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Introduction: Adenosine deaminase (ADA) in pleural fluid is a useful marker for diagnosing tuberculous pleurisy. However, recent studies have reported a lower specificity of pleural fluid ADA levels. We previously developed a diagnostic flowchart for patients with pleural fluid ADA ≥40 U/L, incorporating variables such as pleural fluid lactate dehydrogenase <825 U/L, predominant pleural fluid neutrophils or cell degeneration, and a pleural fluid ADA/total protein ratio <14. This flowchart was effective in distinguishing between tuberculous pleurisy and other diseases. Here, we conducted a validation analysis of this flowchart., Materials and Methods: We retrospectively collected data from 458 patients with pleural fluid ADA concentrations ≥40 U/L across eight institutions from January 2019 to December 2023. The diagnostic accuracy rate, sensitivity, and specificity of the diagnostic flowchart were analysed and compared to those in the original study., Results: Eighty-seven patients were diagnosed with tuberculous pleurisy, and 371 patients were diagnosed with other diseases. The diagnostic accuracy, sensitivity, and specificity for diagnosing tuberculous pleurisy were 77.7%, 86.2%, and 75.7%, respectively. Compared with that in the original study, the rate of tuberculous pleurisy was lower (19.0% vs. 44.5%, p < 0.001), but the diagnostic accuracy rates were not significantly different (p = 0.253). On the basis of the findings from this validation study, we have revised the flowchart to enhance its utility., Conclusion: The diagnostic flowchart exhibited high diagnostic accuracy in this validation study, comparable to that in the original study. This validation confirms the effectiveness of the flowchart, even in settings with a low incidence of tuberculosis., Competing Interests: Declaration of competing interest The authors have no conflicts of interest., (Copyright © 2024 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.)

Background: Pleural effusion indicates an imbalance between pleural fluid formation and removal. Classified into exudative and transudative, with common symptoms of dry cough, dyspnea and pleuritic chest pain. Confirmed etiology has to be established for effective treatment., Objective: Correlate clinical and biochemical profile of various etiologies of pleural effusion., Materials & Methods: Retrospective observational study of 2 years in the department of respiratory medicine, GMC Bhopal on 280 cases of pleural effusion., Results: Most common etiology was tubercular 202 (72.4%) followed by malignant in 36 (12.8%). With respect to tubercular, malignant pleural effusion has relative risk (RR) of 0.138 (p value < 0.05) in the age group of 51-60 years, which is statistically significant. Patients of tuberculosis complained of fever 158 (78.2%) whereas with malignancy complained of chest pain 16 (44.4%) followed by hemoptysis 12 (33.3%). For hemoptysis, with respect to tubercular, malignant effusion has RR of 5.68 (p value < 0.05) which is significant. History of smoking was significant in malignant effusion with RR of 2.57 (p value < 0.05) as compared to tubercular. Pleural fluid ADA was >70 in 83.7% in tubercular effusion, glucose was <60 mg/dl in 79% tubercular, malignant and bacteriological cause, LDH was >1000 in 88.4% in bacteriological and 72.3% in malignant effusion., Conclusion: Lack of tools for confirming diagnosis leads to diagnostic dilemma and delay in treatment initiation, leading to deterioration and untoward fatality in some cases. Our goal is early diagnosis by correlating clinical symptoms with biochemical profile and help initiate rapid treatment., Competing Interests: Conflicts of interest The authors have none to declare., (Copyright © 2023 Tuberculosis Association of India. Published by Elsevier B.V. All rights reserved.)

Background: Tubercular Pleural effusion (TBPE) is one of most common extrapulmonary tuberculosis. It can be difficult to diagnose due to low sensitivity of pleural fluid smear, culture and CBNAAT. Diagnosis of TBPE is then dependent on the level of pleural fluid Adenosine Deaminase (ADA). Thoracoscopic pleural biopsy gives definite diagnosis specially in Low Pleural fluid ADA setting., Aims and Objective: This study was planned to find out the prevalence of tubercular etiology in patients of exudative pleural effusion with low ADA (ADA <40 IU/L)., Material and Methods: A Prospective, observational study was carried out in a tertiary teaching institute in north India. Total 142 patients of pleural effusion with low ADA were enrolled. All patients underwent rigid thoracoscopy for confirmation of their diagnosis., Results: Out of 142 patients, male were 78 (55%) and female were 64 (45%). Mean age of patients were 57.4 years. Tuberculosis was diagnosed as a cause of effusion in 22 (15.5%) out of 142 patients. Majority of TBPE patients had pleural thickening as thoracoscopic finding. Mean ADA level in TBPE was 27.36 ± 11.6 as compared to 18.55 ± 9.02 in non tubercular pleural effusion patients and this difference was significant statistically (P- 0.002)., Conclusion: The diagnosis of patients having exudative, low ADA pleural effusion can be very easily confirmed by thoracoscopy guided pleural biopsy which has a very high diagnostic yield., Competing Interests: Conflicts of interest The authors have none to declare., (Copyright © 2023 Tuberculosis Association of India. Published by Elsevier B.V. All rights reserved.)

