Adenosine Deaminase Activity Levels Research Articles

Adenosine deaminase levels in cerebrospinal fluid as a diagnostic test for tuberculous meningitis in children.

Adenosine deaminase activity (ADA) was estimated in cerebrospinal fluid (CSF) of 30 patients of tuberculous meningitis (TBM) and 10 patients each of partially treated pyomeningitis (PTM), aseptic meningitis (AM) and pyogenic meningitis (PM). Mean ADA levels in CSF of TBM patients were higher (18.22 U/L) as compared to 6.28 U/L, 3.43 U/L and 7.98 U/L in PTM, AM and PM respectively. This difference of ADA values in CSF between TBM and other types of meningitis was statistically significant (p<0.01) different. Sensitivity and specificity of ADA levels in CSF of children to diagnose tuberculous meningitis was 66.6% and 90% respectively at 10 U/L cut off of ADA levels in CSF. ADA levels in CSF could also differentiate PTM, AM and PM from TBM with a specificity of 90%, 100% and 80% respectively.

Adenosine deaminase activity in cerebrospinal fluid of HIV-infected patients: limited value for diagnosis of tuberculous meningitis

Adenosine deaminase activity (ADA) determination in cerebrospinal fluid (CSF) is considered a specific test for the diagnosis of tuberculous meningitis. In order to study the variability of this marker in patients with different neurological disorders associated with HIV infection, and its utility for the diagnosis of tuberculous meningitis in these patients, the ADA levels in 417 CSF samples from HIV-infected patients with neurological symptoms were reviewed. HIV infection, HIV-associated neurological disorders, and progressive multifocal leukoencephalopathy were not associated with elevated ADA in CSF. Among patients with meningitis, receiver operating characteristic curve analysis gave an optimal ADA cut-off point of 8.5 IU/l for the diagnosis of tuberculous meningitis, with 57% sensitivity, 87% specificity, and an area under the curve of 0.747 (similar to that for CSF glucose concentration). False-positive results were found in patients with neurological CMV disease and cryptococcal, lymphomatous, and probable candidal meningitis. The results of this study indicate that ADA determination in CSF has limited utility for the diagnosis of tuberculous meningitis in HIV-infected patients.

Adenosine deaminase activity in bronchoalveolar lavage in Turkish patients with smear negative pulmonary tuberculosis

The sputum smear-negative patients have been a diagnostic challenge for health professionals. Adenosine deaminase (ADA) activity has been shown to rise in various body fluids of patients with tuberculosis (Tb). A prospective clinical trial was conducted to determine the diagnostic value of ADA activity in bronchoalveolar lavage (BAL) in sputum smear-negative subjects highly suggestive for pulmonary Tb. Nineteen (M/F: 15/4, mean age 46.8±16.5 years) sputum smear-negative patients highly suggestive for pulmonary Tb constituted Group I. Acid fast bacilli (AFB) grew on sputum and/or BAL culture of all subjects in this group. Twenty-nine patients (M/F: 19/10, mean age 55.7±8.0 years) with non-tuberculous pulmonary diseases constituted Group II. Ten of them had interstitial lung disease, nine lung cancer, five pneumonia and five COPD. Twelve subjects (M/F: 7/5, mean age 48.4±12.8 years) constituted the controls (Group III) undergoing fiberoptic bronchoscopy (FOB) for various indications and the lungs were found to be normal eventually. Albumin and ADA activity levels were measured in plasma and BAL in all the subjects. LocalADA was calculated. PlasmaADA and BALADA of Group I was significantly higher (P<0.001) than that of the other groups. LocalADA was also the highest in Group I when compared with the others (P<0.001) but that of Group II was also higher (P<0.01) when compared with controls. With a cut-off value derived from the control subjects, sensitivity of BALADA was 100% and specificity 85.3%. Sputum PCR results are available in a couple of days whereas that of BALADA are available in a couple of hours and BALADA costs cheaper than PCR in our country. Therefore, we conclude that BALADA may be a useful, cheaper and faster diagnostic test in sputum smear-negative patients highly suggestive for pulmonary Tb. LocalADA need not be calculated as it is also significantly higher in Group II subjects and thus not as reliable as BALADA.

