Role of Adenosine Deaminase Estimation in Differentiation of Tuberculous and Non-tuberculous Exudative Pleural Effusions

Efficacy of procalcitonin and pentraxin-3 as early biomarkers for differential diagnosis of pleural effusions

Objectives

Pleural effusion, defined as an abnormal accumulation of fluid in pleural space, can be of two types: transudative and exudative. The primary aim of the study was to assess the predictive accuracy of procalcitonin (PCT) and pentraxin-3 (PTX-3) in comparison to other biochemical markers such as C-reactive protein (CRP), and adenosine deaminase (ADA) in the differential diagnosis of pleural effusions.

Methods

A cross-sectional analytical study was conducted on patients with pleural effusion. Multiple comparisons and receiver-operating characteristics (ROC) analyses were made to evaluate the diagnostic significance of biochemical markers.

Results

Sixty-six patients with exudative pleural effusion classified as malignant, tuberculous, and parapneumonic effusions (malignant pleural effusion [MPE], tuberculous [TPE], and parapneumonic [PPE]) were included. Significant differences in pleural fluid levels in both PCT (p-value: 0.001) and PTX-3(p-value: 0.001), as well as serum levels of PCT (p-value: 0.001), were observed between the three groups. ROC analysis showed both PTX-3 and PCT having favorable discrimination ability with high sensitivity (≥90%) and specificity to predict PPE from TPE and MPE.

Conclusions

Evaluation of serum and pleural fluid PCT and levels of PTX-3 in the pleural fluid may be used as an early biomarker to differentiate the etiology of pleural effusion.

Diagnostic accuracy of cerebrospinal fluid adenosine deaminase in detecting Tuberculous Meningitis

Objective

To determine diagnostic accuracy of Cerebro Spinal Fluid (CSF) Adenosine De-Aminase (ADA) in detecting Tuberculous Meningitis (TBM) keeping CSF Polymerase Chain Reaction (PCR) for Mycobacterium Deoxy Ribonucleic Acid (DNA) as gold standard.

Methods

This cross sectional validation study was conducted at Department of General Medicine of PNS Shifa Naval Hospital Karachi, Pakistan from Oct 2015 to Mar 2017 for a total duration of one and a half year. One hundred and thirty six patients were included. The diagnosis of TBM was based clinically on symptoms like fever, headache, altered mental state and signs of meningeal irritation with CSF findings of increased proteins, low glucose and lymphocytic pleocytosis. Lumbar puncture was done and approximately 4ml of CSF sample was withdrawn for analysis. Diagnosis of TBM was confirmed by doing CSF PCR test for mycobacterium tuberculosis DNA.

Results

Total 136 patients were enrolled in this study. Mean age in our study was 47.09±12.80 years, whereas frequency and percentages of male and female patients was 102 (75%) and 34 (25%) respectively. The diagnostic accuracy, sensitivity, specificity, positive predictive value and negative predictive value of CSF ADA level in detecting TBM was 71.32%, 84.21%, 95.45%, 98.97% and 53.85% respectively.

Conclusion

The study concludes that diagnostic accuracy of CSF ADA in detecting TBM is high which is proposed as an investigation to differentiate it from other causes of meningitis in places where PCR test is not available.

A Label-Free Fluorescent Assay for the Rapid and Sensitive Detection of Adenosine Deaminase Activity and Inhibition

Adenosine deaminase (ADA), able to catalyze the irreversible deamination of adenosine into inosine, can be found in almost all tissues and plays an important role in several diseases. In this work, we developed a label-free fluorescence method for the detection of adenosine deaminase activity and inhibition. In the presence of ADA, ATP has been shown to be hydrolyzed. The ATP aptamer was shown to form a G-quadruplex/thioflavin T (ThT) complex with ThT and exhibited an obvious fluorescence signal. However, the ATP aptamer could bind with ATP and exhibited a low fluorescence signal because of the absence of ADA. This assay showed high sensitivity to ADA with a detection limit of 1 U/L based on an SNR of 3 and got a good linear relationship within the range of 1–100 U/L with R² = 0.9909. The LOD is lower than ADA cutoff value (4 U/L) in the clinical requirement and more sensitive than most of the reported methods. This technique exhibited high selectivity for ADA against hoGG I, UDG, RNase H and λexo. Moreover, this strategy was successfully applied for assaying the inhibition of ADA using erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA) and, as such, demonstrated great potential for the future use in the diagnosis of ADA-relevant diseases, particularly in advanced drug development.

Pleural sarcoidosis diagnosed on the basis of an increased CD4/CD8 lymphocyte ratio in pleural effusion fluid: a case report

Introduction

Pleural effusion induced by sarcoidosis is rare, and pleural sarcoidosis is often diagnosed by thoracoscopic surgery. The diagnosis of pleural sarcoidosis using thoracentesis may be less invasive when sarcoidosis is already diagnosed histologically in more than one organ specimen. Here we report the case of a 64-year-old woman with pleural sarcoidosis diagnosed on the basis of an increased CD4/CD8 lymphocyte ratio in pleural effusion fluid obtained by thoracentesis. This case report is important because it highlights the usefulness of the CD4/CD8 lymphocyte ratio in pleural effusion as an indicator of pleural involvement of sarcoidosis.