Background: Pericardial effusion is the accumulation of fluid in the pericardial cavity. In nations with high tuberculosis (TB) load, TB is the most common cause of pericardial effusion. 1-2% of patients with pulmonary TB develop Pericardial TB worldwide. Multi-drug-resistant (MDR) TB, including extrapulmonary TB (EPTB) cases, are rising in number. Adenosine Deaminase (ADA) is an enzyme in lymphocytes and myeloid cells, which has certain immune functions in the body. ADA levels are increased in inflammatory conditions, like pleural, pericardial, or joint effusions, of bacterial etiology, granulomatous conditions, neoplasms, and autoimmune pathologies. TB is the only lymphocytosis involving disease with increased ADA levels. MDR EPTB is rare, but cases are on the rise, and tuberculous pericardial effusion is one such example. Hence, it is important to know the percentage of cases detected by a culture that can be identified by cartridge-based nucleic acid amplification test (CBNAAT), their resistance patterns, and to identify potential markers like ADA, which can help in early identification of cases. The objectives of this study were to identify the Mycobacterium tuberculosis (MTB) bacilli in culture, and correlate them with cartridge-based nucleic acid amplification test (CBNAAT) results and their drug-resistance, in the Pericardial tubercular effusion, and to find if Adenosine Deaminase (ADA) levels can be used as a predictor of the presence of MTB in pericardial fluid., Methodology: We enrolled 52 patients with moderate to large tuberculous pericardial effusion, based on pericardial fluid analysis, CBNAAT, and culture methods, between January 2021 and December 2021., Results: The mean age of the patients was 41.85 + 17.88 years, with a median of 38 years. Males made up 57.7% of the total patients. MTB was detected in 16 (30.8%) patients in the CBNAAT evaluations. 14 (87.5%) of the CBNAAT-positive TB patients were sensitive to Rifampicin, whereas the remaining 2 (12.5%) were resistant to Rifampicin on CBNAAT. MTB was found to be growing in 8 (15.38%) drug sensitivity test cultures. Out of these 8, 6 were sensitive to first-line drugs, whereas 2 were resistant to both Isoniazid and Rifampicin. The presence of cough was found to have a significant difference between CBNAAT-detected MTB positive and negative patients (p = 0.020), whereas an insignificant difference was found for the presence of hypertension, diabetes mellitus, obesity, dyspnea, or fever. There was also an insignificant difference between the number of patients positive for the Tuberculin skin test, between the two groups. ADA was significantly higher in the MTB-detected CBNAAT group (85.91 + 37.60U/L vs 39.78 + 24.31U/L, p = 0.005), whereas the total leukocyte count, lymphocytes, neutrophils, random blood sugar levels, and serum protein levels had no significant difference. The area under the Receiver Operator Curve (CBNAAT positive: dependent variable; ADA: test result variable) was 0.854 (null hypothesis rejected), with a standard error of 0.078., Conclusions: Culture is the gold standard method to diagnose tuberculosis. Detection of MTB on pericardial fluid culture is very uncommon, though in our study, culture came out positive in 16% of patients, and 4% were resistant to rifampicin and isoniazid. Higher ADA levels in pericardial fluid are an indicator of tuberculous pericardial effusion., Competing Interests: Conflicts of interest The authors have none to declare., (Copyright © 2023 Tuberculosis Association of India. Published by Elsevier B.V. All rights reserved.)

Background: Tuberculous pleural effusion (TPE) is usually characterized by lymphocytic predominance and high pleural fluid adenosine deaminase (pfADA), while parapneumonic pleural effusion (PPE) is usually characterized by neutrophilic predominance. However, in some cases, neutrophils can be predominant in TPE. In such cases, the differential diagnosis between TPE and PPE is challenging and has been rarely investigated. The aim of this study was to evaluate the accuracy of pfADA, pleural fluid lactate dehydrogenase (pfLDH) and other parameters, such as age/pfADA in the differential diagnosis of neutrophil-predominant TPE (NP-TPE) and PPE., Methods: Between January 2003 and August 2018, 19 patients with NP-TPE and 54 patients with PPE at Shanghai Jiao Tong University Affiliated Sixth People's Hospital were retrospectively reviewed. Age, blood and pleural fluid findings, and eight ratios that consisted of routine biomarkers were compared between the two groups in ≤50 and >50 years old groups. ROC curve analysis was used to evaluate diagnostic performance., Results: The three parameters with the largest AUC were age/pfADA, pfADA and pfLDH in ≤ 50 years old group, and pfADA, age/pfADA and the percentage of neutrophils in pleural fluid (pfN%) in >50 years old group. For patients ≤ 50 years old, pfADA combined with pfLDH or age/pfADA combined with pfLDH could increase the specificity to 100%, while the sensitivity of the former was high (84.6% vs 76.9%). For patients >50 years old, both pfADA combined with pfN% and age/pfADA combined with pfN% could increase the specificity to 90.3% with the same sensitivity., Conclusions: Although pfADA played an important role in the discrimination of NP-TPE from PPE, combining pfADA with pfLDH for patients ≤50 years old or combining pfADA with pfN% for patients >50 years old might improve diagnostic performance., (Copyright © 2020 Southern Society for Clinical Investigation. Published by Elsevier Inc. All rights reserved.)

Background: The aim of this study was to assess the validity of GeneXpert MTB/RIF (Xpert) and adenosine deaminase (ADA) in the diagnosis of tuberculous peritonitis (TBP)., Methods: The laboratory results of peritoneal effusion (PE) specimens from patients with symptoms suggestive of TBP, attending three TB specialized hospitals between January 2016 and December 2018, were included retrospectively. Clinically diagnosed TBP was set as the gold standard to evaluate the performance of these methods., Results: In total, 191 individuals presenting with symptoms suggestive of TBP were included for analysis. The sensitivities of MGIT culture and Xpert were 17.2% and 18.3%, respectively. In addition, the TBP cases (69.8±6.0U/l) had higher amounts of ADA in their PE samples than the non-TBP cases (12.6±1.6U/l; p<0.01). Using a threshold of 31.5U/l to differentiate the TBP group from non-TBP group, the ADA assay provided a sensitivity of 89.6% and a specificity of 92.1%. The mean ADA concentration was significantly higher in bacteria-positive cases than in bacteria-negative cases (p<0.01)., Conclusions: In conclusion, the study data demonstrate the high sensitivity and specificity of the ADA test for the early diagnosis of TBP. In addition, the ADA concentration is directly correlated with the mycobacterial load., (Copyright © 2019 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: In clinical practice, pleural and peritoneal effusions are usual diagnosis. We evaluated the performance of a hybrid panel of biomarkers in the diagnosis of the main diseases affecting pleura and/or peritoneum., Methods: Samples of pleural/ peritoneal fluid from 120 patients were evaluated for: CEA (carcinoembryonic antigen), VEGF-A (vascular endothelial growth factor A), PD-L1/B7-H1 (programmed death-ligand 1), NGAL (neutrophil gelatinase-associated lipocalin), TREM-1 (triggering receptor expressed in myeloid cells type-1) and IFNγ (gamma-interferon) by Luminex®; CALP (Calprotectin) by ELISA, and ADA (adenosine deaminase) by enzymatic deamination., Results: For malignant effusion (ME) diagnosis, CEA and NGAL presented superior performance than VEGF-A, PD-L1 and CALP. A CEA-NGAL association showed good sensitivity (86.6%) and accuracy (79.2%). For non-tuberculous infectious effusion (NTBIE), NGAL presented the best performance with sensitivity (75.0%), specificity (62.0%) and accuracy (65.0%) higher than TREM-1 and CALP; however, when associated, although with good sensitivity, there was important decrease in specificity. For tuberculous pleural effusion (TPE), IFNy-ADA presented excellent sensitivity (100%), specificity (87.6%), NPV (100%) and accuracies (~90%)., Conclusions: CEA, NGAL, ADA and IFNy were useful in discriminating ME and TPE. However, for NTBIE diagnosis, the hybrid panel did not demonstrate advantages over the classic parameters., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

