Circulating soluble CD27 and CD30 in workers exposed to 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD).

Previous studies suggest that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure may be associated with non-Hodgkin lymphoma (NHL) but findings remain inconclusive. There is a need for mechanistic studies to evaluate the biologic plausibility of this association. In this cross-sectional study, we investigated changes in plasma levels of interleukin 1 receptor antagonist (IL1RA) and soluble (s)CD27 and sCD30 which have been found to be predictive of lymphoma, among workers of a cohort occupationally exposed to TCDD. Eighty-five workers who had been exposed to TCDD more than 30 years before blood collection were included in the current investigation. Plasma level of the markers was measured by ELISA. Current plasma levels of TCDD were determined by high-resolution gas chromatography/isotope dilution high-resolution mass spectrometry. TCDD blood levels at time of last exposure were estimated using a one-compartment first order kinetic model. Exposure-response analyses showed no significant association between blood levels of sCD27, and sCD30 and current and estimated TCDD levels at time of last exposure. IL1RA showed a borderline significant decrease with increasing plasma TCDD levels (P = 0.07), which reached formal statistical significance when excluding subjects with chronic diseases. In conclusion, no clear dose-response relationship was observed between the measured markers and TCDD level. However, there was a suggestion that markers in particular IL1RA tended to decrease with increasing TCDD levels. This observation is consistent with our earlier observation on decreasing cytokine levels, suggesting immunosuppression, with increasing exposures. These findings possibly provide new insights in the etiology of NHL and the mechanisms through which TCDD can increase lymphoma risk.