Study of employees with anhydride-induced respiratory disease after removal from exposure

The purpose of this study was to determine the clinical and immunologic status of hexahydrophthalic anhydride (HHPA)-exposed employees who had developed an immunologic respiratory disease and who have been removed from exposure for at least 1 year. In a surveillance study spanning 4 years, we identified 28 employees with HHPA-induced immunologic respiratory disease who had been removed from exposure for at least 1 year. Seven had asthma, nine had hemorrhagic rhinitis, four had both, and eight had allergic rhinitis alone. Respiratory symptoms were assessed by physician-administered questionnaires. For each employee, a physical examination, spirometry, and chest roentgenograph were performed. Antibody against HHPA conjugated to human serum albumin (HHP-HSA) was measured using an enzyme-linked immunosorbent assay. Symptoms, signs, and spirometry normalized in all but one employee. There were no chest-roentgenograph findings at follow-up that could be attributed to HHPA. There was a decline in antibody liter for both immunoglobulin E and G against HHP-HSA. In this group of 28 employees, there was only one employee with mild asthma after removal from exposure for at least I year. Although specific antibody was still present in many, the titers were generally lower at follow-up than at presentation.