Molecular basis for paradoxical carriers of adenosine deaminase (ADA) deficiency that show extremely low levels of ADA activity in peripheral blood cells without immunodeficiency.

Adenosine deaminase (ADA) deficiency causes an autosomal recessive form of severe combined immunodeficiency and also less severe phenotypes, depending to a large degree on genotype. In general, ADA activity in cells of carriers is approximately half-normal. Unexpectedly, healthy first-degree relatives of two unrelated ADA-deficient severe combined immunodeficient patients (mother and brother in family I; mother in family II) had only 1-2% of normal ADA activity in PBMC, lower than has previously been found in PBMC of healthy individuals with so-called "partial ADA deficiency." The level of deoxyadenosine nucleotides in erythrocytes of these paradoxical carriers was slightly elevated, but much lower than levels found in immunodeficient patients with ADA deficiency. ADA activity in EBV-lymphoblastoid cell lines (LCL) and T cell lines established from these carriers was 10-20% of normal. Each of these carriers possessed two mutated ADA alleles. Expression of cloned mutant ADA cDNAs in an ADA-deletion strain of Escherichia coli indicated that the novel mutations G239S and M310T were responsible for the residual ADA activity. ADA activity in EBV-LCL extracts of the paradoxical carriers was much more labile than ADA from normal EBV-LCL. Immunoblotting suggested that this lability was due to denaturation rather than to degradation of the mutant protein. These results further define the threshold level of ADA activity necessary for sustaining immune function.

Adenosine deaminase activity in the CSF of patients with aseptic meningitis: utility in the diagnosis of tuberculous meningitis or neurobrucellosis.

We assayed 229 CSF samples from 180 adults with meningitis of different etiologies for adenosine deaminase activity (ADA) and evaluated the usefulness of this assay in the differential diagnosis of aseptic meningitis. Cases of meningitis were classified as tuberculous meningitis (TBM), pyogenic meningitis, viral meningitis, self-resolving aseptic meningitis without a specific diagnosis, meningitis associated with other infections, and neoplastic meningitis. We also tested 117 CSF specimens for which parameters were normal. We chose a cutoff point of 10 IU/L on the basis of our results and found elevated ADA levels in 50% of the patients with TBM (no differences between patients with AIDS and those who did not have AIDS were observed). Among samples from patients with aseptic meningitis, we observed high ADA levels in only two of five of the patients with neurobrucellosis. Therefore, we concluded that in cases of aseptic meningitis, a CSF ADA level of > or = 10 IU/L has a sensitivity of 48%, a specificity of 100%, a positive predictive value of 1, and a negative predictive value of 0.91 as a diagnostic criterion for TBM or neurobrucellosis. ADA levels were also > 10 IU/L in 30% of the patients with pyogenic meningitis, but this diagnosis was easily excluded on other grounds.

Significance of Adenosine Deaminase Activity and Its Isoenzymes in Tuberculous Effusions

Adenosine deaminase (ADA) activity is increased in effusions caused by certain clinical conditions including tuberculosis and bacterial infections. In this study, the ADA isoenzyme patterns in tuberculous and parainfective effusions were investigated to determine the isoenzyme responsible for this increase in activity. Fifty-one tuberculous effusions and six parainfective effusions were investigated. All effusions had increased ADA activity (median values of 126 and 127 units/L, respectively). In the tuberculous effusions, ADA2 isoenzyme was found to be primarily responsible for total activity, with a median contribution of 88 percent. The ADA1 (both ADA1m and ADA1c isoenzymes) was the major isoenzyme in the parainfective effusions with a median contribution of 70 percent. The ADA2 isoenzyme activity most likely reflects monocyte-macrophage turnover or activity, while ADA1 probably originates from lymphocytes or neutrophils. It is therefore essential to determine the isoenzyme profile when interpreting ADA activity levels in effusions. The measurement of the individual isoenzymes will enhance the diagnostic utility of ADA activity determinations in pleural effusions.

