ICOS gene polymorphisms in systemic lupus erythematosus: A case-control study.

The inducible T-cell costimulator (ICOS) may play an important role in adaptive immunity by regulating the interaction between T cells and antigen-presenting cells. Disruption of this molecule can lead to autoimmune diseases, in particular systemic lupus erythematosus (SLE). In this study, we aimed to explore the possible association between ICOS gene polymorphisms and SLE as well as their influence on disease susceptibility and clinical outcomes. A further objective was to assess the potential impact of these polymorphisms on RNA expression. A case-control study, including 151 patients with SLE, and 291 unrelated healthy controls (HC) matched in gender, and geographical origin, was performed to genotype two polymorphisms located in the ICOS gene: rs11889031 (-693 G/A) and rs10932029 (IVS1 + 173 T/C); using the polymerase chain reaction (PCR)-restriction fragment length polymorphism method. The different genotypes were validated by direct sequencing. The expression level of ICOS mRNA was assessed by quantitative PCR in peripheral blood mononuclear cells of SLE patients and HC. The results were analysed using Shesis and spss.20. Our results revealed a significant association between ICOS gene rs11889031 > CC genotype and SLE disease (codominant genetic model 1, (C/C vs. C/T), p = .001, odds ratio [OR] = 2.18 IC [1.36-3.49]); codominant genetic model 2, (C/C vs. T/T) p = .007, OR = 15.29 IC [1.97-118.5]); dominant genetic model, (C/C vs. C/T + T/T) p = .0001, OR = 2.44 IC [1.53-3.9]). Besides, there was a marginal association between rs11889031 > TT genotype and T allele with a protective role from SLE (recessive genetic model, p = .016, OR = 0.08 IC [0.01-0.63] and p = 7.6904E - 05, OR = 0.43 IC = [0.28-0.66], respectively). Moreover, statistical analysis indicated that the rs11889031 > CC genotype was linked with clinical and serological manifestations of SLE, including blood pressure, and anti-SSA antibodies production in SLE patients. However, the ICOS gene rs10932029 polymorphism was not associated with susceptibility to SLE. On the other side, we did not note any effect of the two selected polymorphisms on the level of ICOS mRNA gene expression. The study showed a significant predisposing association of the ICOS rs11889031 > CC genotype with SLE, in contrast to a protective effect of rs11889031 > TT genotype in Tunisian patients. Our results suggest that ICOS rs11889031 may act as a risk factor for SLE and could be used as a genetic susceptibility biomarker.

Genes regulating oxidative-inflammatory response in circulating monocytes and neutrophils in septic syndrome.

Despite significant progress in the past decades, sepsis still lacks a specific treatment. Under normal conditions, leucocytes play a critical role in controlling infection and it is suggested that their activity is impaired during sepsis which contribute to the dysregulation of immune reactions. Indeed, in response to infection, several intracellular pathways are affected mainly those regulating the oxidative- inflammatory axis. Herein, we focused on the contribution of NF-kB, iNOS, Nrf2, HO-1 and MPO genes in the pathophysiology of septic syndrome, by analyzing the differential expression of their transcripts in circulating monocytes and neutrophils, and monitoring the nitrosative/oxidative status in septic syndrome patients. Circulating neutrophils of septic patients displayed a significant overexpression of NF-kB compared to other groups. In monocytes, patients with septic shock expressed the highest levels of iNOS and NF-kB mRNA. However, genes involved in cytoprotective response had increased expression in patients with sepsis, in particular, the Nrf2 and its target gene HO-1. Moreover, patient monitoring indicates that the iNOS enzyme expression and NO plasma levels may play a role in assessing the severity of septic conditions. Overall, in either monocytes or neutrophils, we pointed out the major role of NF-κB and Nrf2 in the pathophysiological process. Therefore, therapies targeted to redox abnormalities may be useful for better management of septic patients.

miRNA implication in the pathogenesis and the outcome of Tunisian endemic pemphigus foliaceus.

