Bronchiectasis develops as a result of genetic and environmental factors and its etiopathogenesis is not still clear. Recent studies have revealed that inflammatory cytokines, which are formed as a result of chronic infection and inflammation, play a role in the pathogenesis of bronchiectasis. For this purpose, the level of inflammatory cytokines in bronchiectasis and the presence or absence of a genetic predisposition with the gene polymorphism of these cytokines was investigated.
Material and methods
A total of 60 patients, 40 study cases and 20 controls, which were monitored with the diagnosis of bronchiectasis were included in the study. In these individuals, cytokine levels [interleukin (IL)-6, IL-8, IL-10, and tumor necrosis factor (TNF)-α] in serum and bronchoalveolar lavage (BAL) fluid, along with the routine blood tests, were determined. Furthermore, the polymorphism in IL-6, IL-8, IL-10, and TNF-α cytokine genes and its frequency were studied in the obtained DNA by the automatic sequence analysis method and the results were compared.
It was found that in serum and BAL fluid of the patient group, the IL-8 level was high, whereas the IL-10 level was low (P<0.05). No significant difference was detected in the other cytokines (P>0.05). It was found that in cytokine gene polymorphisms IL-8 -251 A/T, IL-10 -592 A/C, and IL-10 -819 T/C genotypes are associated with increased risk of bronchiectasis. It was detected that the IL-8 -251 A/T genotype increased the risk of having the disease by 4.19 fold. (OR =4.19, 95% CI =1.24-14.17, P=0.021). The IL-10 -592 C/A genotype increased the risk of having the disease by 5.71 fold (OR = 5.71, 95% CI =1.35-24.06, P=0.017) and the IL-10 -819 T/C genotype increased the risk of having the disease by 5.06 fold (OR =5.06, 95% CI =1.20-21.27, P=0.048). No significant correlation was found between the other polymorphisms and bronchiectasis.
The IL-8, IL-10 levels and the gene polymorphism of these cytokines differ. In addition to detecting higher levels of pro-inflammatory IL-8 and lower levels of anti-inflammatory IL-10, detection of gene polymorphism related to these two cytokines in bronchiectasis gives rise to the thought that cytokines may have role in a predisposition to bronchiectasis. However, as the number of patients is small, precise remarks could not be made on this subject. There is need for further studies include a larger number of patients.