Adenosine Deaminase Activity In Patients Research Articles

ADENOSINE DEAMINASE ACTIVITY IN PATIENTS WITH ANKYLOSING SPONDYLITIS

Although the pathogenesis of ankylosing spondylitis (AS), which is a systemic disease characterized by inflammation, is largely unknown, pro-inflammatory mediators, oxidative stress, and immunity are thought to be involved in the development and the prognosis of the disease. It was aimed in this study to reveal activities of adenosine deaminase (ADA), a cornerstone enzyme in different pathways. Twenty nine AS patients and 16 healthy volunteers were included in the study. Patients were divided into two groups as active and inactive phases. Additionally, the patients were re-grouped according to axial/peripheral involvement. ADA and myeloperoxidase (MPO) activities, and advanced oxidation protein products (AOPP) levels were measured in plasma of the study groups. While the significant increases were observed in AOPP and MPO levels in AS patients compared to the control group, when the patients were divided into subgroups, only ADA was significantly decreased in active patients. On the other hand, there was no significant difference in AOPP, MPO, and ADA levels in groups created according to axial/peripheral involvement. Based on these findings, it is thought that the decrease in ADA levels in AS patients can give an idea about the prognosis of the disease and can be used as an activity marker. Keywords: Adenosine deaminase, advanced oxidation protein products, ankylosing spondylitis, autoinflammation, myeloperoxidase.

Increased serum adenosine deaminase activity in patients with adult-onset Still's disease

BackgroundAdult-onset Still's disease (AOSD) is a systemic inflammatory disease of unknown etiology, lacking specific diagnosis and disease activity evaluation indicators. This study will analyze the activity and clinical significance of Adenosine deaminase (ADA) in AOSD patients.MethodsTotally 53 AOSD patients, 60 patients with other autoimmune diseases including systemic lupus erythematosus (SLE), sjogren syndrome (SS) and rheumatoid arthritis (RA), as well as 60 healthy subjects were included in this study. AOSD activity was determined by Pouchot score. We analyzed the correlation between ADA activity and clinical parameters. In addition, the correlation between ADA activity and disease activity score was also analyzed.ResultsThis study showed that the activity of ADA in AOSD patients was significantly higher than that of healthy controls, SLE, SS and RA patient groups (p < 0.0001). The ADA activity of AOSD patients decreased significantly after systemic treatment (p < 0.0001). Correlation analysis showed that ADA activity was positively correlated with ALT(r = 0.54, p < 0.0001), AST (r = 0.82, p < 0.0001) and serum ferritin (r = 0.67, p < 0.001). ADA activity was negatively correlated with white blood cell (r = − 0.42, p = 0.002) and platelet counts (r = − 0.44, p = 0.001). We also found a significant positive correlation between the activity of ADA and Pouchot score in AOSD patients (r = 0.51, p = 0.001). Receiver operating characteristic (ROC) curve analysis showed that ADA activity had a sensitivity of 93.3%, and a specificity of 83% for the diagnosis of AOSD, with an area under the curve of 0.93.ConclusionThis study showed that serum ADA activity can be used as a potential biomarker for AOSD diagnosis and disease activity assessment.

The roles of adenosine deaminase in autoimmune diseases.

Autoimmune diseases patients are characterized by the autoimmune disorders, whose immune system can't distinguish between auto- and foreign- antigens. Thus, Immune homeostasis disorder is the key factor for autoimmune diseases development. Adenosine deaminase (ADA) is the degrading enzyme for an immunosuppressive signal - adenosine, and play an important role in immune homeostasis regulation. Increasing evidences have shown that ADA is involved in various autoimmune diseases. ADA activity were changed in multiple autoimmune diseases patients and could be served as a biomarker for clinical diagnosis. In this study, we analyze the change of ADA activity in patients with autoimmune diseases, and we underline its potential diagnostic value for autoimmune diseases patients.

A STUDY ON THE CORRELATION OF ADENOSINE DEAMINASE AND GLYCATED HAEMOGLOBIN IN THE PATIENTS OF TYPE 2 DIABETES MELLITUS.

