TLR4 Polymorphisms (T399I/D299G) Association with Schizophrenia and Bipolar Disorder in a Tunisian Population.

Immune dysregulation has been widely described in the pathophysiology of schizophrenia (SCZ) and bipolar disorder (BD). Particularly, TLR4-altered activation was proposed as one of the underlying processes of psychosis onset. Since TLR4 activation was altered by T399I and D299G polymorphisms, we hypothesized that those variants could present common genetic factors of SCZ and BD. A total of 293 healthy volunteers and 335 psychotic patients were genotyped using PCR-RFLP. Genotype, allele, and haplotype distribution between controls and patients were evaluated according to clinical parameters. Statistical analyses were adjusted by logistic regression. In dominant model, T399I CT + TT and allele frequency were significantly higher in controls compared to psychotic population (p = 0.004, p = 0.002, respectively), SCZ (p = 0.02, p = 0.01, respectively), and BD (p = 0.03, p = 0.02, respectively). Similarly, D299G AG + GG and allele frequency were significantly higher in controls compared to psychotic population (p = 0.04, p = 0.04, respectively) and SCZ (p = 0.04, p = 0.03, respectively). T399I CT + TT and T allele were overrepresented in controls compared to paranoid subgroup (Padjusted = 0.04, p = 0.04, respectively) and type I BD (p = 0.04). Moreover, T399I and D299G were less prevalent in SCZ late-onset age (p = 0.03, p = 0.02, respectively). TA haplotype was associated with protection from psychoses (p = 0.02) and particularly from schizophrenia (p = 0.04). In conclusion, TLR4 polymorphisms could present a preventive genetic background against psychoses onset in a Tunisian population. While T399I could be associated with protection against SCZ and BD, presenting an overlapping genetic factor between those psychoses, D299G was suggested to be associated with protection only from schizophrenia.

Association between polymorphisms of TLR2-1-6 and bipolar disorder in a tunisian population.

BACKGROUND: Bipolar disorder (BD) is a complex neuropsychiatric disease that has been strongly linked to immune dysregulation. In particular, an abnormal inflammatory response mediated by toll-like receptor 2 - 1/6 (TLR2-1/6) was described in BD. Nevertheless, genetic factors' contribution is still unknown. Thus, we suggested that functional polymorphisms of TLR2, 1 and 6 could be involved in BD predisposition. METHODS AND RESULTS: TLR2, 1 and 6 polymorphisms were genotyped by PCR-RFLP in 292 controls and 131 patients from a Tunisian population. Polymorphisms and haplotype associations were explored in BD and binary logistic regression analysis was performed for more powerful associations. In dominant model, we found a significantly higher genotype and minor allele frequencies in healthy females compared to patients for TLR2-196-174Ins/Del (p = 0.04; OR = 0.3, p = 0.04; OR = 0.3, respectively) and for TLR6-S249P only with minor allele (p = 0.03; OR = 0.2). In contrast, TLR2-R677W CT + TT and T allele frequencies were significantly higher in BD (padjusted<10- 4; ORadjusted =46.6, p < 10- 4; OR = 6.3, respectively), specifically in females (CT + TT: 100%). Similarly, TLR1-R80T showed significantly increased GC + CC and C allele frequencies in patients compared to controls (padjusted=0.04; ORadjusted=4, p = 0.009; OR = 4.3, respectively). Moreover, haplotype investigation demonstrated that InsGTCGT (p < 10- 4, OR = 275) and delGCCGT (p = 0.03, OR = 18.5) were significantly overrepresented in BD patients compared to controls. CONCLUSIONS: We suggest that TLR2-196-174Ins/Del and TLR6-S249P could be protective factors of females against BD. However, TLR2-R677W and TLR1-R80T could be strongly associated with higher risk of BD. Interestingly, TLR2-R677W could be a genetic marker for BD in females. However, further studies with larger groups are needed to confirm these findings.

Association of VEGF-A and KDR polymorphisms with the development of schizophrenia.

