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Query: UMLS:C0085110 (SCID)
 11,041 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Severe combined immunodeficiency (SCID) is a syndrome of profoundly impaired cellular and humoral immunity. In humans, SCID is most commonly caused by mutations in the X-linked gene IL2RG, which encodes the common gamma chain, gamma c, of the leukocyte receptors for interleukin-2 and multiple other cytokines. To investigate the frequency and variety of IL2RG mutations that cause SCID, we analyzed DNA, RNA, and B-cell lines from a total of 103 unrelated SCID-affected males and their relatives using a combination of molecular and immunologic techniques. Sixty-two different mutations spanning all eight IL2RG exons were found in 87 cases, making possible correlations between mutation type and functional consequences. Although skewed maternal X chromosome inactivation, single-strand conformation polymorphism, mRNA expression, and cell surface staining with anti-gamma c antibodies were all helpful in establishing IL2RG defects as the cause of SCID, only dideoxy fingerprinting and DNA sequence determination each detected 100% of the IL2RG mutations in our series. Abnormal gamma c chains may be expressed in the lymphocytes of as many as two thirds of patients with X-linked SCID. Specific mutation diagnosis thus remains technically challenging, but it is important for genetic counseling and perhaps for helping to select appropriate subjects for retroviral gene therapy trials, This is a US government work. There are no restrictions on its use.
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PMID:Mutation analysis of IL2RG in human X-linked severe combined immunodeficiency. 905 18

IL2RG, the gene encoding the common gamma chain, gamma c, of the receptor for interleukin-2 and other cytokines, has been identified as the disease gene for severe combined immunodeficiency (SCID) of the X-linked type. Specific mutational diagnosis for X-linked SCID has thus become possible. For many women at risk for carrying an IL2RG mutation, no samples were saved from an affected male relative prior to either death or bone marrow transplantation (BMT). To establish optimal methods for genetic evaluation of such women, we compared mutational screening by single-strand conformational polymorphism, heteroduplex analysis and dideoxy fingerprinting (ddF). Abnormally migrating band patterns were followed up with direct sequencing for identification of specific mutations. The most sensitive method, ddF, detected heterozygous alterations, subsequently confirmed to represent significant mutations, in all of 19 unrelated obligate or suspected carriers studied. Some of these women, as well as others at risk for carrying an X-linked SCID mutation, enrolled in a study of prenatal diagnosis after fetal testing for gender determination. Originally using linkage analysis and, more recently, specific detection of IL2RG mutations, we evaluated pregnancies at risk for X-linked SCID prospectively on a research basis. Of 27 male fetuses tested 14 were predicted to be unaffected and confirmed to have normal immune status at birth. Among pregnancies predicted to be affected, 2 were terminated, while 11 affected males were born at term. Nine of these received neonatal BMT, one had BMT at 3 months of age, and one underwent a successful experimental in utero BMT. In our study cohort accurate prenatal diagnosis assisted decision making and expanded treatment options for families at risk for having infants with a severe, but treatable genetic disorder that presents early in life.
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PMID:Carrier and prenatal diagnosis of X-linked severe combined immunodeficiency: mutation detection methods and utilization. 915 Jul 30

Severe combined immunodeficiency (SCID) is caused by a variety of underlying defects. Approximately 40% of cases are thought to be of the X-linked type (SCIDX1), which is phenotypically characterised by the absence, or very low numbers, of T cells, but normal or even high B cell numbers. The gene responsible for SCIDX1 is that coding for the common gamma chain (gamma c), a component of multiple cytokine receptors. Mutations in this gene have been demonstrated in a large number of boys affected by typical SCIDX1. We describe a sporadic case of a boy who had SCID with absent B cells and absent T cells, but in whom a mutation in the gamma c gene has been demonstrated. In the absence of a typical X-linked pedigree, the phenotype in this boy suggested an autosomal recessive form of SCID and the family would usually have been counselled accordingly. This family raises the question of the true frequency of SCIDX1 amongst sporadic male cases of SCID and highlights the need to screen these boys for gamma chain mutations.
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PMID:B-cell-negative severe combined immunodeficiency associated with a common gamma chain mutation. 915 Jul 40

