Diagnostic significance of interferon-gamma in tuberculous pleural effusions.
OBJECTIVE
Tuberculosis (TB), the single most frequent infectious cause of death worldwide, also is a major cause of pleural effusion, which in TB usually has lymphocytic and exudative characteristics. Differential diagnosis between TB and nontuberculous pleural effusion can be sometimes difficult, representing a critically important clinical problem.


METHODS
We studied 46 patients presenting with pleural effusion to the National Sanyo Hospital between April 2000 and January 2001 (34 men and 12 women; mean age, 64 years). Ten patients (22%) had tuberculous pleurisy, 19 patients (41%) had malignant pleuritis, and 17 patients (37%) had pleural effusion due to an etiology other than tuberculosis or cancer. Pleural fluid concentrations of four suggested markers were measured using commercially available kits.


RESULTS
The pleural fluid levels (mean +/- SE) of adenosine deaminase (83.3 +/- 18.2 U/L vs 25.8 +/- 20.4 U/L, p < 0.0001), interferon-gamma (137 +/- 230 IU/mL vs 0.41 +/- 0.05 IU/mL, p < 0.0001), immunosuppressive acidic protein (741 +/- 213 micro g/mL vs 445 +/- 180 micro g/mL, p < 0.001) and soluble interleukin 2 receptor (7,618 +/- 3,662 U/mL vs 2,222 +/- 1,027 U/mL, p < 0.0001) were significantly higher for tuberculous pleuritis than for other causes of effusion. Receiver operating characteristic analysis demonstrated that pleural fluid content INF-gamma was the best indicator of tuberculous pleurisy among four relevant biological markers.


CONCLUSIONS
INF-gamma in pleural fluid is the most sensitive and specific among four biological markers for tuberculous pleuritis. Thus, our results suggest that determination of INF-gamma at the onset of pleural effusion is informative for the diagnosis of tuberculous pleuritis. Further studies including larger numbers of patients are needed to verify this result.
Aoe
Keisuke
K
Department of Respiratory Medicine, National Sanyo Hospital, Respiratory Disease Center, Yamaguchi, Japan. keisukeaoe@mtf.biglobe.ne.jp
Hiraki
Akio
A
Murakami
Tomoyuki
T
Eda
Ryosuke
R
Maeda
Tadashi
T
Sugi
Kazuro
K
Takeyama
Hiroyasu
H
D000243:Adenosine Deaminase / Q000378:metabolism; D015415:Biomarkers; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000378:metabolism; D010996:Pleural Effusion / Q000175:diagnosis* / Q000209:etiology; D016066:Pleural Effusion, Malignant / Q000175:diagnosis; D012372:ROC Curve; D015375:Receptors, Interleukin-2 / Q000378:metabolism; D018709:Statistics, Nonparametric; D014396:Tuberculosis, Pleural / Q000150:complications / Q000175:diagnosis*
D015415:Biomarkers; D009363:Neoplasm Proteins; D015375:Receptors, Interleukin-2; C030193:immunosuppressive acidic protein; D007371:Interferon-gamma; D000243:Adenosine Deaminase