Total and anti-mycobacterial IgE levels in serum from patients with tuberculosis and leprosy.

A radioallergosorbent assay (RAST) was developed and used to determine the levels of IgE antibodies to soluble antigens of Mycobacterium tuberculosis (BCG vaccine strain) in sera from patients with tuberculosis and leprosy and in healthy control subjects. Total IgE levels in the same sera were quantitated with a commercial radioimmunoassay kit. Patients with tuberculosis and leprosy had higher total and specific IgE levels than the control groups but the overlap of levels in patients and controls was too great to render the difference diagnostically useful. Specific IgE levels were elevated in both tuberculosis and leprosy patients, suggesting that this antibody response is towards the shared mycobacterial antigens. No differences in total or specific IgE levels were found between healthy hospital workers occupationally exposed to patients with tuberculosis and factory workers who are not exposed.