MULTIPLE IGE-MEDIATED SENSITIZATIONS TO ENZYMES AFTER OCCUPATIONAL EXPOSURE - EVALUATION BY SKIN PRICK TEST, RAST, AND IMMUNOBLOT

We investigated 10 sensitized and 10 nonsensitized workers from a phar maceutic factory who had been exposed to powdered trypsin, chymotrypsi n, bromelain, papain, amylase, and lipase. Ten nonallergic subjects se rved as a control group. Titrated skin prick tests (SPT), RAST, and im munoblot studies were performed with all six enzymes. SPT reactivity r evealed multiple sensitizations to proteolytic enzymes, i.e., papain ( specifically sensitized/total number of sensitizations: 9/10), trypsin (8/10), chymotrypsin (8/10), and bromelain (7/10) and appeared to be more frequent and more pronounced than sensitizations to amylase (3/10 ) or lipase (3/10). The low molecular weight of proteolytic enzymes (2 0-30 kDa) and their biologic activity might facilitate mucosal penetra tion more easily and thus - compared to amylase and lipase - permit an immune response and induction of allergic hypersensitivity. Immunoblo t studies demonstrated IgG-binding bands in both SPT-positive and -neg ative workers, indicating exposure to the enzymes, but not in 10 unexp osed control subjects. IgE-binding bands of the enzymes were detected only in workers with a positive SPT reaction and/or a positive RAST re sult. IgG bands were more frequent and the IgG/IgE ratio was increased in workers without allergic complaints compared to symptomatic worker s. This might indicate that high levels of specific IgG antibodies to enzymes are associated with an immune response lacking allergic manife stations in spite of IgE-mediated sensitizations to the enzymes. Atopi c subjects were at greater risk of developing IgE-mediated sensitizati on (7/10) and allergic symptoms to enzymes (5/7). However, even withou t risk of atopy, IgE-mediated hypersensitivity occurred in a few subje cts (3/13) exposed to enzymes by inhalation for prolonged periods of t ime.