Lack of immunoglobulin E response to longstanding strongyloidiasis.

Patients harbouring worm infections usually have very marked elevations of serum immunoglobulin E (IgE) concentration. However, in a group of twenty ex-Far East prisoners of war with strongyloidiasis only two (10%) had raised levels due to the worm, and these were only moderately elevated. This poor IgE response may be related to the very longstanding nature of the infection (at least 30 years). The patients may have a form of immunological incompetence, or may have become immunologically tolerant to the parasite.