Adenosine Deaminase Isoenzymes Research Articles

Evaluation of the Effect of Sampling Time on Biomarkers of Stress, Immune System, Redox Status and Other Biochemistry Analytes in Saliva of Finishing Pigs.

Simple SummarySaliva is a sample with a high potential in pigs since it is usually easy to obtain and its collection from animals causes less stress than blood sampling. However, the possible effects of daily variations in many salivary biomarkers are still unknown in this species. In our report, the possible variations depending on the sampling time in the day in a panel of 26 salivary biomarkers related to stress, immune system, redox status and other physiological functions in the saliva of pigs were evaluated. In our experimental conditions, daily variations were observed in cortisol, α-amylase, total esterase, butyrylcholinesterase, lipase, adenosine deaminase isoenzyme 1, uric acid, superoxide dismutase, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, creatine kinase, lactate dehydrogenase, triglycerides and lactate. In some analytes, these differences appeared in both sexes, whereas others only showed differences in one sex. These variations should be taken into consideration for an appropriate interpretation of these analytes in the saliva of healthy pigs.This study aims to evaluate the possible variations due to the sampling time in the day in 26 analytes of pigs’ saliva, related to stress, the immune system, redox status and other biomarkers related to metabolism and selected tissues and organs, in order to know the possible effects of the hour of the day in their interpretation. These analytes were measured in saliva obtained from a population of 40 clinically healthy pigs from 8 a.m. to 8 p.m., every 4 h in the same day. In our experimental conditions, daily variations were observed in cortisol, salivary α-amylase, total esterase activity, butyrylcholinesterase, lipase, adenosine deaminase isoenzyme 1, uric acid, superoxide dismutase, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, creatine kinase, lactate dehydrogenase, lactate and triglycerides. These changes appeared in both sexes, except for adenosine deaminase isoenzyme 1 and superoxide dismutase which only showed differences in females. In conclusion, this report indicates that, in the experimental conditions of this trial, the time of the day and sex can influence the values obtained in various salivary analytes in pigs. These variations should thus be taken into consideration for an adequate interpretation of these analytes when used for the evaluation of health and welfare in this species.

Distinct Roles of Adenosine Deaminase Isoenzymes ADA1 and ADA2: A Pan-Cancer Analysis.

ObjectiveAdenosine deaminase (ADA) plays an important role in immune response, which includes two isoenzymes: ADA1 and ADA2. This study aims to explore the roles of ADA1 and ADA2 in cancers.MethodsHuman Protein Atlas (HPA) and Gene Expression Profiling Interactive Analysis (GEPIA2) databases were used to analyze the mRNA expression of ADA1 and ADA2 in human normal cells and tumor tissues. The enzyme assay was used to detect the ADA1 and ADA2 activities in serum from cancer patients. The Kaplan–Meier (KM) plotter was used to analyze the prognostic value of ADA1 and ADA2. TIMER2.0 was used to explore how ADA1 and ADA2 correlate with immune infiltration and immune checkpoints. cBioPortal database was used to investigate the mutations of ADA1 and ADA2. LinkedOmics was used to screen the ADA1 and ADA2 expression-related genes.ResultsADA1 was significantly increased in several tumor tissues, including cholangiocarcinoma (CHOL), lymphoid neoplasm diffuse large B-cell lymphoma (DLBC), head and neck squamous cell carcinoma (HNSC), kidney renal clear cell carcinoma (KIRC), ovarian serous cystadenocarcinoma (OV), pancreatic adenocarcinoma (PAAD), thymoma (THYM), and uterine carcinosarcoma (UCS). ADA2 expression was significantly increased in esophageal carcinoma (ESCA), glioblastoma multiforme (GBM), acute myeloid leukemia (LAML), OV, PAAD, skin cutaneous melanoma (SKCM), and stomach adenocarcinoma (STAD). There were no significant changes in serum ADA1 activities in most cancers, while serum ADA2 activities were increased in most cancers. For prognosis, high ADA1 expression was associated with the poor survival in several cancers, including esophageal squamous cell carcinoma (ESCC), HNSC, KIRC, kidney renal papillary cell carcinoma (KIRP), liver hepatocellular carcinoma (LIHC), lung adenocarcinoma (LUAD), and uterine corpus endometrial carcinoma (UCEC). However, high ADA2 expression showed a favorable prognosis in breast invasive carcinoma (BRCA), cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC), HNSC, KIRC, KIRP, LUAD, OV, PAAD, sarcoma, and THYM. ADA1 showed a moderate positive correlation with multiple infiltrating immune cells in most cancers. ADA2 was positively correlated with B cells, CD8 T cells, monocytes/macrophages, and dendritic cells (DCs) and was strongly negatively correlated with myeloid-derived suppressor cells. Function analysis showed that ADA1 expression-related genes were mainly enriched in cell division biological progression. However, ADA2-related genes were mainly associated with immune response.ConclusionAs isoenzymes, ADA1 and ADA2 showed opposite prognostic values and different correlative patterns with immune infiltrating. These data demonstrated the distinct roles of ADA1 and ADA2 in cancer. ADA2 might act as a protective factor in cancer.

