Kamel Hamzaoui

Expression of Th-17 and RORgammat mRNA in Behçet’s Disease

Summary Background To investigate plasma IL-17 level and the expression of Th17 cell transcription factor RORγt in the pathogenesis of Behçet’s Disease (BD). Material/Methods Blood samples were collected from 73 patients with BD (45 patients were in active stage), 20 systemic lupus erythematosus (SLE) and 12 multiple sclerosis patients (MS). Twelve patients with BD were investigated both in their active and remission stages. Samples were processed to detect IL-17A level in plasma by enzyme-linked immunosorbent assay (ELISA). Related gene expression was assessed by real-time reverse transcription polymerase chain reaction. Function of Th17 cells in active BD patients with erythema nodosum (EN)-like eruption was studied in relation to human umbilical vein endothelial cells (HUVECs). Results We demonstrated the presence of Th17 cells and RORγt among the peripheral blood mononuclear cells (PBMC). The percentage of circulating Th17 cells and the ability to produce interleukin-17A (IL-17A) were increased in samples derived from patients with active BD, MS and SLE patients. We observed that IL-17A from patients with active BD could induce adhesion molecule messenger RNA expression in HUVECs. Conclusions RORγt determined Th17 cell might be involved with increased IL-17A in BD. Our results indicate that IL-17 contributes to the active proinflammatory pattern that is characteristic of inflammatory diseases and patients with active BD.

RORC and Foxp3 axis in cerebrospinal fluid of patients with Neuro-Behçet's Disease

Neurological manifestations are present in 5% to 30% of patients with Behçets disease (BD). Neuro-Behçets Disease (NBD) is hypothetically caused by T helper (Th) cells, which development is dependent on the expression of lineage-specific transcription factors. Cerebrospinal fluid (CSF) mRNA expression of TBX21, GATA3, RORC, FOXP3 and EBI3 were assessed in 18 NBD patients and 26 controls disease [16 noninflammatory neurological disease (NIND) and 10 headache attributed to Behçets disease (HaBD)]. Expression of TBX21 (Th1), RORC (Th17) and Foxp3 (Treg) were increased in NBD patients compared to HaBD and NIND patients. EBI3 and Th2-associated GATA3 expressions were found to be decreased (P<0.0001 and P<0.0001) in NBD patients. Analysis of transcription factor ratios, revealed an increase in the RORC/FOXP3 and TBX21/GATA3 ratios in NBD patients (P<0.0001; P<0.0003). Our findings indicate that both Th1 and Th17 mRNA expressions involving a possible impairment of Treg cells. This might play a role in CSF-NBD inflammation, permitting activation of harmful T cell subpopulations. The TBX21/GATA3 and RORC/FOXP3 ratios dysregulations in NBD are consistent with those reported in other inflammatory diseases and indicating the plasticity existing between Th1, Th17 and Treg cells during inflammation.

Associations of vitamin D receptor gene polymorphisms FokI and BsmI with susceptibility to rheumatoid arthritis and Behçet's disease in Tunisians

OBJECTIVES Reports of immunomodulating effects of vitamin D suggest a need for examining allele and genotype frequencies of the vitamin D nuclear receptor gene (VDR) in patients with autoimmune diseases. T-helper-1 (Th1) counts in peripheral blood are increased in both rheumatoid arthritis (RA) and Behçets disease (BD). We studied VDR polymorphisms in patients with these two diseases in Tunisia. METHODS In 108 patients with RA, 131 patients with BD, and 152 controls, we studied FokI and BsmI VDR polymorphisms, using the restriction fragment length polymorphism technique. RESULTS The FokI polymorphism alleles and genotype were significantly more common in the RA group than in the controls (P=0.001 and P=0.005, respectively). The FokI F allele and F/F genotype were significantly associated with BD (P=0.0003 and P=0.002, respectively). Furthermore, in the group with BD, the FokI polymorphism was significantly associated with the presence of vascular manifestations (P=0.006). In patients with RA, the FokI polymorphism was significantly associated with female gender (P=0.003). No significant associations were found between the Bsm1 polymorphism and RA or BD. CONCLUSION The VDR F allele is associated with RA and BD in Tunisians.

Contribution of VDR polymorphisms to type 1 diabetes susceptibility: Systematic review of case–control studies and meta-analysis