AIM: Several approaches indicate different blood flow disturbances in schizophrenia. VEGF-A is widely recognized as one of the key molecules involved in the angiogenesis process through mainly its receptor KDR. The current work was designed to investigate the potential association between three polymorphisms (rs699947; rs833061 and rs3025039) in VEGF-A gene and two SNPs (rs2305948 and rs1870377) within KDR gene and predisposition to schizophrenia among the Tunisian cohort. METHODS: We carried-out a case-control study composed of 200 patients with schizophrenia and 200 healthy subjects using PCR-RFLP. RESULTS: Of all analyzed polymorphisms, only rs833061, rs3025039 and rs1870377) showed a significant risk for schizophrenia (PAdjusted = 0.04, PAdjusted=<0.001, PAdjusted = 0.005 respectively). Following the stratified analysis, rs3025039 was more prevalent among undifferentiated form (PAdjusted=<0.001) and more specifically with male sex (PAdjusted=<0.001). Yet, rs1870377 was correlated with paranoid subtype (PAdjusted = 0.002) and particularly with male sex (PAdjusted = 0.005). We found also that rs699947 is associated to negative symptoms before and after treatment (P = 0.004; P = 0.001 respectively) and rs3025039 had an impact on positive and negative symptoms only after treatment (P = 0.03; P = 0.008 respectively). Haplotype analysis revealed a strong LD between rs833061 and rs3025039 only for controls and undifferentiated patients (P = 0.005). Moreover, the rs699947*C âˆ¼ rs833061*T âˆ¼ rs3025039*T haplotype, with only one mutated allele rs3025039*T, conferred a high risk to schizophrenia (P = 0.016) and, in particular, to undifferentiated and paranoid forms (P = 0.03; P = 0.02 respectively). Among the last-mentioned subgroup, we noticed another overrepresented haplotype (rs699947*A âˆ¼ rs833061*T âˆ¼ rs3025039*T; P = 0.01). Furthermore, the rs2305948*G âˆ¼ rs1870377*T haplotype carrying the minor allele rs1870377*T displayed increased frequencies in the whole group of patients and particularly among paranoid subtype (P = 0.013; P=<0.001 respectively). CONCLUSION: Our results show that all SNPs associated with the development or the severity of schizophrenia, were subsequently correlated with a decrease in the VEGF-A levels or influence KDR binding affinity. These data need to be strengthened by further independent analyses.

A Preventive Role of RANTES Genetic Variation against Undifferentiated Schizophrenia.

AIM: Due to conflicting data from relevant studies, evidence for chemokine alterations in the pathophysiology of schizophrenia (Scz) remains inconclusive. Thus, we aimed to investigate the impact of rs2107538, rs2280788, and rs2280789 polymorphisms in CCL5 gene, as well as rs333 within CCR5 gene and the development of Scz in a Tunisian cohort. METHODS: We performed a case-control study composed of 200 patients and 200 controls using RFLP-PCR. RESULTS: Among the analyzed polymorphisms, only rs2107538 imparted protection against Scz and more specifically to male sex. This protective effect remained valid for the undifferentiated form. Moreover, this SNP had an impact on patients' symptomatology. When focusing on haplotypes, we noticed that the rs2107538-rs2280788-rs2280789 ACT genetic combination, with only one mutated allele rs2107538A, displayed reduced frequency in both Scz (as a whole group) and undifferentiated subtype. The haplotype distribution profile implies that the A allele at rs2107538 could induce a protective effect by increasing RANTES production. CONCLUSION: Additional independent analyses are required to corroborate these findings and elucidate the functional implications of the discovered preventing genotypes and haplotypes in Scz.

Association between TLR2 polymorphisms (- 196-174 Ins/Del, R677W, R753Q, and P631H) and schizophrenia in a Tunisian population.

