Exposure-response relationships in the formation of specific antibodies to hexahydrophthalic anhydride in exposed workers

OBJECTIVES--Exposure-response relationships in the formation of specific antibodies to hexahydrophthalic anhydride (HHPA) was studied in exposed workers. METHODS--The relation between exposure to HHPA and the levels of specific immunoglobin E [(radioallergosorbent test (RAST)] and immunoglobin G (enzyme-linked immunosorbent assay) antibodies was investigated in a cross-sectional study on 95 workers from two plants using epoxy resin with HHPA as a hardener; the mean time of exposure was 7 (range 0.1-25) years. RESULTS--The specific immunoglobin E and immunoglobin G was significantly increased in exposed workers when they were compared with unexposed workers or external referents. There was no significant difference in the number of RAST positives [N = 23 (24%)] between the groups of workers exposed to or = 50 micrograms.m-3. No effects were found of atopy or smoking habits on the prevalence of RAST positives. Five out of seven workers positive for immunoglobulin E in the group with the lowest exposures reported frequent short-time (minutes per day) exposures exceeding 50 micrograms.m-3. A correlation was seen between specific immunoglobulin E and G antibodies (rs = 0.5). CONCLUSIONS--The results indicate that HHPA is a sensitizing compound even at low exposure levels and that short-time peak exposures may have an impact on immunoglobulin E sensitization