Pemphigus foliaceus (PF) is a bullous autoimmune skin disease diagnosed through sera and skin analyses. PF severity is associated with maintained anti-Dsg1 sera levels and its prognosis is unpredictable. MicroRNA (miRNA), dynamic regulators of immune function, have been identified as potential biomarkers for some autoimmune diseases. This study aimed to assess the miRNA expression of miR-17-5p, miR-21-5p, miR-146a-5p, miR-155-5p and miR-338-3p using quantitative real-time PCR in peripheral blood mononuclear cells (PBMC) and lesional skin samples from untreated and treated PF patients (both remittent and chronic) over 3 months. Overall, miRNA expression was significantly higher in PBMC than in biopsy samples. Blood miR-21 expression was increased in untreated patients compared to controls and had a diagnostic value with an AUC of 0.78. After 6 weeks, it decreased significantly, similar to anti-Dsg1 antibodies and the PDAI score. In addition, a positive correlation was observed between cutaneous miR-21 expression and the disease activity score. Conversely, cutaneous expressions of miR-17, miR-146a and miR-155 were significantly higher in treated chronic patients compared to remittent ones. The cutaneous level of miR-155 positively correlated with pemphigus activity, making it a potential predictive marker for patients' clinical stratification with an AUC of 0.86.These findings suggest that blood miR-21 and cutaneous miR-155 can be used as supplemental markers for PF diagnosis and activity, respectively in addition to classical parameters.

Evaluation of X chromosome inactivation in endemic Tunisian pemphigus foliaceus.

BACKGROUND: Almost 5% of the world's population develops an autoimmune disease (AID), it is considered the fourth leading cause of disability for women, who represent 78% of cases. The sex ratio when it comes to the most prevalent AID varies from 9:1 in systemic lupus erythematosus (SLE) to 13:1 in endemic Tunisian pemphigus foliaceus (PF). METHODS: To test the potential involvement of skewed x-inactivation in the pathogenesis of Tunisian PF, we analyzed the methylation status of a highly polymorphic CAG repeat in the androgen receptor gene and evaluated the x chromosome inactivation (XCI) patterns in peripheral blood-leukocyte-derived DNA samples of female patients with PF (n = 98) compared to healthy control (HC) subjects (n = 150), as well as female patients with SLE (n = 98) were enrolled as a reference group. RESULTS: XCI status was informative for 50 of the 98 PF patients (51%) and 70 of the 150 HC women (47%). Extremely skewed XCI patterns were more frequent in PF and SLEwomen than HC, but the difference was statistically significant only in women with SLE. No statistical difference was observed in XCI patterns between PF and SLE patients. PF phenotype-XCI correlation analysis revealed that (i) skewed XCI patterns may be involved in the disease's subtype and (ii) it was more pronounced in the endemic group than the sporadic one. Furthermore, preferential XCI showed an increase in heterozygote genotypes of PF's susceptibility polymorphisms in immunity-related X genes (FOXP3, AR, and TLR7) in PF patients compared to HC. CONCLUSION: Our results suggest that skewed XCI could lead to hemizygosity of X-linked alleles that might unmask X-linked deleterious alleles.

Differential Expression of Anti-Inflammatory RNA Binding Proteins in Lupus Nephritis.

Lupus nephritis (LN) is a type of immunological complex glomerulonephritis characterized by chronic renal inflammation which is exacerbated by infiltrating leukocytes and fueled by a variety of pro-inflammatory cytokines. A profound understanding of the pathogenesis of LN is necessary to identify the optimal molecular targets. The role of RNA-binding proteins (RBPs) in post-transcriptional gene regulation in the immune system is being explored in greater depth to better understand how this regulation is implicated in inflammatory and autoimmune diseases. Tristetraprolin (TTP), Roquin-1/2, and Regnase-1 are 3 RBPs that play a critical role in the regulation of pro-inflammatory mediators by gating the degradation and/or translational silencing of target mRNAs. In this study, we proposed to focus on the differential expression of these RBPs in immune cells and renal biopsies from LN patients, as well as their regulatory impact on a specific target. Herein, we highlight a novel target of anti-inflammatory treatment by revealing the mechanisms underlying RBP expression and the interaction between RBPs and their target RNAs.

Th17 and Th1 cells in systemic lupus erythematosus with focus on lupus nephritis.

Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by T cells imbalance. Indeed, a correlation between levels of Th17 cells and disease activity has been reported. Our work aimed to study the functional association of subpopulations of Th cells and SLE with (lupus nephritis, LN) or without (lupus erythematosus, LE) renal involvement in Tunisian patients through the detection of intracellular cytokines and surface marker expression. The IL23R and RORC mRNA expression levels were evaluated. The level of Th17 and Th1 cells was higher in LE and LN patients compared to healthy controls (HC) (p = 0.007 and p = 0.018, respectively), while Th1/17 cells were increased only in LN patients compared to HC (p = 0.011). However, no significant difference was described in the mRNA expression levels of RORC and IL-23R between SLE and HC. Our findings suggest that the Th1/Th17 differentiation mechanisms are altered in SLE and that this imbalance should have an important influence on the development and severity of the disease.

Autoantibodies to Zinc Transporter 8 and SLC30A8 Genotype in Type 1 Diabetes Childhood: A Pioneering Study in North Africa.

Background: Type 1 diabetes (T1D) occurs as a result of insulin deficiency due to destructive lesions of pancreatic ß cells. In addition to classical autoantibodies (Abs) to islet cell antigens, antizinc transporter 8 Abs (ZnT8-Ab) have been recently described in T1D. Objective: As no data on ZnT8-Ab in Tunisian patients has been reported, we aim to evaluate the relationships between ZnT8-Ab, ZnT8 coding gene (SLC30A8) promoter polymorphism, and T1D risk in newly diagnosed children. Methods: ZnT8-Ab were measured in the serum of T1D newly affected children (n = 156) who were admitted to the pediatric department of the Hedi Chaker University Hospital of Sfax. Rs13266634 was genotyped in T1D children and 79 of their first-degree parents. The SPSS software was used to analyze the serological data. Allelic association analysis was conducted with family-based association tests implemented in the FBAT program v1.5.1. Results: ZnT8-Ab was detected in 66/156 (42.3%) of T1D newly diagnosed children. Among them, 6 (9%) presented ZnT8-Ab as the only humoral marker. The inclusion of ZnT8-Ab increased the number of Ab-positive patients to 90% and reduced the negative ones by 27%. There was no evidence of any overtransmission of any allele of the rs13266634 C/T polymorphism from parents to affected T1D children, nor of any correlation with any clinical or serological parameter. After the T1D disease onset age adjustment, a significant association was observed with the C allele suggesting that it could have a susceptibility role. Conclusion: ZnT8-Ab appears as a relevant diagnostic marker for T1D in Tunisian children, especially at the onset of the disease as teenagers.

Role of innate immune receptors TLR4 and TLR2 polymorphisms in systemic lupus erythematosus susceptibility.

AIM: Through their recognition of various bacterial cell wall components, TLR2 and TLR4 participate in the innate response and modulate the activation of adaptive immunity. Therefore, the genetic background of these receptors might play a crucial role in autoimmune diseases such as systemic lupus erythematosus (SLE). In this study, we investigated the possible association between polymorphisms within TLR2 and TLR4 genes with SLE susceptibility. MATERIAL AND METHODS: A total of 100 SLE patients and 200 unrelated healthy controls of the Tunisian population were enrolled in the study.TLR4rs4986790, TLR4rs4986791, and TLR2rs5743708 genotyping were performed using a polymerase chain reaction-restriction fragment length polymorphism method. The number of guanine-thymine (GT) repeat microsatellite in the intron 2 of TLR2 gene was analyzed by sequencing. RESULTS: We reported a lack of allelic and genotypic association between SNPs of TLR4 and TLR2 genes and SLE pathogenesis. No correlation was found with any SLE features. However, SLE susceptibility was associated with the GT repeat microsatellite polymorphism in the human TLR2 gene. Further subclassification of alleles into three subclasses revealed a significant association between the long-sized repeats ((GT) >23) and SLE. CONCLUSION: Though the results showed the absence of genetic association of TLR4 and TLR2 SNPs with the risk of developing SLE, we have identified a protective association between the microsatellite polymorphism in intron 2 of the TLR2 gene and SLE. Functionally, these (GT)n repeats may confer modifying effects or susceptibility to certain inflammatory conditions.

Annexin A1 and its receptor gene polymorphisms in systemic lupus erythematosus in the Tunisian population.

