Serum Kynurenine in Bronchial Asthma and Chronic Bronchitis

Estimations of serum kynurenine were carried out in 20 normal Individuals, 20 patients with clinical evidence of chronic airway obstruction, and in 46 patients with airway obstruction in whom its presence and degree were also assessed by spirometry. The selection of patients was based on avoiding any possible cause of elevated serum kynurenine, at the same time ensuring a satisfactory state of nutrition, as well as normal liver function. The serum kynurenine mean value of the normal individuals was ± SD = 10 ± 2.29 mg percent. In the 20 patients with clinical evidence of chronic airway obstruction (no spirometry), all except one had higher serum kynurenine than the normal subjects. Of the 46 patients with clinical and spirometric evidence of chronic airway obstruction, 32 (69.6 percent) had high serum kynurenine values which were correlated with their indirect maximum breathing capacities.