Background: There has recently been an accumulation of evidence suggesting that endothelial cells (EC) play a crucial role in the pathogenesis of bronchial asthma. We examined the prevalence and isotypes of anti-EC antibodies (AECA) in the sera of children with asthma and determined the antigenic targets associated with AECA reactivity.
Methods: Levels of each class of AECA were determined by cellular ELISA in 156 children with asthma and in 203 control children. Sodium dodecyl sulfate– polyacrylamide gel electrophoresis and western blot analysis were performed in samples that contained high levels of AECA.
Results: In the cellular ELISA, the IgE class of AECA was detected significantly more frequently in children with asthma (25/156; 16.0%) than in healthy controls (2/203; 1.0%; P < 0.01). There were no differences in the frequencies of detection of IgG, IgA and IgM classes of AECA between patients and controls. The IgE–AECA was more frequently detected in younger children (23/69 vs 2/87 for children younger and older than 4 years of age, respectively). There was no correlation between the level of IgE–AECA and that of total IgE or house dust mite-specific IgE. In western blot analysis, IgE antibodies against a component of EC with a molecular mass of 75 kDa were detected in 20 of 25 patients (80.0%) positive for IgE–AECA, but they were less frequently detected in patients negative for IgE–AECA (2/34 (5.9%); P < 0.01).
Conclusions: These results demonstrate that a small fraction of asthmatic children has IgE–AECA and that the antigenic target of IgE–AECA is a component of the EC with a molecular weight of 75 kDa.