The informative value of adenosine deaminase isoenzymes testing in the diagnosis of tuberculous pleurisy with the relevance to the age of patients

The objective of the study: to assess the diagnostic informative value of ADA isoenzymes – ADA-1 and ADA-2 – in the pleural fluid in case of tuberculous pleurisy with the relevance to the age of patients. Subjects and methods. In 200 patients with pleural effusion of tuberculous etiology and 152 patients with pleural effusion of non-tuberculous etiology, the activity of ADA (and its isoenzymes of ADA-1 and ADA-2) was tested. Results. In patients with tuberculous pleurisy, the activity of ADA, ADA-1 and ADA-2 was significantly higher than in patients with pleurisy of a different etiology. Tests of ADA activity (above the threshold value of 30 u/L) had sensitivity and specificity of 95 and 94%, respectively. The sensitivity of testing the activity of ADA-1 and ADA-2 (above the threshold value of 20 u/L) was 30 and 93% with the specificity of 96% and 88%, respectively. The frequency of detecting the activity of ADA and ADA-2 above the threshold did not depend on the cellular nature of tuberculous pleurisy. The activity of ADA-2 was associated with the percentage of pleural fluid lymphocytes in the case of tuberculosis. No influence of age on the diagnostic informative value of ADA and ADA-2 was found out. ADA-1 activity was weakly positively correlated with the age of the patients.

Adenosine Deaminase Activity and HLA-DRB as Diagnostic Markers for Rheumatoid Arthritis.

Rheumatoid Arthritis (RA) is a chronic multi systemic disorder with the unclarified ethiopathology. Although several markers have been presented for recognition of RA, but none of them has been specific. New markers such as HLA typing and activity of Adenosine Deaminase (ADA) isoenzymes could be useful and specific. The aim of this study is to evaluate the pattern of ADA isoenzymes activity and HLA typing in both RA patients and healthy cases. Blood samples were collected from 55 RA patients and 60 healthy subjects, over a period of 6 months. Levels of C-reactive Protein (CRP), Rheumatoid Factor (RF) and ADA (ADA1, ADA2, total ADA) were measured using AVITEX kit and HITACHI Auto Analyzer. In addition, HLA-DRB1*01,*04 and *10 was detected using PCR-SSP. ADA activity, particularly ADA2 level, was significantly higher among RA group (Pv <0.05). The concentrations of tADA in patients with RF and CRP positive were significantly higher (Pv <0.05). The allele prevalence of DRB1*01 was significantly higher in RA patients (13.1%) compared with control group (5.5%, respectively) (P <0.05, Bonferroni adjustment P<0.003). Calculated sensitivity and specificity for diagnostic tests in this study are listed as: CRP (75%), RF (80%), ADA (84%) and RF (90%), ADA (83%), CRP (72%), respectively. Increased tADA level and the frequency of DRB1*10 and *01 caused susceptibility to RA.

Adenosine Deaminase 1 as a Biomarker for Diagnosis and Monitoring of Patients with Acute Lymphoblastic Leukemia.

