Assay of pleural fluid interleukin-6, tumour necrosis factor-alpha and interferon-gamma in the diagnosis and outcome correlation of tuberculous effusion.
OBJECTIVE
To assess the usefulness of interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) in the diagnosis and prediction of outcome of pleural tuberculosis.


METHODS
Pleural fluid from 32 TB and 34 non-TB patients was sent for assay of IL-6, TNF-alpha and IFN-gamma. Clinical parameters at presentation and residual pleural scarring at completion of treatment were assessed for pleural TB cases.


RESULTS
The pleural fluid Levels of IL-6, TNF-alpha and IFN-gamma in TB patients were significantly higher than those with non-TB effusions (P values of <0.001, 0.018 and <0.001, respectively by independent t-test). Utility of these cytokines for diagnosis of pleural TB was evaluated using receiver operating characteristic (ROC) curve analysis. The cut-off values for IL-6, TNF-alpha and IFN-gamma determined in this analysis were 4000, 4 and 60 pg/ml respectively, and their sensitivity and specificity were 90.6% and 76.5%, 90.6% and 79.4%, 100% and 100%, respectively. The pretreatment pleural fluid IL-6 levels had a positive correlation with the number of febrile days after treatment (Pearson correlation test: r=0.60, P=0.009). A negative correlation was found between the percentage reduction in pleural fluid cytokines after 2 weeks treatment and the extent of residual pleural scarring (IL-6: r=-0.62, P=0.041; TNF-alpha: r=-0.65, P=0.030; IFN-gamma: r=0.83, P=0.002).


CONCLUSIONS
Pleural fluid IL-6, TNF-alpha and IFN-gamma assays are useful in the diagnosis of pleural TB. The initial IL-6 level correlates with the number of febrile days. The percentage change of cytokines after 2 weeks of treatment also helps to predict residual pleural scarring.
Wong
Chi-fong
CF
Tuberculosis & Chest Unit, Grantham Hospital, 125 Wong Chuk Hang Road, Aberdeen, Hong Kong, China. wongcf2001@yahoo.com.hk
Yew
Wing-wai
WW
Leung
Simon Kwok-fai
SK
Chan
Chiu-yeung
CY
Hui
Mamie
M
Au-Yeang
Carrie
C
Cheng
Augustine Fun-bun
AF
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001826:Body Fluids / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000032:analysis*; D015850:Interleukin-6 / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification; D010994:Pleura / Q000737:chemistry / Q000382:microbiology; D010996:Pleural Effusion / Q000382:microbiology*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014396:Tuberculosis, Pleural / Q000175:diagnosis*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis*
D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma