Epidemiological evaluation of release of monocyte TNF-alpha as an exposure and effect marker in pneumoconiosis: a five year follow up study of coal workers.
OBJECTIVE
To determine (a) reproducibility with previous cross sectional findings, and (b) the predictive value of initial release of tumour necrosis factor-alpha (TNF-alpha) towards later progression of coalworkers' pneumoconiosis (CWP).


METHODS
Release of monocyte TNF-alpha after in vitro stimulation with coal mine dust, silica, and endotoxin was measured in 104 retired miners and was related to stage of CWP (chest radiograph) and cumulative exposure. A subgroup of 46 miners was screened by high resolution computed tomography (HRCT). Prospective analysis of TNF-alpha (40 out of 104 miners involved in the previous TNF-alpha study) was done by relating initial TNF-alpha to five year progression of CWP measured by comparison of paired chest radiographs.


RESULTS
As observed previously, dust stimulated release of TNF-alpha was increased in miners, especially in the early stages of pneumoconiosis. Cumulative exposure was related to pneumoconiotic stage but not to release of TNF-alpha. This excluded TNF-alpha as an exposure marker. Initial concentrations (1987) of TNF-alpha were related to later progression of CWP. Miners who showed abnormally high dust stimulated release of TNF-alpha had an increased risk of progression in CWP (relative risk 8.1).


CONCLUSIONS
These results show (a) the significant involvement of TNF-alpha in pneumoconiosis in humans induced by coal dust and (b) that this routine test possibly constitutes a powerful tool to estimate individual prognosis of pneumoconiotic disease, even after the end of occupational exposure.
Schins
R P
RP
Department of Health Risk Analysis and Toxicology, University of Limburg, Maastricht, The Netherlands.
Borm
P J
PJ
D000367:Age Factors; D001530:Belgium / Q000453:epidemiology; D015415:Biomarkers / Q000032:analysis; D003031:Coal; D003032:Coal Mining; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004391:Dust; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000378:metabolism*; D016273:Occupational Exposure / Q000032:analysis*; D011009:Pneumoconiosis / Q000000981:diagnostic imaging / Q000453:epidemiology*; D011859:Radiography; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis*
D015415:Biomarkers; D003031:Coal; D004391:Dust; D014409:Tumor Necrosis Factor-alpha