Effect of Blood Transfusion on Immune Function: IX. Effect on Lymphocyte Metabolism

Blood transfusions have been repeatedly shown to be immunosuppressive in nature. The intracellular mechanisms of this immunosuppression have not been extensively investigated. We investigated the effect of blood transfusions on lymphocyte intracellular metabolism of glucose and amino acids, as well as levels of adenosine deaminase activity and nucleotide triphosphate concentrations. Blood transfusions were found to increase the rate of glucose and glutamine metabolism, to increase nucleotide triphosphate concentrations, and to increase the level of adenosine deaminase activity. This increased level of lymphocyte metabolism in the face of immunosuppression would appear to indicate that the transfusion-induced immunosuppression is an active dynamic process.

Clinical significance of serum adenosine deaminase activity in patients with mycosis fungoides.

Adenosine deaminase is one of the key enzymes in purine nucleotide degradation. This enzyme exists in most of the human tissues and the activity is high in lymphatic tissues, especially in T lymphocytes. Elevated adenosine deaminase activity in T cell leukemia has been reported, and its inhibitor, deoxycoformycin, has been developed as an antitumor agent. In some types of leukemia, serum adenosine deaminase activity increases in accordance with the severity of the disease. Although mycosis fungoides rarely involves peripheral blood, tumor cells do invade the skin. In order to evaluate the clinical significance of adenosine deaminase in mycosis fungoides, adenosine deaminase activity was measured in sera of 15 patients with mycosis fungoides at various stages. The mean enzyme activity was 23.2 IU/l, which was high with statistical significance compared with healthy controls (P < 0.001). Nine of twelve patients in the plaque stage (T2N0M0, IB) showed higher adenosine deaminase activity than did the normal population. The mean adenosine deaminase activity in sera in the patients in the plaque stage (T2N0M0, IB) was as high as 19.0 IU/l (range 13.7-21.4) with statistical significance compared with healthy control (P < 0.001). Three tumor stage patients without visceral involvement (T3N0M0, IIB) showed higher levels of adenosine deaminase activity (19.7, 21.5, 24.4 IU/l). An erythrodermic patient (T4N0M0, III) also had a high adenosine deaminase activity 28.4 IU/l. Two tumor stage patients with organ involvement (T3N0M1, IVB) exhibited extremely high adenosine deaminase activity (60.9, 32.2 IU/l). The adenosine deaminase activity in sera showed a tendency to become higher with the extension of the stages.(ABSTRACT TRUNCATED AT 250 WORDS)

A case of tuberculous pericarditis—Use of adenosine deaminase activity (ADA) in early diagnosis

Pericardial tuberculosis is rare, and because of the difficulty in isolating the causative organism, the diagnosis is often missed. Adenosine deaminase, an enzyme associated with purine metabolism, shows markedly high levels of activity in tuberculous effusion. We report a case of tuberculous pericarditis diagnosed by high levels of adenosine deaminase activity, and where the pericardial fluid cultures revealed acid-fast organisms.

Developmental expression of adenosine deaminase in the upper alimentary tract of mice

Abstract The distribution and localization of adenosine deaminase (ADA) was studied during postnatal development of the alimentary tract in mice. There was detectable enzyme activity in all organs examined, but a range of more than 10,000 fold in the relative levels of specific activity was observed among adult tissues. A comprehensive survey of multiple adult tissues revealed that the highest levels of ADA occur in the upper alimentary tract (tongue, esophagus, forestomach, proximal small intestine). Immunohistochemical analysis revealed that ADA was predominantly localized to the epithelial lining of the alimentary mucosa: the keratinized squamous epithelium that lines the forestomach, esophagus, and surface of the tongue; and the simple columnar epithelium of the proximal small intestine (duodenum, proximal jejunum). Biochemical analysis revealed that ADA was one of the most abundant proteins of these mucosal tissue layers, accounting for 5%–20% of the total soluble protein. Tissue-specific differences in ADA activity correlated both with levels of immunoreactive protein and RNA abundance. The level of ADA activity in the upper alimentary tissues was subject to pronounced developmental control, being low at birth and achieving very high levels within the first few weeks of postnatal life. The appearance in development of ADA-immunoreactivity coincided with maturation of the mucosal epithelium. These results suggest that ADA is subject to strong cell-specific developmental regulation during functional differentiation of certain foregut derivatives in mice.

