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Cyclin-dependent kinases 4/6 (CDK4/6) and D1-type cyclins (CCND1) can regulate the pro-inflammatory functions of various cytokines during the inflammatory response. This study investigated the association between CDK4/6-CCND1 variants and susceptibility in patients with Behcet's disease (BD). This case-control study enrolled 542 patients with BD and 754 healthy controls. Fourteen tagged single nucleotide polymorphisms (tag SNPs) of the CDK4/6-CCND1 gene were genotyped using the Sequenom MassARRAY system and iPLEX® Pro assay. The results indicated that the frequency of the CDK6 rs2282983 TT genotype was higher in the BD group than the control group (Pc = 0.040, OR = 1.408, 95% CI = 1.124-1.765), and CDK6 rs2282983 CT and rs42034 AG were negatively associated with BD (Pc = 3.647 × 10 -4 , OR = 0.598, 95% CI = 0.471-0.758; Pc = 0.039, OR = 0.626, 95% CI = 0.459-0.852, respectively). Furthermore, statistical analysis showed that CDK6 rs2282983 TT and CT genotypes were significantly associated with skin lesions in patients with BD (Pc = 0.042, OR = 1.436, 95% CI = 1.130-1.824; Pc = 0.001, OR = 0.594, 95% CI = 0.461-0.764, respectively). This study suggests that the CDK6 loci rs2282983 and rs42034 might confer genetic susceptibility to BD in a Han Chinese population, which could provide new insights into the pathogenesis of BD., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Objective: To explore susceptibility loci associated with uveitis in Behçet's disease (BD)., Methods: We conducted a 2-stage study, consisting of a genome-wide association study (GWAS) stage and a replication stage, in a Chinese population. The GWAS stage included 978 cases with BD-related uveitis and 4,388 controls, and the replication stage included 953 cases with BD-related uveitis and 2,129 controls. Luciferase reporter analysis and chromatin immunoprecipitation assay were performed to explore the functional role of susceptibility genetic variants near ZMIZ1., Results: Three independent HLA alleles (HLA-B51 [3.75 × 10 -190 ], HLA-A26 [1.50 × 10 -18 ], and HLA-C0704 [3.44 × 10 -16 ]) were identified as having a genome-wide association with BD-related uveitis. In the non-HLA region, in addition to confirming 7 previously reported loci, we identified 22 novel susceptibility variants located in 16 loci. Meta-analysis of the Chinese cohort consisting of 1,931 cases and 6,517 controls and a published Japanese cohort of 611 cases and 737 controls showed genome-wide significant associations with ZMIZ1, RPS6KA4, IL10RA, SIPA1-FIBP-FOSL1, and VAMP1. Functional experiments demonstrated that genetic variants of ZMIZ1 were associated with enhanced transcription activity and increased expression of ZMIZ1., Conclusion: This GWAS study identified a novel set of genetic variants that are associated with susceptibility to uveitis in BD. These findings enrich our understanding of the contribution of genetic factors to the disease., (© 2021 American College of Rheumatology.)

Background: Earlier, we reported that the microRNA (miR)-155 expression in dendritic cells (DCs) from Behcet's disease (BD) patients was decreased and affected cytokine production of DCs. In this study, we investigated the mechanisms whereby miR-155 regulates cytokine production by DCs., Methods: The formation of autophagosomes in DCs was detected by transmission electron microscopy. Western blotting was used to detect the protein levels of LC3, Beclin-1, P62, p-mTOR, and p-Akt in DCs. TNF-α, IL-6, and IL-1β expression were investigated by ELISA. MiR-155 mimics were transfected to DCs to evaluate its effects on autophagy and cytokine production. RNA interference was used to downregulate the expression of TAB2., Results: The formation of autophagosomes was found in DCs of active BD patients. The expressions of LC3-II, Beclin-1, and P62 were significantly increased in DCs of active BD patients compared to that of inactive BD patients and healthy controls. The expressions of IL-6, IL-1β, and TNF-α were significantly increased in DCs of active BD patients compared to that of healthy controls. The autophagy promoter (3-MA) and inhibitor (rapamycin) significantly decreased or increased the expression of TNF-α, IL-6, and IL-1β by DCs. The expression of LC3-II and Beclin-1 was significantly increased, but the expression of P62 proteins was decreased in DCs transfected with miR-155 mimics or after TAB2 was downregulated. The expression of TNF-α, IL-6, and IL-1β was decreased in DCs after miR-155 was upregulated or TAB2 was downregulated. The ratios of p-Akt/Akt and p-mTOR/mTOR were decreased in DCs after miR-155 was upregulated., Conclusions: These results suggest that miR-155 affects the production of TNF-α, IL-6, and IL-1β by DCs through activation of the Akt/mTOR signaling pathway and by affecting the process of autophagy.