Since immune dysregulation has been well studied in schizophrenia pathophysiology, recent studies showed a potent role of TLR2 in neuroinflammation process underlying schizophrenia pathogenesis. However, the genetic predisposition is still unclear. Thus, we hypothesized that TLR2 polymorphisms - 196-174 Ins/Del (rs111200466), R753Q (rs5743708), R677W (rs121917864), and P631H (rs5743704) could be involved in schizophrenia predisposition. A case-control study was performed on a Tunisian population composed of 250 healthy controls and 250 patients genotyped by PCR-RFLP. Genotype and allele distribution were evaluated with sex, schizophrenia subtypes, and other clinical features. We also assessed a haplotype analysis for TLR2 polymorphisms with schizophrenia. Our results showed higher ins/del genotype frequency in healthy women compared to patients (p = 0.006; OR = 0.2). In the other hand, logistic regression showed higher ins/del genotype frequency in controls compared to paranoid patients (p = 0.05; OR = 0.48, adjusted). Frequencies of CT and T allele of R677W were significantly higher in patients compared to controls (p < 10-4, OR = 10.39; p < 10-4, OR = 4, adjusted, respectively). R753Q polymorphism was exclusively detected in patients (GA + AA = 2.5%) particularly in men with disorganized subtype. P631H did not show any association with schizophrenia. Finally, haplotype analysis showed that InsGTC and delGTC were associated with higher risk of schizophrenia (p = 0.0001, OR = 8.58; p = 0.04, OR = 5.01, respectively). In the Tunisian population, our results suggested that TLR2 R677W could be associated with susceptibility for schizophrenia, while - 196-174 Ins/Del suggested a trend of protection in women. Otherwise, R753Q could have an effect on schizophrenia especially for disorganized subgroup.

Inteurleukin-8 gene variations and the susceptibility to schizophrenia.

The relevance of Interleukin-8 (IL-8) cytokine alteration in the peripheral and central system has been widely shown in psychosis while variation in the IL-8 gene remains largely unexplored and to the best of our knowledge, IL-8 polymorphisms have never been specifically targeted in Schizophrenia (Scz). Thus, we set out to search a potential correlation between rs4073, rs2227306 and rs1126647 polymorphisms in IL-8 gene and the development of Scz in a sample of the Tunisian population in a candidate gene approach. Targeted polymorphisms were analysed in 206 patients and 195 controls using PCR-RFLP method. Among all analysed polymorphisms, only rs1126647 showed a significant risk for Scz. After stratification analysis, we noted a significant association of TT genotype and T allele at rs1126647 with paranoid form, and more specifically with female sex. We find that the rare haplotypes at rs4073-rs2227306-rs1126647 of TTT, ACT and TCT, each containing the risk allele rs1126647T, were associated with increased risk for paranoid Scz while only the TCT combination constituted a risk factor for Scz more generally. Our findings support that IL-8 gene may be involved in susceptibility to Scz but this still preliminary and needs to be strengthened by further independent analyses.

Haplotypes of TNFα/ß Genes Associated with Sex-Specific Paranoid Schizophrenic Risk in Tunisian Population.

Several medical research findings have announced a strong association between the biology of cytokines and various brain activities. Since growing evidences suggest the crucial and complex role of the tumor necrosis factor in the CNS, we have hypothesized that functional genetic variants of the LTA and TNFA genes (LTA +252A/G (rs909253) and TNFA -857C/T (rs1799724) and TNFA -238G/A (rs361525)) may be involved in the predisposition to schizophrenia. This research is based on a case-control study. The RFLP-PCR genotyping was conducted on a Tunisian population composed of 208 patients and 208 controls. We found a strong significant overrepresentation of the minor alleles (G, T, and A, respectively) in all patients compared with controls (p = 0.003, OR = 1.55; p = 0.005, OR = 1.78; and p = 0.0001, OR = 1.74, respectively). This correlation was confirmed for male but not for female patients. Interestingly, the frequencies of the minor alleles were significantly more common among patients with paranoid schizophrenia when compared with controls (p = 0.003, OR = 1.75; p = 5 · 10-6, OR = 3.04; and p = 4 · 10-6, OR = 2.35, respectively). This potential association was confirmed by a logistic binary regression analysis only for the development of the paranoid form of schizophrenia (p = 0.001/OR = 2.6; p = 0.0002/OR = 3.2; and p = 0.0004/OR = 3.1, respectively) and remained not significant for the other subtypes. Moreover, our study showed an important association between GCA haplotype and the development of this pathological form (p = 10-4, OR = 3.71). In conclusion, our results proved a significant association between the three polymorphisms and paranoid schizophrenia, at least in the Tunisian population, suggesting a substantially increased risk for paranoid schizophrenia with dominant inheritance of these three minor alleles.

