Use of haptenizing ELISA to evaluate respiratory disease in a worker exposed to capacitor-coating powder

We were asked to evaluate respiratory disease in a worker exposed to a powder containing unidentified components that was heated and used to coat capacitors. Because the powder was used as a coating material, we hypothesized that the capacitor-coating powder (CCP) contained either an anhydride or an isocyanate. We modified the initial step of a standard ELISA so that we could use CCP as a hapten in this assay. With this modified ELISA technique and inhibition analysis with antisera of known specificity, we determined that CCP contained a substance that cross-reacted with trimellitic anhydride. Later, we confirmed from the manufacturer that it contained benzophenone tetracarboxylic dianhydride. With the modified ELISA assay we also determined that the worker we were to evaluate did not have antibody to CCP or trimellitic anhydride. From clinical and immunologic evaluation we diagnosed chronic obstructive lung disease. Thus, this modified assay has proved useful in the evaluation of a worker exposed to a powder whose contents were not initially known and may prove useful in immunologic evaluation of workers in other industrial settings.