Case presentation

A 64-year-old Japanese woman visited our hospital with an initial symptom of dyspnea on exertion for a period of 4 months. Chest computed tomography showed bilateral hilar and multiple mediastinal lymphadenopathy, multiple small nodular shadows in her bilateral lungs, small nodular shadows along the interlobar pleura, and bilateral pleural effusion. Her serum angiotensin-converting enzyme and soluble interleukin-2 receptor levels were elevated. Histological analysis of a resected subcutaneous nodule, and biopsy specimens from a right mediastinal lymph node and from her right lung revealed non-caseous epithelioid granulomas. Her bronchoalveolar lavage fluid exhibited a predominance of lymphocytes together with an increase in the CD4/CD8 lymphocyte ratio. The lymphocytic predominance and the increased CD4/CD8 lymphocyte ratio were also detected in the right-sided pleural effusion fluid obtained by thoracentesis. We diagnosed sarcoidosis with pleural involvement. Because pleural effusion did not resolve spontaneously and her symptom of dyspnea on exertion worsened, corticosteroid therapy was initiated, which ameliorated the sarcoidosis and the pleuritis.

Conclusions

Analysis of the CD4/CD8 lymphocyte ratio in pleural effusion fluid obtained by thoracentesis may be helpful for the diagnosis of pleural sarcoidosis when the diagnosis is already made by histological examination of more than one organ specimen.

Diagnostic utility of adenosine deaminase in exudative pleural effusions

Objective:

To determine the diagnostic utility of adenosine deaminase (ADA) in exudative pleural effusions of different etiologies.

Setting and Design:

It was an observational study conducted at a tertiary care teaching institute.

Materials and Methods:

Of a total of 171 pleural fluid samples, 122 were found to be exudates and were included in the study. Pleural fluid ADA was done for all included patients. Pleural fluid ADA ≥40 U/l was taken as diagnostic cut off for TB effusion.

Statistical Analysis:

Sensitivity, specificity positive and negative predictive value of pleural fluid ADA for diagnosing TB was calculated by using clinical calculator – 1, Richard Lowry 2001-2013.

Results:

There were 171 patients with pleural effusion, out of which 122 (71.8%) were found to be exudative and were studied further. There were 49 (40.1%), 36 (29.5%) and 33 (27%) cases of TB, malignancy and para pneumonic effusion respectively, whereas 4 (3.3%) cases remained undiagnosed. Median ADA values for TB, malignancy and para pneumonic effusion were 55.8 U/l (range 9.7-756 U/l), 18 U/l (6.5-81 U/l) and 25 U/l (3.4-172 U/l) respectively. Pleural fluid ADA >40U/l yielded 85.7% sensitivity, 80.8% specificity, 75% positive predictive value and 89.5% negative predictive value.

Conclusion:

Pleural fluid ADA remains useful in diagnosing tuberculosis pleural effusion. The median ADA for TB effusion in present cohort was 51.8 IU/ml. Pleural fluid ADA of 40 U/L yielded 89.5% negative predictive value and 75% positive predictive value. Pleural fluid ADA is cost effective and good screening test for diagnosis of TB.

Adenosine Deaminase Levels in CSF of Tuberculous Meningitis Patients

Background

Tuberculosis kills five lakh patients in India every year, out of which 7-12 % are with meningeal involvement. Delay in its diagnosis and in initiation of treatment results in poor prognosis and sequlae in up to 25% of cases. The aim of the present study is to look for a simple, rapid, cost effective, non-invasive and fairly specific test in differentiating tubercular etiology from other causes.

Methods

Forty patients between the age of 6 - 24 months attending hospital with symptoms and signs of meningitis were selected and divided into two groups: tubercular and non-tubercular, depending upon the accepted criteria. CSF was drawn and ADA estimated.

Results

Out of 19 tubercular patients, 18 had CSF ADA at or above the cutoff value while one had below. Out of 21 non-tuberculous patients, two had ADA levels at or above the cutoff value while 19 had below this value. Results of our study indicate that ADA level estimation in CSF is not only of considerable value in the diagnosis of TBM, CSF ADA level 10 U/L as a cutoff value exhibited 94.73% sensitivity and 90.47% specificity in differentiating tuberculous from non-tuberculous meningitis; it also has 90.00% positive predictive value and 95.00% negative predictive value.

Conclusions

It can be concluded that ADA estimation in CSF is not only simple, inexpensive and rapid but also fairly specific method for making a diagnosis of tuberculous etiology in TBM, especially when there is a dilemma of differentiating the tuberculous etiology from non-tuberculous ones. For this reason ADA estimation in TBM may find a place as a routine investigation.

Keywords

Cerebrospinal fluid; Adenosine deaminase; Tuberculous meningitis