Tuberculous meningitis (TBM) is the most severe form of extra-pulmonary tuberculosis. The definite diagnosis of this disease is difficult and can result in delayed treatment. Conventional culture yields low sensitivity while high-sensitivity diagnostic techniques are costly and unpractical. Adenosine deaminase (ADA) is used to diagnose several settings of extra-pulmonary tuberculosis but it is limited in TBM especially among HIV-infected patients. We retrospectively reviewed the data of patients with non-suppurative meningitis and compared the patient data with TBM and other causes including carcinomatous, lymphomatous, lymphocytic and fungal meningitis. We found that HIV infection, diabetes mellitus, duration of symptoms <14 days, radiologic findings of hydrocephalus, and CSF ADA level >10 IU were associated with TBM. The scoring system based on these parameters and their coefficients in the final model achieved an area under the receiver operating characteristic curve of 0.95,625. The indices were HIV infection = 5, diabetes mellitus = 3, duration of symptoms <14 days = 5, hydrocephalus = 4, and ADA in CSF >10 IU = 5. Based on the assumed costs of the patients with false negative and false positive, an appropriate cut off value of 10 was selected and the sensitivity was 92% and specificity was 89%., (Copyright © 2018 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

A study on gender differences in the normal range of biomarkers in porcine saliva samples has the scope for further attention. In the present study, the salivary protein profiles of age-matched healthy male and female finishing pigs were compared. The levels of salivary adenosine deaminase (ADA) activity, haptoglobin (Hp) and C-reactive protein (CRP) have been quantified in 32 male and 32 female pigs to ensure the presence of gender effect on the median levels of salivary biomarkers. Moreover, the total salivary protein content was quantified and compared. The overall salivary protein distribution was compared with SDS-PAGE in 14 male and 14 female pigs and the possible gender influence in the salivary protein profile was analysed by 2DE in 6 male and 6 female pigs. Statistically significant differences were observed in the median values of Hp, CRP, and ADA between male and female pigs (p<0.005). Although the total salivary protein content was not different between the sexes, the salivary protein distribution and profile showed specific gender differences in three proteins of the lipocalin family: the odorant-binding protein, salivary lipocalin and lipocalin 1. These proteins have been related to animal immune status and should be further explored as possible porcine salivary biomarkers., Significance: The biological relevance of the reported research is based on the possible gender influence on the discovery of salivary biomarkers in porcine production. As differences have been reported in the salivary protein distribution in male pigs in comparison to that of female pigs, the normal-range values, according to gender, of the newly discovered biomarkers should be explored and defined prior to its application in the porcine production system. A hormonal sexual influence is highly hypothesized., (Copyright © 2017 Elsevier B.V. All rights reserved.)

A novel capillary electrophoresis (CE) method was developed for simultaneous analysis of adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) in red blood cells (RBCs). The developed method considered and took advantage of the natural conversion from the ADA product, inosine to hypoxanthine. The transformation ratio was introduced for ADA and PNP analysis to obtain more reliable results. After optimizing the enzymatic incubation and electrophoresis separation conditions, the determined activities of ADA and PNP in 12 human RBCs were 0.237-0.833 U/ml and 9.013-10.453 U/ml packed cells, respectively. The analysis of ADA in mice RBCs indicated that there was an apparent activity difference between healthy and hepatoma mice. In addition, the proposed method was also successfully applied in the inhibitor screening from nine traditional Chinese medicines, and data showed that ADA activities were strongly inhibited by Rhizoma Chuanxiong and Angelica sinensis. The inhibition effect of Angelica sinensis on ADA is first reported here and could also inhibit PNP activity., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Objectives: Delay in the treatment of pleural infection may contribute to its high mortality. In this retrospective study, we aimed to evaluate the diagnostic accuracy of pleural adenosine deaminase in discrimination between Gram-negative and Gram-positive bacterial infections of the pleural space prior to selecting antibiotics., Methods: A total of 76 patients were enrolled and grouped into subgroups according to Gram staining: 1) patients with Gram-negative bacterial infections, aged 53.2±18.6 years old, of whom 44.7% had empyemas and 2) patients with Gram-positive bacterial infections, aged 53.5±21.5 years old, of whom 63.1% had empyemas. The pleural effusion was sampled by thoracocentesis and then sent for adenosine deaminase testing, biochemical testing and microbiological culture. The Mann-Whitney U test was used to examine the differences in adenosine deaminase levels between the groups. Correlations between adenosine deaminase and specified variables were also quantified using Spearman's correlation coefficient. Moreover, receiver operator characteristic analysis was performed to evaluate the diagnostic accuracy of pleural effusion adenosine deaminase., Results: Mean pleural adenosine deaminase levels differed significantly between Gram-negative and Gram-positive bacterial infections of the pleural space (191.8±32.1 U/L vs 81.0±16.9 U/L, p<0.01). The area under the receiver operator characteristic curve was 0.689 (95% confidence interval: 0.570, 0.792, p<0.01) at the cutoff value of 86 U/L. Additionally, pleural adenosine deaminase had a sensitivity of 63.2% (46.0-78.2%); a specificity of 73.7% (56.9-86.6%); positive and negative likelihood ratios of 2.18 and 0.50, respectively; and positive and negative predictive values of 70.6% and 66.7%, respectively., Conclusions: Pleural effusion adenosine deaminase is a helpful alternative biomarker for early and quick discrimination of Gram-negative from Gram-positive bacterial infections of the pleural space, which is useful for the selection of antibiotics.