Isolation and characterization of S49 mouse lymphoma cell mutants deficient in adenosine deaminase.

Adenosine deaminase-deficient mutants of a mouse lymphoma cell line S49 have been isolated by a two-step selection process. In the first step, we derived mutant lines containing haploid levels of adenosine deaminase activity from wild-type cells. The selective medium contained tritiated deoxyadenosine, deoxycytidine, and deoxycoformycin. Wild-type cells were killed, presumably because of suicidal incorporation of tritiated deoxyadenosine via the adenosine deaminase pathway. The second step was to derive, from the partially deficient mutants, sublines that were virtually lacking adenosine deaminase, using tritiated deoxyadenosine and deoxycytidine. Four mutant clones were found to contain less than 5% of the enzyme activity of wild-type cells and virtually no immunoreactive adenosine deaminase protein. Northern blot analysis showed that the levels of adenosine deaminase mRNA were drastically reduced. Back-selection for adenosine deaminase-positive revertants can be accomplished by using a medium containing deoxyadenosine (as a sole source of purine), aminopterin, and thymidine or, alternatively, by using deoxyadenosine alone in a serum-free medium.

Developmental expression of adenosine deaminase in placental tissues of the early postimplantation mouse embryo and uterine stroma.

In this study, we have investigated the distribution of adenosine deaminase (ADA) in embryonic, extra-embryonic, and decidual tissues of the developing mouse embryo. ADA catalyzes a key step in purine metabolism converting adenosine to inosine. ADA specific activity (nmol/min/micrograms protein) was present at low levels in the embryo-decidual unit during the first 2 days of postimplantation development but then increased starting late on Day 6 of gestation (Day 0 plug). By Day 9, ADA specific activity was 80-fold higher than on Day 6. A histochemical staining method for ADA activity was applied to cryostat sections of the implantation site. The developmental increase localized primarily to the trophoblast/antimesometrial decidua interface between Days 7 and 9 of gestation, and decidua basalis and the metrial gland by Day 11. Immunofluorescent staining with sheep anti-mouse ADA antiserum confirmed the presence of ADA antigenicity in tissues forming the maternal/fetal interface. ADA specific activity was 19-fold higher in homogenates of the Day 11 decidua/parietal yolk sac than in the thymus, a tissue generally thought of as ADA-rich. High levels of ADA activity and immunoreactivity were also detected in the embryonal plasma during organogenesis, but the embryo proper showed only low levels. These results indicate that ADA is tightly regulated within tissues forming the maternal/fetal interface during early postimplantation stages of development.

Enzymes of adenosine metabolism in mouse sperm suspensions.

The enzymes of adenosine metabolism were investigated in suspensions of epididymal mouse spermatozoa incubated under conditions which support capacitation in vitro. High levels of adenosine deaminase activity were found in sperm suspensions, but the enzyme was located in the surrounding medium and was not intrinsic to spermatozoa. 5'-Nucleotidase was also present in the surrounding medium while in sperm cells it existed as an ecto-enzyme. Adenosine was not metabolized by washed spermatozoa under conditions used for the assay of adenosine deaminase or adenosine kinase, but it was metabolized rapidly by unwashed sperm suspensions. Incubation of sperm suspensions in conditions which modulate fertilizing ability resulted in small alterations in intrinsic 5'-nucleotidase activity of spermatozoa. In contrast, the activity of adenosine deaminase was not consistently modulated by such manipulations. Adenosine deaminase and 5'-nucleotidase exhibited similar kinetic parameters to enzymes from other sources and their activities were inhibited by coformycin and alpha, beta-methylene adenosine 5'-diphosphate, respectively. These studies highlight the low adenosine-metabolizing ability of spermatozoa coupled with the extensive metabolism in the medium which surrounds them. Extracellular adenosine metabolism can therefore occur and may modulate capacitation in vitro.

