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The study assessed the long-term consequence of gene therapy for severe combined immunodeficiency (SCID) due to the lack of adenosine deaminase (ADA), a fatal disorder of purine metabolism and immunodeficiency. It found that gene therapy, in combination with reduced-intensity conditioning, was a safe and effective treatment for SCID in patients with ADA deficiency.

Gene transfer into HSCs is an effective treatment for SCID, although potentially limited by the risk of insertional mutagenesis. We performed a genome-wide analysis of retroviral vector integrations in genetically [...]

Hematopoietic stem cell (HSC) gene therapy for adenosine deaminase (ADA)--deficient severe combined immunodeficiency (SCID) has shown limited clinical efficacy because of the small proportion of engrafted genetically corrected HSCs. We describe an improved protocol for gene transfer into HSCs associated with nonmyeloablative conditioning. This protocol was used in two patients for whom enzyme replacement therapy was not available, which allowed the effect of gene therapy alone to be evaluated. Sustained engraftment of engineered HSCs with differentiation into multiple lineages resulted in increased lymphocyte counts, improved immune functions (including antigen-specific responses), and lower toxic metabolites. Both patients are currently at home and clinically well with normal growth and development. These results indicate the safety and efficacy of HSC gene therapy combined with nonmyeloablative conditioning for the treatment of SCID., Gene therapy trials have demonstrated the safety and feasibility of engineering hematopoietic stem cells (HSCs) for treating inherited hematopoietic diseases (1-6). In these studies, however, the frequency of multipotent genetically [...]

Diamond-Blackfan anemia (DBA) is congenital pure red-cell anemia due to a differentiation block in erythroid precursors. The disease is commonly caused by mutations in genes for ribosomal proteins. Despite the identification of disease causal genes, the disease pathogenesis is not completely elucidated. The ribosomal abnormalities are assumed to inhibit globin translation which may lead to excess free heme, stimulating a generation of free radicals and thereby damaging the precursors. We studied the effect of hemin (heme chloride) on cultured human erythroid precursors and found that contrary to aforementioned hypothesis, although hemin moderately stimulated free radicals, it did not cause apoptosis or necrosis. In erythroid precursors derived from DBA patients, hemin significantly stimulated growth and hemoglobinization. Thus, heme toxicity is unlikely to play a role in the pathophysiology of most DBA cases. Moreover, its beneficial effect in culture suggests a therapeutic potential. [ABSTRACT FROM AUTHOR]

Background: Eukaryotic chromosomes end with telomeres, which in most organisms are composed of tandem DNA repeats associated with telomeric proteins. These DNA repeats are synthesized by the enzyme telomerase, whose activity in most human tissues is tightly regulated, leading to gradual telomere shortening with cell divisions. Shortening beyond a critical length causes telomere uncapping, manifested by the activation of a DNA damage response (DDR) and consequently cell cycle arrest. Thus, telomere length limits the number of cell divisions and provides a tumor-suppressing mechanism. However, not only telomere shortening, but also damaged telomere structure, can cause telomere uncapping. Dyskeratosis Congenita (DC) and its severe form Hoyeraal-Hreidarsson Syndrome (HHS) are genetic disorders mainly characterized by telomerase deficiency, accelerated telomere shortening, impaired cell proliferation, bone marrow failure, and immunodeficiency. Methodology/Principal Findings: We studied the telomere phenotypes in a family affected with HHS, in which the genes implicated in other cases of DC and HHS have been excluded, and telomerase expression and activity appears to be normal. Telomeres in blood leukocytes derived from the patients were severely short, but in primary fibroblasts they were normal in length. Nevertheless, a significant fraction of telomeres in these fibroblasts activated DDR, an indication of their uncapped state. In addition, the telomeric 39 overhangs are diminished in blood cells and fibroblasts derived from the patients, consistent with a defect in telomere structure common to both cell types. Conclusions/Significance: Altogether, these results suggest that the primary defect in these patients lies in the telomere structure, rather than length. We postulate that this defect hinders the access of telomerase to telomeres, thus causing accelerated telomere shortening in blood cells that rely on telomerase to replenish their telomeres. In addition, it activates the DDR and impairs cell proliferation, even in cells with normal telomere length such as fibroblasts. This work demonstrates a telomere length-independent pathway that contributes to a telomere dysfunction disease. [ABSTRACT FROM AUTHOR]

Resnick IB, Averbuch D, Aker M, Engelhard D. IsPneumocystis cariniipneumonia after stem cell transplantations a contagious disease?Clin Transplant 2005 DOI: 10.1111/j.1399-0012.2005.00346.x© Blackwell Munksgaard, 2005We report of twins who underwent hematopoietic stem cell transplantation (HSCT) for neonatal acute leukemia. Hospitalized in the same room from the time the first one demonstrated respiratory symptoms, they both developedPneumocystis jiroveci(formerlycarinii) pneumonia (PCP) 2 wk apart. This observation suggests that PCP may be a contagious disease in HSCT recipients. This may be especially true for infants and young children who are at risk of primaryP. jiroveciinfection, and should be avoided. [ABSTRACT FROM AUTHOR]

Scorpion sting in children is a hazardous and potentially lethal condition. Fifty-one infants and children were admitted to the Pediatric Departments at the Hadassah-Hebrew University Hospitals in Jerusalem, during a 5-year period, following scorpion sting. Fifteen (29.4%) had severe systemic signs of envenomation and two (3.9%) died. Analysis of our data showed that patients with severe toxicity were brought to the hospital after a significantly longer time lapse than were the patients with mild-to-moderate symptoms. The current management of children with scorpion envenomation consists of administration of specific antivenom and close surveillance in an intensive care unit, where vital signs and continuous cardiac monitoring enable early initiation of therapy for life-threatening complications, such as cardiac and respiratory failure, convulsions, or hypertension. [ABSTRACT FROM AUTHOR]