Objective: Pleural tuberculosis is the most frequently occurring form of extra pulmonary disease in adults. In up to 40% of cases, the lung parenchyma is concomitantly involved, which can have an epidemiological impact. This study aims to evaluate the pleural and systemic inflammatory response of patients with pleural or pleuropulmonary tuberculosis., Methods: A prospective study of 39 patients with confirmed pleural tuberculosis. After thoracentesis, a high resolution chest tomography was performed to evaluate the pulmonary involvement. Of the 39 patients, 20 exhibited only pleural effusion, and high resolution chest tomography revealed active associated-pulmonary disease in 19 patients. The total protein, lactic dehydrogenase, adenosine deaminase, vascular endothelial growth factor, interleukin-8, tumor necrosis factor-α, and transforming growth factor-β(1) levels were quantified in the patient serum and pleural fluid., Results: All of the effusions were exudates with high levels of adenosine deaminase. The levels of vascular endothelial growth factor and transforming growth factor-β(1) were increased in the blood and pleural fluid of all of the patients with pleural tuberculosis, with no differences between the two forms of tuberculosis. The tumor necrosis factor-α levels were significantly higher in the pleural fluid of the patients with the pleuropulmonary form of tuberculosis. The interleukin-8 levels were high in the pleural fluid of all of the patients, without any differences between the forms of tuberculosis., Conclusion: Tumor necrosis factor-α was the single cytokine that significantly increased in the pleural fluid of the patients with pulmonary involvement. However, an overlap in the results does not permit us to suggest that cytokine is a biological marker of concomitant parenchymal involvement. Although high resolution chest tomography can be useful in identifying these patients, the investigation of fast acid bacilli and cultures for M. tuberculosis in the sputum is recommended for all patients who are diagnosed with pleural tuberculosis.

Background: Adenosine deaminase (ADA) catalyzes the deamination of adenosine to inosine. The activity of ADA in body fluids has clinical utility in the assessment of suspected tuberculosis., Methods: The conversion of adenosine to inosine was monitored in 96-well microplates as a continuous decrease at 265 nm for 15 min at ambient temperature. Analytical precision, sensitivity, linearity, accuracy, and enzyme stability were validated. Reference intervals were established from >120 tuberculosis-negative pleural, peritoneal, and cerebrospinal fluid samples., Results: The molar extinction coefficients of adenosine and inosine at 265 nm were 12,715 and 4,918 l/mol.cm and their difference was used to calculate ADA activity. Maximum within-day imprecision was <11% and maximum total precision was <19%. Analytical sensitivity was 0.5 U/l and the assay was linear to 40 U/l. ADA recovery was 96-110% over an activity range of 11.7-25.3 U/l. ADA was stable for 1, 7 and 30 days at ~25 °C, 4-8 °C, and -20 °C storage, respectively. Upper reference limits were 9.4, 7.3, and 1.5 U/l for pleural, peritoneal, and cerebrospinal fluid, respectively., Conclusions: The microplate-based kinetic ADA assay has favorable performance characteristics. This method eliminates the need for assay calibration and allows 96 samples to be tested simultaneously., (Copyright © 2012 Elsevier B.V. All rights reserved.)

The investigation of a pleural effusion is, in general, a very straight forward process with the combination of clinical history, examination, radiology and pleural fluid analysis leading to diagnosis in most cases. While most fluid samples are sent for routine analysis including protein, LDH, glucose, cytology and microbiology, there are a number of more unusual fluid analyses available which in some cases directly lead to, and in others are suggestive of the diagnosis. Moreover, other fluid markers are constantly being evaluated as a diagnostic tool. In this review, we describe these non-routine pleural fluid analyses in detail. English language publications in MEDLINE and references from relevant articles from January 1 1990 to August 1 2009 were reviewed. Keywords searched in combination were pleural fluid, effusion, analysis, transudate, exudate and diagnosis., (Copyright 2010 Elsevier Ltd. All rights reserved.)

Background: Tuberculous pleural effusions (TPE) are common. The diagnosis is often problematic. As the determination of ADA is often unavailable in some countries, the aim of this study was to evaluate the diagnostic usefulness of other data from pleural fluid analysis, in young patients from populations with high prevalence of tuberculosis (TB)., Methods: We analysed 218 patients with pleural effusion (165 tuberculous, 21 infectious, 11 neoplastic, 16 miscellaneous, 3 idiopathic). We performed two regression models; one included pleural fluid ADA values (model 1), and the other without ADA (model 2)., Results: Model 1 selected two variables (ADA >35U/L) and lymphocytes (>31.5%) and correctly classified 216/218 effusions (1 false negative, 1 false positive). Model 2 (without ADA) selected three variables: lymphocytes (>31.5%), fever and cough, and correctly classified 207/218 effusions (8 false negatives, 3 false positives). The sensitivity of models 1 and 2 was 99.4% and 95.2%, specificity 98.1% and 94.3% and accuracy 99% and 95%., Conclusions: In geographic areas with high prevalence of TB and a low prevalence of HIV, in young patients (

Objective: To improve physicians' ability to discriminate tuberculous from malignant pleural effusions through a simple clinical algorithm that avoids pleural biopsy., Design: We retrospectively compared the clinical and pleural fluid features of 238 adults with pleural effusion who satisfied diagnostic criteria for tuberculosis (n=64) or malignancy (n=174) at one academic center (derivation cohort). Then, we built a decision tree model to predict tuberculosis using the C4.5 algorithm. The model was validated with an independent sample set from another center that included 74 tuberculous and 293 malignant effusions (validation cohort)., Results: Among 12 potential predictor variables, the classification tree analysis selected four discriminant parameters (age>35 years, pleural fluid adenosine deaminase>38U/L, temperature>or=37.8 degrees C, and pleural fluid LDH>320U/L) from the derivation cohort. The generated flowchart had 92.2% sensitivity, 98.3% specificity, and an area under the ROC curve of 0.976 for diagnosing tuberculosis. The corresponding operating characteristics for the validation cohort were 85.1%, 96.9% and 0.958., Conclusions: Applying a decision tree analysis that contains simple clinical and laboratory data can help in the differential diagnosis of tuberculous and malignant pleural effusions.

Background: Conventional tests are not always helpful in making a diagnosis of tuberculous pleurisy. Many studies have investigated the usefulness of adenosine deaminase (ADA) in pleural fluid for the early diagnosis of tuberculous pleurisy. We conducted a meta-analysis to determine the accuracy of ADA measurements in the diagnosis of tuberculous pleurisy., Methods: After a systematic review of English language studies, sensitivity, specificity, and other measures of accuracy of ADA concentration in the diagnosis of pleural effusion were pooled using random effects models. Summary receiver operating characteristic curves were used to summarize overall test performance., Results: Sixty-three studies met our inclusion criteria. The summary estimates for ADA in the diagnosis of tuberculous pleurisy in the studies included were sensitivity 0.92 (95% confidence interval 0.90-0.93), specificity 0.90 (95% confidence interval 0.89-0.91), positive likelihood ratio 9.03 (95% confidence interval 7.19-11.35), negative likelihood ratio 0.10 (95% confidence interval 0.07-0.14), and diagnostic odds ratio 110.08 (95% confidence interval 69.96-173.20)., Conclusions: ADA determination is a relative sensitive and specific test for the diagnosis of tuberculous pleurisy. Measurement of ADA in pleural effusion is thus likely to be a useful diagnostic tool for tuberculous pleurisy. The results of ADA assays should be interpreted in parallel with clinical findings and the results of conventional tests.