Background &amp; Objectives: Adenosine modulates insulin action on various tissues and its concentration in tissues is affected by Adenosine Deaminase (ADA) levels. ADA is an enzyme involved in purine metabolism and is considered to be a marker of T cell activation. Immunological disturbances in type 2 diabetic individuals have an association with cell mediated responses and inappropriate T-lymphocyte function. Hence, the study was undertaken to determine the levels of Serum ADA activity in patients of type 2 DM and its correlation with parameters of glycemic profile such as Fasting blood sugar (FBS) and Glycated Haemoglobin.&#x0D; Material and Methods- A total of 100 patients diagnosed for type 2 DM visiting the Outpatient Department of General Medicine and Endocrinology at Mahatma Gandhi Medical College &amp; Hospital, Jaipur were enrolled for the study based on predefined inclusion and exclusion criteria. Blood samples were collected for all enrolled patients and analysed for the investigations like Serum BSF, HbA1c and Serum ADA.&#x0D; Results- In the study, BSF, mean HbA1c and serum ADA level was significantly higher in diabetic group in comparison to control group (p=0.000). The diabetic group was subdivided on the basis of HbA1c levels, HbA1c ≤ 8% as good glycemic control and HbA1c &gt; 8% as poor glycemic control. BSF, mean HbA1c and serum ADA levels were observed to be significantly higher in poor glycemic control group as compared to that of good glycemic control. A significant positive correlation between S. ADA and HbA1c activity was also seen (r= 0.388).&#x0D; Conclusion- Increased ADA level can be used to determine the glycemic status in the patients of type 2 DM and serve as a marker for insulin resistance. Hence, by analysing ADA levels in diabetes, glycemic control and insulin resistance can be assessed. Raised ADA levels can be an early indicator of progressive diabetic change and help to take preventive measures for the development of diabetic complication and thereby improving the outcome of the disease.&#x0D; Keywords- Diabetes Mellitus, Adenosine Deaminase, Glycated haemoglobin

Study on Changes in Serum Adenosine Deaminase Activity in Patients with Hepatitis

Study on Changes in Serum Adenosine Deaminase Activity in Patients with Hepatitis

Diagnostic Value of Serum Adenosine Deaminase (ADA) Level for Pulmonary Tuberculosis.

Background:Diagnosis of tuberculosis (TB) is not always easy, thus employing methods with a short duration and acceptable sensitivity and specificity is necessary to diagnose TB.Objectives:The aim of this study was to investigate the diagnostic value of serum adenosine deaminase (ADA) level for diagnosis of pulmonary tuberculosis.Patients and Methods:A total of 160 sex and age-matched subjects were included in this study, and were divided to four groups; forty patients with pulmonary tuberculosis (PTB) diagnosed based on the national TB program (NTP), forty patients with non-tuberculosis bacterial pneumonia, forty patients with lung cancer and forty people who were healthy in every respect. Serum adenosine deaminase activity in patients of each group was measured by the Giusti and Galanti calorimetry method using a commercial kit (Diazyme, USA). The ANOVA analysis was used to compare groups for quantitative variables.Results:Mean serum ADA level in the PTB group was clearly higher than the mean serum ADA in the other three groups. Mean serum ADA was 26 IU/L in PTB patients, 19.48 IU/L in patients with pneumonia, 15.8 IU/L in patients with lung cancer, and 10.7 IU/L in the control group (P < 0.05). In regard to the cut off value of 26 IU/L for ADA in patients with PTB sensitivity and specificity was defined as 35% and 91%, respectively.Conclusions:Serum ADA activity with high specificity percentage may be a useful alternative test in restricted resource areas to rule out diagnosis of PTB. However, serum ADA activity is not a useful tool for TB diagnosis.

No association between serum adenosine deaminase activity and disease activity in Crohn's disease.

Adenosine deaminase activity is proposed as a marker of inflammation in some inflammatory conditions. To investigate the association of serum adenosine deaminase activity and disease activity in Crohn's disease patients. In a cross-sectional study, 30 consecutive known cases of Crohn's disease (15 with active disease and 15 in remission) referring to a university hospital in Tehran (Iran) and 15 age- and gender-matched healthy controls were studied. Disease activity was assessed using the Crohn's disease activity index (cutoff >150). Total serum adenosine deaminase activity, C-reactive protein, erythrocyte sedimentation rate, and fecal calprotectin were evaluated in patients. Serum adenosine deaminase activity was measured in controls. Mean age of the patients was 36.8 ± 12.6 years, and 56.7 % were male. Serum adenosine deaminase activity in patients with active disease, patients in remission, and controls was 12.3 ± 5.9, 14.6 ± 6.2, and 11.9 ± 6.4 U/L, respectively (P = 0.458). Compared with patients in remission, those with active disease had higher erythrocyte sedimentation rate (40.4 ± 30.6 vs. 16.9 ± 16.0 mm/h, P = 0.014) and higher frequency of positive C-reactive protein (66.6 vs. 13.3 %, P = 0.004) and positive fecal calprotectin tests (86.6 vs. 33.3 %, P = 0.004). Serum adenosine deaminase activity was not correlated with erythrocyte sedimentation rate (r = 0.05, P = 0.761) and was not different between patients with positive and negative C-reactive protein (12.2 ± 5.4 vs. 14.2 ± 6.5 U/L, P = 0.393) and fecal calprotectin tests (11.7 ± 5.3 vs. 16.0 ± 6.5 U/L, P = 0.063). In patients with Crohn's disease, serum adenosine deaminase activity is not associated with clinical disease activity or with other inflammation markers and cannot be suggested as an inflammation marker.