BACKGROUND: An association between ANXA1, FPR1 and FPR2 gene polymorphisms and the patho-physiology of many human diseases was suggested by numerous studies. OBJECTIVE: Our study aimed to evaluate association between common polymorphisms in the 9q21.13 and 19q13.41 and susceptibility to systemic lupus erythematosus (SLE) in the Tunisian population. MATERIALS: We performed a case-control study on 107 Tunisian SLE patients and 122 healthy controls to explore 9 polymorphisms of the three studied genes: rs2811226 and rs3739959 (ANXA1), rs5030880, rs1042229, rs1461765570, rs17849971, rs867228 (FPR1), rs17694990 and rs11666254 (FPR2). RESULTS: Four polymorphisms were found to be linked with SLE susceptibility: rs3739959-ANXA1 > G and GG (p = 0.021, OR = 1.73 and p = 0.014, OR = 2.06 respectively), rs867228-FPR1 > TT (p = 0.014, OR = 4.59), rs11666254-FPR2 > GG (p = 0.019, OR = 8.34) and rs17694990-FPR2 > T (p = 0.05, OR = 1.506). In homogenous groups of SLE patients depending on clinical manifestations and serological results, previous associations were confirmed with a panoply of manifestations of lupus including lupus nephritis, malar rash, mouth ulceration and hypocomplementia. CONCLUSION: Our study showed an association between ANXA1 > rs3739959, FPR1 > rs867228, FPR2 > rs11666254, FPR2 > rs17694990 and SLE susceptibility. Our results also showed a strong association between the two ANXA1 studied SNPs and LN which allowed us to suggest these two SNPs as biomarkers of LN development in SLE. Further research is needed to understand by which mechanism the gene variants affect susceptibility to SLE. Key Points • Lupus erythematosus is an autoimmune disease in which a panoply of factors are implicated • Annexin A1 interaction with its receptors are suggested as a target in therapy of a panoply of human disease in particular cancers • The present results highlighted the implication of Annexin A1 and its receptors gene polymorphisms in the physiopathology of lupus, in particular in the involvement of renal and cutaneous lesions.

RNA receptors, TLR3 and TLR7, are potentially associated with SLE clinical features.

The influence of intracellular Toll-like-receptors (TLR), recognized as nucleic acid sensors, in the immunopathogenesis of systemic lupus erythematosus (SLE) is increasingly explored. Yet, the results of both functional and genetic studies remain conflictual. We evaluated the association between TLR3 and TLR7 genes selected variants and SLE and investigated the possible relationship with clinical and serological parameters. Then, we studied the genetic expression of these receptors, and if the TLR7 gene evades X chromosome inactivation (XCI). Our study covers 106 cases and 200 controls, genotyped using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. TLR3 and TLR7 expression level was assessed by qPCR carried, respectively, on renal tissues and PBMC, and methylation status was evaluated by methylation-specific PCR. Results were statistically analysed using Shesis software, χ2 , and Mann-Whitney test. Significant associations with SLE susceptibility were found for the TLR3 rs3775291, rs5743305 and rs3775294 polymorphisms. Further subgroup analysis, TLR3 rs3775291 and rs3775294 polymorphisms were significantly associated with lupus nephritis (LN) and even correlate with the presence of auto-antibodies binding RNA molecules. SLE and LN were more common in men with rs3853839-G variant within TLR7 gene versus those carrying the C allele. Moreover, the role of the G allele in the TLR7 expression up-regulation was confirmed. However, gene expression analysis showed no significant differences in TLR3 and TLR7 mRNA levels between LN patient biopsies and healthy tissues (p > .05). When comparing patients and controls, no statistical difference was observed in XCI pattern. Otherwise, notable associations were raised between TLR3 and TLR7 gene variants and clinical and serological lupus features pointing towards the role of genetic background in the physiopathogenesis of the disease.

Vitamin D status and CYP27B1-1260 promoter polymorphism in Tunisian patients with systemic lupus erythematosus.

AIM: An association between serum vitamin D (Vit D) levels and systemic lupus erythematosus (SLE) has been reported by several studies that suggested the involvement of genetically determined characteristics of enzymes of vitamin D metabolism. Our study aimed to evaluate the relationship between 25 hydroxyvitamin D (25[OH]D) level, the most representative metabolite of VitD status, and polymorphism of the cytochrome P450, CYP27B1 gene, which influence vitamin D metabolism, and serum levels, in SLE Tunisian patients. MATERIAL AND METHODS: A cross-sectional study has been conducted in SLE patients (supplemented and not supplemented patients), matched to healthy controls by age and gender. The 25[OH]D serum level was measured by chemiluminescence assay and CYP27B1-1260 genetic polymorphism was carried out using PCR-RFLP methods. Statistical analysis was made using Shesis and SPSS.20 Software. RESULTS: Controls and Vit D not supplemented patients' groups presented the highest percentage of hypovitaminosis D. A significant difference in the mean level of circulating 25[OH]D between Vit D supplemented SLE patients and controls was observed (23.91 ng/ml and 7.18 ng/ml, respectively p = 3.4 105 ). Our results showed a correlation of high 25[OH]D level with complement component 3 levels and prednisolone drug. Moreover, the analysis of CYP27B1-1260 polymorphism in SLE patients and controls revealed a nonsignificant allelic or genotypic association. CONCLUSION: Despite the sunny climate, the high prevalence of Vit D deficiency is common in Tunisia. This hypovitaminosis D feature may affect the Vit D levels in our SLE patients but a direct association with the disease or with the genetically determined features remains unclear. More studies are needed to establish thresholds and susceptibility genes according to the characteristics of each population.

