Dong-Ho Nahm

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

BACKGROUNDnThe role of specific IgG to toluene diisocyanate (TDI) in the pathogenesis of TDI-induced asthma still remains unclear.nnnOBJECTIVEnWe 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.nnnMETHODSnOne 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.nnnRESULTSnThe 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).nnnCONCLUSIONnThese 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.

Food allergy to meat and milk in adults

with a clinical diagnosis of ‘happy wheezers’. One child was atopic. Structural airway anomalies were found in 15 patients (44%). The final diagnosis was primary tracheoor broncho-malacia in 14 patients (42%): five had tracheomalacia alone (Fig. 1), four bronchomalacia alone, and five had TBM. Tracheomalacia was localized in the middle third (60%) and lower third (40%) of the trachea. One patient had laryngomalacia unassociated with any TBM. It is worth noting that a bronchoscopic diagnosis of TBM was reached in 9/12 (75%) of the children diagnosed as ‘happy wheezers’. Our study shows that recurrent/persistent wheezing failing to respond to conventional asthma therapy in children <3 years of age is often associated with TBM (42% of cases in our series), according with previous reports in children (2–5). The novelty of our study lies in that we investigated a subset of infants labeled as ‘happy wheezers’ – and 75% of them revealed TBM at bronchoscopy. TBM is a weakness of the trachea and mainstem bronchi such that the airway is more susceptible to collapse during expiration (Fig. 1), causing airflow limitation and wheezing that may mimic asthma (5). Mild–moderate airway malacia is a self-limiting disease, and most infants grow out of the condition by the time they are 2–3 years old (4, 5). A recent report estimated the incidence of primary airway malacia to be at least 1/ 2100 children (4), supporting the conviction that TBM is underdiagnosed. In accordance with previous studies, we believe that FB is a safe and useful tool for achieving a definitive diagnosis and preventing any inappropriate asthma treatment (1, 4). Limits of our study are that the results cannot be generalized to all wheezing young children, because we studied a highly selected group, and that we cannot rule out the possibility of TBM and asthma coexisting in the same child. In conclusion, this study suggests that TBM is quite a common airway anomaly in children with recurrent/ persistent wheezing failing to respond to conventional asthma therapy. We also suggest that many infants diagnosed as ‘happy wheezers’ may, in fact, have underlying tracheobronchomalacia.