Occupational airborne exposure, specific sensitization and the atopic status: evidence of a complex interrelationship

BACKGROUND: We have investigated the relationship between atopic status and long-term occupational exposure to latex proteins or methyl diethyl diisocyanate (MDI) as high and low molecular weight asthma-inducing agents, respectively. METHODS: This study is based on retrospective analyses of two groups of symptomatic outpatients: 184 healthcare workers with latex exposure and 156 workers with isocyanate (MDI) exposure. We analysed atopic and non-atopic subgroups according to exposure duration and the frequencies of specific sensitization. RESULTS: 45% of the healthcare subgroup specifically sensitized to latex were atopic, whereas in the non-sensitized healthcare subgroup only 26% were atopic. On the other hand, subjects specifically sensitized to MDI were rarely atopic (only 15%), whereas in the subgroup non-sensitized to MDI atopy was present in 38%. After prolonged durations of exposure, the proportion of atopics was further elevated in most healthcare subgroups but it decreased in the MDI-exposed subjects. CONCLUSIONS: We hypothesize that latex proteins as sensitizing agents might promote the development of atopy, whereas exposure to the low molecular weight MDI might inhibit the atopic status.