Vitamin D receptor (VDR) polymorphisms have been inconsistently investigated in type 1 diabetes (T1D). However, the results are inconsistent and inconclusive. The current study aimed to investigate the role of TaqI, BsmI, ApaI and FokI VDR polymorphisms in T1D disease. Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, a systematic search and meta-analysis of the literature, since 1998 until december 2013, was conducted. Subgroup analyses were performed to detect potential sources of heterogeneity from selected study characteristics. Meta-analyses yielded a non-significant association of TaqI polymorphism with T1D [OR=1.014 (0.783-1.312); P=0.918] in the recessive model. The BsmI polymorphism was not associated with T1D [OR=1.44 (0.944-1.386); P=0.171] in the dominant model. Also, ApaI polymorphism was not associated with T1D risk [OR=0.996 (0.859-1.155); P=0.960] in the homozygous model. The FokI polymorphism was not associated with T1D risk [OR=0.968 (0.743-1.263); P=0.813] in dominant model. Stratification according to study characteristics showed that publication year, age, gender, estimated vitamin D levels and latitude moderated significantly association between VDR polymorphisms and T1D disease. Meta-analysis on haplotypes revealed that BAT might be a significant risk factor for T1D [OR=1.331 (0.957-1.850; P=0.089]. However, the bAT was found to be a significant protective factor [OR=0.639 (0.460-0.887); P=0.007]. As conclusion, individual VDR polymorphisms seemed not to be associated with T1D risk. However, haplotypes contributed significantly to disease susceptibility. Study characteristics moderated the association between VDR polymorphisms and T1D. These results suggested that, in T1D pathogenesis, VDR polymorphisms interact with each other and with environmental factors.

Vitamin D reduces the differentiation and expansion of Th17 cells in young asthmatic children.

Vitamin D [25(OH)D3] deficiency has been associated with asthma as in many inflammatory and autoimmune pathologies; however, there is still a lack of data about the effects of administration of vitamin D in immune regulation in young asthmatic patients. In this study, we investigated its inhibitory effect on the immune response in young asthmatic patients and the possible mechanisms involved. Peripheral blood CD4(+) T cells from 10 asthmatic patients and 10 healthy controls were cultured under Th17 polarizing conditions in the presence or absence of [25(OH)D3], IL-17 cytokine production was determined by ELISA and flow cytometry. Messenger RNA (mRNA) expression of several factors related to Th17 cell function was determined by real-time PCR. The effect of [25(OH)D3]-treated dendritic cells (DCs) on CD4(+) T cell response was determined by ELISA and flow cytometry. Stimulation of naive CD4(+) T cells under Th17 polarizing conditions showed a higher Th17 cell differentiation in asthmatic patients than healthy controls. The addition of [25(OH)D3] significantly inhibited Th17 cell differentiation both in patients [P<0.001] and in normal controls [P=0.001] in a dose-dependent way. [25(OH)D3] was able to inhibit the gene expression of RORC, IL-17, IL-23R, and CCR6. [25(OH)D3]-treated DCs significantly inhibited IL-17 production [P=0.002] and decreased the percentage of CD4(+)IL-17(+) [P=0.007] in young asthmatics. The findings suggest that the inhibitory effect of [25(OH)D3] on the Th17 response was mediated via both T cells and DCs. DCs pathway is involved in the direct inhibition of 25(OH)D3 on Th17 cell differentiation in young asthmatics.

Interleukin-17A and -17F genes polymorphisms in lung cancer

Interleukin-17 (IL-17) is a proinflammatory cytokines produced by T helper 17 (Th17) cells, which plays an important role in both innate and adaptive immune systems. Genetic variants in the IL-17 genes may influence the immunopathogenesis of many cancers. In our study, we investigated the association of three single-nucleotide polymorphisms (SNPs: -152 G/A, 7488 A/G and 7383 A/G) in the IL-17A and IL-17F genes with lung cancer risk, in the Tunisian population. The genotypic and allelic distributions of IL-17A and IL-17F genes polymorphisms were analyzed by Polymerase Chain-Reaction (PCR) and Restriction Fragment Length Polymorphism (RFLP) for 239 patients and 258 healthy controls. Our results revealed a statistically significant association between IL-17F 7488G allele and increased lung cancer risk (P=0.028). Stratification analysis indicated that IL-17F 7488G allele enhances the risk of lung cancer development among men and oldest age subject groups (P<0.05). Patients with IL-17F 7488G allele were also more likely to be diagnosed at advanced stage (P=0.04), or with metastatic lung cancer (P=0.035). Furthermore, no significant association between IL-17F 7383 A/G, IL-17 -152G/A polymorphisms and lung cancer risk was observed (P>0.05). However, we reported contradictory findings on the association of IL-17 -152 G/A polymorphisms with lung cancer risk. In addition, we suggested the existence of a biological interaction between IL-17A, but not IL-17F polymorphisms and smoking. Our findings suggest that IL-17F 7488G allele is associated with increased lung cancer risk in the Tunisian population.

