Expression of human beta defensin (HBD-1 and HBD-2) mRNA in nasal epithelia of adult cystic fibrosis patients, healthy individuals, and individuals with acute cold.

Background: Lack or inactivation of defensins may facilitate chronic bacterial colonization in the cystic fibrosis (CF) lung. CF nasal epithelium exhibits typical biochemical abnormalities and can be used to study defensin expression in CF.

Objectives: To evaluate the expression of beta defensin (HBD-1 and HBD-2) mRNA and the presence of inflammatory markers (percentage of neutrophils and IL-8 mRNA expression) in CF and non-CF nasal mucosa.

Methods: Case-control study. Nasal brushing samples were obtained from 22 stable adult CF patients and 32 non-CF controls (25 healthy individuals and 7 individuals with acute cold). Samples were subjected to analysis involving mRNA expression (semiquantitative RT-PCR) and differential cell counting.

Results: Defensins and inflammatory markers were expressed at low levels in healthy individuals and at high levels in subjects with acute cold. In non-CF controls, defensin expression correlated significantly with inflammatory parameters (p < 0.001). In CF, defensin mRNA expression was comparable to healthy individuals (p = 0.2). In contrast to non-CF controls, in CF patients high levels of inflammatory markers did not correlate with defensin mRNA levels.

Conclusions: Defensin expression is not upregulated in CF epithelium in response to inflammatory stimuli. Further studies are necessary to elucidate whether this is a consequence of the CF gene mutation.