IGE in human urine and milk.

IgE was found in urine from healthy adult volunteers at very low levels (approximately 0.003-0.010 IU/ml), corresponding to a 24-h excrection rate of 3-16 IU. IgE was not detected in 36 out of 47 samples of milk and colostrum. In samples from six women the protein was present at low concentration 1-2 days postpartum but was not detected in later samples (usually day 5 or 6). Mammary secretions from four allergic donors were studied, and IgE was detected at low concentrations in samples from the two most severely affected individuals. The levels of IgE observed in both urine and milk suggest that there is no significant synthesis of the protein in either the urinary tract or in mammary tissue.