Detection of IgE-mediated respiratory sensitization in workers exposed to hexahydrophthalic anhydride.

Twenty-seven workers with occupational exposure to hexahydrophthalic anhydride (HHPA) from an epoxy resin molding system were studied to evaluate the nature of their reported respiratory complaints. The workers were evaluated by questionnaire, pulmonary function tests, and serologic investigations. The presence of serum-specific IgE and IgG to an HHPA-human serum albumin (HSA) conjugate was measured by use of RAST and ELISA assays. Estimates of exposure to HHPA were made for each worker on the basis of job description and environmental sampling. Seven workers reported symptoms of asthma and rhinitis; four workers had symptoms consistent with occupational asthma. Fourteen of the remaining 20 workers reported nasal or ocular symptoms while they were at work. No worker demonstrated a significant (greater than 20%) pre-to postshift decrement in FEV1. Twelve workers had significant levels of specific IgE to HHPA-HSA; 11 had elevated levels of specific IgG to HHPA-HSA. A group of workers estimated to have higher exposures to HHPA had a significantly higher mean total IgE level (p less than 0.05) and significant titers of HHPA-HSA-specific IgE or IgG, or both (p = 0.048) as compared to a group with lower exposure to the anhydride. All four workers with occupational asthma/rhinitis had significant levels of specific IgE to HHPA-HSA (ranging from 8.7% to 23.4% RAST binding); three workers did not work directly in the HHPA area but were located in nearby sections of the plant with lower exposures to HHPA. Three workers with symptoms of asthma not clearly associated with the workplace did not have significantly elevated specific IgE levels. Another radioimmunoassay with the use of beads coated with mouse monoclonal antihuman IgE was used to quantitate the amount of specific anti-HHPA-HSA binding (range 1.0 ng to 32.6 ng/ml) present in workers' sera. The solid-phase bead radioimmunoassay was inhibited by the homologous HHPA-HSA conjugate but not by HHPA hapten alone in two workers, suggesting that these workers were sensitized to new antigenic determinants. We conclude that HHPA is a potent industrial sensitizer and is capable of inducing IgE-mediated disease. Prospective investigations are required to define the incidence and severity of clinical sensitivity.

Induction of leucocyte migration inhibitory factor (LIF) by stimulation with free hapten and water-insoluble epoxy resin.

The indirect leucocyte migration inhibition test was applied to the contact sensitivity to a hapten (dinitrofluorobenzene, DNFB) and a water-insoluble epoxy resin (Araldite). Sensitized guinea-pig leucocytes were pulsed with DNFB, which was not conjugated to a carrier protein, or with Araldite which was made particulate by ultrasonication. When these pulsed leucocytes were incubated for 24 hr, they released significant amounts of leucocyte migration inhibitory factor (LIF). The optimal dose for pulse-stimulation was 10 microgram/ml. A correlation was observed between the degree of contact sensitivity and the production of LIF.

[Patch tests performed with Epidian in workers exposed to epoxy resins]. / Wyniki prób platkowych z Epidianami u pracowników narazonych na dzialanie zywic epoksydowych

The patch tests according to the Jadassohn-Bloch's method were made with five Polish epoxy resins--"Epidian"--in 487 workers exposed to their action, and in 113 persons of the control group. The percentage of sensitized persons among 487 examined amounted to 22,8%, the results of test in the control group being negative. It has been found that particularly sensitizing action is produced by the non hardened resins (the percentage of persons sensitized in the group working at non hardened resins was 26,7, at hardening ones--2.6).

Asthma due to inhaled chemical agents--epoxy resin systems containing phthalic acid anhydride, trimellitic acid anhydride and triethylene tetramine.

Six workers with a diagnosis of occupational asthma and one with chronic bronchitis were examined for sensitivity to epoxy resin systems and certain of their components. In six cases the chemical agent responsible for their symptoms was identified by careful inhalation challenge testing, simulating their exposure at work and thus providing a precise aetiological diagnosis. In one worker asthma followed exposure to triethylene tetramine fume; four were sensitive to acid anhydrides, three to phthalic acid anhydride as a fume or powder and one to trimellitic anhydride. On worker thought to be sensitive to toluene di-isocyanate gave negative reactions to this and positive reactions to a phthalic acid anhydride epoxy resin and another thought to have asthma from acid anhydride fumes was found to be sensitive only to toluene di-isocyanate. Immediate, non-immediate or combined asthmatic reactions were elicited.