Purpose: To evaluate the clinical and laboratory characteristics of pleural effusions secondary to tuberculosis (TB) or cancer (CA)., Methods: A total of 326 patients with pleural effusion due to TB (n=182) or CA (n=144) were studied. The following parameters were analyzed: patient gender, age and pleural effusion characteristics (size, location, macroscopic fluid aspect, protein concentration, lactate dehydrogenase (DHL) and adenosine deaminase activity (ADA) and nucleated cell counts)., Results: Young male patients predominated in the tuberculosis group. The effusions were generally moderate in size and unilateral in both groups. Yellow-citrine fluid with higher protein (p < 0.001) levels predominated in effusions from the tuberculosis group (5.3 + 0.8 g/dL) when compared to the CA group (4.2 +/- 1.0 g/dL), whereas DHL levels were more elevated in CA (1,177 +/- 675 x 1,030 +/- 788 IU; p = 0.003) than in TB. As expected, ADA activity was higher in the TB group (107.6 +/- 44.2 x 30.6 +/- 57.5 U/L; p < 0.001). Both types of effusions presented with high nucleated cell counts, which were more pronounced in the malignant group (p < 0.001). TB effusion was characterized by a larger percentage of leukocytes and lymphocytes (p < 0.001) and a smaller number of mesothelial cells (p = 0.005). Lymphocytes and macrophages were the predominant nucleated cell in neoplastic effusions., Conclusion: Our results demonstrate that in lymphocytic pleural exudate obtained from patients with clinical and radiological evidence of tuberculosis, protein and ADA were the parameters that better characterize these effusions. In the same way, when the clinical suspicion is malignancy, serous-hemorrhagic lymphocytic fluid should be submitted to oncotic cytology once this easy and inexpensive exam reaches a high diagnostic performance (approximately equal 80%). In this context, we suggest thoracocentesis with fluid biochemical and cytological examination as the first diagnostic approach for these patients.

Study Objective: Measurement of pleural fluid adenosine deaminase (ADA) levels is useful in the differential diagnosis of pleural effusions. However, at ambient temperatures, the levels of this enzyme decline with time. The purpose of the present study was to identify, test, and optimize additives that stabilize ADA, consequently eliminating the need for dry ice or other cold specimen transport media., Design: A preliminary screen of historically proven stabilizing agents for specific proteins demonstrated effectiveness of glycerol for maintenance of pleural fluid ADA levels. Systematic studies for exploitation of the glycerol effect included the following: (1) supplements to the glycerol of promising alternate compounds, (2) long-term stability studies at ambient and elevated temperatures, (3) a field test of an effective mixture as a means for reduction of specimen transport costs, (4) thermal stability studies for optimization of the agents for use at otherwise denaturing temperatures, and (5) inclusion of pleural fluids from patients with a variety of etiologies, including tuberculous pleurisy, in order to gauge the effectiveness of the stabilizing agents on both the high and low molecular weight forms of ADA., Results: A mixture of glycerol and ethylene glycol, each at 5% concentration, maintained pleural fluid ADA levels for at least 21 days at both room temperatures and 37 degrees C. A field test of 32 pleural fluids found that ADA levels in specimens containing this mixture, sent to the laboratory by surface mail at ambient temperatures, were nearly identical to those in aliquots of the same fluids shipped over dry ice. The bias in the measurement was 0.49 IU/L, with a precision of 2.49 IU/L. The correlation coefficient between the two measurements was 0.97. Thermal stability studies found that tuberculous pleural fluids containing 10% glycerol and 0.10 mol/L sodium sulfate maintained constant ADA levels for at least 10 days at 45 degrees C, an otherwise denaturing temperature for nonstabilized specimens., Conclusion: The addition of stabilizing agents to pleural fluid specimens allows the transport of those specimens to distant laboratories at ambient temperatures without a decline in the ADA levels. Employment of those agents will decrease the cost of the test and facilitate its use in second- and third-world countries.

Background: Diagnosis of tuberculous pleuritis is difficult because of its nonspecific clinical presentation and insufficient efficiency of traditional diagnostic methods. We investigated the use of adenosine deaminase (ADA) activity in tuberculous pleuritis diagnosis., Methods: We optimized a kinetic assay and retrospectively analysed 210 patients with exudative pleural effusions. Using the ROC curve, we determined the optimal cutoff for TB pleurisy., Results: One hundred forty-seven exudative samples were nontuberculous (non-TB) and 63 were tuberculous (TB). There was statistically significant difference (p<0.0001) between the means of pleural fluid ADA levels among the TB and non-TB populations. The disease prevalence of TB pleurisy in the studied population was 30%. The cutoff value for diagnosing TB effusions was >55.8 U/L, with a sensitivity of 87.3% (95% CI: 76.5-94.3%) and specificity of 91.8% (95% CI: 86.2-95.7%). The positive predictive value (PPV) was 82.1% and the negative predictive value (NPV) was 94.4%. A pleural fluid ADA value <16.81 IU/L suggests that a tuberculous effusion is highly unlikely (100% sensitive with 100% NPV and 0% negative likelihood ratio for a pleural fluid ADA level>/=16.81 U/L). In addition, the area under the ROC curve was 0.933 (S.E.=0.0230, 95% CI: 0.890-0.963)., Conclusion: Pleural fluid total ADA assay is a sensitive and specific test suitable for rapid diagnosis of TB pleurisy.

Study Objective: We sought a marker to differentiate tuberculous pleural effusions from nontuberculous pleural effusions, which otherwise can be difficult., Patients: We studied 55 patients with pleural effusions, 20 (36%) with tuberculous pleuritis and 35 (64%) with a nontuberculous etiology., Measurements and Results: Pleural fluid levels of adenosine deaminase, interferon (INF)-gamma, interleukin (IL)-12p40, IL-18, immunosuppressive acidic protein, and soluble IL-2 receptors were measured and were subjected to receiver operating characteristic analysis. INF-gamma had the greatest sensitivity and specificity for tuberculous pleuritis among the six biological markers studied., Conclusion: The determination of INF-gamma levels in pleural fluid is the most informative in the diagnosis of tuberculous effusion.