JAK3 is a protein tyrosine kinase that specifically associates with the common gamma chain (gammac), a shared subunit of receptors for interleukin (IL) 2, 4, 7, 9, and 15. Patients deficient in either JAK3 or gammac presented with virtually identical forms of severe combined immunodeficiency (SCID), underscoring the importance of the JAK3-gammac interaction. Despite the key roles of JAK3 and gammac in lymphocytic development and function, the molecular basis of this interaction remains poorly understood. In this study, we have characterized the regions of JAK3 involved in gammac association. By developing a number of chimeric JAK3-JAK2 constructs, we show that the binding specificity to gammac can be conferred to JAK2 by transferring the N-terminal domains of JAK3. Moreover, those JAK3-JAK2 chimeras capable of binding gammac were also capable of reconstituting IL-2 signaling as measured by inducible phosphorylation of the chimeric JAK3-JAK2 protein, JAK1, the IL-2 receptor beta chain, and signal transducer and activator of transcription 5A. Subsequent deletion analyses of JAK3 have identified the N-terminal JH7-6 domains as a minimal region sufficient for gammac association. Furthermore, expression of the mutant containing only the JH7-6 domains effectively competed with full-length JAK3 for binding to gammac. We conclude that the JH7-6 domains of JAK3 are necessary and sufficient for gammac association. These studies offer clues toward a broader understanding of JAK-mediated cytokine signaling and may provide a target for the development of novel therapeutic modalities in immunologically mediated diseases.
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PMID:The amino terminus of JAK3 is necessary and sufficient for binding to the common gamma chain and confers the ability to transmit interleukin 2-mediated signals. 919 65

Defects of the common gamma chain subunit of the cytokine receptors (gamma c) or of Jak3, a tyrosine kinase required for gamma c signal transduction, result in T-B+ severe combined immunodeficiency (SCID). However, atypical cases, characterized by progressive development of T lymphocytes, have been also reported. We describe a child with SCID caused by Jak3 gene defects, which strongly but not completely affect Jak3 protein expression and function, who developed a substantial number (> 3,000/microL) of autologous CD3+CD4+ T cells. These cells showed a primed/activated phenotype (CD45R0+ Fas+ HLA-DR+ CD62L(lo)), defective secretion of T-helper 1 and T-helper 2 cytokines, reduced proliferation to mitogens, and a high in vitro susceptibility to spontaneous (caused by downregulation of bcl-2 expression) as well as activation-induced cell death. A restricted T-cell receptor repertoire was observed, with oligoclonal expansion within each of the dominant segments. These features resemble those observed in gamma c-/y and in Jak3-/- mice, in which a population of activated, anergic T cells (predominantly CD4+) also develops with age. These results suggest that residual Jak3 expression and function or other Jak3-independent signals may also permit the generation of CD4+ T cells that undergo in vivo clonal expansion in humans; however, these mechanisms do not allow development of CD8+ T cells, nor do they fully restore the functional properties of CD4+ T lymphocytes.
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PMID:Development of autologous, oligoclonal, poorly functioning T lymphocytes in a patient with autosomal recessive severe combined immunodeficiency caused by defects of the Jak3 tyrosine kinase. 944 56

Severe combined immunodeficiency (SCID) comprises a heterogenous group of disorders that are fatal unless treated by bone marrow transplantation (BMT). The most common form of SCID (T-B+ SCID) is due to mutations of either the common gamma chain (gammac) or of gammac-coupled JAK3 kinase. We report an unusual JAK3 defect in a female who was successfully treated > 20 years ago with a BMT using her HLA-identical father as the donor. Persistence of genetically and biochemically defective autologous B cells, associated with reconstitution of cellular and humoral immunity, suggests that integrity of the gammac-JAK3 signalling pathway is not strictly required for immunoglobulin production.
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PMID:Molecular and biochemical characterization of JAK3 deficiency in a patient with severe combined immunodeficiency over 20 years after bone marrow transplantation: implications for treatment. 975 72