Autoantibodies against Desmoglein 1 and 3 in South Tunisian pemphigus.

BACKGROUND: Desmoglein (Dsg) 1 and 3 are the 2 major autoantigens in pemphigus foliaceus (PF) and pemphigus vulgaris (PV). AIM: We aimed to determine anti-Dsg1 and 3 Abs'usefulness in the diagnosis of pemphigus and to assess the correlation of these antibodies (Abs) with clinical phenotype and disease activity in south Tunisian patients. METHODS: We retrospectively analyzed 131 samples from 82 patients (52 with PF and 30 with PV) during follow-up. Anti-Dsg1 and 3 Abs were measured by ELISA. Consecutive anti-Dsg1 and 3 Abs were correlated with disease activity. Receiver operating characteristics (ROC) curve were calculated to determine anti-Dsg1 and 3 Abs'cut-offs with optimal sensitivity and specificity for disease activity. RESULTS: Anti-Dsg1 and 3 levels were associated to in PF and PV patients respectively (p<0,001). Anti-Dsg1 and 3 Ab were associated with skin (95%) and mucosal (60%) lesions, respectively. A significant decrease of anti-Dsg1 Abs was observed in patients with PF in clinical remission (36 ± 62 U/mL; (p=0,04). No correlation was found between anti-Dsg3 Abs and the course of mucosal lesions in PV (p=0,3). During follow-up, anti-Dsg1 Abs correlated with relapses (177 ±60 U/mL ; p=0,04). The 161,5 U/mL cut-off for anti-Dsg1 Abs provided 100% specificity and 86,4% sensitivity in PF disease activity. The 30,7U/mL cut-off for anti-Dsg3 provided 89,5% sensitivity and 100% specificity in PV. CONCLUSIONS: High anti-Dsg3 Abs values are not always associated with PV disease activity. Anti-Dsg1 Abs showed a closer relationship with skin activity in PS and should be therefore taken into account in management of pemphigus patients.

Chromosome 2q33genetic polymorphisms in Tunisian endemic pemphigus foliaceus.

BACKGROUND: Several studies have suggested that polymorphisms within genes encoding T-lymphocyte immune regulating molecules: CD28, CTLA-4, and ICOS, may alter the signaling process and subsequently could be involved in susceptibility to a broad spectrum of autoimmune diseases. METHODS: This study aimed to replicate associations between common polymorphisms in the 2q33.2 cluster and susceptibility to pemphigus foliaceus (PF) in the Tunisian population. We investigated seven polymorphisms: rs3116496 and rs1879877 (CD28), rs231775, rs3087243, and (AT)n repeat (CTLA4); rs11889031 and rs10932029 (ICOS) in a case-control study which enrolled 106 Tunisian PF patients and 205 matched healthy controls. RESULTS: We confirmed the associations with CTLA4((AT)13 , p = 0.00137, OR = 3.96 and (AT)20 , p = 0.008, OR = 5.22; respectively) and ICOS genes (rs10932029>CT, p = 0.034, OR = 2.12 and rs10932029>TT, p = 0.04 and OR = 0.41). CONCLUSION: Our results indicate that susceptibility to PF is located in the proximal and the distal 3' flanking region of the CTLA4/ICOS promoter. These findings may open avenues to the treatment of patients with biological drugs targeting CTLA4/ICOS molecules, in a personalized manner to achieve more effective treatment.

Update on immunogenetics of Tunisian endemic pemphigus foliaceus.

