Diverse Profiles of Immunoreactivity in Toluene Diisocyanate (TDI) Asthma

Abstract

Possible immunoreactivity to chemically well-characterized mono- and diisocyanate protein conjugates was reevaluated in 15 workers with TDI [toluene diisocyanate] asthma and 17 normal [nonexposed] volunteers. Lymphocytes of 9 sensitive workers were incubated with TDI human serum albumin [HSA] conjugates. Leukocyte inhibitory factor [LIF] was produced. Leukocyte inhibitory factor was induced by hexamethylene diisocyanate [HDI] protein conjugates in 4 of these workers who had no prior history of exposure to HDI. Disappearance of TDI- and HDI-induced LIF was noted in several sensitive workers who were removed from further TDI exposure. Three LIF-positive workers demonstrated positive intracutaneous reactivity to TDI-HSA. One worker had a markedly positive RAST [radioallergosorbent test] [25.5% binding] to a monofunctional [p-tolyl isocyanate] protein reagent. Isocyanates apparently have the potential for elicity heterogeneous immune responses in certain subpopulations of exposed workers. Continued contact with isocyanates may be necessary for maintenance of specific immunity. Possible cross reactivity between TDI and HDI may be determined by new antigenic sites created by isocyanate protein interactions.