SummaryBackgroundAcute lymphoblastic leukemia (ALL) is known as the most prevalent pediatric malignancy all around the world. Identification of specific biomarker is necessary for early diagnosis and effective therapy. It is believed that Adenosine deaminase (ADA) as an enzyme involved in the purine salvage pathway increases in ALL patients. Herein, the quantity and pattern of ADA isoenzymes were surveyed among ALL patients in comparison to healthy subjects.MethodsSerum and RBC samples of three different groups of ALL patients, including newly diagnosed cases without any drugs administration, subjects with the relapsed disease, patients in the remission stage after therapy, and the healthy subjects were enrolled in the study. Then, the activity and pattern of ADA1, ADA2 and ADA1+cp were determined using ADA kit and electrophoresis on SDS-PAGE, respectively. To confirm the presence of ADA enzyme, the fresh serums, extractions from erythrocytes, JM cell line as a human T lymphocyte line and J774 A.1 as mouse monocyte line were electrophoresed on 1.2% agarose gel and stained with the specific dye.ResultsThe activities of ADA1 isoenzyme and total ADA in new cases and subjects with the relapsed disease were significantly higher than their activities in the patients in the remission stage and healthy controls (p<0.001). The unbounded ADA1 isoenzyme was found to exist in the erythrocyte, lymphocyte and monocyte. But in serum, all the ADA1 was bounded to the cp protein.ConclusionsADA1 is the key isoenzyme elevating in ALL patients, therefore this isoenzyme could be a useful biomarker to diagnose ALL patients and monitor their therapies.

ADENOSINE DEAMINASE AND ITS ISOENZYMES IN ASCITES WITH DIFFERENT ETIOLOGIES

Adenosine deaminase (ADA) activity was increased in certain clinical conditions including tuberculosis and bacterial infections. In this study, the ADA isoenzymes patterns were assayed in ascites of different etiologies Ninety two Patients with ascites were selected and investigated to determine the cause of ascites. Total ADA and its isoenzymes were assayed spectophotometerically besides polyacrylamide gel electrophoretic. Results . In ascitic fluid secondary to parainfection, TB, abdominal cancer and liver cirrhosis, total ADA were 34.5± 11.1, 87.6± 23.6, 32.7± 10.1 and 28.5± 7.3 U/l respectivly, ADA1m were 24.5± 11.1, 4.3± 1.9, 2.8± 2.2 and 10.1± 3.3 U/l respectivly, ADA1c were 7.8± 3, 16.5± 6.2, 4.7± 1.3 and 10.1± 3.3 U/l respectivly but, ADA2 were 2.2± 3.9, 65.9± 33.5, 26.2± 6.2 and 3.3± 9.7 U/l respectivly. Conclusion Total ADA above 41 U/l and ADA2 above 32 U/l in ascetic fluid have high sensitivity value in TB peritonitis. Ascitic fluid ADA1m/ADA more than 50% has high specificty value in parainfective peritonitis. Total ascitic ADA less than 41 U/L and ADA2/ADA ratio more than 50% have high specificity in abdominal cancer.

Serum Adenosine Deaminase (ADA) Activity: A Novel Screening Test to Differentiate HIV Monoinfection From HIV-HBV and HIV-HCV Coinfections.

CD4(+) cell count, the common HIV infection screening test, is costly and unable to differentiate HIV monoinfection from its concurrent infection with hepatitis B or C virus. We aimed to ascertain diagnostic value of serum adenosine deaminase (ADA) activity as a useful tool to differentiate HIV mono- and co-infection. Blood samples were collected from 30 HIV-HBV and 30 HIV-HCV coinfected patients, 33 HIV positive subjects, and 72 controls. CD4(+) cell count, serum total ADA (tADA), and ADA1, and ADA2 isoenzyme activities were determined and their sensitivity and specificity were computed. tADA and ADA2 activities were significantly higher and CD4(+) counts were markedly lower in all patients compared with controls. Strong inverse agreements between CD4(+) cell counts and both tADA and ADA2 activities were observed. Serum tADA and ADA1 activities showed the highest specificity and the highest sensitivity, respectively, for differentiating HIV monoinfection from HIV-HBV and HIV-HCV coinfections. We showed strong agreement and correlation between CD4(+) cell count and ADA enzyme activity. Based on high ADA sensitivity and specificity, it is concluded that determination of ADA activity might be a novel diagnostic tool to distinguish of HIV monoinfection from its coinfection with HBV or HCV.