Evaluation of Oxidative Stress Status and Adenosine Deaminase Activity in Hyperthyroid and Hypothyroid Patients

A few prospective studies evaluated the oxidative stress variables and adenosine deaminase activity in patients with hyperthyroidism and hypothyroidism. Thus; we aimed to investigate oxidative stress variables and adenosine deaminase activity in patients with hyperthyroidism and hypothyroidism. Study populations consisted of 20 patients with hyperthyroidism, 20 patients with hypothyroidism and 20 age matched healthy volunteers as control groups. Plasma nitric oxide, malondialdehyde levels and glutathione, adenosine deaminase activities were measured in all subjects. plasma nitric oxide and adenosine deaminase levels were higher in patients with hyperthyroidism, but lower in patients with hypothyroidism compared to those of controls (P

Clinical characteristics and cerebrospinal fluid adenosine deaminase activity in patients with meningitis caused by Varicella-Zoster virus

Clinical characteristics and cerebrospinal fluid adenosine deaminase activity in patients with meningitis caused by Varicella-Zoster virus

A study on the serum adenosine deaminase activity in patients with typhoid Fever and other febrile illnesses.

Adenosine Deaminase (ADA) has been suggested to be an important enzyme which is associated with the cell mediated immunity, but its clinical significance in typhoid fever has not yet been characterized. The present study was taken up to evaluate the serum ADA activity in patients of typhoid fever. The levels of ADA were also measured in the patients who were suffering from other febrile illnesses. This was a case control study. The subjects who were included in this study were divided into 3 groups. Group A consisted of 50 normal healthy individuals who served as the controls. Group B consisted of 50 patients, both males and females of all age groups, who were suffering from culture positive typhoid fever. Group C consisted of 50 patients who were suffering from febrile illnesses other than typhoid fever like viral fever, gastro enteritis, malaria, tonsillitis, upper respiratory tract infections, etc. The serum levels of ADA were estimated in all the subjects who were under study. The serum ADA level was found to be increased in the patients of typhoid fever as compared to that in those with other febrile illnesses and in the controls. From the present study, it can be concluded that there was a statistically significant increase in the serum ADA levels in the patients with typhoid.

Comparison of Superoxide Dismutase, Glutathione Peroxidase and Adenosine Deaminase Activities between Respiratory and Nocturnal Subtypes of Patients with Panic Disorder

Objective: There is mounting evidence indicating that oxidative and inflammatory processes may have an important role in the pathogenesis of panic disorder (PD). PD is a heterogeneous disease, and panic attacks are divided according to the different symptom clusters as respiratory, nocturnal, non-fearful, cognitive, or vestibular subtypes. The aim of this study was to compare whole-blood and serum superoxide dismutase (SOD), glutathione peroxidase and adenosine deaminase activities in PD patients with/without nocturnal, respiratory subtypes and healthy subjects. Methods: The study was conducted including 60 patients with PD and 30 healthy control subjects. The Panic Attack Symptom Checklist, Panic and Agoraphobia Scale, Hamilton Depression Rating Scale and Hamilton Anxiety Rating Scale were administered to the patients. Biochemical analyses were performed after all the blood samples were collected. Results: We found that whole-blood SOD and glutathione peroxidase activities of patients were significantly lower and adenosine deaminase activities of patients were higher than those of healthy controls. There were no statistically significant differences between respiratory and nocturnal subtypes. In addition, there were no marked relationships between the duration of illness and panic-agoraphobia scores of patients with nocturnal subtypes. Hamilton Depression Rating Scale and Hamilton Anxiety Rating Scale scores of patients with the nocturnal subtype were markedly higher than those of patients without the nocturnal subtype. Conclusion: The results suggest that oxidative and inflammatory processes may play a role in the pathophysiology of PD. These findings may support the idea that both nocturnal and respiratory subtypes of PD have different symptom clusters of the same disease.

