RAST-detection of specific IgE in diphenylmethane diisocyanate exposed workers: considerations in performance of the test.
Some parameters which might affect RAST results, i.e. incubation length, degree of ligand substitution, and total IgE levels, were examined in a RAST system employing diphenylmethane diisocyanate--human serum albumin (MDI-HSA) conjugates as antigens, both in exposed symptomatic and in non-exposed subjects. The reaction equilibrium was reached after 9 and 18 h. respectively, in the first and the second step of the test. A marked correlation with the degree of ligand substitution was observed, the highest sensitivity being achieved with the lowest (2.9) MDI/HSA molar ratio examined. Higher (up to 50) degrees of substitution resulted in progressively lower levels of radioactivity bound and in a loss of specificity, as confirmed by RAST inhibition experiments. At high levels of ligand substitution, high titers of total serum IgE affected RAST results.
Spiazzi
A
A
Institute of Immunological Sciences, University of Verona, Italy.
Boccagni
P
P
Germano
P
P
Pezzini
A
A
D001249:Asthma / Q000139:chemically induced / Q000175:diagnosis* / Q000276:immunology; D003485:Cyanates / Q000009:adverse effects*; D006801:Humans; D007073:Immunoglobulin E / Q000032:analysis*; D017953:Isocyanates; D008024:Ligands; D009784:Occupational Diseases / Q000139:chemically induced / Q000175:diagnosis* / Q000276:immunology; D011852:Radioallergosorbent Test / Q000379:methods*; D012680:Sensitivity and Specificity; D012709:Serum Albumin / Q000276:immunology; D013997:Time Factors; D001559:Benzhydryl Compounds
D003485:Cyanates; D007073:Immunoglobulin E; D017953:Isocyanates; D008024:Ligands; D012709:Serum Albumin; C005969:4,4'-diphenylmethane diisocyanate; D001559:Benzhydryl Compounds