Development and utilization of a new simple assay for DNA-protein crosslinks as a biomarker of exposure to welding fumes.

A new method for DNA-protein crosslinks involving selective precipitation of DNA containing crosslinked proteins by K+ sodium dodecyl sulfate was utilized in the peripheral white blood cells of 21 male metal arc welders and in 26 male controls of similar age and racial characteristics who were not exposed to welding fumes. DNA was quantitated by Hoescht fluorescence. Although the concentration of nickel and chromium in the peripheral blood was low and did not differ between subjects in the two groups, one-fourth of the welders had levels of DNA-protein crosslinks that were above the upper limit of the controls. Mean crosslink values were 1.85% (+/- 1.14) among the welders and 1.17% (+/- 0.46) among the controls, a 58%, statistically significant difference (P = 0.01). Thus, many welders appeared to be burdened with an excess of DNA-protein crosslinks suggesting exposure to crosslinking agents and, possibly, a detectable biologic effect of potential genotoxic consequences.