Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An inherited deficiency of adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4) produces selective lymphopenia and immunodeficiency disease in humans. Previous experiments have suggested that lymphospecific toxicity in this condition might result from the selective accumulation of toxic deoxyadenosine nucleotides by lymphocytes with high deoxycytidine kinase, levels and low deoxynucleotide dephosphorylating activity. The present experiments were designed to determine if deoxyadenosine analogs which are not substrates for adenosine deaminase might similarly be toxic toward lymphocytes and lymphoid tumors. Two such compounds, 2-chlorodeoxyadenosine and 2-fluorodeoxyadenosine, at concentrations of 3 nM and 0.15 microM, respectively, inhibited by 50% the growth of human CCRF-CEM malignant lymphoblasts in vitro. Each was phosphorylated in intact cells by deoxycytidine kinase accumulated as the nucleoside triphosphate, and inhibited DNA synthesis more than RNA synthesis. Both deoxynucleosides had significant chemotherapeutic activity against lymphoid leukemia L1210 in mice.
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PMID:Deoxycytidine kinase-mediated toxicity of deoxyadenosine analogs toward malignant human lymphoblasts in vitro and toward murine L1210 leukemia in vivo. 625 65

An in vivo murine model for immunodeficiency of both B and T cells is produced by continuous intraperitoneal infusion of 2'-deoxycoformycin (DCF), a specific tightly binding inhibitor of adenosine deaminase (ADase; adenosine aminohydrolase, EC 3.5.4.4). After DCF infusion, ADase of thymus, spleen, and lymph nodes was inhibited to varying degrees ranging from 57% to 100%. Immunodeficiency under these conditions was indicated by: (i) a striking decrease in lymphocyte response to the T-cell mitogens concanavalin A and phytohemagglutinin; (ii) an impairment of delayed hypersensitivity measured by the footpad reaction; (iii) a decrease in antibody production measured in both in vivo and in vitro plaque-forming cell assay; (iv) a significant prolongation of mouse skin allograft survival after transplantation into the C57BL/6J (H-2b) strain of skin from BALB/c (H-2d) mice; and (v) a marked lymphopenia. Histological examination indicated lymphoid degeneration in the thymus, lymph nodes, and spleen with no alterations in other tissues including bone marrow, kidney, lung, gastrointestinal tract, and liver except for the occurrence of hepatitis. A decrease in the number of Thy-1-positive cells in both spleen and lymph nodes further supported the fact of cytotoxicity of DCF to T cells. Anorexia and weight loss were observed within 5 days of continuous DCF infusion at 0.4 mg/kg body weight per day. These data indicate that this method provides an experimental model for future studies on the biochemical mechanisms responsible for the genetically determined severe combined immunodeficiency disease in man.
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PMID:Animal model for immune dysfunction associated with adenosine deaminase deficiency. 696 8

Hereditary deficiency of the enzyme adenosie deaminase (adenosine aminohydrolase, EC 3.5.4.4) results in an immunodeficiency syndrome characterized by a marked reduction in circulating lymphocytes. We have administered 2'-deoxycoformycin, a potent inhibitor of adenosine deaminase, to a patient with a lymphoproliferative malignancy. The clinical consequences of pharmacologic inhibition of adenosine deaminase activity included an abrupt decrease in the lymphocyte count, abnormalities of renal and hepatic function, and hemolytic anemia. The plasma concentrations of adenosine and deoxyadenosine rose to peak values of 13 microM and 5 microM, respectively, and erythrocyte dATP levels increased to 110 pmol/10(6) cells over 9 days. There was a corresponding decrease in erythrocyte ATP levels from 128 to < 6 pmol/10(6) cells. A similar profound reductin in ATP occurred in the erythrocytes of a second patient. The rapid and unexpected depletion of ATP associated with dATP accumulation may account, at least in part, for the toxicity associated with 2'-deoxycoformycin administration. The inverse relationship of ATP and dATP raises major questions about the control of energy metabolism in erythrocytes.
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PMID:ATP depletion as a consequence of adenosine deaminase inhibition in man. 696 3

Adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4)-deficient patients recently were found to have abnormally high levels of dATP, a negative allosteric effector of ribonucleotide reductase (ribonucleoside-diphosphate reductase, 2'-deoxyribonucleoside-diphosphate:oxidized thioredoxin 2'-oxidoreductase, EC 1.17.4.1). Therefore it was proposed that the immunodeficiency associated with adenosine deaminase deficiency is mediated through inhibition of ribonucleotide reductase and hence DNA replication. HeLa cells, treated with an adenosine deaminase inhibitor, erythro-9(2-hydroxy-3-nonyl)adenine, and deoxyadenosine to mimic the adenosine deaminase-deficient state, were monitored to determine directly the effects on ribonucleotide reductase activity and levels. A low concentration of erythro-9-(2-hydroxy-3-nonyl)adenine, which did not inhibit cell growth, nevertheless retarded the cells in G2 + M phase of the cell cycle and increased reductase activity. Reductase activity was also elevated in cells treated with a low level of deoxyadenosine which did not affect the cell cycle or cell growth. However, ribonucleotide reductase activity was reduced to one-half of the control value in cells treated with either enough deoxyadenosine to inhibit cell growth or with a combination of erythro-9(2-hydroxy-3-nonyl)adenine and deoxyadenosine, each at concentrations which individually do not inhibit cell growth. Removal of deoxynucleotides, particularly dATP, from these extracts increased ribonucleotide reductase activity to several-fold higher than control values. The reduced activity of ribonucleotide reductase in the simulated adenosine deaminase-deficient HeLa cells provides direct evidence for the thesis that adenosine deaminase deficiency disease is mediated through elevated levels of dATP which inhibit ribonucleotide reductase. In addition, the cell cycle patterns and ribonucleotide reductase levels suggest that the regulatory substance(s) that controls the level of ribonucleotide reductase is not operative until the late S or G2 phase of the cell cycle.
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PMID:Adenosine deaminase impairment and ribonucleotide reductase activity and levels in HeLa cells. 699 99

Adenosine deaminase (ADA, EC 3.5.4.4) is a ubiquitous enzyme in the purine catabolic pathway. In contrast to the widespread tissue distribution of this enzyme, inherited ADA deficiency in human results in a tissue-specific severe combined immunodeficiency. To explain the molecular basis for this remarkable tissue specificity, we have used a genetic approach to study ADA deficiency. We demonstrate that ADA deficiency causes depletion of CD8low transitional and CD4+CD8+ double-positive thymocytes by an apoptotic mechanism. This effect is mediated by a p53-dependent pathway, since p53-deficient mice are resistant to the apoptosis induced by ADA deficiency. DNA damage, known to be caused by the abnormal accumulation of dATP in ADA deficiency, is therefore responsible for the ablation of T-cell development and for the immunodeficiency. The two thymocyte subsets most susceptible to apoptosis induced by ADA deficiency are also the two thymocyte subsets with the lowest levels of bcl-2 expression. We show that thymocytes from transgenic mice that overexpress bcl-2 in the thymus are rescued from apoptosis induced by ADA deficiency. Thus, the tissue specificity of the pathological effects of ADA deficiency is due to the low bcl-2 expression in CD8low transitional and CD4+CD8+ double-positive thymocytes.
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PMID:p53 expression is required for thymocyte apoptosis induced by adenosine deaminase deficiency. 766 98

Deficiency of adenosine deaminase (ADA) results in severe combined immunodeficiency disease (SCID). The cause for this is believed to be the accumulation of one of the substrates for ADA, 2'-deoxyadenosine to which especially T cells are hypersensitive. This disease can be treated successfully with bone marrow transplantation if a suitable donor is available. Alternatively, the human ADA gene could be introduced into the autologous bone marrow. We have generated a retroviral vector containing the human ADA gene. With this vector we were able to restore human ADA-activity in ADA-SCID T cells to normal levels resulting in a sensitivity to 2'-deoxyadenosine that is also found for T cells from a healthy donor. In murine studies we have shown that our retrovirus can infect pluripotent hemopoietic stem cells resulting in long-term (> 6 months) expression of human ADA in the hemopoietic system of transplanted animals. These results were confirmed in rhesus monkeys where we were able to detect the provirus in both peripheral blood mononuclear cells and granulocytes for as long as the animals were analyzed, i.e. up to more than 1 year post bone marrow transplantation. On the basis of these results we have proposed a clinical protocol for the treatment of ADA-SCID patients with bone marrow gene therapy.
Immunodeficiency 1993
PMID:Bone marrow gene therapy for adenosine deaminase deficiency. 790 79

Adenosine deaminase (ADA) deficiency is an autosomal recessive disorder resulting in immunodeficiency. Since the cDNA for ADA was cloned approximately 10 years ago, investigators have determined the molecular basis for disease in many patients with ADA deficiency. Mutations that have been identified include point mutations causing amino acid substitutions, premature stop codons, RNA splicing errors, and deletion mutations. Approximately one third of patients are homozygous for their mutation; in some of these cases the parents are known to be related. One mutation, Ala329-Val, is the most common, being present in 8 of the 21 ADA-deficient SCID patients whose mutations have been reported.
Immunodeficiency 1994
PMID:Molecular basis of adenosine deaminase deficiency. 803 66

