Adenosine deaminase (ADA) isoenzyme analysis in pleural effusions: diagnostic role, and relevance to the origin of increased ADA in tuberculous pleurisy.

The rise in adenosine deaminase (ADA) activity in the pleural fluid of tuberculous pleurisy patients, though used for diagnosis, is of unknown origin. In this work, we determined ADA activity and the activities of 2'-deoxyadenosine deaminase and ADA-2 in 350 patients. We also considered whether the results throw light on the origin of high pleural fluid ADA in tuberculous pleurisy and estimated the diagnostic efficiency of 2'-deoxyadenosine deaminase, ADA-2 and total ADA activities with and without the inclusion of the 2'-deoxyadenosine deaminase/ADA activity ratio in a combined criterion. The 350 pleural effusions were classified by previously established criteria as transudates (60 males/18 females) or as tuberculous (49 males/27 females), neoplastic (50 males/39 females), parapneumonic (36 males/19 females), empyematous (11 males/3 females), or miscellaneous (25 males/13 females) exudates. Total ADA, ADA-2 and 2'-deoxyadenosine deaminase activities were, respectively, 127.5 +/- 2.9, 103 +/- 29.5 and 42.8 +/- 14 U.L-1 in tuberculous exudates. With diagnostic thresholds of 47, 40 and 22 U.L-1 respectively, the sensitivities of ADA, ADA-2 and 2'-deoxyadenosine deaminase for tuberculosis were 100, 100 and 95%; their specificities 91, 96 and 92%; and their efficiencies 93, 97 and 93%, respectively. One hundred and one effusions (all 76 tuberculous, 12 neoplastic, 4 parapneumonic and 9 empyematous exudates) had total ADA levels > 47 U.L-1; of these, 8 neoplastic, 1 parapneumonic and all the tuberculous exudates had a 2'-deoxyadenosine deaminase/ADA activity ratio < 0.49. The criterion of simultaneously having ADA > 47 U.L-1, ADA-2 > 40 U.L-1 and a 2'-deoxyadenosine deaminase/ADA activity ratio < 0.49 was satisfied by all the tuberculous effusions but only eight others (all neoplastic) (sensitivity 100%, specificity 97%, efficiency 98%). We conclude that: 1) high total ADA activity in tuberculous pleural effusions is due mainly to an increase in ADA-2, and, therefore, originated from the only known source monocytes and macrophages; 2) ADA-2 was a more efficient diagnostic marker of tuberculous pleurisy than total ADA activity, although the difference was not statistically significant; and 3) among effusions with high total ADA the 2'-deoxyadenosine deaminase/ADA activity ratio differentiates tuberculous effusions from empyemas and parapneumonic effusions, but fails to discriminate well between tuberculous and neoplastic effusions.

Diagnostic value of simultaneous determination of pleural adenosine deaminase and pleural lysozyme/serum lysozyme ratio in pleural effusions.

We have determined simultaneously the ADAp and Lp/Ls ratio in 138 pleural effusions: 61 tuberculous; 42 malignant; 14 transudates; five parapneumonic uncomplicated; six empyematous; and ten cases belonging to a miscellaneous group which included two disseminated lupus erythematosus; two posttraumatic; one pancreatitis; one pleuropericarditis by Mycoplasma; one viral pleuropericarditis; and three pulmonary embolisms. This has allowed us to clear the overlapping for the ADAp activity among tuberculous patients (two cases of lupus and three cases of malignant effusions) in our series. The overlap in the Lp/Ls ratio among tuberculous patients, two malignant, and two parapneumonic uncomplicated cases was also cleared. Fixing the ADAp values at 33 U and the Lp/Ls ratio at 1.2, the tuberculous pleural effusion cases were differentiated from the nontuberculous with a sensibility, positive predictive value, negative predictive value, and safety diagnosis of 100 percent. It has been proven that there is a good correlation between ADAp and Lp/Ls ratio (r = 0.717) and the ADAp and Lp (r = 0.660).

[Determination of adenosine deaminase in 295 samples of pleural fluid]. / Dosage de l'adénosine désaminase dans 295 liquides pleuraux.

The activity of adenosine deaminase has been measured in 295 specimens of pleural fluid from 248 patients. The effusions were due in part to pleural tubercle (n = 8), rheumatoid arthritis (n = 2) empyema (n = 4), or malignant lymphoma (n = 5); the remainder were due to effusions of other aetiologies (n = 229). The disorders of the first group of patients are known to be associated with an elevated level of ADA. The two groups of patients were compared by fixing the upper limit of normal at 50 U/l. There was a 97% specificity even though the sensitivity was only 42%. However the relative smallness of the group of patients who were suffering from tuberculosis, rheumatoid arthritis, empyema and malignant lymphoma means that the interpretation of the sensitivity of the test should be subject to caution.

