Association of Fas/Apo1 gene promoter (-670 A/G) polymorphism in Tunisian patients with IBD

AIM: To detect a possible association between the polymorphism of the (-670 A/G) Fas/Apo1 gene promoter and susceptibility to Crohn's disease (CD) and ulcerative colitis (UC) in the Tunisian population. METHODS: The (-670 A/G) Fas polymorphism was analyzed in 105 patients with CD, 59 patients with UC, and 100 controls using the polymerase chain reaction restriction fragment length polymorphism method. RESULTS: Significantly lower frequencies of the Fas -670 A allele and A/A homozygous individuals were observed in CD and UC patients when compared with controls. Analysis of (-670 A/G) Fas polymorphism with respect to sex in CD and UC showed a significant difference in A/A genotypes between female patients and controls (P corrected = 0.004 in CD patients and P corrected = 0.02 in UC patients, respectively). Analysis also showed a statistically significant association between genotype AA of the (-670 A/G) polymorphism and the ileum localization of the lesions (P corrected = 0.048) and between genotype GG and the colon localization (Pcorrected = 0.009). The analysis ofinflammatory bowel disease patients according to clinical behavior revealed no difference. CONCLUSION: Fas-670 polymorphism was associated with the development of CD and UC in the Tunisian population.

Cytokine and apoptosis gene polymorphisms influence the outcome of hepatitis C virus infection

BACKGROUND:Hepatitis C virus (HCV) infection is thought to be chronic and the factors leading to viral clearance or persistence are poorly understood.This study was undertaken to investigate the possibility of a significant relationship between the spontaneous clearance or the persistence of hepatitis C virus (HCV) infection and cytokine and apoptosis gene polymorphisms in Tunisian patients on hemodialysis.METHODS:Polymorphisms of the genes IL-1 (-889 IL-1α,-511 and +3954 IL-1β,IL-1Ra),IL-18 (-137 and-607),IL-12 (-1188) and Apo1/Fas (-670) were determined by PCR-RFLP,PCR-SSP and PCR-VNTR in 100 healthy blood donors and 100 patients infected with HCV and undergoing hemodialysis.The patients were classified into two groups:G1 consisted of 76 active chronic hepatitis patients (positive for HCV RNA) and G2 consisted of 24 hemodialysed patients who spontaneously eliminated the virus (negative for HCV RNA).RESULTS:The frequency of genotype association [-137GC/-607CA] IL-18 was higher in G2 (41.7%) than in G1 (15.8%) (P=0.008;OR=0.26;95% CI,0.10-0.73).We also found a higher frequency of the AA genotype of the Apo1/Fas gene in G2 (41.6%) than in G1 (17.5%) (P=0.026;OR=3.49;95% CI,1.13-10.69).Adjustment for known covariate factors (age,gender and genotype) confirmed these univariate findings and revealed that the genotype association GC-CA of the (-137 and-607) IL-18 gene and the AA genotype of the Apo1/Fas gene were associated with the clearance of HCV (P=0.041 and 0.017,respectively).CONCLUSION:The two genotypes GC-CA of the (-137 and-607) IL-18 polymorphism and the AA genotype of the Apo1/Fas gene influence the outcome of HCV infection in Tunisian patients on hemodialysis.

Natural evolution of hepatitis C virus infection in hemodialysis Tunisian patients and CTLA-4 SNP's

AIM: To analyze the polymorphisms of CTLA-4 gene involved in the response against hepatitis C virus(HCV) infection.METHODS: We recruited 500 hemodialysed patients from several hemodialysis centers, all HCV-antibody positive, spread over different regions of Tunisia, as part of a national survey in 2008 conducted in the laboratory of immunology at the Charles Nicolle hospital Tunisia, classified into two groups G1(PCR+) and G2(PCR-) according to the presence or absence of viral RNA. Of these patients, 307 were followed prospectively on a viral molecular level over a period from 2002 to 2008, divided into two groups based on the persistence and viral clearance. PCR-RFLP was performed for the analysis of SNPs(+49) A/G and(+6230) G/A CTLA-4 for these 500 patients and 358 healthy controls.RESULTS: Analysis of clinical and virological charac-teristics of our cohort suggests a nosocomial infection in our hemodialysed patients with transfusion history as a primary risk factor and a predominance of genotype 1b. The haplotype analysis revealed an increase of frequencies of GG(+49)/(CT60) CTLA-4 in the entire patients group compared to controls(P = 0.0036 and OR = 1.42; 95%CI: 1.12-1.79, respectively). This haplotype is therefore associated with susceptibility to HCV infection. CONCLUSION: Our study suggests a possible role of CTLA-4 polymorphisms in the outcome of HCV infection in the Tunisian hemodialysed population.

Lymphoid tyrosine phosphatase R620W variant and inflammatory bowel disease in Tunisia

AIM:To assess the possible association between PTPN22(R620W) gene polymorphism and inflammatory bowel disease(IBD).METHODS:One hundred and sixty-four patients with IBD 105 Crohn's disease(CD) and 59 ulcerative colitis(UC) and 100 healthy controls were recruited.Genotyping of the PTPN22 gene 1858C→T polymorphism was performed by restriction fragment length polymorphism-polymerase chain reaction with Rsa Ⅰ digestion.RESULTS:The genotypic and allelic frequencies of(R620W) PTPN22 gene polymorphism reveal a significant association of the PTPN22 620-W allele with IBD,compared to the healthy control group(OR:17.81,95% CI:4.18-21.86,P = 0.00001).Nevertheless,nodifference in this polymorphism was found between CD and UC patients.No significant association was found between the frequencies of genotypes of the PTPN22 gene with either the clinical features such as sex,age,age at disease onset,and extent of colitis,or the production of serological markers(anti-Saccharomyces cerevisiae antibody in CD and perinuclear anti-neutrophil cytoplasmic antibody in UC).CONCLUSION:These observations confirm the association of IBD susceptibility with the PTPN22 1858T(620-W) allele in Tunisian patients.