Clinical and immunologic evaluation of trimellitic anhydride workers in multiple industrial settings

Abstract

This article describes our clinical and immunologic experience in assessing workers exposed to trimellitic anhydride (TMA) in three industrial settings. Since 1977 we have been engaged in a prospective study of workers involved at the site of manufacture of TMA. These studies demonstrate that serologic measurements of total antibody to trimellityl human serum albumin (TM-HSA) and IgE antibody to TM-HSA are predictive of the development of an immunologically mediated respiratory illness and are useful in monitoring workers removed from TMA exposure, in identifying asymptomatic workers who may be at risk in the future, and in defining the nature of sensitization of the workforce. In a different industrial setting, we have been able to study workers who mixed previously manufactured TMA powder with epoxy resins. This study indicated that clinical assessments by a plant physician with a standardized questionnaire, along with serologic tests, could establish the presence or absence of an immunologic respiratory illness caused by the inhalation of TMA dust. In a third industrial situation, workers were exposed to both TMA and phthalic anhydride (PA). Here workers were interviewed by a local physician with minimal experience with TMA-related respiratory illness. In this situation a more detailed questionnaire was utilized, along with serologic tests utilizing the enzyme-linked immunosorbent assay to establish the presence of a TMA- or PA-related syndrome. Immunologic studies demonstrated in workers exposed to both TMA and PA that the antibody responses elicited showed little crossreactivity between antibodies directed against TM-HSA or PA-HSA.