CD26 expression and adenosine deaminase activity in regulatory T cells (Treg) and CD4+ T effector cells in patients with head and neck squamous cell carcinoma

Adenosine deaminase (ADA) is responsible for the deamination of immunosuppressive adenosine to inosine. In human T lymphocytes, ADA is associated with dipeptidyl peptidase IV (CD26). ADA expression and activity were evaluated in regulatory T cells (Treg) and CD4+ T effector cells (Teff) of patients with head and neck squamous cell cancer (HNSCC). CD4+CD39+ and CD4+CD39neg T cells were isolated by single-cell sorting from the peripheral blood of 15 HNSCC patients and 15 healthy donors (NC). CD26/ADA expression in these cells was studied by multicolor flow cytometry, confocal microscopy, RT-PCR and immunohistochemistry in tumor tissues. ADA activity was evaluated by mass spectrometry, suppression of Teff proliferation in CFSE assays and cytokine production by Luminex. CD4+CD39+ Treg had low and CD4+CD39neg Teff high CD26/ADA expression and ADA activity in NC or HNSCC. The frequency and suppressor activity of CD39+CD26neg Treg were elevated in patients relative to NC (p < 0.01). However, ADA activity in patients’ CD4+CD39neg Teff was decreased (p < 0.05), resulting in extracellular adenosine accumulation. Also, patients’ Teff were more sensitive to inhibitory signals delivered via adenosine receptors. IL-2, IL12 and INFγ upregulated ADA expression and activity in CD4+CD39neg Teff, whereas IL-10, PGE2 and CADO downregulated it. The differentially expressed CD26/ADA can serve as surface markers for functionally-active CD39+CD26neg Treg.

Evaluation of Cerebrospinal Fluid Adenosine Deaminase Activity for the Differential Diagnosis of Tuberculous and Nontuberculous Meningitis

IntroductionThe diagnosis value of adenosine deaminase (ADA) activity in cerebrospinal fluid (CSF) of tuberculous meningitis (TBM) has been well documented. However, the cutoff point of CSF ADA has not been fully assessed. In the current study, the authors set to calculate the cutoff points of ADA and monitor the changes of CSF ADA activities in patients with TBM after antitubercular therapy. MethodsCSF ADA activity in patients with different types of meningitis was measured by Trinder enzyme-coupled assay. ResultsThe mean CSF ADA values in the patients with TBM, bacterial meningitis, viral meningitis, cryptococcal meningitis and noninfectious neurologic disorders were 14.1 ± 5.4, 9.6 ± 5.5, 4.3 ± 2.5, 7.8 ± 3.4 and 2.6 ± 1.3 U/L, respectively. CSF ADA activity was significantly higher in TBM compared with patients with non-TBM (P < 0.05). Moreover, the best cutoff point for differentiating between TBM and non-TBM was 9.5 U/L. In addition, CSF ADA activity was decreased in patients with TBM after antitubercular therapy in a time-dependent manner. ConclusionsThe determination of ADA with a cutoff value of 9.5 U/L in CSF is a useful aid for the differential diagnosis of TBM and non-TBM. Moreover, dynamic monitoring of CSF ADA activity may be an indicator for evaluating antitubercular therapy in TBM.

Adenosine deaminase activity in patients with ovarian neoplasms

The aim of this study was to investigate the serum and peritoneal fluid adenosine deaminase (ADA) activity in patients with benign and malignant ovarian neoplasms. This is a prospective cross-sectional study performed in Cukurova University, Department of Gynecologic Oncology. Eighty-four patients with ovarian mass were included in this study within 13 months. The levels of serum and peritoneal fluid ADA levels were measured and compared in patients with benign and malignant ovarian neoplasms and also low- and high-grade malignant tumors. Serum and peritoneal fluid ADA levels were found to be significantly higher in patients with ovarian cancers as compared with benign ovarian tumors (p = 0.001). Additionally, ADA levels were found to be significantly different according to the histopathological subtypes and grade of ovarian cancers. However, there was no significant difference for ADA levels between the benign and low-grade malignant tumors. There was an important correlation between the peritoneal fluid and serum ADA levels. Serum and peritoneal fluid ADA levels were found to be higher in malignant ovarian neoplasms. This finding may be useful to understand the biochemically characteristics of malignant ovarian tumors and ADA may be a useful biomarker in diagnosis and management of ovarian tumors.