X-linked severe combined immunodeficiency (XSCID) constitutes a disorder of the immune system caused by mutations in the gene encoding the common gamma chain (gammac), a subunit of the IL-2, IL-4, IL-7, IL-9 and IL-15 receptors, which are necessary for lymphocyte development and function. In this study the IL2RG gene of 31 patients with severe combined immunodeficiency (SCID) was examined by nonradioactive single-strand conformation polymorphism and sequence analysis. Among the 11 patients with XSCID, ten different mutations were identified in the IL2RG gene, including eight novel mutations. Ninety percent of the mothers of the XSCID patients are carriers of the mutated allele. One patient showed low numbers of B-cells, a striking deviation from the classical B-cell-positive and T-cell-negative phenotype.
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PMID:Mutations in the gene for the common gamma chain (gammac) in X-linked severe combined immunodeficiency. 992 12

Combined regimens of classical antiviral treatments have not, until now, lead to the eradication of HIV-1. A specific anti-HIV immune response may have to be boosted or transferred to patients after suppression of viral replication, in order to eradicate residual infected cells from their sanctuaries. Cytotoxic T cells engineered to express recombinant chimeric receptors can be redirected against HIV-infected cells and could represent the basis of a new type of immunotherapy. Several HIV epitopes have been targeted successfully in vitro. Two types of binding domains (antibody fragments, CD4) fused with various signal transducing units (zeta chain of the CD3 complex, Fc epsilon RI gamma chain) have been tested for their ability to redirect effector cells to HIV infected lymphocytes. CD4-zeta-expressing myeloid and natural killer cells conferred SCID mice protection against challenge with tumor cells expressing HIV-env. Finally, the safety of the adoptive transfer of syngeneic CD4-zeta -modified T cells in HIV-infected individuals is currently under evaluation.
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PMID:Gene therapy approaches to HIV-infection: immunological strategies: use of T bodies and universal receptors to redirect cytolytic T-cells. 1009 36

Janus kinase 3 (JAK3) is a cytoplasmic tyrosine kinase required for T cell development and activated by cytokines that utilize the interleukin-2 (IL-2) receptor common gamma chain (gamma(c)). Genetic inactivation of JAK3 is manifested as severe combined immunodeficiency disease (SCID) in humans and mice. These findings have suggested that JAK3 represents a pharmacological target to control certain lymphoid-derived diseases. Here we provide novel evidence that AG-490 potently inhibits the autokinase activity of JAK3 and tyrosine phosphorylation and DNA binding of signal transducer and activator of transcription 5a and 5b (STAT5a/b). Similar inhibitory effects were observed with other cytokines that use gamma(c). AG-490 also inhibited IL-2-mediated proliferative growth in human T cells with an IC50) = 25 microM that was partially recoverable. Moreover, we demonstrate that this inhibitor prevented tetanus toxoid antigen-specific T cell proliferation and expansion but failed to block activation of Zap70 or p56Lck after anti-CD3 stimulation of human T cells. Taken together, these findings suggest that AG-490 inhibits the JAK3-mediated Type II signaling pathway but not the T cell receptor-derived Type I pathway and possesses therapeutic potential for T cell-derived pathologies such as graft-versus-host disease, allergy, and autoimmune disorders.
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PMID:Tyrphostin AG-490 inhibits cytokine-mediated JAK3/STAT5a/b signal transduction and cellular proliferation of antigen-activated human T cells. 1038 Sep 15

The JAK3 gene, encoding a tyrosine kinase functionally coupled to cytokine receptors which share the common gamma chain, has been identified as the defective gene for autosomal recessive severe combined immunodeficiency (SCID). Thus, specific mutational diagnosis has become possible. We screened all exons with a combined single strand conformational polymorphism and hetero-duplex formation assay followed by sequence analysis to identify specific mutations in two families. This assay was used on chorionic villus sampling derived DNA in two fetuses from two unrelated families, where we found mutations in both parents. We were able to exclude the mutations in both fetuses by the 12th week of gestation. The described method for first-trimester prenatal diagnosis of autosomal recessive T-B+SCID provides a valid tool to aid in genetic counselling and possibly prenatal therapy in this disease.
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PMID:Prenatal diagnosis of JAK3 deficient SCID. 1041 14


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