Background: Traditional diagnostic tests for pericardial tuberculosis (TB) are insensitive and often require long culture periods, and this has led to more emphasis being placed on biochemical tests such as the pericardial adenosine deaminase (ADA) test. However, controversy exists as to its diagnostic utility. In addition, the use of interferon (IFN)-gamma, which is a reliable indicator of pleural and peritoneal TB, has not been explored in pericardial effusions. We investigated ADA and IFN-gamma levels in pericardial effusions of different etiologies., Methods and Results: A prospective study was carried out from February 1995 to February 1998 at Tygerberg Hospital (South Africa), with pericardial taps being performed under echocardiographic guidance. During this period, 110 consecutive patients presenting with large pericardial effusions were included in the study. Diagnoses were made according to predetermined criteria, and they included TB (n = 64), malignancy (n = 12), nontuberculous infections (n = 5), other effusions (n = 19), and effusions of uncertain origin (n = 10). The median ADA level in the tuberculous group was 71.7 U/L (range, 10.3 to 303.6 U/L), which was significantly higher than that in any other group (p < 0.05). With a cutoff level for ADA activity of 30 U/L, sensitivity was 94%, specificity was 68%, and positive predictive value was 80%. IFN-gamma levels were determined in 30 subjects. The median IFN-gamma concentration in the tuberculous group was > 1,000 pg/L, which was significantly higher than in any other diagnostic group (p < 0.0005). A cutoff value of 200 pg/L for IFN-gamma resulted in a sensitivity and specificity of 100% for the diagnosis of pericardial TB., Conclusion: Pericardial fluid levels of ADA and IFN-gamma are useful in the diagnosis of tuberculous pericarditis.

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.

Objectives: Adenosine deaminase (ADA) can aid in the diagnosis of tuberculous pleural effusions, but false-positive findings from lymphocytic effusions have been reported. We studied the ADA levels in a variety of nontuberculous lymphocytic effusions and analyzed the relationships between ADA and conventional hematologic and biochemical parameters., Methods: One hundred six lymphocytic pleural fluid samples (lymphocyte count > 50%) were analyzed. These included post-coronary artery bypass grafting (CABG) effusions (n = 45), malignant effusions (n = 27), miscellaneous exudative effusions (n = 10), and transudative effusions (n = 24). ADA levels were determined using the Giusti method. In 22 randomly selected cases, ADA was measured again on the same sample 6 weeks later., Results: The ADA level reached the diagnostic cutoff for tuberculosis (40 U/L) in only three cases (2.8%): two lymphomas and one complicated parapneumonic effusion. There was no significant correlation between effusion ADA levels and the total leukocyte (r = 0.08), differential lymphocyte (r = 0.18) or monocyte (r = - 0.18) counts. ADA levels were significantly lower in the transudative effusions (7.2 +/- 3.5 U/L) than in post-CABG (16.6 +/- 7.2 U/L), malignant (15.3 +/- 11.2 U/L), and other exudative (15.4 +/- 13.1 U/L) effusions (p < 0.001). ADA measurements were consistent when assayed 6 weeks apart (r = 0.95; p < 0.00001; coefficient of variation, 14%)., Conclusions: ADA levels in nontuberculous lymphocytic effusions seldom exceeded the diagnostic cutoff for TB. Effusion ADA levels cannot be predicted from total or differential leukocyte counts. Post-CABG pleural fluids had ADA levels similar to other nontuberculous lymphocytic effusions. ADA is stable in effusion fluids, and its measurement is reproducible.

An elevated level of adenosine deaminase (ADA) in pleural liquid has been considered as a supplemental diagnostic marker for tuberculous pleurisy. However, this is complicated by false-positives and -negatives. Recently, it has been revealed that various cytokines are intimately involved in the pathognomonic physiology of tuberculosis. In this study, interleukin-8 (IL-8), tumour necrosis factor alpha (TNFalpha) and interferon gamma (IFNgamma) were compared with ADA in pleural liquid of patients with inflammatory (21 cases), malignant (28 cases) and tuberculous (21 cases) disease. The pleural ADA, IL-8, TNFalpha and IFNgamma levels in the tuberculous group were higher than in the other three groups. Analysis of receiver operating characteristic (ROC) curves, to evaluate the utility of the various parameters, demonstrates values for the area under the curve (AUC) of 0.770, 0.875, 0.892 and 0.987, respectively for IL-8, TNFalpha, ADA and IFNgamma. No false-positives were encountered with IFNgamma and only one case with a small volume of pleural liquid was a false-negative. This indicates that IFNgamma is a very reliable marker of tuberculous pleurisy.

Objectives: Tuberculosis, a reemergent killer, is threatening to assume serious proportions all over the world, particularly in view of the AIDS pandemic. The detection of mycobacterial DNA by polymerase chain reaction (PCR) in clinical samples is a promising approach for the rapid diagnosis of tuberculous infections. The aims of this study were to evaluate PCR for detection of Mycobacterium tuberculosis in pleural fluids and to correlate the results with adenosine deaminase activity (ADA) estimation and acid-fast bacilli (AFB) screening., Methods: The sensitivity and specificity of PCR in detection of mycobacterial DNA in 20 samples of tuberculous pleural effusion were evaluated using 40 samples of nontubercular pleural effusion as controls. The results were correlated with the ADA in all 60 pleural fluids. In addition, AFB detection by Ziehl-Neelsen staining on cytospin smears of all pleural fluids was also compared., Results: Of the 20 samples of tuberculous pleural effusion, mycobacterium could be detected by AFB staining in 4 samples. Fourteen samples were PCR positive. None of the samples from the control group were AFB or PCR positive. The sensitivity of PCR, therefore, was 70.0% with specificity of 100% (positive predictive value, 100%; negative predictive value, 86.95%). The sensitivity of AFB screening was at best 20%. The mean of ADA values in tubercular pleural effusions was 63.21 U/L (SD, 33.01), and the mean in the control samples was 51.1 U/L (SD, 29.71). Taking a cut-off value of 50 U/L, both the sensitivity and specificity of ADA estimation in diagnosing tuberculosis were only 55%., Conclusion: PCR represents a rapid and sensitive method for the detection of mycobacterial DNA in tuberculous pleural effusions. AFB screening has low sensitivity, and ADA estimation has both low sensitivity and specificity. Therefore, when the clinical suspicion is high and smear result is negative, but the signs and symptoms of M tuberculosis are apparent, PCR is the method of choice for identifying the infection.