Opposite effects of recombinant interferon-alpha A and deoxycoformycin on adenosine deaminase activity in the Daudi B lymphoblastoid cell line

Interferon-alpha and the adenosine deaminase (ADA) inhibitor deoxycoformycin (dCF) have each been shown to be efficacious in the treatment of some lymphoid malignancies and to have potent antiproliferative activities in vitro. This study examined whether dCF and recombinant interferon-alpha A (rIFN-alpha A) were additive, synergistic, or antagonistic in their effects on the cultured B lymphoblastoid cell line Daudi. Treatment of Daudi cells for three to four days with doses of rIFN-alpha A that were growth inhibitory was unexpectedly found to increase the level of ADA activity per cell two- to threefold and therefore to prevent the inhibition of ADA by limiting concentrations of dCF. However, the opposite effects of dCF and rIFN- alpha A on ADA activity did not lead to antagonistic effects on growth inhibition. The higher concentrations of dCF (with deoxyadenosine) necessary for appreciable growth inhibition could inhibit the increased ADA activity in rIFN-alpha A-treated cells, thus resulting in additive antiproliferative effects.

Opposite Effects of Recombinant Interferon-αA and Deoxycoformycin on Adenosine Deaminase Activity in the Daudi B Lymphoblastoid Cell Line

Interferon-alpha and the adenosine deaminase (ADA) inhibitor deoxycoformycin (dCF) have each been shown to be efficacious in the treatment of some lymphoid malignancies and to have potent antiproliferative activities in vitro. This study examined whether dCF and recombinant interferon-alpha A (rIFN-alpha A) were additive, synergistic, or antagonistic in their effects on the cultured B lymphoblastoid cell line Daudi. Treatment of Daudi cells for three to four days with doses of rIFN-alpha A that were growth inhibitory was unexpectedly found to increase the level of ADA activity per cell two- to threefold and therefore to prevent the inhibition of ADA by limiting concentrations of dCF. However, the opposite effects of dCF and rIFN-alpha A on ADA activity did not lead to antagonistic effects on growth inhibition. The higher concentrations of dCF (with deoxyadenosine) necessary for appreciable growth inhibition could inhibit the increased ADA activity in rIFN-alpha A-treated cells, thus resulting in additive antiproliferative effects.

Antigenicity of UV radiation-induced murine tumors correlates positively with the level of adenosine deaminase activity.

The specific activities of adenosine deaminase (ADA) in 16 murine tumor cell lines derived from seven UV light-induced neoplasms (melanoma and fibrosarcoma) were determined. In each case, the specific activity of ADA correlated positively with the antigenicity of the tumor cells. Highly antigenic cell lines that regress upon introduction into syngeneic hosts had on average 4- to 6-fold higher ADA specific activities than cell lines of low antigenicity that grow progressively in syngeneic hosts. The antigenic differences are probably not related to intracellular cAMP levels, as the level of cAMP differed only 2-fold between the two groups of cell lines.

Genetic Expression of Adenosine Deaminase in Human Lymphoid Malignancies

Adenosine deaminase (ADA) is an enzyme in the purine catabolic pathway that has been used as an enzymatic marker of T cell lymphoblastic malignancies due to its high specific activity in thymocytes and immature T cells. We have investigated whether the level of ADA activity in lymphoid leukemic cells correlates with the amount of ADA-specific RNA and/or immunoreactive protein in these cells as an initial step toward characterizing the nature of the genetic regulation of ADA expression during differentiation. We have found a good correlation between the steady state levels of ADA-specific RNA and ADA-immunoreactive protein in T lymphoblastic leukemic cell lines, mature T cell lines, a B lymphoblast cell line, and leukemic cells directly isolated from four patients with acute lymphoblastic leukemia and three patients with chronic lymphocytic leukemia. Southern blot analysis of DNA from these cells shows no evidence for differences in ADA gene copy number or gene rearrangement to account for the variability in ADA expression. We conclude that levels of ADA in lymphoid leukemic cells are directly related to the amount of ADA-specific mRNA present. These findings imply that ADA expression in leukemic cells reflects either the transcriptional activity of the ADA gene or the stability of ADA mRNA in these cells.

