A novel polymorphism (g1344G>C ) in exon 2 of the CD14 gene

Toll-like receptors and airway inflammation

The respiratory tract opens to the external environment at the oral side edge, and the other edge of the respiratory tract connects to the closed space (alveoli), and so to preserve the sterility in the terminal respiratory tract is critical for protection against pathogens. The recognition machinery for the invasion of microbes is indispensable for the preservation of the sterility in the lungs. Our general understanding of how microbes are recognized by the innate immune system has increased considerably over the past several years, and the contribution of Toll-Like Receptors (TLRs) to innate immunity is now well documented. In the meantime, it has come to understand that many inflammatory processes may depend on TLR signaling, it has been considered to be involved in the pathogenesis of airway inflammatory diseases such as airway infections, bronchial asthma, and occupational airway diseases. In this review, we focus on physiological roles of TLRs in defense mechanisms of the airways, and pathophysiological roles on airway diseases.

Polymorphisms of the CD14 gene and atopic phenotypes in Czech patients with IgE-mediated allergy

IgE-mediated allergy is a common chronic disorder resulting from interactions between genetic and environmental factors. The gene encoding CD14 is a positional candidate gene for allergic diseases as it is localised on chromosome 5q31.1, a region linked to asthma and bronchial hyperresponsiveness. We investigated the relationship among atopic phenotypes and six polymorphisms in the CD14 gene. Polymerase chain reaction with RFLP analyses was used to determine the CD14 genotypes in subjects with IgE-mediated allergic diseases (n=282) and random controls (n=187). No significant differences in allele or genotype frequencies for individual polymorphisms between patients and controls were found. However, when atopic patients were subdivided into subjects with positive and with negative skin prick tests for separate antigens, T allele of the 1341G/T polymorphism was significantly associated with positive reactivity to mites (P=0.007) and moulds (P=0.041). Similarly, the C allele frequency of the -159C/T variant was increased in patients with positive skin prick tests for mites (P=0.046) and moulds (P=0.056). In haplotype analysis, the common -1619A/-1359G/-550C/-159C/+1188G/+1341T haplotype was associated with positive reaction to these antigens (P values: 0.0008-0.0035). Our study supports the idea that CD14 plays a role in IgE-mediated allergic diseases, and its gene polymorphisms can be important for manifestation of these disorders.

Innate immune responses to LPS in mouse lung are suppressed and reversed by neutralization of GM-CSF via repression of TLR-4

The innate immune inflammatory response to lipopolysaccharide (LPS, an endotoxin) is essential for lung host defense against infection by gram-negative bacteria but is also implicated in the pathogenesis of some lung diseases. Studies on genetically altered mice implicate granulocyte-macrophage colony-stimulating factor (GM-CSF) in lung responses to LPS; however, the physiological effects of GM-CSF neutralization are poorly characterized. We performed detailed kinetic and dose-response analyses of the lung inflammation response to LPS in the presence of the specific GM-CSF-neutralizing antibody 22E9. LPS instilled into the lungs of BALB/c mice induced a dose-dependent inflammation comprised of intense neutrophilia, macrophage infiltration and proliferation, TNF-alpha and matrix metalloproteinase release, and macrophage inflammatory protein-2 induction. The neutralization of anti-GM-CSF in a dose-dependent fashion suppressed these inflammatory indexes by 85% when given before or after LPS or after repeat LPS challenges. Here we report for the first time that the physiological expression of Toll-like receptor-4 in lung is reduced by anti-GM-CSF. We observed that lower Toll-like receptor-4 expression correlated with a similar decline in peak TNF- levels in response to endotoxin. Consequently, sustained expression of key inflammatory mediators over 24 h was reduced. These data expand the understanding of the contribution of GM-CSF to innate immune responses in lung and suggest that blocking GM-CSF might benefit some lung diseases where LPS has been implicated in etiology.

A polymorphism in the promoter of the CD14 gene (CD14/-159) is associated with the development of coronary artery lesions in patients with Kawasaki disease

OBJECTIVE

To investigate whether a polymorphism in the CD14 gene is associated with Kawasaki disease (KD).

STUDY DESIGN

We extracted DNA from the whole blood of 69 control children and 67 patients with KD. We determined a polymorphism in the CD14 gene at position -159 upstream from the major transcription site (CD14/-159) by restriction fragment assay. We then investigated the association between CD14/-159 and the onset of KD and development of coronary artery lesion (CAL).

RESULTS

The genomic and allelic frequencies of the polymorphism were not different between normal children and KD patients. The KD patients with TT genotypes at CD14/-159 had more CAL complications than those with CT and CC (OR, 4.05; 95% CI, 1.34-12.22). The frequencies of the T allele was significantly higher than that of the C allele in KD patients with CAL (OR, 2.20; 95% CI, 1.23-3.94). Their data were confirmed in the patients whether the patients were treated with intravenous gamma-globulin. KD patients with TT genotypes had significantly higher levels of C-reactive protein and vascular endothelial growth factor, which had previously been reported as risk factors for CAL, than those with CC genotypes.

CONCLUSION

These results indicate that the T allele and TT genotype at CD14/-159 are risk factors for CAL in KD, and that the development of CAL in KD may be related to the magnitude of CD14 toll-like receptor response.