Pemphigus foliaceus (PF) is an autoimmune blistering skin disease characterized by the presence of bullous skin lesions, the absence of mucous tissue involvement, and the production of auto-antibodies directed against a keratinocyte transmembrane protein localized in the desmosome and member of the cadherines, desmoglein 1. These pathogenic auto-antibodies are responsible for the intra-epidermal formation of blisters through the loss of keratinocyte adhesion, the so-called acantholysis process. The endemic form of PF observed in the south of Tunisia is characterized by a significantly higher incidence rate compared to the sporadic form in northern countries, occurrence mainly in young women and the absence of cases during childhood. Tunisian endemic PF is an ideal research model for the decryption of the puzzle of genetic and environmental factors and their interactions in the development of autoimmune diseases. In this review, we will summarize recent findings regarding the epidemiologic and immunologic features of Tunisian PF and its genetic and environmental factors.

Pemphigus herpetiformis in South Tunisia: a clinical expression of pemphigus foliaceus?

BACKGROUND: Pemphigus herpetiformis (PH) is a rare subtype of pemphigus combining clinical features of dermatitis herpetiformis and the immunopathologic characteristics of pemphigus. We aimed to analyze the epidemiological, clinical, and immunological presentation and management of the disease in a cohort of south Tunisian patients with a long-term follow-up. METHODS: We included all patients with confirmed PH followed from January 1987 to December 2015 in the dermatology department. RESULTS: We included 24 south Tunisian female patients with a mean age of 36 years (20-63), mainly from rural origin (84%). All patients had exclusive skin lesions. Clinical features combined erythematous, vesicular, or bullous lesions, with circinate borders mainly on the trunk and limbs associated with severe pruritus (91%). Peripheral hypereosinophilia was noted in 31% of cases. Histological examination demonstrated no intraepithelial (50%), suprabasal (35%), or subcorneal cleavage (15%). Eosinophilic spongiosis was seen in 42% of cases. On direct immunofluorescence, there was an intercellular staining in 96% of cases composed mainly of IgG and C3 (79%). Indirect immunofluorescence was positive in 71% of cases. Reactivity was mainly directed against Dsg1. Dapsone alone was inefficient. All patients received systemic corticosteroids. Most patients (64%) relapsed. Iatrogenic complications and cutaneous infections were noted in 40% and 16% of cases, respectively. CONCLUSION: PH is characterized by the occurrence of exclusive skin lesions in young women with a good response to corticosteroids but not to Dapsone. Reactivity mainly against Dsg1 suggests that PH in south Tunisia is a particular variant of nonendemic pemphigus foliaceus.

Genetic association and phenotypic correlation of TLR4 but not NOD2 variants with Tunisian inflammatory bowel disease.

OBJECTIVE: The common association between NOD2/CARD15 and TLR4 gene variants with inflammatory bowel disease (IBD) has not been replicated in all studies. We studied the polymorphism of these two genes in Tunisian patients with IBD. METHODS: Polymorphisms of NOD2 (R702W, G908R and L1007fs) and TLR4 (Asp299Gly and Thr399Ile) genes were analyzed in 106 patients with IBD (68 with ulcerative colitis [UC], 38 with Crohn's disease [CD]) and 160 healthy controls using polymerase chain reaction-restriction fragment length polymorphism. Genotypes and phenotypes were correlated. RESULTS: The mutated allele of TLR4-Thr399Ile was strongly associated with IBD (9.4% in IBD, 7.4% in UC and 13.2% in CD vs 2.5% in controls; P = 0.0004, 0.014 and 0.00006, respectively). Heterozygous genotypes were significantly more frequent in patients with IBD (17.0%), UC (14.7%) and CD (21.1%) than in controls (5.0%) (P = 0.0012, 0.012 and 0.001, respectively). Interestingly, the wild genotype was found to be protective (odds ratio 0.24). The mutated allele of TLR4-Asp299Gly was more frequent in controls (6.8%) than in patients with IBD (2.9%). A phenotypic correlation of Asp299Gly-AG genotype with arthritis in UC patients was detected (P = 0.003). Regarding the NOD2 gene, the common variations studied were not polymorphic and there was no genetic association with IBD. CONCLUSION: The TLR4-Thr399Ile variant was strongly associated with susceptibility to IBD, whereas TLR4-Asp299Gly seems to play a role in the clinical expression of UC. The rarity and non-association of NOD2 mutations with IBD may reveal a genetic characteristic of the population in our region.

The Increased Expression of Toll-Like Receptor 4 in Renal and Skin Lesions in Lupus Erythematosus.

