Complement components and IgE in patients with asthma and aspirin idiosyncrasy.

Levels of circulating IgE, total haemolytic complement, and components C4 and C3 were measured in 16 asthmatics with aspirin idiosyncrasy and in control subjects. IgE levels were mostly within normal limits. No differences were found between the complement profiles-in particular the C4 levels-in the two groups. As low levels of C4 have been found in patients with intrinsic asthma, these results would suggest a fundamental difference between asthmatics with aspirin idiosyncrasy and others with intrinsic asthma.