Evaluation of antibody binding to diisocyanate protein conjugates in a general population.
BACKGROUND
Specific IgG binding to diisocyanate-human serum albumin (HSA) has been proposed as an indicator of diisocyanate exposure. One residential study reported IgG binding to diisocyanate conjugates in 8% of residents living near a factory using toluene diisocyanate (TDI). Because comparable assays were not performed using individuals distant from such facilities, the significance of this finding is uncertain.


OBJECTIVE
To determine the prevalence of diisocyanate specific antibodies in sera from individuals "not known to be exposed" to diisocyanates.


METHODS
Serum samples from 139 anonymous donors without known diisocyanate exposure were assayed by means of enzyme-linked immunosorbent assay for IgG or IgE specific for TDI-HSA, diphenylmethane diisocyanate (MOI)-HSA, and hexamethylene diisocyanate (HDI)-HSA. Positive responses (optical density > or = 0.1 and > or = 3 SDs above the mean of 8 laboratory controls) were run 3 times. Competitive inhibition was performed for sera exhibiting binding of optical density of at least 0.2.


RESULTS
We detected IgG reactive with HDI-HSA, diphenylmethane diisocyanate-HSA, and TDI-HSA in 18 (13%), 0, and 7 donors (5%), respectively. Inhibition (>50%) was demonstrated in 6 of 9 participants with elevated HDI-HSA levels and in 2 of 7 with elevated TDI-HSA levels. We detected IgE reactive with the same antigens in 3 donors (2%); however, none were confirmed to be positive using the biotin-streptavidin IgE assay.


CONCLUSIONS
Specific and nonspecific IgG binding to HDI-HSA and TDI-HSA were detected in individuals without known exposure to isocyanates. These antibody measurements may not be reliable indicators of diisocyanate exposure in nonoccupational populations and should not be interpreted as surrogates of diisocyanate exposure in the absence of defined referent populations.
Bernstein
David I
DI
Division of Immunology and Allergy, University of Cincinnati, Ohio 45267-0563, USA. daveib@fuse.net
Ott
M Gerald
MG
Woolhiser
Michael
M
Lummus
Zana
Z
Graham
Cynthia
C
D000293:Adolescent; D000328:Adult; D000918:Antibody Specificity / Q000276:immunology; D003485:Cyanates / Q000276:immunology*; D004781:Environmental Exposure; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood* / Q000276:immunology; D017953:Isocyanates / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000175:diagnosis; D016273:Occupational Exposure; D015995:Prevalence; D014051:Toluene 2,4-Diisocyanate / Q000276:immunology*; D001559:Benzhydryl Compounds
D003485:Cyanates; D007074:Immunoglobulin G; D017953:Isocyanates; D014051:Toluene 2,4-Diisocyanate; C015262:1,6-hexamethylene diisocyanate; C005969:4,4'-diphenylmethane diisocyanate; D001559:Benzhydryl Compounds