Circulating immunoglobulin levels in patients with pulmonary tuberculosis with special reference to IgE

This study has demonstrated high levels of circulating IgE in a group of patients with pulmonary tuberculosis compared with a control group. There was little or no specific binding of circulating IgE to M. tuberculosis but when the serum was heated to 56 degrees C for 1 hour 5/20 of the patients investigated showed appreciable levels of binding. It is suggested that the IgE which binds to M. tuberculosis exists in a heat-labile complex with an anti IgE antibody and that this complex formation may represent a protective host mechanism.