Adenosine deaminase (ADA) deficiency is identified here as a cause of adult onset immunodeficiency. Two sisters who noted recurrent, predominantly chest infections in their twenties were found in their thirties to have CD4+ lymphopenia and lymphocyte ADA activity of approximately 5% of the lower limit of normal. Immune function, measured by proliferation of PBMCs in vitro to mitogens and specific Ags, was impaired. Inheritance of a polymorphic marker showed that both patients were heterozygous at the ADA locus. In the paternal allele there was a deletion resulting from homologous recombination between two alu elements that normally flank the first exon and the polymorphic marker. The recombination site was distinct from that in similar deletions described in two infants having severe combined immunodeficiency. This allele is predicted to result in a null phenotype. In the mutant allele inherited from the mother, a C to T transition in a CpG dinucleotide changed the codon for arginine 211, which lies in a conserved sequence close to the active site, to that for cysteine. This mutation has been observed previously in a child in whom the other allele was also a null mutation, but who was diagnosed as having partial ADA deficiency because immune function was apparently normal. The late onset of immunodeficiency in our patients suggests that immune function in children with partial ADA deficiency may deteriorate with time and that ADA deficiency should be regarded as a possible cause of adult onset immune dysfunction of unknown etiology.
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PMID:Adult onset immunodeficiency caused by inherited adenosine deaminase deficiency. 805 29

Adenosine deaminase (ADA) deficiency is the cause of about one third of the autosomal recessively inherited cases of severe combined immunodeficiency. Disease severity in ADA deficiency is variable, presumably related in part to heterogeneity in the genotypes causing the disease. We now report on two children in a single family with ADA deficiency who presented with distinct clinical courses. One child presented with severe immunodeficiency and recurrent infections that led to the diagnosis of severe combined immunodeficiency and ADA deficiency at 7 months of age. The older child, who was diagnosed at 3 years of age (after the diagnosis of the younger child), did not have a history of serious or opportunistic infections. Although she was lymphopenic, immune responsiveness was intact, in terms of antibody production, delayed-type hypersensitivity, and in vitro T-cell function. The difference in clinical course in these two siblings is an important observation and demonstrates that the phenotypic expression of ADA deficiency can vary within a family, even in a situation in which protective isolation from infectious pathogens was not a factor in causing the milder course. These observations indicate that expression of disease severity in ADA deficiency may depend to a significant degree on environmental factors and/or on heterogeneity at other genetic loci, which may regulate or modify the expression of the ADA gene or the activity of its product. Furthermore, these observations highlight the importance of recognizing patients with ADA deficiency who present with less severe disease and support the impression that functional immunity in patients with the "late-onset" form of ADA deficiency can deteriorate over time.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Heterogeneity of phenotype in two siblings with adenosine deaminase deficiency. 812 Feb 81

Genetic deficiency of adenosine deaminase (ADA) results in varying degrees of immunodeficiency, including neonatal onset severe combined immunodeficiency (ADA- SCID) and milder, later onset immunodeficiency. We have determined the molecular basis of disease in a child from a consanguineous mating with ADA- SCID of clinically and biochemically reduced severity, diagnosed at 15 months of age and characterized by retention of more immunologic function than is typical of the fulminant neonatal onset type. The course was notable for an early predominance of bacterial infections and eosinophilia. In contrast to its absence in most ADA- SCIDs, residual ADA activity (1-2% of normal) could be detected in EBV-transformed B cells. Consistent with the increased residual ADA, excretion of the substrate deoxyadenosine and accumulation of the toxic metabolite deoxyATP were less than seen in ADA- SCID patients with fulminant disease. Sequence analysis of cDNA revealed a G853C transversion, predicting a substitution of proline for arginine at codon 253 (Arg253Pro). The parents were heterozygous and the child was homozygous for the mutation, as shown by sequence analysis of amplified genomic DNA. Transient expression of mutant cDNA in Cos cells revealed an electrophoretically abnormal, more negatively charged ADA with 1-2% of normal activity. These observations are consistent with replacement of positively charged arginine by proline, the lower accumulation of toxic metabolites, and the milder phenotype. By contrast, transient expression of a Gly216Arg mutant cDNA, associated, when homozygous, with neonatal onset ADA-SCID, did not reveal ADA activity. Mutations such as Arg253Pro, which retain residual activity of monomeric ADA, should be dominant for ameliorating the phenotype in patients carrying two different allelic mutations. Identification of additional similar mutations may be significant in evaluating the goals for and efficacy of current trials of gene and gene product replacement.
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PMID:Severe combined immunodeficiency of reduced severity due to homozygosity for an adenosine deaminase missense mutation (Arg253Pro). 825 46


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