Adenosine deaminase activity in patients with Crohnʼs disease

Crohn's disease (CD) is a common chronic inflammatory bowel disease. During the disease a cascade of immunologic events occur including mucosal influx of inflammatory cells like neutrophils. Adenosine deaminase (ADA) is important in inflammatory responses and serves as a marker of activated leukocytes. In this study, we investigated the activity of total ADA (tADA) and its isoenzymes, ADA1 and ADA2, in serum and neutrophils derived from 20 active patients with CD, 20 patients in remission, as well as in 15 healthy controls. Patients with active disease had significantly (P<0.001) higher levels of tADA in serum (22.9±4.9 U/l) than patients in remission or healthy controls (14.0±3.4 U/l and 13.2±2.4 U/l respectively). ADA2, the main isoenzyme in the serum was higher in active patients by 60% as compared with patients in remission and healthy controls (19.7±1.9 U/l, 12.3±1.2 U/l, and 12.2±0.9 U/l respectively). We did not find a significant difference in these parameters between healthy controls and stable patients. There was a positive correlation (R=0.516) between tADA activity and C-reactive protein levels in patients with CD. Enhanced activity in tADA was also detected in neutrophils that were obtained from all patients with CD as compared with healthy controls (15.3±2.9 U/g, 14.1±2.3 U/g, and 9.4±2.9 U/g protein, respectively). This is mainly due to a significant increment (up to 51%) in ADA1 activity, the main isoenzyme in the neutrophils (84% out of the tADA). The cause of this increment remains to be elucidated. The results obtained in this study demonstrated elevated levels of tADA and ADA2 in patients with active disease. As the patient improves and becomes clinically stable these levels decrease, approaching normal values. tADA and ADA2 can be used as markers of inflammation, and provide a supportive indicator of CD activity.

Serum adenosine deaminase activity in patients with systemic lupus erythematosus: a study based on ADA1 and ADA2 isoenzymes pattern

Adenosine deaminase (ADA) plays a crucial role in the development and maintenance of normal immune system. So, any immunological imbalances could associate with its altered activity in serum. This study evaluated the activity of total ADA and its isoenzymes in serum of 45 patients with systemic lupus erythematosus (SLE). Included were 23 patients with active SLE, 22 during the inactive phase of the disease, and 45 healthy subjects. Our results provided evidence that the significantly elevated total ADA activity in serum of SLE patients is correlated mainly with the increased ADA2 level. The highest mean ADA2 activity during the relapse phase of the disease could be an indication to the macrophages, the main source of ADA2. It might be concluded that ADA and its isoenzymes analysis in serum of patients could be used as a useful and non-invasive diagnostic tool in evaluation of SLE active phase and the disease severity.

Changes in Adenosine Deaminase Activity in Patients with Type 2 Diabetes Mellitus and Effect of DPP-4 Inhibitor Treatment on ADA Activity

BackgroundDipeptidyl peptidase 4 (DPP-4, also known as CD26) binds with adenosine deaminase (ADA) to activate T lymphocytes. Here, we investigated whether ADA activity is specifically affected by treatment with DPP-4 inhibitor (DPP4I) compared with other anti-diabetic agents.MethodsFasting ADA activity, in addition to various metabolic and biochemical parameters, were measured in 262 type 2 diabetes mellitus (T2DM) patients taking various anti-diabetic agents and in 46 non-diabetic control subjects.ResultsADA activity was increased in T2DM patients compared with that in non-diabetic control subjects (mean±standard error, 23.1±0.6 U/L vs. 18.6±0.8 U/L; P<0.05). ADA activity was correlated with fasting plasma glucose (r=0.258, P<0.05), HbA1c (r=0.208, P<0.05), aspartate aminotransferase (r=0.325, P<0.05), and alanine aminotransferase (r=0.248, P<0.05). Compared with the well-controlled T2DM patients (HbA1c<7%), the poorly controlled group (HbA1c>9%) showed significantly increased ADA activity (21.1±0.8 U/L vs. 25.4±1.6 U/L; P<0.05). The effect of DPP4I on ADA activity in T2DM patients did not differ from those of other oral anti-diabetic agents or insulin. T2DM patients on metformin monotherapy showed a lower ADA activity (20.9±1.0 U/L vs. 28.1±2.8 U/L; P<0.05) compared with that of those on sulfonylurea monotherapy.ConclusionOur results show that ADA activity is increased in T2DM patients compared to that in non-diabetic patients, is positively correlated with blood glucose level, and that DPP4I has no additional specific effect on ADA activity, except for a glycemic control- or HbA1c-dependent effect.

