Usefulness of pleural complement activation products in differentiating tuberculosis and malignant effusions.
OBJECTIVE
To determine whether measurement of the complement activation products SC5b-9 and C3a-desArg in pleural fluid can reliably differentiate tuberculous from malignant pleural effusions.


METHODS
Twenty-four patients with tuberculous pleuritis, 29 with malignant pleural effusion, and 30 control subjects with transudates were enrolled in the study. SCSb-9 and C3a-desArg were measured in pleural fluid using commercial ELISA tests, and their performances were evaluated using receiver operating characteristic (ROC) analysis.


RESULTS
Patients with tuberculous pleuritis had higher mean levels of pleural SC5b-9 (5052 microg/L) and C3a-desArg (7436 microg/L) than those with malignant effusions (1048 and 2835 microg/L, respectively), whereas only SC5b-9 concentrations in the latter were comparable with controls. The area under the ROC curve (AUC) was 0.84 for SC5b-9 and 0.81 for C3a-desArg. Pleural SC5b-9 showed an accuracy of 80.8%, compared with 78.8% for C3a-desArg, when cut-off points of 1500 and 4500 microg/L, respectively, were used. Using a stepwise logistic regression model, the combination of pleural SCSb-9 > or =1500 microg/L, age < or =35 years, and pleural monocyte percentage > or =90% provided the highest accuracy for tuberculous pleurisy (88.5%, AUC 0.95).


CONCLUSIONS
This pilot study suggests that pleural SC5b-9 is clinically useful for differentiating tuberculous and malignant pleural effusions.
Porcel
J M
JM
Department of Internal Medicine, University Hospital Arnau de Vilanova, University of Lleida, Spain.
Vives
M
M
Gázquez
I
I
Vicente de Vera
M C
MC
Pérez
B
B
Rubio
M
M
D000328:Adult; D000706:Anaphylatoxins / Q000032:analysis*; D015926:Complement C3a / Q000031:analogs & derivatives* / Q000032:analysis; D015938:Complement Membrane Attack Complex; D003165:Complement System Proteins / Q000032:analysis*; D003937:Diagnosis, Differential; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006023:Glycoproteins / Q000032:analysis*; D006801:Humans; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D010865:Pilot Projects; D010996:Pleural Effusion / Q000737:chemistry / Q000166:cytology; D016066:Pleural Effusion, Malignant / Q000175:diagnosis*; D011446:Prospective Studies; D012372:ROC Curve; D014396:Tuberculosis, Pleural / Q000175:diagnosis*
D000706:Anaphylatoxins; D015938:Complement Membrane Attack Complex; D006023:Glycoproteins; C047610:SC5b-9 protein complex; C044541:complement C3a, des-Arg-(77)-; D015926:Complement C3a; D003165:Complement System Proteins