Human papillomavirus genotypes and HPV-16 variants distribution among Tunisian women with normal cytology and squamous intraepithelial lesions.

BACKGROUND: Little is known about the epidemiological characteristics of papillomavirus (HPV) infection among North African countries. Herein, we conducted a molecular epidemiological study to investigate prevalence of HPV type and HPV-16 variants among cervical-screened unvaccinated Tunisian women. METHODS: Cross-sectional study was performed on 494 Tunisian women visiting Women's Healthcare Centers. HPV-DNA detection was carried out on cervical samples using real-time polymerase chain reaction. HPV genotyping and HPV-16 variants were characterized by direct sequencing of L1 viral capsid gene. RESULTS: The overall HPV prevalence was 34% (95% CI: 30-38%) with significantly higher prevalence among women with squamous intraepithelial lesions (SIL) than those with no intraepithelial lesions (NIL) 84% (95% CI: 76-92%) and 24.5% (95% CI: 20-29%) respectively. The distribution of HPV prevalence according to women's age shows a U-shaped curve and the highest HPV prevalence rates were observed among the youngest (≤25 years; 51.2%, 95% CI: 37-67%) and the oldest women (>55 years; 41.7%, 95% The HPV-16 prevalence was 32.8% (95% CI: 22-45%) among women with SIL and 9.2% (95% CI: 6-12%) among women with NIL. Whereas, the HPV-18 prevalence was 1.3% (95% CI: 0-5%) among women with SIL and 0.3% (95% CI: 0-1%) among women with NIL. Among HPV-16 positive women, European lineage (E) was identified as the predominant HPV-16 variant (85.7%, 95% CI: 76-95%). The frequency of E variant was lower among SIL than among NIL women (81%, 95% CI: 64-99%, and 88%, 95% CI: 77-100%, respectively). Conversely, the African-2 variant frequency was higher among SIL than among NIL women (18%, 95% CI: 1-36% and 6%, 95% CI: 2-14%, respectively). In multivariate analysis, young age was the only risk factor that is independently associated with HPV infection. Moreover, HPV infection and menopause were both found to be independently associated with SIL and HSIL. CONCLUSION: HPV DNA testing should be proposed to young and menopausal Tunisian women. Considering HPV prevalence, only 13% of the Tunisian women could be protected by the bivalent HPV vaccine. These results may be helpful for designing an adapted HPV testing and vaccination program in Tunisia.

Lack of effect of tumor necrosis factor-alpha -308 G/A polymorphism on severity of liver fibrosis in Tunisian hepatitis C virus (HCV)-infected patients.

OBJECTIVES: Tumor necrosis factor alpha (TNF-alpha) plays a key role in the immune response. An elevated plasma level of TNF-alpha was repeatedly observed in patients with active liver injury or cirrhosis regardless of the aetiology. The G/A transition at position -308 in the promoter region have been shown to influence TNF-alpha expression. In this study, we aimed to evaluate the impact of TNF-alpha -308 G/A functional polymorphism on fibrosis severity in Tunisian Hepatitis C Virus (HCV)-infected patients. METHODS: TNF-alpha -308 G/A polymorphism was evaluated by polymerase chain reaction (PCR) amplification followed by Restriction Fragment Length Polymorphism (RFLP) method in 53 chronic hepatitis C patients. Single-nucleotide polymorphism (SNP) frequencies were compared with regard to liver fibrosis severity as assessed by the METAVIR scoring system (F1-F2; n=22 versus F3-F4; n=31). RESULTS: The genotype distribution of the TNF-alpha -308 G/A polymorphism among the HCV-infected patients was as follows : GG : 67.9%, GA : 32.1%, AA : 0%. With regard to fibrosis score, no significant differences in TNF-alpha genotype distribution were observed between F1-F2 and F3-F4 patients (p=0.15). CONCLUSION: No significant association between TNF-alpha -308 polymorphism and and the severity of liver fibrosis was found in our Tunisian cohort.

NS5A(ISDR-V3) region genetic variability of Tunisian HCV-1b strains: Correlation with the response to the combined interferon/ribavirin therapy.