Association of Adenosine Deaminase, Superoxide Dismutase, and Catalase Activities with Helicobacter pylori

Our purpose was to investigate associations between adenosine deaminase (ADA), superoxide dismutase (SOD), and catalase (CAT) activities and H. pylori.Ninety-nine patients were studied. Eight antral mucosal biopsies were taken for biochemical assessment of ADA, CAT, AND SOD activity and histological assessment. H. pylori density wAS evaluated according to the updated Sydney system. Patients were divided into three groups according to Sydney classification. ADA activity was found to be higher in patients having H. pylori in the present study. Also, ADA activity was higher in patients with a severe density of H. pylori. SOD level was found to be significantly higher with increased H. pylori density in our study (P < 0.05). In addition, SOD activity was higher in it H. Pylori-positive than H. pylori-negative patients. We did not find CAT activity in some antral tissue specimens. The significantly high levels of ADA activity in patients with H. pylori infection may reflect the regulator role of ADA in acid secretion. The higher ADA level with increased H. pylori density and H. pylori positivity indicate the probable malign lymphoid process of the stomach. But these findings must be confirmed with larger studies that include different gastric lesions.

Influence of Age on The Adenosine Deaminase Activity in Patients with Exudative Pleural Effusion

Background : Pleural fluid adenosine deaminase (ADA) activity can be helpful in a differntial diagnosis of an exudative pleural effusion because it is increased in a tuberculous pleural effusion. The ADA activity is determined mainly by the lymphocyte function. Age-associated immune decline is characterized by a decrease in T-lymphocyte function. For that reason, the pleural fluid ADA level would be lower in older patients with exudative pleural effusion. This study focused on the influence of age on the pleural fluid ADA activity in patients with exudative pleural effusion. Methods : A total of 81 patients with exudative pleural effusion were enrolled in this study. In all patients, the pleural fluid ADA activity was measured using an automated kinetic method. Results : The mean age of the patients was years. In all patients with exudative pleural effusion, the pleural fluid ADA activity revealed a significant difference between young patients (under 65 years of age) and old patients (p IU/L in young patients Vs. IU/L in old patients (p IU/L in young patients Vs. IU/L in old patients (p>0.05), and did not show any correlation with age (r=-0.263, p>0.05). The diagnostic cutoff value of pleural fluid ADA activity for tuberculous pleural effusion was lower in the older patients (25.9 IU/L) than in the younger patients (49.1 IU/L) or all patients (38.4 IU/L) with exudative pleural effusion. Conclusion : Tuberculous pleural effusion is an important possibility to consider in older patients with a clinical suspicion of a tuberculous pleural effusion, although no marked increase in the pleural fluid ADA activity is usually detected. For a diagnosis of a tuberculous pleural effusion in old patients, the cutoff for the pleural fluid ADA activity should be set lower.

Relationship Between Age and Pleural Fluid Adenosine Deaminase Activity in Patients with Tuberculous Pleural Effusion

Background : ADA is an enzyme found in most cells, and is involved in purine metabolism, but its chief role concerns the proliferation and differentiation of lymphocytes, especially T-lymphocytes. For that reason ADA has been looked on as a marker of cell-mediate immunity, which is the key mechanism of the tuberculous pleural effusion. Thus, the pleural fluid ADA activity is increased in the tuberculous pleural effusion. Age associated immune decline is characterized by decreases in both B and T-lymphocyte function and the former may be largely a result of the latter. Therefore, the pleural fluid ADA activity would be lower in old rather than in young, patients with tuberculous pleural effusion. We studied the relationship between age, and pleural fluid ADA activity, in patients with tuberculous pleural effusion. Materials and Methods : In the 46 patients with tuberculous pleural effusion enroll in this study, the pleural fluid ADA activities were measured by means of an automated kinetic method. Results : The mean age of the patients was years, with a male to female ratio of 30:16. The patients were divided into two groups, young patients, regarded as years with 28 and 18 patients, respectively. The pleural fluid ADA activity in both groups show significant differences : IU/L(young patients) Vs. IU/L(old patients)(p