Allergen: Isocyanate HDI conjugated to a human serumalbumin (HSA) carrier.
Certain protein allergens and chemicals capable of acting as haptens occur at high concentrations in workplace environments. They represent a significant sensitization risk also for less atopic individuals due to their often high concentration in the air.
Isocyanates are widely used in the production of polyurethane plastics, glues and paints. Individuals at risk are polyurethane foam makers, upholsterers, spray painters, wire coating workers, plastic molders, rubber workers, fabric coaters, metal rod coaters, truck body insulators and persons applying artificial turf and others.
Isocyanates have been mentioned in relation to the Sick Building Syndrome.
The three isocyanates (TDI, MDI and HDI) are closely related structurally being HSA-conjugated haptens and there is some allergenic crossreactivity (1). However, the major specificity depends on the type of isocyanate exposure.
A wide spectrum of potentially allergic respiratory symptoms have been described and up to 5% of exposed workers have been reported to have developed asthma at work (2). IgE antibodies to isocyanates have been found in 14-19% of sensitised workers (1, 3).
Non-immunological, irritative mechanisms are likely to be of importance.
- Baur X: Immunologic cross-reactivity between different albumin-bound isocyanates. J Allergy Clin Immunol 1983, 71, 197-205.
- Butcher BT, Karr RM, O’Neil CE, Wilson MR, Dharmarajan V, Salvaggio JE, Weill H: Inhalation challenge and pharmacologic studies of toluene di-isocyanate(TDI)-sensitive workers. J Allergy Clin Immunol 1979, 64, 146-152.
- Butcher BT, O’Neil CE, Reed MA, Salvaggio JE: Radioallergosorbent testing of toluene di-isocyanate-reactive individuals using p-tolyl isocyanate antigen. J Allergy Clin Immunl 1980, 66, 213-216.