Pleural SC5b-9 in differential diagnosis of tuberculous, malignant, and other effusions.
A monoclonal antibody against soluble phase-terminal complement complex (SC5b-9) was used to try to differentiate pleural effusions of tuberculous vs malignant and other origin. Effusions of tuberculous origin showed a significantly higher SC5b-9 level than did plasma, suggesting activation of complement in the pleural space. All 26 patients with tuberculous effusions showed SC5b-9 levels in pleural fluid exceeding 2.0 mg/L, while 20 with malignant effusions had levels less than 2.0 mg/L. However, rheumatoid, some parapneumonic, and treated malignant effusions showed SC5b-9 levels above 2.0 mg/L. Considering a value exceeding 2.0 mg/L, the specificity and sensitivity of the SC5b-9 estimation in tuberculosis were 0.74 and 1.0, respectively. The mean values for C4d and Bb fragments of complement were significantly (p < 0.05) higher in the tuberculous than in the malignant effusions. However, the values for Bb in 16 (62 percent) of the 26 patients with tuberculous or malignant effusions were in the same range. The activity of adenosine deaminase (ADA) was higher in the tuberculous than in the malignant effusions. While 18 of 26 patients with tuberculous effusions showed an ADA value exceeding 50 mU/ml, the estimated cutoff point (sensitivity = 0.69), 35 of the 36 nontuberculous effusions showed a true negative value (specificity = 0.97). A correlation between ADA and SC5b-9 values was observed in pleural effusions. These observations suggest that the estimation of SC5b-9 in pleural fluid presents a new approach to differentiating tuberculous vs malignant effusions.
Hara
N
N
Research Institute for Diseases of the Chest, Medical School of Kyushu University, Fukuoka, Japan.
Abe
M
M
Inuzuka
S
S
Kawarada
Y
Y
Shigematsu
N
N
D000243:Adenosine Deaminase / Q000032:analysis; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D051561:Complement C3 Convertase, Alternative Pathway; D003179:Complement C3b / Q000032:analysis; D003181:Complement C4 / Q000032:analysis; D015935:Complement C4b; D015938:Complement Membrane Attack Complex; D003165:Complement System Proteins / Q000032:analysis*; D003937:Diagnosis, Differential; D005122:Exudates and Transudates / Q000737:chemistry*; D005260:Female; D006023:Glycoproteins / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000032:analysis; D010996:Pleural Effusion / Q000175:diagnosis* / Q000209:etiology / Q000276:immunology; D016066:Pleural Effusion, Malignant / Q000175:diagnosis; D014397:Tuberculosis, Pulmonary / Q000150:complications / Q000175:diagnosis
D003181:Complement C4; D015938:Complement Membrane Attack Complex; D006023:Glycoproteins; D010446:Peptide Fragments; C047610:SC5b-9 protein complex; D003179:Complement C3b; D015935:Complement C4b; C032261:complement C4d; D003165:Complement System Proteins; D051561:Complement C3 Convertase, Alternative Pathway; D000243:Adenosine Deaminase