In the non-structural protein 5A (NS5A) of hepatitis C virus (HCV), mutations within the interferon sensitivity-determining region (ISDR), the PKR-binding domain (PKR-BD), the variable region 3 (V3), and the interferon/ribavirin resistance-determining region (IRRDR) have been correlated with the IFN-based therapy response. In Tunisia, where a high prevalence of HCV-1b has been found, no data regarding the implication of NS5A in treatment response were available. The current study examined the relationship between the pre-treatment mutation number within ISDR, PKR-BD, V3, IRRDR, as well as in the entire ISDR-V3 region of NS5A (aa 2209-2379) and the response to the 48-week course of combined IFN plus ribavirin therapy in 15 HCV-1b-infected Tunisian patients. Referring to HCV-J sequence, a significant high genetic variability was observed within PKR-BD in the sustained virological responder patients compared to non-responders (P = 0.040). More importantly, when considering the entire region from ISDR to V3, referred to as NS5A(ISDR-V3), a clear difference in the mutation number was observed between sustained virological responders (19.6 +/- 3.16) and non-responders (15.0 +/- 1.41) (P = 0.002). Additionally, a more detailed analysis of NS5A(ISDR-V3) region revealed an elevated degree of mutation rate within the region located between amino acids 2282 and 2308 (P = 0.0006). Interestingly, an analysis of specific amino acid variations defined proline and serine at position 2300 as signature patterns for sensitive and resistant strains, respectively. The genetic variability within the NS5A region of HCV-1b strains was associated with the response to the combined IFN plus ribavirin therapy in our Tunisian cohort.

Interleukin-10 and interferon-gamma gene polymorphisms in patients with nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is a multifactorial disease. Cytokines driving the immune response seem to be disturbed in NPC patients. Since interleukin-10 (IL-10) is known to reduce the production of interferon-gamma (IFN-gamma), we supposed that genetic differences in IL-10 and IFN-gamma expression could be a mechanism by which NPC cells escape antitumour immune response. As the production of each cytokine is affected by the genetic background, we investigated the possible association between single nucleotide polymorphisms in genes of IL-10 and IFN-gamma with NPC. Different IL-10 -1082 G/A and IFN-gamma+874 Tau/Alpha genotypes were determined in 160 patients with nasopharyngeal carcinoma and 197 healthy controls. No association was found either for each SNP studied alone or for the combined analysis for both IL-10 and IFN-gamma polymorphisms among NPC patients in comparison with controls. Compared with individuals from high incidence countries, we noted huge significant differences in genotype distribution between individuals from low and intermediate NPC incidence countries. Polymorphisms of the IL-10 and IFN-gamma do not appear to be associated with NPC risk in the Tunisian population. Nevertheless, we strongly believe that the relationship between cytokines polymorphisms and NPC susceptibility deeply depends on the ethnicity.

Association of interleukin-18 polymorphisms and plasma level with the outcome of chronic HCV infection.

Hepatitis C virus (HCV) infection is the main cause of chronic liver disease throughout the world, and may progress to cirrhosis and hepatocellular carcinoma (HCC). Immunological factors, especially cytokines and some host genetic variations, rather than direct HCV action, seem to play an important role in the pathogenesis of HCV infection. Elevated levels of interleukin-18 (IL-18) were described previously for chronically (HCV)-infected patients. This study is aimed at investigating IL-18 promoter polymorphisms (-607C/A and -137G/C) in HCV-infected patients with different disease severities (chronic hepatitis C, liver cirrhosis and HCC) and establishing an association between these polymorphisms and IL-18 plasma concentration with the outcome of chronic HCV infection. The carriage of at least one C allele at position -607 (CC + CA) was associated with a higher risk of cirrhosis and HCC (P = 0.032). Compared with controls, HCV-infected patients had significantly higher levels of IL-18 (P = 0.0001) that correlate with disease severity (P = 0.01, P = 0.001, P = 0.0006, respectively). In conclusion, we supposed a possible implication of IL-18 promoter polymorphisms in the pathogenesis of chronic HCV infection.

The peroxisome proliferator activated receptorgamma2 (PPARgamma2) Pro12Ala variant: lack of association with type 2 diabetes in obese and non obese Tunisian patients.

