared with MSD (22% and 5%, respectively) recipients (P < .01 for both). In the surviving patients there was no difference in T-cell reconstitution at the last follow-up between the URD and MSD recipients; however, MSD recipients were more likely to achieve B-cell reconstitution (72% vs 17%, P < .001).
CONCLUSION: Unconditioned URD HCT achieves excellent rates of donor T-cell engraftment similar to that seen in MSD recipients, and reconstitution rates are adequate. However, only a minority will have myeloid and B-cell reconstitution, and attention must be paid to graft-versus-host disease prophylaxis. This approach might be safer in children ineligible for intense regimens to spare the potential complications of chemotherapy.

PMID: 25109802 [PubMed – as supplied by publisher]

Powered by WPeMatico

Approach to pathogenesis of hematological malignancies from a viewpoint of primary immunodeficiency.

Rinsho Ketsueki. 2014 Jul;55(7):769-79

Authors: Takagi M

PMID: 25098512 [PubMed – in process]

Powered by WPeMatico

The CARD11-BCL10-MALT1 (CBM) signalosome complex: Stepping into the limelight of human primary immunodeficiency.

J Allergy Clin Immunol. 2014 Aug;134(2):276-84

Authors: Turvey SE, Durandy A, Fischer A, Fung SY, Geha RS, Gewies A, Giese T, Greil J, Keller B, McKinnon ML, Neven B, Rozmus J, Ruland J, Snow AL, Stepensky P, Warnatz K

Abstract
Next-generation DNA sequencing has accelerated the genetic characterization of many human primary immunodeficiency diseases (PIDs). These discoveries can be lifesaving for the affected patients and also provide a unique opportunity to study the effect of specific genes on human immune function. In the past 18 months, a number of independent groups have begun to define novel PIDs caused by defects in the caspase recruitment domain family, member 11 (CARD11)-B-cell chronic lymphocytic leukemia/lymphoma 10 (BCL10)-mucosa-associated lymphoid tissue lymphoma translocation gene 1 (MALT1 [CBM]) signalosome complex. The CBM complex forms an essential molecular link between the triggering of cell-surface antigen receptors and nuclear factor κB activation. Germline mutations affecting the CBM complex are now recognized as the cause of novel combined immunodeficiency phenotypes, which all share abnormal nuclear factor κB activation and dysregulated B-cell development as defining features. For this “Current perspectives” article, we have engaged experts in both basic biology and clinical immunology to capture the worldwide experience in recognizing and managing patients with PIDs caused by CBM complex mutations.

PMID: 25087226 [PubMed – in process]

Powered by WPeMatico

Respiratory Syncytial Virus Infections in Infants Affected by Primary Immunodeficiency.

J Immunol Res. 2014;2014:850831

Authors: Lanari M, Vandini S, Capretti MG, Lazzarotto T, Faldella G

Abstract
Primary immunodeficiencies are rare inherited disorders that may lead to frequent and often severe acute respiratory infections. Respiratory syncytial virus (RSV) is one of the most frequent pathogens during early infancy and the infection is more severe in immunocompromised infants than in healthy infants, as a result of impaired T- and B-cell immune response unable to efficaciously neutralize viral replication, with subsequent increased viral shedding and potentially lethal lower respiratory tract infection. Several authors have reported a severe clinical course after RSV infections in infants and children with primary and acquired immunodeficiencies. Environmental prophylaxis is essential in order to reduce the infection during the epidemic season in hospitalized immunocompromised infants. Prophylaxis with palivizumab, a humanized monoclonal antibody against the RSV F protein, is currently recommended in high-risk infants born prematurely, with chronic lung disease or congenital heart disease. Currently however the prophylaxis is not routinely recommended in infants with primary immunodeficiency, although some authors propose the extension of prophylaxis to this high risk population.

PMID: 25089282 [PubMed – as supplied by publisher]

Powered by WPeMatico