[Detection of the IgE receptor CD23 in sarcoidosis]

In 30 sarcoidosis patients the soluble IgE receptor sCD23 was determined. Compared to healthy controls a marked increase of this molecule could be detected in serum (4.9 versus 0.9 ng/ml). In 19 patients who underwent bronchoscopy a strong expression of CD23 on alveolar macrophages could be demonstrated in immunochemistry compared to healthy controls (40.8 versus 12.6%). Determination of total IgE and anti-IgE antibodies did not allow discrimination between healthy controls and sarcoidosis patients. Our data suggest that alveolar macrophages are an important source for soluble CD23 in serum. CD23 expression might reflect functional activation of macrophages since our results do not appreciate a role for IgE-related reactions in sarcoidosis.