Dyskeratosis congenita (DKC) is a rare syndrome characterized by cutaneous hyperpigmentation, nail dystrophy, leukoplakia, and pancytopenia. The purpose of this case study was CO describe the management of a 7-year-old girl diagnosed which DKC who urgently needed dental treatment under general anesthesia before bone marrow transplantation (BMT). The patient presented normal skin, nails, and hair, but oral examination revealed a number of ulcers, leukoplakia, gingival recessions, alveolar bone loss, and dental caries. Hematologic preparation included raising blood parameters, and the anesthesiologist to had consider pulmonary infection. The alveolar bone loss and the gingival recessions required the consultation of a periodontist. Avoiding stainless steel crowns was necessary due to potential plaque accumulation in the crown margins. The goal of this dental treatment was eliminating potential sources of infection before transplantation was conducted. It is importance for the pediatric dentist to recognize the medical aspects associated with dental management prior co BMT, and to incorporate them into the treatment plan. [ABSTRACT FROM AUTHOR]

Recent evidence suggests that kindlin-3 is a major coactivator, required for most, if not all, integrin activities. Here we stud-led the function of klndlln-3 in regulating NK cell activation by studying a patient with kindlin-3 deficiency (leukocyte adhe-sion deficiency-Ill). We found that kindlin-3 is required for NK cell migration and adhesion under shear force. Surprisingly, we also found that kindlin-3 lowers the threshold for NK cell activation. Loss of kindlin-3 has a pronounced effect on NK cell-mediated cytotoxicity triggered by single activating receptors. In con-trast, for activation through multiple re-ceptors, kindlln-3 deficiency is overcome and target cells killed. The realization that NK cell activity Is Impaired, but not ab-sent in leukocyte adhesion deficiency, may lead to the development of more efficient therapy for this rare disease. (Blood. 2012;120(19):3915-3924) [ABSTRACT FROM AUTHOR]

The inhibition of NK cell killing is mainly mediated via the interaction of NK inhibitory receptors with MHC class I proteins. In addition, we have previously demonstrated that NK cells are inhibited in a class I MHC-independent manner via homophilic carcinoembryonic Ag (CEA) cell adhesion molecules (CEACAM1)-CEACAM1 and heterophilic CEACAM1-CEA interactions. However, the cross-talk between immune effector cells and their target cells is not limited to cell interactions per se, but also involves a specific exchange of proteins. The reasons for these molecular exchanges and the functional outcome of this phenomenon are still mostly unknown. In this study, we show that NK cells rapidly and specifically acquire CEA molecules from target cells. We evaluated the role of cytotoxicity in the acquisition of CEA and demonstrated it to be mostly killing independent. We further demonstrate that CEA transfer requires a specific interaction with an unknown putative NK cell receptor and that carbohydrates are probably involved in CEA recognition and acquisition by NK cells. Functionally, the killing of bulk NK cultures was inhibited by CEA-expressing cells, suggesting that this putative receptor is an inhibitory receptor.

Griscelli syndrome (GS) type 2 is an autosomal recessive disorder represented by pigment dilution and impaired cytotoxic T lymphocyte (CTL) activity. NK activity has been scarcely investigated in GS patients. Here, we describe a new patient, possessing a hemophagocytic syndrome with a homozygous Q118X nonsense RAB27A mutation. Single specific primer-polymerase chain reaction (SSP-PCR) was developed based on this mutation and is currently used in prenatal genetic analysis. As expected, CTLs in the patient are not functional and NK cytotoxicity against K562 or 721.221 cells is diminished. Surprisingly, however, we demonstrate that CD16-mediated killing is intact in this patient and is therefore RAB27A independent, whereas NKp30-mediated killing is impaired and is therefore RAB27A dependent. We further analyzed the signaling pathways of these 2 receptors and demonstrated phosphorylation of Vav1 after CD16 activation but not after NKp30 engagement. Thus, we identify a novel homozygous mutation in the RAB27A gene of a new GS patient, observe for the first time that some activating NK receptors function in GS patients, and demonstrate a functional dichotomy in the killing mediated by these human NK-activating receptors.

Leukocyte arrest on vascular endothelium under disruptive shear flow is a multistep process that requires in situ integrin activation on the leukocyte surface by endothelium-displayed chemoattractants, primarily chemokines. A genetic deficiency of leukocyte adhesion to endothelium associated with defective beta2 integrin expression or function (LAD-1) has been described. We now report a novel severe genetic disorder in this multistep process associated with functional defects in multiple leukocyte integrins, reflected in recurrent infections, profound leukocytosis, and a bleeding tendency. This syndrome is associated with an impaired ability of neutrophil and lymphocyte beta1 and beta2 integrins to generate high avidity to their endothelial ligands and arrest cells on vascular endothelium in response to endothelial chemoattractant signals. Patient leukocytes roll normally on endothelial selectins, express intact integrins and G protein-coupled chemokine receptors (GPCR), spread on integrin ligands, and migrate normally along a chemotactic gradient. Activation of beta2 integrins in response to GPCR signals and intrinsic soluble ligand binding properties of the very late activation antigen-4 (VLA-4) integrin are also retained in patient leukocytes. Nevertheless, all integrins fail to generate firm adhesion to immobilized ligands in response to in situ GPCR-mediated activation by chemokines or chemoattractants, a result of a primary defect in integrin rearrangement at ligand-bearing contacts. This syndrome is the first example of a human integrin-activation deficiency associated with defective GPCR stimulation of integrin avidity at subsecond contacts, a key step in leukocyte arrest on vascular endothelium under shear flow.