Toxoplasma gondii infection in schizophrenia and associated clinical features.

The belief that latent toxoplasmosis is asymptomatic has been questioned, in particular due to the repeated highlighted link between the Toxoplasma gondii infection and an increased incidence of schizophrenia. However, to understand this relationship, the effect of infection with Toxoplasma gondii on the severity of schizophrenia has been poorly studied. Our work focused on comparing the prevalence of Toxoplasma infection between schizophrenic patients and healthy controls, as well as comparing the clinical features and the demographic characteristics between Toxoplasma-seronegative and Toxoplasma-seropositive patients with schizophrenia. The rate of IgG antibody in the schizophrenia patients was 74.8% compared 53.8% in controls. Patients with schizophrenia had a significantly higher mean of serum IgG antibodies to T. gondii compared to controls. The seropositive male patients had a higher age of disease onset, a higher BPRS score, a greater negative PANSS score and a lower GAF score than the seronegative male patients. These results suggest a higher severity of clinical symptoms in the male patients with schizophrenia. This study provides further evidence to the hypothesis that exposure to Toxoplasma may be a risk factor for schizophrenia. Moreover, toxoplasmosis in men with schizophrenia may lead to more severe negative and cognitive symptoms and a less favorable course of schizophrenia.

Maternal tumor necrosis factor receptor 2 gene variants associated with pre-eclampsia in Tunisian women.

AIM: The tumor necrosis factor receptor 2 (TNFR2) is expressed in placental tissue and it is involved in immune responses, inflammation, angiogenesis and blood pressure regulation; which makes it an attractive pre-eclampsia (PE) candidate gene. Furthermore, TNFR2 expression is altered in the first trimester in placentas of women who are destined to develop PE. Therefore, we examined the association between maternal and fetal genetic variants of TNFR2 and PE. MATERIAL AND METHODS: Women with PE (n = 157) and their offspring with PE (n = 60) were compared to a control group of women (n = 97) and their offspring (n = 52) in the same Tunisian hospital-based population. We genotyped by polymerase chain reaction and restriction fragment length polymorphism the T/G polymorphism at position 676 in exon 6 (rs1061622) of the TNFR2 gene and examined its association with PE. RESULTS: The frequencies of TNFR2 (G/G) genotype and G allele were higher in the mothers with PE (n = 154) compared to the control group (15.3% vs 4.1% and 37% vs 26.3%, respectively); furthermore, the difference reached statistical significance (P = 0.002, odds ratio = 4.9; 95% confidence interval: 1.69-17.4 and P = 0.03, odds ratio = 1.69; 95% confidence interval: 1.03-2.8, respectively). In contrast, the fetal genotype and allele frequencies of this polymorphism had no effect on the risk of PE. CONCLUSIONS: The exon 6 polymorphism in TNFR2 (rs1061622) or a gene at proximity is associated specifically with PE at least in the Tunisian population and could increase the risk for PE for mothers carrying the homozygote minor allele. Nevertheless, these results need to be confirmed in other populations.

Characterization of ST80 Panton-Valentine leukocidin-positive community-acquired methicillin-resistant Staphylococcus aureus clone in Tunisia.

The spread of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has been reported in communities worldwide. In this study, we characterized 64 Tunisian CA-MRSA by agr typing, polymerase chain reaction assay for 20 virulence genes, staphylococcal chromosomal cassette mec (SCCmec) typing, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and protein A gene (spa) typing. All our isolates were lukS-PV-lukF-PV positive, etd positive, and edin positive. They harbored SCCmec type IV and belonged to agr group 3. PFGE typing showed that our isolates were distributed in 11 different pulsotypes. spa typing and MLST, performed with isolates representative of each PFGE pattern, revealed that all isolates had a unique spa type (t044) and a common sequence type (ST80). The isolates showed susceptibility to the majority of antibiotics, and resistance to kanamycin, erythromycin, and tetracycline, but intermediate resistance to fusidic acid. Full analysis of our results revealed that our isolates were nonmultiresistant and belonged to a single clonal type ST80.

