Immune reactivity to mite allergens in nonatopic subjects: immune deviation or immune ignorance

Most subjects without IgE to Dermatophagoides pteronyssinus do not have IgG to Der p 1 or Der p 2 (as measured by RIA). However, by immunoblot or ELISA, IgG reactivity (mostly IgG1) to mite components is easily detectable. This discrepancy is caused largely by immune reactivity to mite components with a high molecular weight under native conditions (possibly mite gut flora cross-reactive with human gut flora) and partially by the presence of IgG with low affinity for fluid-phase antigen. We conclude that the pattern of IgG antibody in subjects without IgE to mites does not support the notion of immune deviation, but rather indicates a lack of a mite-induced high-affinity immune response.