Study Objectives: Pleural tuberculosis (TB) is a diagnostic challenge because of its nonspecific clinical presentation and paucibacillary nature. The inefficiency of conventional laboratory methods and the reliance on pleural biopsy have motivated the evaluation of alternative diagnostic strategies. We have evaluated polymerase chain reaction (PCR) directed to the IS6110 sequence of Mycobacterium tuberculosis, the determination of adenosine deaminase (ADA) activity, and measurement of interferon (IFN)-gamma levels in pleural fluid in the diagnosis of pleural TB., Patients: ADA activity, IFN-gamma levels, and PCR were evaluated in 140 cases of pleural effusion, 42 with confirmed pleural TB, 19 with probable pleural TB, 70 with a nontuberculous etiology, and 9 having an undetermined etiology., Results: ADA activity, IFN-gamma levels, and PCR were 88%, 85.7%, and 73.8% sensitive, respectively, and 85.7%, 97.1%, and 90% specific, respectively, for pleural TB that had been confirmed by either culture or pleural biopsy specimens. The combination of PCR, IFN-gamma measurement, and ADA activity determination allowed the selective increase of sensitivity and specificity for probable and confirmed cases compared to individual methods. Positive and negative predictive values for these individual or combined methods were maintained over a wide range of prevalence of pleural TB in the patient population presenting with pleural effusions. Fever and younger age were associated with tuberculous pleural effusion (p < 0. 0001), while blood in sputum and older age were associated with malignant etiology (p < 0.008)., Conclusions: These clinical variables together with the use of ADA activity determination, PCR, and measurement of IFN-gamma levels provide the basis for the rapid and efficient diagnosis of pleural TB in different clinical settings.

The effect of four variables (adenosine, glutamate dehydrogenase, phosphate buffer, and pH) on the measured catalytic concentration of adenosine deaminase (EC 3.5.4.4) was studied by Response Surface Methodology (RSM). This multivariate methodology offers an empirical approach to the study of enzyme assays and allows to detect the interaction between different variables of the system. Response-surface data showed maximum adenosine deaminase catalytic concentration at pH 7.2, adenosine 20 mmol/l, phosphate buffer 200 mmol/l and glutamate dehydrogenase 850 mu kat/l when pleural fluids were used as samples. Optimum conditions for a material containing purified adenosine deaminase from human erythrocytes differed only slightly from that obtained for the pleural fluid.

We analysed the efficacy of pleural adenosine deaminase (ADAp) and the ADA1/ADAp ratio in the diagnosis of pleural tuberculosis in 103 pleural effusions, 27 of which were tuberculosis (TB) and 76 other diagnoses (non-TB). Smears, cultures and pleural biopsies were carried out in all cases, and were used for final diagnosis. The diagnostic yield of the parameters under study were as follows: smears/cultures of mycobacteria in fluid 11.1%/33.3%; biopsy 33.3%/51.8% and tuberculosis granulomas 85.1%. The levels of ADAp and ADA1/ADAp ratio in TB and non-TB groups showed very significant differences (P < 0.00001); in the TB group: ADAp 54.7 +/- 23.5 IU and ADA1/ADAp 0.27 +/- 0.08; in the non-TB group: ADAp 18.3 +/- 43.2 IU and ADA1/ADAp 0.64 +/- 0.14. The assay established ADA levels in pleural fluid > or = 40 IU and an ADA1/ADAp ratio < or = 0.42 as cut-off levels to identify individuals in the TB group, with a sensitivity of 88.8%/100%, a specificity of 92%/98.6%, a positive predictive value (PPV) of 80%/96.4%, a negative predictive value (NPV) of 95.8%/100% and an accuracy of 91.2%/99.02%. The ADAp levels in 27 patients with TB, showed close correlation with the number of monocyte macrophages (P = 0.001), but not with the number of lymphocytes (P = n.s.). The ADA1/ADAp ratio overcomes the limitations of ADAp (false positives and negatives), and is the most useful parameter for diagnosis on account of a high diagnostic yield, low cost and speed of the assay for identifying a pleural tuberculosis diagnosis, when compared with traditional methods.

Objectives: To evaluate the diagnostic use of pleural fluid adenosine deaminase (ADAPF) levels in tuberculous pleuritis (TBpl), with a special reference to HIV coinfection and a Bayesian analysis., Methods: We investigated a total of 216 patients with pleural effusion, including 100 with TBpl, 68 with malignant effusion, 6 with transudates, 19 with empyema, 15 with miscellaneous diseases, and 8 with diseases of unknown etiology., Results: The mean values (SE) of ADAPF were 110 (4.5) U/L in patients with TBpl vs 28 (5.3) U/L in patients with a malignancy, 18 (5.7) U/L in patients with transudates, 13 (2.1) U/L in patients with diseases of unknown etiology, 22 (5.1) U/L in patients with miscellaneous diseases, and 191 (26.3) U/L in patients with empyema (Kruskal-Wallis test, p < 0.001). The ADAPF level was 110 (4.5) U/L in 37 HIV-positive patients with TBpl vs 114 (4.1) U/L in 52 HIV-negative patients with TBpl (Mann-Whitney U test, p > 0.05). A receiver operating characteristic curve identified the best cutoff at 60 U/L, yielding measures for sensitivity (0.95), specificity (0.96), positive predictive values (PPVs; 0.96), and negative predictive values (0.95). A Bayesian analysis showed a posttest probability of PPV ranging from 0.5 to 0.99, resulting from a pretest probability of 0.05 to 0.9., Conclusions: ADAPF is diagnostically useful across the various prevalences of TBpl, and its best diagnostic utility is in areas of intermediate prevalence of the disease. Moreover, the diagnostic value of ADAPF is independent of HIV serologic status.

