Mediation of hypersensitivity reactions during hemodialysis by IgE antibodies against ethylene oxide.

Sera from 329 hemodialysis patients, 46 of whom had experienced a hypersensitivity-type reaction during hemodialysis, were screened by an enzyme-allergosorbent test (EAST) for IgE antibodies specific for ethylene oxide (ETO). In seven of nine patients who had experienced a severe hypersensitivity reaction (type II or type III), high titers of IgE antibodies against ETO (greater than 3.0 PRU/mL) were found. However, plasma levels of IgE specific for ETO were in the normal range (less than 0.35 PRU/mL) in most (30/37) patients who had experienced a mild (type I) reaction. Selected sera from patients who had experienced severe reactions were further examined for IgE directed against isopropyl myristate (IPM), 2-chloroethanol, and extracts from unsterilized dialyzers. Importantly elevated serum levels of specific IgE against these substances could not be documented. Extracts of an ETO-sterilized, hollow-fiber dialyzer were positive, whereas extracts of an ETO-sterilized dialyzer containing a flat membrane were negative in the EAST. This difference can be explained by the different amounts of ETO present in the dialyzers. We conclude that ETO causes most severe hypersensitivity reactions by an IgE-mediated mechanism. On the other hand, the pathogenesis of mild (type I) reactions is less clearly associated with ETO allergy. Our results also suggest that other potentially allergenic substances in dialyzers (e.g., IPM, 2-chloroethanol) rarely induce specific IgE antibodies in dialysis patients.