Conversion Rate of Leukotriene C 4 to Leukotriene E 4 Is Decreased in Children with Asthma

Abstract

Cysteinyl leukotrienes (cysLTs; LTC₄, LTD₄, and LTE₄) are important mediators in asthma. LTC₄ is metabolized to less active LTE₄ via LTD₄ by glutamyl transpeptidases and dipeptidases. The enzymatic conversion of LTC₄ to LTE₄ may be a regulatory mechanism in asthma. We examined the conversion rate of LTC₄ to LTE₄ in children it to asthma, and compared it to that in controls. After serum specimens from children with asthma were incubated with exogenous LTC₄ for 30 minutes at 37°C, the levels of LTC₄ and LTE₄ were measured by high-performance liquid chromatography. Conversion rate of LTC₄ to LTE₄ was significantly lower in children with asthma (67.6 ± 4.8 LTE₄ ng/mg of protein per minute) than controls (86.8 ± 4.4 LTE₄ ng/mg of protein per minute). The result indicates that the conversion rate of LTC₄ to LTE₄ may contribute to the pathogenesis of childhood asthma.