OBJECTIVES: Peroxisome proliferator activated receptorgamma2 (PPARgamma2) is a nuclear receptor that regulates adipocyte differentiation, lipid metabolism and probably insulin sensitivity. There have been several reports on the relationship between the PPARgamma2 Pro12Ala genotype and the development of obesity or type 2 diabetes. We designed a case-controlled study to investigate the potential association of the genetic variation of the PPARgamma2 gene with type 2 diabetes in Tunisians. METHODS: We used the polymerase chain reaction and restriction enzyme digestion to characterize the variation of the Pro12Ala polymorphism of the PPARgamma2 gene in 242 unrelated Tunisian patients with type 2 diabetes and 246 healthy control subjects. RESULTS: Analysis of the Pro12Ala polymorphism of the PPARgamma2 gene in patients with type 2 diabetes and in control subjects revealed no significant differences in the PPARgamma2 allele frequencies between diabetic patients and control subjects. However the PPARgamma2 Ala12 allele was found significantly associated with a high level of systolic blood pressure in diabetic patients. Stratification of diabetic patients on obese and non obese subjects showed non significant differences in the PPARgamma2 Ala12 frequency between the two groups. CONCLUSION: These results suggest that the PPARgamma2 gene is unlikely a major gene for type 2 diabetes mellitus or obesity in Tunisian subjects.

Polymorphism of stress protein HSP70-2 gene in Tunisians: susceptibility implications in type 2 diabetes and obesity.

OBJECTIVES: Tumor necrosis factor alpha (TNFalpha) is expressed primarily in adipocytes and elevated levels of this cytokine have been linked to obesity and insulin resistance. Several studies have shown statistical evidence of linkage between obesity and the chromosomal region encompassing the TNFalpha gene, suggesting that TNF alpha and/or a nearby gene is involved in the pathogenesis of obesity. Recently we analyzed the -308 TNFalpha polymorphism and that of HSP70-2 gene in Tunisian patients with obesity and no significant difference in allele frequencies of the -308 TNFalpha polymorphism was found between obese patients and controls. In contrast, polymorphism in HSP70-2 gene was found to be highly associated with obesity. Both TNFalpha and HSP70-2 genes have been mapped within the major histocompatibility complex (MHC). We designated a case-controlled study to investigate a potential association of genetic variation of the TNFalpha and that of the heat shock protein 70-2 (HSP70-2) with type 2 diabetes. METHODS: We used the polymerase chain reaction and restriction enzyme to characterize the variation of the TNFalpha promoter region and that of the HSP70-2 gene in 280 unrelated Tunisian patients with type2 diabetes and 274 healthy control subjects. RESULTS: Analysis of the -308 TNFalpha polymorphism in patients with type 2 diabetes and in control subjects revealed that the heterozygous TNF1/TNF2 genotype was significantly less frequent in the patient group (p=0.003), suggesting that TNF1/TNF2 may be considered as a protective marker against type 2 diabetes (OR=0.58). In contrast, a significant relative risk of type 2 diabetes was found associated with the P2-HSP70-2 homozygous genotype in non obese diabetic subjects (OR=1.97; p=0.0012). CONCLUSION: These results along with those showing high frequency of P2-HSP70-2 genotype in obese Tunisians, suggest that HSP70-2 polymorphism has susceptibility implications in both obesity and diabetes.

Genetic variation in the stress protein hsp70-2 gene is highly associated with obesity.

BACKGROUND: Tumor necrosis factor-alpha (TNF-alpha) expression is increased in adipose tissue of both rodent models of obesity and obese humans. It has therefore been considered as a candidate gene for obesity. Several studies have indeed shown statistical evidence of linkage between obesity and the chromosomal region encompassing the TNF-alpha gene, suggesting that TNF-alpha and/or a nearby gene (eg hsp70 gene) is involved in the onset and progression of weight gain. We designed a case-controlled study to investigate the potential association of polymorphism of the TNF-alpha and that of a stress protein (hsp70-2) with obesity. METHODS: We used the polymerase chain reaction and restriction enzyme digestion to characterize the variation of the TNF-alpha promoter region and that of the hsp70-2 gene in 343 unrelated Tunisian patients with obesity and 174 healthy control subjects. RESULTS: Analysis of the -308 TNF-alpha polymorphism in patients with obesity and in control subjects did not reveal an association between TNF-alpha alleles and obesity. In contrast, polymorphism analysis of the hsp70-2 gene in patients with obesity demonstrated highly significant differences in genotypic distribution of this bi-allelic locus compared to the control subject group. Homozygosity for one hsp70-2 allele was highly associated with obesity (r2=7.12; P<10(-6)). CONCLUSION: Tunisian persons carrying the P2/P2 genotype of the hsp70-2 gene may have an increased risk of obesity.