Specific IgG, but not specific IgE, antibodies to toluene diisocyanate-human serum albumin conjugate are associated with toluene diisocyanate bronchoprovocation test results.

Background: The role of specific IgG to toluene diisocyanate (TDI) in the pathogenesis of TDI-induced asthma still remains unclear.
Objective: We sought to evaluate the clinical significance of serum-specific IgG to TDI-human serum albumin (HSA) conjugate in subjects with TDI-induced asthma compared with specific IgE antibody.
Methods: One hundred three subjects were enrolled and divided into 4 groups according to specific bronchoprovocation test (BPT) results: 50 subjects with TDI-induced asthma with positive results on TDI BPT were defined as group 1, 13 symptomatic workers exposed to TDI with negative results on TDI BPT were defined as group 2, 20 unexposed patients with allergic asthma were defined as group 3, and 20 unexposed healthy control subjects were defined as group 4. Serum-specific IgG and IgE antibodies to TDI-HSA conjugate were detected by means of ELISA.
Results: The prevalence of specific IgG antibody to TDI-HSA conjugate was significantly higher in group 1 than in group 2 (46% vs 7.7%, P =.01) or group 3 (0%, P <.01). No significant difference was noted between group 2 and group 3 (P >. 05). However, the prevalence of specific IgE antibody to TDI-HSA conjugate was not significantly different between group 1 and group 2 (14% vs 7.7%, P >.05) or group 2 and group 3 (7.7% vs 0%, P >.05). There was no significant difference in prevalence of specific IgE or specific IgG according to the type of asthmatic response during the TDI BPT (P >.05). Overall, statistically significant association was noted between the prevalence of specific IgE and IgG antibodies in 103 subjects (P <.05), but no difference was noted within group 1 subjects only (P >.05).
Conclusion: These findings demonstrate that the presence of serum-specific IgG is closely related to TDI BPT results, and it may contribute to the development of TDI-induced asthma.