[Application of quantitative polymerase chain reaction in the differentiation of sarcoidosis and proliferative tuberculosis].
OBJECTIVE
To evaluate the role of mycobacterial infection in the pathogenesis of sarcoidosis by examination of mycobacterial DNA in tissue samples of sarcoidosis and tuberculosis, and to examine the value of quantitative real-time polymerase chain reaction (PCR) in the differentiation of the two diseases.


METHODS
Mycobacterium tuberculosis DNA was measured by quantitative real-time PCR from formalin-fixed and paraffin-embedded sections of biopsy samples of lymph nodes and lung tissues from 31 patients with sarcoidosis, 30 patients with tuberculosis and 15 patients with other diseases (as the control samples) in Shanghai Pulmonary Hospital from January 1998 to December 2003. Lung tissues from 15 normal embryonic mice served as the negative control.


RESULTS
The positive rate of mycobacterial DNA in the tuberculosis samples (30/30) was higher than that of the sarcoidosis samples (6/31) and of the control samples (2/15). The difference between sarcoidosis and normal samples showed no statistical significance. The absolute and relative copies of mycobacterial DNA in the tuberculosis samples were significantly higher than those in the sarcoidosis and the control samples; while there was no statistical difference between the sarcoidosis and the control samples. There was no positive result in the lung tissues of the embryonic mice.


CONCLUSIONS
The results do not show any relationship between mycobacterial infection and sarcoidosis. Quantitative PCR may be a reliable method for the differentiation of sarcoidosis from tuberculosis.
Li
Qiu-Hong
QH
Department of Respiratory Diseases, Shanghai Pulmonary Hospital, Shanghai 200433, China.
Zhao
Lan
L
Li
Hui-Ping
HP
Shen
Yue-Ping
YP
Zhang
Rong-Xuan
RX
Zheng
Hui
H
Fan
Yu-Mei
YM
D000328:Adult; D000368:Aged; D000818:Animals; D004269:DNA, Bacterial / Q000032:analysis; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000302:isolation & purification; D016133:Polymerase Chain Reaction / Q000379:methods*; D012507:Sarcoidosis / Q000175:diagnosis*; D014376:Tuberculosis / Q000175:diagnosis*
D004269:DNA, Bacterial