Molecular forms of adenosine deaminase in pleural effusions.

The molecular forms of adenosine deaminase (ADA) were studied in pleural effusions with high ADA activity. The molecular forms were separated by polyacrylamide gel electrophoresis (PAGE), and the molecular masses estimated by gel filtration. Effusions investigated were: tuberculosis (TB) (20 cases), lymphoma (3 cases), chronic myelogenous leukemia (1 case) and empyema (6 cases). Two ADA forms were identified, a small form (Smf-ADA) and a large form (Lmf-ADA). Without exception, the tuberculous effusions have shown only Lmf-ADA. All the other effusions contained both forms, the Smf-ADA being predominant. This was also the ADA pattern seen in normal lymphocytes. These findings may indicate different mechanisms of ADA release or origins of ADA in the various effusions. The Lmf-ADA may be secreted by activated T cells in TB, which would confirm the notion that ADA activity reflects cellular immunity. In contrast, in the nontuberculous cases the ADA probably leaked from damaged lymphocytes or neutrophils, hence the reflection of the cellular ADA pattern. The PAGE pattern may also be of value in distinguishing between TB and these other causes of high pleural fluid ADA.

Low levels of functional of alpha 1-proteinase inhibitor in the promotion of C3-cleavage by granulocyte-neutral proteases in pleural empyema.

It has been suggested that C3 breakdown by granulocyte-neutral proteases in pleural empyemas may be related to a decreased inhibitor potential for these enzymes. In the present study it was shown that in 17 infected pleural effusions, high proteolytic activity on 125I-labeled C3 (16.3% +/- 4.4%) correlated with low functional levels of alpha 1-proteinase inhibitor (alpha 1-PI), as determined by trypsin-inhibitory capacity (56.2 +/- 20.1 IU/ml; rs = -0.97, P less than .001), whereas in 18 sterile pleural effusions there was no such correlation (125I-labeled C3 cleavage, 2.2% +/- .2%; trypsin-inhibitory capacity, 192.6 +/- 26.7 IU/ml). However, alpha 1-PI and alpha 2-macroglobulin protein concentrations in infected and sterile effusions (as measured by immunodiffusion) were similar. Fifteen strains of three bacterial species--Streptococcus pneumoniae, Pseudomonas aeruginosa, and Proteus mirabilis--isolated from patients with pneumonia or empyema inactivated the elastase-inhibitory capacity of alpha 1-PI in vitro. These results show that in empyemas functional levels of alpha 1-PI were too low to inactivate granulocyte elastase and that some bacterial species may contribute to the low inhibitor potential of infected pleural fluid by direct alpha 1-PI inactivation.

Cleavage of C3 by neutral proteases from granulocytes in pleural empyema.

The possibility of direct inactivation of C3 by granular enzymes from polymorphonuclear leukocytes (PMNLs) in pleural empyema was examined. As a group, pleural empyema from 10 patients with purulent effusions and a positive bacteriologic culture cleaved significantly more 125I-labeled C3 bound to Sepharose (18.4% +/- 7.3%) than did 19 sterile pleural effusions (2.4% +/- 0.9%; P less than 0.001) and sonicates from bacterial strains commonly found in empyema (1.4% +/- 0.2%). Granular enzymes from 7 X 10(6) PMNLs cleaved 78.5% of 125I-labeled C3 bound to Sepharose. When proteolysis of 125I-labeled C3 after incubation with pleural empyema or PMNL granular enzymes was examined with polyacrylamide gel electrophoresis, breakdown products were similar. Granulocyte elastase-like activity was detected in four samples of pleural empyema. Granulocyte elastase inhibitors, as well as 10% human serum, effectively suppressed cleavage of C3 and elastase-like activity. In pleural empyemas, granula enzymes from PMNLs, especially elastase, apparently contribute to low complement-mediated opsonic activity by direct inactivation of C3.

Pathogenesis of sinus empyema.

The crucial event in the pathogenesis of sinus empyema is the ostial obstruction. On the basis of recent reports, some consequences of the obstruction on the local bacterial-host interrelationship have been outlined. The anaerobic gas environment of the empyema is one quality important to the selection of bacteria but probably also to the efficiency of the antibacterial activity of the granulocytes. Release of proteolytic enzymes from neutrophilic granulocytes in the sealed sinus may jeopardize the bacterial engulfment due to proteolytic degradation of opsonins. A longstanding exposure of the sinus mucosa to uninhibited proteolytic enzymes may explain the irreversible lesion of the mucosa in chronic sinusitis.