Exudative pleural effusion in chronic kidney disease: An aetiological dilemma.

Exudative pleural effusion in chronic kidney disease: An aetiological dilemma.

Serum dipeptidyl peptidase-IV: A better screening test for early detection of mucopolysaccharidosis?

We aimed to investigate the diagnostic utility of serum DPP-IV enzyme activity, urinary GAG/Cre ratio, chitotriosidase activity, total adenosine deaminase (ADA) and ADA-1 isoenzyme activity in the diagnosis of MPS.31 MPS patients which were previously diagnosed by clinical and enzymatic analysis and 31 healthy controls matched with age and gender were included in this study.Serum DPP-IV enzyme activity, urinary GAG/Cre ratio, total ADA and ADA-1 isoenzyme activity were significantly higher in patients than in controls (p<0.001, p<0.001, p=0.038 and p=0.006, respectively). There were significant correlations between serum DPP-IV enzyme activity and urinary GAG/Cre ratios, ADA-1 activity, ADA-1/total ADA (r=0.498, p<0.001; r=0.348, p=0.006; r=0.270, p=0.034, respectively). Area under ROC curve for DPP-IV enzyme activity was 0.988, p<0.001 and for urinary GAG/Cre ratio was 0.986, p<0.001. DPP-IV enzyme activity and urinary GAG/Cre ratio were the most significant parameters according to the univariate logistic regression analysis (p=0.001 and p<0.001, respectively).The measurement of serum DPP-IV enzyme activity can be used complementary to the urinary GAG/Cre ratio for first-line MPS screening, since it is more less prone to age and hydration related interferences.

Diagnostic Value of Serum Adenosine Deaminase Activity in HIV Infected Patients of Kurdish Population

Adenosine deaminase (ADA) is a hydrolytic enzyme involved in the deamination of adenosine to inosine. ADA is involved in T-lymphocyte differentiation and development. This study was aimed to determine the diagnostic value of the adenosine deaminase (ADA) activity test for the diagnosis of HIV positive patients in the Kurdish population. This descriptive analytical case-control study was performed on 30 healthy and 60 HIV positive subjects. Blood CD4+ cell count was recorded and serum total ADA, and ADA1 and ADA2 isoenzyme activities were determined. Serum total ADA and ADA2 isoenzyme activity was significantly higher in HIV positive patients than in healthy subjects. CD4+ cell counts markedly decreased in all patients and showed a significant inverse correlation with ADA activities. Using a cut-off level of 36.52 U/L and 30.98 U/L for serum total ADA and ADA2, respectively, sensitivity and specificity were 90.9% and 90.27% for total ADA and 93% and 90% for ADA2, respectively. Serum ADA was significantly increased in HIV infected patients. Therefore, because of its low cost and simplicity to perform, ADA activity might be considered a useful diagnostic tool among the other markers in this disease.

Adenosine Deaminase Isoenzymes in the Diagnosis and Monitoring of Rheumatoid Arthritis

Adenosine Deaminase Isoenzymes in the Diagnosis and Monitoring of Rheumatoid ArthritisThe aim of this study was determination of the catalytic activities of adenosine deaminase (ADA), ADA1 and ADA2 isoenzymes in the serum of patients suffering from rheumatoid arthritis (RA) who were and were not treated with methotrexate (MTX), and identification of the possibilities of using these biochemical parameters in diagnosing and monitoring the treatment effects in RA. Catalytic activities of total ADA (tADA) and ADA2 in serum were determined by a spectrophotometric method. A statistically significant correlation was found between the total ADA and ADA1 values, as well as between tADA and ADA2 in the serum of all patients suffering from RA. Determination of ADA1 and ADA2 isoenzyme catalytic activities in the serum of patients who might be suffering from RA improves the diagnostic value of total ADA catalytic activity determination. ADA2 catalytic activity in serum can be a useful biochemical marker in diagnosing and monitoring RA. Decrease in ADA1 isoenzyme catalytic activities in the serum of patients suffering from RA who were treated with MTX can help in the observation of MTX therapy effects.