Toll-like receptor 4 (TLR-4), a bacterial lipopolysaccharide sensor, is an innate immunity essential modulator. It is expressed on both immune and non-immune cells and may contribute to the cutaneous and renal manifestations during lupus erythematosus (LE). Our purpose is to evaluate TLR-4 expression and analyzing its role in lupus nephritis (LN) and chronic cutaneous lupus erythematosus (CLE) pathogenesis. TLR-4 immunohistochemical staining was performed on 30 LN renal biopsies compared with 11 healthy renal tissues and 30 skin biopsies from CLE patients compared with 15 normal individuals. CLE patients' biopsies showed a strong and diffuse TLR-4 expression throughout the epidermis and labeled inflammatory infiltrate and glands in the dermis whereas controls' skin expressed weakly TLR-4 only in the epidermis basal layer. LN glomeruli and tubules showed an increased and more intense TLR-4 expression compared with normal controls where TLR-4 expression was weak and rarely detected in glomeruli, diffuse and weak in tubules. A significant difference in TLR-4 expression between LN classes, both in glomeruli and tubules, was observed. These data confirm an up-regulation of TLR-4 expression in the affected tissues of CLE and LN patients and highlight the critical role of TLR-4 in the pathogenesis of cutaneous and renal disorders in LE.

Role of FOXP3 gene polymorphism in the susceptibility to Tunisian endemic Pemphigus Foliaceus.

OBJECTIVE: Forkhead box P3 (FOXP3) is an essential and crucial transcription factor of regulatory T-cells. Genetic polymorphisms in the promoter region of FOXP3 gene may alter the gene expression level and, therefore, contribute to several autoimmune diseases susceptibility. We aimed to investigate the possible role of genetic variants of four SNPs (rs3761547, rs3761548, rs3761549 and rs2294021) and a (GT)n microsatellite located in FOXP3 gene in the susceptibility to Tunisian Pemphigus Foliaceus (PF). METHOD: A case-control study was conducted on 98 patients with different clinical features of PF and 182 matched healthy controls using PCR-RFLP method. RESULTS: According to the epidemio-demographic features of the disease, patients were classified into two groups: an endemic group (n=33, mean age=31 [18-48]) versus a sporadic one (n=65, mean age=36 [19-84]). In the whole population, rs3761548, rs3761549 and rs2294021 were associated with the susceptibility to PF. Interestingly, significant differences of gene distributions between the two sub-groups of patients were observed. In the endemic group, all associations observed in the whole population were maintained and reinforced and a new association was revealed with rs3761547; while in the sporadic group, only the association with rs3761549 was conserved. Further, the haplotype analysis showed that the G-A-C-15-C risk haplotype was significantly much more expressed in PF patients and specially in the endemic group. The phenotype-genotype correlation revealed that the rs3761548>AA genotype was significantly correlated with the severity of the disease including Nickolsky sign, generalized form of the disease and the earliest age onset. CONCLUSION: These results underline the particular genetic background of the Tunisian endemic PF and suggest the implication of FOXP3 gene in the susceptibility and the clinical course of the disease.

Autoimmune diseases association study with the KIAA1109-IL2-IL21 region in a Tunisian population.

Autoimmune diseases (ADs) share several genetic factors resulting in similarity of disease mechanisms. For instance polymorphisms from the KIAA1109-interleukin 2 (IL2)-IL21 block in the 4q27 chromosome, has been associated with a number of autoimmune phenotypes. Here we performed a haplotype-based analysis of this AD related region in Tunisian patients. Ten single nucleotide polymorphisms (rs6534347, rs11575812, rs2069778, rs2069763, rs2069762, rs6852535, rs12642902, rs6822844, rs2221903, rs17005931) of the block were investigated in a cohort of 93 systemic lupus erythematosus (SLE), 68 ulcerative colitis (UC), 39 Crohn's disease (CD) patients and 162 healthy control subjects of Tunisian origin. In SLE population, haplotypes AGCAGGGTC, AGAAGAGTC, AGAAGGGTC and AGCCGAGTC provided significant evidence of association with SLE risk (p = 0.013, 0.028, 0.018 and 0.048, respectively). In the UC population, haplotype AGCCGGGTC provided a susceptibility effect for UC (p = 0.025). In the CD population, haplotype CAGGCC showed a protective effect against the development of CD (p = 0.038). Haplotype AAGGTT provided significant evidence to be associated with CD risk (p = 0.007). Our results support the existence of the associations found in the KIAA1109/IL2/IL21 gene region with ADs, thus confirms that the 4q27 locus may contribute to the genetic susceptibility of ADs in the Tunisian population.