Pleural interleukin-1 beta in differentiating transudates and exudates: comparative analysis with other biochemical parameters.
BACKGROUND
The differential diagnosis of pleural effusion is a frequent clinical problem. The possible role of pleural fluid cytokines in discriminating transudates from exudates has not been studied adequately.


OBJECTIVE
The aim of this study was to evaluate the serum and pleural fluid levels of interleukin-1 beta (IL-1 beta) and to compare it with common biochemical parameters such as cholesterol (CHOL), lactate dehydrogenase (LDH), total protein and albumin.


METHODS
One hundred and six consecutive patients with pleural effusion were studied. IL-1 beta was measured simultaneously in blood and pleural fluid using a radioimmunoassay. Standard laboratory methods were employed for biochemical parameters.


RESULTS
Using ROC analysis, a pleural IL-1 beta cutoff level 18.16 fmol/ml had a sensitivity of 76.8%, a specificity of 58.3% and a positive predictive value (PPV) 86.3% in the discrimination of transudates vs. all exudates. Serum IL-1 beta levels were higher in the nonmalignant group but without statistical difference compared with transudate patients. In addition, a significant difference was found between serum IL-1 beta in the malignant group in comparison with those of the transudate group (p < 0.01), also IL-1 beta levels were significantly increased in exudate effusion when compared with transudate (p < 0.001, p < 0.05, respectively). CHOL values of > or =65 mg/dl had 92.7% sensitivity, and 100% specificity and PPV for both.


CONCLUSIONS
The results of this study suggest that although IL-1 beta could be a marker with relatively good sensitivity and PPV for the differentiation of pleural effusion, the cost and time needed do not support its use as a routine laboratory test.
Alexandrakis
Michael G
MG
Department of Hematology, Medical School University of Crete, Heraklion, Greece. bouros@med.uoc.gr
Kyriakou
Despina
D
Alexandraki
Rea
R
Pappa
Konstantina A
KA
Antonakis
Nikolaos
N
Bouros
Demosthense
D
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002784:Cholesterol / Q000032:analysis; D003937:Diagnosis, Differential; D005122:Exudates and Transudates / Q000737:chemistry*; D005260:Female; D006801:Humans; D007375:Interleukin-1 / Q000032:analysis* / Q000097:blood; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000737:chemistry* / Q000175:diagnosis; D016066:Pleural Effusion, Malignant / Q000737:chemistry* / Q000175:diagnosis; D011506:Proteins / Q000032:analysis; D012372:ROC Curve; D011863:Radioimmunoassay; D012680:Sensitivity and Specificity
D007375:Interleukin-1; D011506:Proteins; D002784:Cholesterol; D007770:L-Lactate Dehydrogenase