Mantle cell lymphoma involvement of the pleura and tuberculous pleurisy with pulmonary tuberculosis: a case report and literature review

A 78-year-old Japanese woman was admitted to our hospital for fever, dry cough, and right pleural effusion. She was diagnosed with mantle cell lymphoma (MCL) at 73 years of age and was treated with carcinostatics, but MCL was refractory. Chest computed tomography (CT) on admission revealed a localized trabecular shadow in the middle lobe of the right lung and right pleural effusion with thickened visceral pleura. Right pleural effusion was exudative, lymphocytes were dominant, and adenosine deaminase isoenzymes were elevated. (18)F-fluorodeoxyglucose positron emission tomography/CT revealed positive findings in the right thickened visceral pleura and right middle lobe. We suspected tuberculosis, but bronchoscopy revealed that the washing fluid was negative for Ziehl-Neelsen staining. Thoracoscopy under local anesthesia revealed redness on the parietal and visceral pleura and fibrin network. Pathological findings from pleural biopsy included granulomas, Langhans-type giant cells, and diffuse invasion of lymphocytes with atypical nuclei. Immunophenotypes were CD5(+), CD10(-), CD19(+), CD20(+), λ(+), CD25(+) by flow cytometry and CD20(+), CD45RO(-), cyclin D1(+), bcl2(+), bcl6(-) by immunohistochemistry. We diagnosed MCL involvement of the pleura, and highly suspected tuberculous pleurisy. The patient received antituberculosis therapy with rifampicin, isoniazid, pyrazinamide, and ethambutol. After 4 weeks, culture of bronchoscopy washing fluid was positive for Mycobacterium tuberculosis. We diagnosed pulmonary tuberculosis. Patients with malignant lymphoma are vulnerable to tuberculosis. In addition to diagnosing MCL involvement of the pleura, it is important to consider the possibility of complication with tuberculosis.

Analysis of serum adenosine deaminase (ADA) and ADA1 and ADA2 isoenzyme activities in HIV positive and HIV–HBV co-infected patients

Objectives To determine adenosine deaminase (ADA) activity as a possible diagnostic marker in HIV and HIV–HBV co-infected patients. Design and methods Blood samples were collected from 72 healthy, 33 HIV positive and 30 HIV–HBV co-infected subjects. Blood CD4+ cell count was recorded and serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total ADA, and ADA1 and ADA2 isoenzyme activities were determined. Results Serum ALT, AST, total ADA and ADA2 isoenzyme activities were significantly higher in HIV positive and HIV–HBV co-infected groups compare to the control ( p < 0.05), whereas serum ALP showed no differences between groups. CD4+ cell counts markedly decreased in all patients and showed a significant inverse correlation with ADA activities (R 2 = 0.589, p < 0.001). Conclusions Serum ADA was significantly increased in HIV and HIV–HBV co-infections. Therefore, because of its low cost and simplicity to perform, ADA activity might be considered as a useful diagnostic tool among the other markers in these diseases.

Serum Adenosine Deaminase Activity in Domestic Animals: Reference Values

This study was aimed to determine normal serum adenosine deaminase (ADA) activity in domestic animals in both sexes and that were considered healthy on the basis of clinical and laboratory examinations. In this study, 262 non-pregnant animals of both sexes, belonging to 5 species [cattle (n = 50), sheep (n = 65), goat (n = 52), dog (n = 55), and cat (n = 40)] were used. Serum total ADA and ADA1 isoenzyme activities were found to be 6.34 ± 0.31 IU/l and 6.34 ± 0.31 IU/l in cattle, 7.57 ± 0.30 IU/l and 7.31 ± 0.47 IU/l in sheep, 7.52 ± 0.36 IU/l and 6.44 ± 0.72 IU/l in goat, 2.56 ± 0.13 IU/l and 2.03 ± 0.30 IU/l in dogs, 23.36 ± 1.59 IU/l and 21.71 ± 2.13 IU/l in cats, respectively. The serum levels of ADA2 were low in sheep, goats, dogs, and cats, whereas in these species ADA1 was high. Furthermore, there was no serum ADA2 activity in cattle. Additionally, there were no significant differences between genders in ADA activities in all species. As a result, determination of serum normal ADA and its isoenzyme activities in domestic animals will be useful for scientists who want to investigate ADA activity in future in different diseases.