NOD2 is highly expressed in Behçet disease with pulmonary manifestations

BackgroundExcessive Th1 cells and TLRs functions are involved in the pathogenesis of Behcets disease (BD) in response to bacterial antigens. NOD2, an intracellular pathogen recognition sensor, modulates innate defence to muropeptides derived from various bacterial species. To further define a role for NOD2 in BD, we analysed NOD2 transcriptional responses in BAL-MNC from BD patients with pulmonary manifestations.MethodsWe analysed NOD1, NOD2, T-bet and TLRs mRNA expression with real-time polymerase chain-reaction in BAL cells obtained from 23 BD patients with pulmonary manifestations and their matched controls.ResultsWe found that NOD2 mRNA expression was highly up-regulated in BAL cells from BD and sarcoidosis patients compared to healthy control group (P = 0.001). In BD patients, significant correlation was found between NOD2 and T-bet mRNA expression (r = 0.602; P = 0.0009). In BAL from BD patients, NOD2 and T-bet mRNA expression were significantly correlated with BAL-lymphocytes (r = 0.485, P = 0.010; r = 0684, P = 0.0001 respectively). NOD2 in BD was also correlated with TLR 2(r = 0.444; P = 0.021) and TLR 4 (r = 0.574; P = 0.001) mRNA expression.ConclusionOur results indicate that BAL-MNC from BD patients expressed NOD2 as a result of lung inflammation. TLRs and NOD2 synergize for the induction of proinflammatory cytokines. BAL inflammatory cells showed an increased Th1 situation as indicated by increased T-bet mRNA expression.

Association between VDR polymorphisms and rheumatoid arthritis disease: Systematic review and updated meta-analysis of case–control studies

BACKGROUND Vitamin D receptor (VDR) polymorphisms have been inconsistently investigated in rheumatoid arthritis (RA). However, published studies demonstrated differences concerning design and effect size. A meta-analysis is necessary to determine the magnitude of the association between VDR polymorphisms and RA risk. OBJECTIVE The aim of the current study was to quantify the magnitude of the association between TaqI, BsmI, and FokI VDR polymorphisms with RA risk. METHODS Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic search and meta-analysis of the literature were conducted. Analyses were performed in the random effects model by using recessive, dominant, codominant, homozygous, and allele contrast models. RESULTS A total of 1703 cases and 2635 controls in 12 case-control studies were included in the meta-analyses. Results indicated a significant association between TaqI polymorphism and RA disease in homozygous, codominant and allele contrast models (P=0.008, P=0.015, P=0.006 and P=0.002, respectively). Association between BsmI polymorphism and RA risk was marginal in the dominant, codominant and allele contrast models (P=0.057, P=0.071, and P=0.069, respectively). Te association between FokI polymorphism and RA risk was significant in the recessive, dominant and allele contrast models (P=0.045, P=0.027, and P=0.013, respectively). Subgroup analysis showed that publication year, ethnicity, age, latitude, and estimated 25(OH)D levels influenced significantly the association between VDR polymorphisms and RA risk. CONCLUSION TaqI and FokI VDR polymorphisms contributed significantly to RA risk. Study characteristics influenced the association between VDR polymorphisms and RA disease.

Vitamin D receptor TaqI and ApaI polymorphisms: A comparative study in patients with Behçet’s disease and Rheumatoid arthritis in Tunisian population

Recent genetic surveys have identified vitamin D receptor (VDR) as a susceptibility gene for several autoimmune diseases. This study was designed to investigate the association of VDR gene polymorphisms with Behçets disease (BD) and Rheumatoid arthritis (RA). A case-control study including 151 BD, 106 RA patients and an appropriate number of healthy control subjects were performed using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) techniques. Association between TaqI polymorphism and BD was marginal under codominant and recessive models (P=0.078 and P=0.058, respectively). After stratification, we found evidence for a significant association between TaqI polymorphism and BD in the elderly subjects (P=0.037). The minor ApaI a allele tended to confer an increased risk for BD susceptibility (P=0.087). BD patients with VDR homozygous AA or aa genotypes were at increased risk for development of erythema nodosum (EN) skin manifestation (P=0.038). No significant association was observed for VDR ApaI and TaqI polymorphisms with RA risk (P>0.05). TaqI and ApaI polymorphisms might be modestly implicated in BD pathogenesis. They could be considered as potential biomarkers in BD rather than susceptibility genes. However, TaqI and ApaI seemed not to be implicated in RA pathogenesis.

Intercellular adhesion molecule 1 K469E gene polymorphism is associated with presence of skin lesions in Tunisian Behçet's disease patients

Intercellular adhesion molecule 1 (ICAM1) gene polymorphisms have been implicated in the susceptibility to inflammatory diseases. The expression of both soluble and tissue ICAM1 were increased in Behçets disease (BD) but the contribution of ICAM1 gene polymorphisms to this disease remains unknown. We sought to establish the association of ICAM1 gene K469E polymorphism in exon 6 with susceptibility for BD. One hundred and thirty-five Tunisian patients who satisfied the International Study Group criteria for BD and 157 healthy blood donor controls from the same geographic area were genotyped by polymerase chain reaction method for the K469E ICAM1 gene polymorphisms in exon 6. There were no significant differences in the distribution of the K469E allele or genotype frequencies between the BD patients and healthy controls in the ICA1 gene. Among patients, significant association was found between the presence of skin lesions and the studied polymorphism in the distribution of the K469E allele (P = 0.004; odds ratio = 1.26; 95% confidence interval = 2.13-3.62) and genotype frequencies (P = 0.0028; chi(2) = 11.75). Our findings suggest that K469E ICAM1 gene polymorphism was associated with Tunisian BD patients with skin lesions.