Tolllike receptor 4 (TLR4) polymorphisms in Tunisian patients with Crohn's disease: genotype-phenotype correlation

<p>Abstract</p> <p>Background</p> <p>The immune responses to bacterial products through the pattern recognition receptor (PRR) play a pivotal role in pathogenesis of Crohn's disease. A recent study described an association between CD and some gene coding for bacterial receptor like NOD2/CARD15 gene and TLR4. In this study, we sought to determine whether TLR4 gene was associated with Crohn's disease (CD) among the Tunisian population and its correlation with clinical manifestation of the disease.</p> <p>Methods</p> <p>90 patients with CD and 80 healthy individuals are genotyped for the <it>Asp299Gly </it>and <it>Thr399Ile </it>polymorphisms by restriction fragment length polymorphism analysis.</p> <p>Results</p> <p>The allele and genotype frequency of the TLR4 polymorphisms did not differ between patients and controls. The genotype-phenotype correlation permitted to show that the <it>Thr399Ile </it>polymorphism was associated with early onset disease.</p> <p>Conclusion</p> <p>this study reported the absence of association between CD and TLR4 gene in the Tunisian population, but this gene could play a role in clinical expression of the disease.</p

CARD15/NOD2, CD14 and Toll-like 4 Receptor Gene Polymorphisms in Saudi Patients with Crohn’s Disease

Crohn’s disease (CD) is a multifactorial disease with a genetic component and an observed association with genes related to the innate immune response. Polymorphisms in the CARD15/NOD2 gene, in addition to functional variants of the toll-like receptor-4 (TLR4) and CD14 genes, have been associated with the development of Crohn’s disease. There is no information about the frequency of these polymorphisms in the Saudi population. We examined the frequency of the three major CARD15/NOD2 risk alleles (Leu1007fsinsC, Arg702Trp, and Gly908Arg) and the TLR4 (Thr399Il) polymorphism as well as a functional polymorphism in the promoter of the CD14–159C/T in 46 Saudi CD patients and 50 matched controls. Genotyping was performed by allele-specific PCR or by restriction fragment length polymorphism (PCR-RFLP) analysis. The mutant genotype frequencies of the Leu1007fsinsC, Arg702Trp and Gly908Arg in the patient group were 6.5, 21.7 and 6.5%, respectively, compared with frequencies of 0, 4 and 2%, respectively, in the control group. There were 15 patients who carried the mutant alleles for all three CARD15/NOD2 variants, Leu1007fsinsC, Arg702Trp and Gly908Arg, while none of the control candidates carried the three alleles. This genetic study provides evidence that the three major CARD15/NOD2 variant alleles and the CD14 –159C/T polymorphism are associated with Crohn’s disease (CD) susceptibility in the Saudi population; however, there is no evidence that the TLR4 (Thr399Il) or CARD15/NOD2 polymorphisms can be considered risk factors for Crohn’s disease

Rôle de la cellule épithéliale dans l’homéostasie intestinale et les maladies inflammatoires chroniques de l’intestin

La maladie de Crohn (MC) et la rectocolite hémorragique (RCH) sont les principales maladies inflammatoires chroniques de l’intestin (MICI), dont l’étiopathogénie est actuellement mal définie. Au cours de ces maladies, la participation de la cellule épithéliale dans l’installation et la pérennisation de l’inflammation intestinale est de plus en plus impliquée. En effet, l’épithélium intestinal, situé à l’interface entre le milieu intérieur tissulaire et la lumière intestinale, est le pivot des mécanismes de l’homéostasie de la barrière intestinale. Cet épithélium peut être schématiquement considérée comme constitué de trois « barrières » distinctes : une barrière physique, une barrière chimique et une barrière immunitaire. Cette fonction de barrière peut être altérée par différents mécanismes physiopathologiques, comme dans les MICI. Le rôle de la cellule épithéliale dans l’homéostasie intestinale et son implication dans les MICI sont analysés dans cette revue