Effect of Cardiovascular Drugs on Adenosine Deaminase Activity

Adenosine deaminase catalyzes the conversion of adenosine and deoxyadenosine to inosine and deoxyinosine, respectively. Because raising adenosine concentration can affect several physiological processes we studied the effect of a selection of cardiological drugs on adenosine deaminase activity in red blood cells and rabbit plasma after 21 days administration. We determined the activity of adenosine deaminase isoenzymes (ADA(1) and ADA(2)). Simvastatin, aspirin, metoprolol, and isosorbide mononitrate significantly decreased plasma total adenosine activity (by 50%, 34%, 29%, and 19%, respectively; P < .05 to P < .001) mainly by decreasing the activity of ADA(2). As a consequence of decreased ADA(2) activity , the half-life of adenosine will be lengthened. This may, at least in part, explain some of the beneficial effects of analyzed drugs. Our results might be clinically relevant in patients with coronary artery disease, acute coronary syndromes, heart failure, or stroke where the investigated drugs are commonly used. However, our results should be confirmed in large studies in humans.

ADA2 isoform of adenosine deaminase from pleural fluid

Adenosine deaminase isoenzyme 2 (ADA2) was isolated from human pleural fluid for the first time. Molecular and kinetic properties were characterized. It was shown that the inhibitors of adenosine deaminase isoenzyme 1 (ADA1), adenosine, and erithro-9-(2-hydroxy-3-nonyl)adenine (EHNA) derivatives are poor inhibitors of ADA2. Comparison of the interaction of ADA2 and ADA1 with adenosine and its derivative, 1-deazaadenosine, indicates that the isoenzymes have similar active centers. The absence of ADA2 inhibition by EHNA is evidence of a difference of these active centers in a close environment. The possible role of Zn 2+ ions and the participation of acidic amino acids Glu and Asp in adenosine deamination catalyzed by ADA2 were shown.

Serum Adenosine Deaminase Activity in Women with Pre-Eclampsia

The present study investigated serum adenosine deaminase (ADA) activity and the patterns of two ADA isoenzymes, ADA1 and ADA2, and to evaluate the possible role of cell-mediated immunity as causes of the changes in ADA activity in pre-eclampsia. We measured serum activities of total ADA, ADA1 and ADA2 in pre-eclampsia (n = 22) and normal pregnancy (n = 22). Peripheral blood monocyte counts and neopterin levels, reflecting the activation of the monocyte-macrophage cell system, were also measured. In pre-eclampsia, serum total ADA and ADA2 activities were significantly increased compared with normal pregnancy (p < 0.05), which were accompanied by increases in serum neopterin levels. These results suggest that increased total ADA activity reflects increases in ADA2 activity, which may be in part related to enhanced cell-mediated immunity during pre-eclampsia.

Serum adenosine deaminase activity and its isoenzyme pattern in women with normal pregnancies

