[Gamma interferon and adenosine deaminase in pleuritis]
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E Ribera1, J M Martínez-Vázquez, I Ocaña
1Hospital General Vall d'Hebron, Universidad Autónoma, Barcelona.
Abstract:
The concentration of gamma interferon (IFN gamma) and adenosine deaminase (ADA) activity were measured in the pleural fluid of 162 patients to compare their diagnostic significance and to establish a possible correlation between both tests. The IFN gamma levels in tuberculous pleural effusions were quite variable, with a mean of 93 U/ml and a median of 48 U/ml. They were higher than 2 U/ml in all cases, whereas no case of nontuberculous effusion showed higher values. ADA activity was higher than 43 U/l in all tuberculous effusions, with a mean value of 80 U/l, higher than in any other group except lymphoma. In three pleural effusions associated with lymphoma, one with mesothelioma, one with adenocarcinoma and four with empyema, ADA activity was higher than 43 U/l. In these patients, IFN gamma levels were low. There was no correlation in the whole series or in any group between IFN and ADA. Both parameters can be very useful for the diagnosis of tuberculous pleuritis. The measurement of IFN gamma is more specific, although the experience with this test is more limited than with ADA. It has the additional shortcoming of a high cost and it requires facilities for radionuclide use. Therefore, we think that ADA measurement should be considered as a routine test while IFN gamma measurement should be reserved for reference institutions.
Insights
Adenosine deaminase (ADA) and interferon-gamma (IFN-γ) are useful for diagnosing tuberculous pleuritis. ADA is recommended as a routine test due to its cost-effectiveness and broad applicability, while IFN-γ is reserved for specialized institutions.
Area of Science:
- Pulmonology
- Immunology
- Biochemistry
Context:
- Tuberculous pleuritis diagnosis remains a challenge, necessitating reliable biomarkers.
- Pleural fluid analysis offers a direct route for identifying infectious and inflammatory markers.
Purpose:
- To compare the diagnostic utility of pleural fluid adenosine deaminase (ADA) activity and interferon-gamma (IFN-γ) concentration.
- To investigate potential correlations between ADA activity and IFN-γ levels in various pleural effusion types.
Summary:
- Both ADA and IFN-γ levels were elevated in tuberculous pleural effusions, with IFN-γ >2 U/ml and ADA >43 U/l observed in all tuberculous cases.
- Elevated ADA was also noted in lymphoma, mesothelioma, adenocarcinoma, and empyema, but IFN-γ levels were low in these non-tuberculous conditions.
- No significant correlation was found between ADA activity and IFN-γ levels across all patient groups.
Impact:
- ADA measurement is a cost-effective and reliable routine diagnostic test for tuberculous pleuritis.
- IFN-γ measurement offers higher specificity but is limited by cost and resource requirements, making it suitable for reference laboratories.