Decreased plasma CC16 levels are associated with the A38G polymorphism and asthma

Polymorphisms in several genes have been associated with asthma. However, few affect protein level or function. The A38G polymorphism in the Clara cell secretory protein (CC16) gene has been associated with an increased risk of asthma and increased airway responsiveness. Aim: To investigate whether plasma CC16 levels in children were associated with A38G genotype and asthma. Methods: PCR and restriction digestion identified the A38G genotype of 130 asthmatic and non-asthmatic children (aged 1-17). Plasma CC16 levels were analysed using a sensitive latex immunoassay. Results: Mean plasma CC16 levels adjusted for age and gender, were lower in asthmatic (7.96 M-g/l; 95% Cl= 5.83-10.08) than nonasthmatic subjects (9.98μg/l; 95% Cl=7.86-12.06) (p=0.006). Plasma CC16 levels were also significantly lower in subjects with 38A/38A compared to 38G/38G and 38A/38G Plasma CC16 levels*Adjusted Mean (ng/l) 1)5% CI p 38A/38A 6.79 4.56-9.02 38A/38G 9.17 7.07-11.28 0.022 38G/38G 10.01 7.90-12.12 0.003 # All analyses adjusted for age and gender and 38A/38A set as baseline Conclusions: The results of this study show that the 38A sequence is associated with reduced plasma CC16 levels and that individuals with lower plasma CC16 levels are more likely to have asthma. This is further evidence for the role of the 38A allele in the development of asthma.