A gender-specific association of interleukin 1 receptor antagonist polymorphism with schizophrenia susceptibility.

OBJECTIVE: Recent genetic studies have revealed that the interleukin (IL) 1 gene complex is associated with schizophrenia in the Caucasian population; however, data from the North African population are limited. To further assess the role of interleukin 1 receptor antagonist protein (IL1Ra) in schizophrenia, we examined a functional multiallelic polymorphism localised in intron 2 of this receptor gene associated with an altered level of IL1Ra. METHODS: In the present case-control study, we have analysed the (86 bp) n polymorphism of the interleukin 1 receptor antagonist (IL1RN) gene (RS 1794068) by polymerase chain reaction genotyping in 259 patients with schizophrenia and 178 healthy controls from the Tunisian population. RESULTS: We showed that the frequencies of the IL1RN*2/2 genotype and allele 2 were higher in the patient group compared with the control group, and the difference was statistically significant [13.5% vs. 5.6%, p = 10-3, odds ratio (OR) = 3.2% and 32.8% vs. 21.9%, p = 3 × 10-4, OR = 1.76, respectively). When we evaluated the association between this genetic polymorphism and the clinical variables of schizophrenia, we found that the frequencies of the 2/2 genotype and allele 2 were significantly higher in the male patient group (p = 10-4 and 10-5, respectively) compared with the male control group, indicating a substantially increased risk for sex-onset schizophrenia with inheritance of the IL1RN2 allele. When the association between the genotypes and outcome was evaluated by multiple logistic regression analysis, the adjusted OR for the IL1RN genotypes remained statistically significant [1.39; 95% confidence interval (CI) = 1.11-1.73; p = 0.003]. CONCLUSION: The intron 2 polymorphism in IL1RN or a genetic polymorphism at proximity seems to be associated specifically with schizophrenia in the Tunisian male population.

Relationship between GSTM1 and GSTT1 polymorphisms and schizophrenia: a case-control study in a Tunisian population.

There is substantial evidence found in the literature that supports the fact that the presence of oxidative stress may play an important role in the pathophysiology of schizophrenia. The glutathione S-transferases (GSTs) forms one of the major detoxifying groups of enzymes responsible for eliminating products of oxidative stress. Interindividual differences observed in the metabolism of xenobiotics have been attributed to the genetic polymorphism of genes coding for enzymes involved in detoxification. Thus, in this study we investigated the association of glutathione S-transferase Mu-1 (GSTM1) and glutathione S-transferase theta-1 (GSTT1) gene deletion polymorphisms and schizophrenia in a Tunisian population. A case-control study including 138 schizophrenic patients and 123 healthy controls was enrolled. The GSTM1 and GSTT1 polymorphisms were analyzed by multiplex polymerase chain reaction (PCR). No association was found between the GSTM1 genotype and schizophrenia, whereas the prevalence of the GSTT1 active genotype was significantly higher in the schizophrenic patients (57.2%) than in the controls (45.5%) with (OR=0.6, IC 0.37-0.99, p=0.039). Thus, we noted a significant association between schizophrenia and GSTT1 active genotype. Furthermore, the combination of the GSTM1 and GSTT1 null genotypes showed a non-significant trend to an increased risk of schizophrenia. The present finding indicated that GSTT1 seems to be a candidate gene for susceptibility to schizophrenia in at least Tunisian population.

Tumor necrosis factor promoter gene polymorphism associated with increased susceptibility to non-Hodgkin's lymphomas.