Adenosine deaminase (ADA) is a purine enzyme which is essential for the proliferation, maturation and function of lymphoid cells, and congenital deficiency of this enzyme is associated with severe combined immunodeficiency disease. The activity of ADA has changed in diseases characterized by the alteration of cell-mediated immunity such as rheumatoid arthritis, systemic lupus erythematosus and tuberculosis, so ADA has been considered as a nonspecific marker of cell-mediated immunity. In this study we examined changes in serum total ADA activity and the patterns of two ADA isoenzymes, ADA1 and ADA2 in normal pregnant women, and evaluated the possible role of the alteration of cell-mediated immunity during normal pregnancy as causes of changes in ADA activity. We measured serum activities of total ADA, ADA1 and ADA2 in normal pregnant women in the third trimester (n=24) and age-matched healthy nonpregnant women (n=24). Peripheral blood lymphocytes and monocytes were also measured. In normal pregnant women, serum total ADA activity averaged 10.5 +/- 0.5 U/L, which was significantly lower than in nonpregnant women (14.0 +/- 0.5 U/L ) (p<0.05), and mean serum ADA2 activity also significantly reduced that of nonpregnant women (p<0.05). There was no significant difference in ADA1 activity in normal pregnant and nonpregnant women. The decrease in total ADA activity was accompanied by the decrease in lymphocyte count. These results suggest that reduced serum total ADA activity reflects decrease in ADA2 activity, and which may be in part associated with depressed cell-mediated immunity during normal pregnancy.

Significance of cerebrospinal fluid adenosine deaminase isoenzymes in tuberculous (TB) meningitis.

Adenosine deaminase (ADA) exists as two isoenzymes, ADA(1) and ADA(2). It appears that the ADA(2) isoenzyme originates mainly from monocytes and macrophages. In tuberculous pleural effusions most of the ADA activity consists of ADA(2). The aim of this prospective study was to analyse ADA isoenzymes in the CSF of patients with meningitis to investigate whether the expected rise of the ADA(2) isoenzyme would occur in tuberculous meningitis. ADA isoenzyme analysis was performed on the CSF of 15 patients with tuberculous and 11 patients with bacterial meningitis by an automated kinetic enzyme coupled assay in the presence and absence of a specific ADA inhibitor. The ratio of ADA(2)/ADA(Total) was > 0.8 in 14/15 patients with tuberculous meningitis. In bacterial meningitis the ratio was > or =0.8 in 10/11 patients. The ADA(2) isoenzyme is the major contributor to increased ADA activity in the CSF of patients with tuberculous meningitis, probably reflecting the monocyte-macrophage origin of the ADA.

Diagnostic Value of Adenosine Deaminase(ADA) and its Isoenzyme in Pleural Effusion

Background: Etiologic diagnosis of pleural effusion is usually made by clinical characteristics, pleural fluid analysis and pleural biopsy. But, despite careful diagnostic study, the cause of pleural effusion cannot be found in about 20 percent of patients, especially in loculated pleural effusions. Tuberculous pleurisy is one of the most common cause of pleural effusion in Korea. But, pleural fluid culture for Mycobacterium tuberculosis are positive in only 20 to 30 percent of patients and typical pleural biopsy finding in less than 50 percent of patients with this disease. In recent studies, adenosine deaminse(ADA) and its isoenzymes were proposed to be a useful diagnostic tool for differential diagnosis of pleural effusion. We investigated the pattern of ADA and its iscenzyme activities in various cause of pleural effusions to evaluate the diagnostic value of measuring ADA and its isoenzymes. Method: We measured total ADA and its isoenzyme activities in pleural fluid and serum from 54 patients with pleural effusion(25 tuberculous pleural effusion, 10 parapneumonic effusion, 14 malignant pleural effusion, 5 transudative pleural effusion), including 5 loculated tuberculous pleural effusions and 6 loculated parapneumonic effusions. Total ADA activity was measured by the spectrophotometric method and ADA2 isoenzyme activity was measured with same method using EHNA, potent inhibitor of ADA1 isoenzyme activity. Result: Total ADA activity of tuberculous pleural effusion was higher than malignant pleural effusion(p, parapneumonic effusion: , malignant pleural effusion: ). Percentage of ADA2 activity to total ADA activity(ADA2%) of pleural effusion of tuberculous pleurisy was higher than parapneumonic effusion(p, parapneumonic effusion: , malignant pleural effusion: ). In loculated pleural effusion, ADA2% of tuberculous pleural effusion was higher than parapneumonic effusion(tuberculous pleural effusion: , parapneumonic effusion: ). Conclusion: Measurement of ADA isoenzyme activity is useful for differentiating tuberculous pleural effusion from parapneumonic effusion, especially in loculated pleural effusion.