Tryptophane metabolism in bronchial asthma.

Seventeen out of 21 children with severe asthma had an abnormal increase in urinary Kynurenic (KA) and Xanthurenic (XA) acid following oral tryptophane administration. In a second study 11 asthmatic children had significantly greater increases in XA and KA than nine normal healthy children. A micro-assay of KA and XA by column chromatography was performed. The data suggest the presence of a partial block in the metabolism of tryptophane in some children with bronchial asthma.