The tumor necrosis factor (TNF) is a pro-inflammatory cytokine involved in the severity of different immune-regulated diseases including autoimmune, infectious, and malignant diseases. Chronic immune system stimulation could be a potential etiologic factor in these diseases. Given the determining role of TNF acting early in the immune response, we investigated the effect of an inherited genetic polymorphism at TNF promoter (-308A/G) on a predisposition to non-Hodgkin's lymphoma (NHL). The genotype distribution was determined in 194 patients with NHL and 160 age- and sex-matched population-based controls. The comparison of the -308TNF genotypes between the NHL patients and the controls showed a significant excess of A/A genotype that is previously associated with higher TNF production. Indeed, the A/A genotype is present in 7.7% of the cases, but in only 2.5% of the controls. This genotype is associated with a significant increased risk of NHL (odds ratio = 3.63, P = 0.028). These results indicate that the genetic polymorphism which could lead to an increased TNF production or a neighboring gene within the MHC region may influence the susceptibility to NHL in Tunisian population. Other epidemiologic studies carried out in both the Tunisian population and elsewhere are needed to confirm this finding.

A polymorphism in FAS gene promoter associated with increased risk of nasopharyngeal carcinoma and correlated with anti-nuclear autoantibodies induction.

Loss of FAS (CD95) expression is a common feature of malignant transformation, which has been related to loss of epithelial cell differentiation and loss of sensitivity to apoptosis. We investigated the potential association between FAS promoter polymorphism and the genetic susceptibility to the Epstein-Barr virus (EBV)-related nasopharyngeal carcinoma. The in vivo functional significance of the FAS polymorphism was investigated by assessing the correlation between FAS genotypes and the presence of autoantibodies to cytoskeleton and nuclear antigens frequently detected in nasopharyngeal carcinoma. We determined the FAS polymorphism distributions by RFLP-PCR in 170 patients with nasopharyngeal carcinoma and in 224 sex and age-matched controls. We used ELISA and the immunofluorescence analysis to characterize the presence of IgG autoantibodies to the cytoskeleton and nuclear proteins in patients' sera. A significantly increased risk of nasopharyngeal carcinoma was associated with heterozygote FAS-A/G (OR=2.00, P=0.001) and homozygote FAS-G/G (OR=3.19, P=0.0001) variants. The increased frequency of FAS-G/G genotype is correlated with the presence of anti-nuclear autoantibodies in patients with nasopharyngeal carcinoma (P=0.0298). Our results demonstrated that FAS promoter polymorphism was significantly associated with the nasopharyngeal carcinoma in Tunisians. The anti-nuclear autoantibodies induction was also found to be related to FAS polymorphism. The FAS promoter polymorphism associated not only with the increased risk of nasopharyngeal carcinoma in Tunisians but also with immune response deregulation observed in this cancer.

Autoantibodies to tubulin are specifically associated with the young age onset of the nasopharyngeal carcinoma.

By far the highest incidence of the Epstein-Barr virus (EBV)-associated nasopharyngeal carcinomas in young subjects was found in North Africa, a region of intermediate risk for adults. We used the immunofluorescence analysis and ELISA to characterize the presence of IgG autoantibodies to the cytoskeleton and nuclear proteins in sera of 82 Tunisian patients with primary nasopharyngeal carcinoma and those of 82 healthy subjects. To assess the specificity of the sera autoreactivity, inhibition tests were carried out using free autoantigens. Analysis of sera autoreactivity in patients with nasopharyngeal carcinoma and in control subjects showed that 23% of the patients had serum reactivity against more than 1 autoantigen tested compared to 1.2% in the control group (p = 10(-4)). The most frequent auto reactivity in patient's sera was found with tubulin and nuclear proteins (19.5% and 22% respectively vs. 6.1% and 1.2% in controls). The IgG auto reactivity inhibition studies indicate that all autoantigens, except native DNA, showed low values of IC(50) (concentration of antigen causing 50% inhibition of the antibody binding) reflecting the high affinity of these IgG autoantibodies. When patients and controls were stratified according to their age, IgG autoantibodies to tubulin were found specifically associated with the young age onset of the nasopharyngeal carcinoma (age under 25 years). IgG auto reactivity comparison before and after cancer therapy showed that only anti-tubulin reactivity was significantly affected by treatment. Our results demonstrate that the autoantibodies to the cytoskeleton and nuclear proteins are associated with the nasopharyngeal carcinoma in Tunisians. The anti-tubulin IgG autoantibodies may represent a serologic marker for the nasopharyngeal carcinoma in children and adolescents Tunisians.