Genetic expression of adenosine deaminase in human lymphoid malignancies

Adenosine deaminase (ADA) is an enzyme in the purine catabolic pathway that has been used as an enzymatic marker of T cell lymphoblastic malignancies due to its high specific activity in thymocytes and immature T cells. We have investigated whether the level of ADA activity in lymphoid leukemic cells correlates with the amount of ADA- specific RNA and/or immunoreactive protein in these cells as an initial step toward characterizing the nature of the genetic regulation of ADA expression during differentiation. We have found a good correlation between the steady state levels of ADA-specific RNA and ADA- immunoreactive protein in T lymphoblastic leukemic cell lines, mature T cell lines, a B lymphoblast cell line, and leukemic cells directly isolated from four patients with acute lymphoblastic leukemia and three patients with chronic lymphocytic leukemia. Southern blot analysis of DNA from these cells shows no evidence for differences in ADA gene copy number or gene rearrangement to account for the variability in ADA expression. We conclude that levels of ADA in lymphoid leukemic cells are directly related to the amount of ADA-specific mRNA present. These findings imply that ADA expression in leukemic cells reflects either the transcriptional activity of the ADA gene or the stability of ADA mRNA in these cells.

Evidence for negative control of growth by adenosine in the mammalian embryo: Induction of Hmx/+ mutant limb outgrowth by adenosine deaminase

We investigated the growth-regulatory actions of adenosine and adenosine deaminase (ADA) during embryonic limb development in the mouse. Polydactylous outgrowth, an expression of the Hemimelia-extra toe (Hm x) mutant phenotype, was experimentally regulated in hind-limb buds explanted into a serum-free in vitro system at stage 18 of gestation. Its expression was promoted by exposure to 0.1 or 0.2 IU/ml exogenous ADA and suppressed by co-exposure to 10 nM (—)-N 6-(R-phenylisopropy1)-adenosine (N 6-PIA). Evidence that N 6-PIA acted as a high-affinity agonist against the external adenosine receptor was provided by experiments in which 100 μM caffeine, a known antagonist, competitively blocked its effect. The endogenous adenosine content was analyzed by reversed-phase high-performance liquid chromatography with fluorometric detection following its conversion to the 1,N 6ethenoadenosine derivative. At stage 18. the adenosine levels were 0.5 pmol/μg DNA in whole embryos and 0.08 pmol/pg DNA in hindlimb buds. At the same stage, partially purified extracts of the embryonal plasma enriched fraction contained high levels of ADA activity (0.04-0.06 IU/embryo, or 0.7-1.0 IU/mg protein). In contrast, blood cells contained 0.0001 IU/embryo (or 0.01 IU/mg protein). This enzyme occurred as a single kinetic form with a molecular weight of 4500047000 daltons and an apparent K m of 36-38 μM. Its presence in the embryonal plasma argues against an endocrine mechanism of adenosine secretion in favor of autocrine (self-regulatory) or paracrine (proximate-regulatory) mechanisms. Taken together, our results suggest that the in vitro outgrowth of the prospective polydactylous region is induced upon escape from the local growth-inhibitory influence of extracellular adenosine. It is concluded that growth during early limb development is under systemic as well as local control.

Partial adenosine deaminase deficiency: another family from southern Africa.

Adenosine deaminase (ADA) from a partially ADA-deficient Xhosa man has been characterized. This is only the second such case described in southern Africa, the previous one being a Kalahari San ("Bushman"). Red blood cell ADA levels were found to be only 6-9% of normal whereas his white cell ADA levels were much higher at 30% of normal. The stability of the enzyme at 57 degrees C was shown to be greatly decreased indicating a mutation resulting in an enzyme with decreased stability in vivo. The Michaelis constant (Km) for adenosine was found to be normal. Deoxy-ATP levels in the red cells were elevated 2- to 3-times above normal, although this appears to be of no immunological consequence. Starch gel electrophoresis of red cell ADA from family members of the index case, in conjunction with red cell ADA activity levels, suggested that both parents carried a gene for partial ADA deficiency. Isoelectric focusing studies suggested that the two parental partial ADA-deficiency genes were not the same. Electrophoretic studies also revealed that another rare allele of ADA, possibly ADA*5, was segregating within the same family although this event appears to be unconnected with the ADA partial deficiency. A Xhosa population sample was assayed for red cell ADA activity. The results suggested a frequency of 0.015 +/- 0.010 for ADA partial-deficiency alleles, although the number of different alleles involved is not known.