The present study describes a new method for microassay of the activity of 5'-nucleotidase (5'-ND) and adenosine deaminase (ADA) in the microdissected nephron segments. The nephron segments including glomeruli, proximal convoluted and straight tubules (PCT and PST), cortical and medullary thick ascending limbs, and cortical and medullary collecting ducts were microdissected. 5'-ND and ADA in the nondenatured lysate of 20-mm microdissected tubules and 20 glomeruli were separated by agarose gel electrophoresis and by isoelectric focusing, respectively. The gels were incubated with specific substrates and staining dyes to exhibit the dephosphorylation by 5'-ND or deamination by ADA. The enzyme activity was estimated by measuring the intensity of the reaction bands on the gels. The 5'-ND activity was detected in all microdissected tubular segments and glomeruli. Among these nephron segments, PCT and PST exhibited the greatest enzyme activity, averaging 1142 and 939 mU/mg tissue protein, respectively. The activity of ADA was also detected in all tubular segments and glomeruli. However, the greatest activity of this enzyme was found in the glomeruli (649.8 mU/mg protein). Using reverse transcriptase-polymerase chain reaction technique, we verified the presence of mRNA of 5'-ND and ADA in all microdissected tubular segments and glomeruli. Based on these results, we conclude that 5'-ND and ADA are present in all nephron segments studied, but the activity of these enzymes is nonuniformly expressed along the nephron. This microassay is a highly specific, sensitive, and reliable method for the segmental analysis of adenosine metabolism in the kidney., (Copyright 1999 Academic Press.)

We performed diagnostic and therapeutic pericardiostomy with drainage and biopsy in 51 patients with moderate to large pericardial effusions of different etiologies from August 1991 to July 1995. Patients were divided into 4 groups (group 1, tuberculous pericarditis; group 2, suspected tuberculous pericarditis; group 3, acute pericarditis; group 4, malignancy). The pericardial fluid adenosine deaminase level in tuberculosis (87 +/- 10 U/l) was significantly higher than that in malignancy or acute pericarditis (21 +/- 4 U/l, 23 +/- 7 U/l, respectively) (P = 0.0001). The mean pericardial fluid carcinoembryonic antigen level (1.8 +/- 0.3 ng/ml) in benign disease was significantly lower than that (170.7 +/- 46.4 ng/ml) in malignant disease (P = 0.0001). Follow-up study has been done. With a new scoring system (each score 1 for adenosine deaminase > or = 40 U/l, or carcinoembryonic antigen < or = 5 ng/ml) in 25 patients since November 1993, we could diagnose 5 among 7 patients (71%) with tuberculosis, 11 among 13 patients (85%) with malignancy (adenosine deaminase < or = 40 U/l, or carcinoembryonic antigen > or = 5 ng/ml) and 5 among 5 patients (100%) with acute pericarditis (adenosine deaminase < or = 40 U/l, or carcinoembryonic antigen < or = 5 ng/ml), respectively. Our long-term follow-up study suggests that with the new scoring system we can decrease complications or avoid unnecessary procedures or treatments of patients.

Tumour necrosis factor (TNF) and interleukin-1 (IL-1) are powerful mediators with a key role in inflammation. This study was undertaken to study the presence of TNF and IL-1 in tuberculous effusion where there is marked inflammation and where examination of the pleural fluid may give information about the local inflammatory reaction. Adenosine deaminase activity (ADA, a marker of TB pleurisy) was also tested. Tumour necrosis factor, IL-1 and ADA levels were measured in the pleural fluid and serum of 97 patients; 33 with tuberculous effusion, 33 with malignant effusion, and 31 patients with benign non-tuberculous effusion. Pleural fluid TNF and ADA levels were higher in tuberculous (TB) patients than in patients with benign disorders or cancer (P < 0.01). Serum TNF levels were also higher in TB patients than other benign (P < 0.01) or malignant (P < 0.05) effusions. There was a positive correlation between serum and pleural fluid values (r = 0.998-0.999, P < 0.001) although pleural fluid concentration was higher (P < 0.001), possibly suggesting local production in the pleural cavity. Pleural fluid IL-1 levels were not raised in any patient group but there was a positive correlation between TNF and IL-1. In addition, a positive correlation was found between TNF and ADA levels, probably indicating some common production mechanism. Furthermore, ADA sensitivity in the diagnosis of tuberculous effusion was augmented by the combined use of TNF and ADA. The use of both these markers may prove useful in the differential diagnosis of TBC pleurisy.

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.

Spleen exonuclease, which degrades nucleic acids into single 3'-nucleotides, is used in the detection of DNA adducts by 32P-postlabeling. Contamination of the exonuclease with phosphatase activity can reduce the recovery of benzo[a]pyrene and N-hydroxy-2-naphthylamine DNA adducts by 32P-postlabeling. Four preparations of spleen exonuclease containing varying levels of phosphatase activity (< 1-62% of the unmodified 3'-nucleotides being dephosphorylated) were used to hydrolyze the DNA. The exonuclease with the lowest phosphatase activity produced a recovery of up to 9.60 mumol of benzo[a]pyrene adducts per mole of DNA. Recovery of benzo[a]pyrene adducts was reduced to 0.56 mumol of adduct per mole of DNA using the exonuclease with the highest phosphatase activity. Phosphatase in the exonucleases also dephosphorylated N-hydroxy-2-naphthylamine DNA adducts. Surprisingly, recovery of these DNA adducts was nearly 10 times greater using nuclease P1 than when using 1-butanol extraction for adduct enrichment, since arylamine DNA adducts have previously been reported to be poorly detected by 32P-postlabeling after nuclease P1 treatment. Our data indicate that the hydrolysis of DNA by spleen exonuclease may be an important source of variability in both qualitative and quantitative analysis of adducts by 32P-postlabeling.

Adenosine deaminase in pleural fluid (pADA), CA125 in serum (sCA125), and IFN-gamma in pleural fluid (pIFN-gamma) were measured in patients with pleurisy of various causes to evaluate their diagnostic utility in tuberculous pleuritis (TBP). We studied 39 pleural fluid samples, including 11 TBP and 28 non-TBP. With both pADA and sCA125, although the median values were much higher in TBP than in non-TBP groups, there was considerable overlap between the two groups. The sensitivity, specificity, and diagnostic efficiency were 81.8%, 89.3%, and 87.2%, respectively, when pADA values of more than 45 U ml-1 were considered, and they were 100%, 75.0%, and 84.2%, respectively, when sCA125 values of more than 35 U ml-1 were considered. In contrast, pIFN-gamma values were significantly higher in TBP patients (5.8 +/- 3.0 IU ml-1; mean +/- S.D.) than those in non-TBP patients (< 0.3 IU ml-1), leading to both a sensitivity and a specificity of 100%.