Cross sectional study on cytokine production (TNF-α, IL-8) in German coalminers with progressive massive fibrosis and in control miners using a rapid wholeblood assay.

Whole-blood release of tumour necrosis factor (TNF-α) and interleukin 8 (IL-8) was studied in 26 German ex-coalminers with progressive massive fibrosis (≥A, ILO 1980; cases) and 26 ex-miners free of pneumoconiosis (≤ 0/1; controls) using a simple wholeblood assay. Cases and controls were matched individually by age and duration of coalmine dust exposure (5-year window). Whole-blood cytokine release was determined (blinded to case control status) in incubations without additions (spontaneous) and with endotoxin (LPS, 3 ng ml(-1)) or with coalmine dust (CMD; 5 mg ml(-1)). CMD-stimulated TNF-α release was significantly increased and LPS-induced IL-8 release was significantly decreased in cases (matched t-tests: p < 0.01). No effect of duration of exposure was detectable in an unmatched analysis. No clear relationship with lung function parameters independent from case/control-status was observed, although a possible positive association with central airway resistance was indicated by multiple regression for both CMD stimulated TNF-α and LPS-stimulated IL-8. This study on individually matched coalminers validates previous findings on monocyte TNF release as a marker for pneumoconiosis using a method (whole-blood assay) that is more feasible for epidemiological studies. The different response of TNF-α and IL-8 may be useful in studying the occurrence of different endpoints like pneumoconiosis and lung function decrease.