Importance: Although experimental studies support the hypothesis that exposure of infectious agents may trigger an aberrant immune response and contribute to noninfectious uveitis, the association of a definite pathogen with human noninfectious uveitis conditions appears not to have been well established in a population., Objective: To evaluate associations of tuberculosis infection with risk of several noninfectious uveitis conditions., Design, Setting, and Participants: These mendelian randomization and observational analyses were conducted with the genetic data of a Chinese cohort enrolled between April 2008 and January 2018 and a Japanese cohort enrolled between January 2002 and June 2009. We recruited participants for T-SPOT.TB (Oxford Immunotec) assays between July and November 2019. The Chinese cohort included patients with uveitis associated with Behçet disease or other uveitis conditions and control participants. The Japanese cohort and the group given T-SPOT.TB assays included individuals with Behçet disease and control participants. Data analyses for this study were completed from July 2019 to January 2020., Exposures: Genetic variants associated with tuberculosis as natural proxies for tuberculosis exposure., Main Outcomes and Measures: The primary outcome was the odds ratio (OR) for Behçet disease, estimated by an inverse variance weighted mean of associations with genetically determined tuberculosis susceptibility. The T-SPOT.TB positivity rate was examined in individuals with Behçet disease and compared with that of control participants., Results: The Chinese cohort included 999 patients with uveitis associated with Behçet disease, 1585 with other uveitis conditions, and 4417 control participants. The Japanese cohort included 611 individuals with Behçet disease and 737 control participants. The group given T-SPOT.TB assays included 116 individuals with Behçet disease and 121 control participants. Of the Chinese individuals with Behçet disease and control participants, 2257 (41.7%) were female and the mean (SD) age was 35.4 (12.5) years. In the Japanese cohort, 564 (41.8%) were female and the mean (SD) age was 39.1 (12.7) years. Genetically determined tuberculosis susceptibility was associated with an increased risk for Behçet disease. The OR for Behçet disease per 2-fold increase in tuberculosis incidence was 1.26 (95% CI, 1.12-1.43; P = 1.47 × 10-4). Replication using the Japanese cohort yielded similar results (OR, 1.16 [95% CI, 1.08-1.26]). In T-SPOT.TB assays, having a positive result, indicating a history of tuberculosis infection, was found to be an independent risk factor for Behçet disease (OR, 2.26 [95% CI, 1.11-4.60])., Conclusions and Relevance: These human genetic and biomarker data demonstrated that tuberculosis exposure was a risk factor for Behçet disease. This study provides novel evidence linking an infectious agent to the risk of a noninfectious uveitis condition.

Background & Aim: Previous studies showed a vitamin D deficiency in patients with Behçet's disease, suggesting potential benefits of vitamin D supplementation in the prevention and treatment of Behçet's disease. Interpretation of these studies may be limited by reverse causality or confounding bias. We aim to determine the causal association between serum 25-hydroxyvitamin D [25(OH)D] and the risk of Behçet's disease by Mendelian randomization., Methods: An allele score formed by four variants (rs2282679, rs10741657, rs12785878 and rs6013897) that were associated with serum 25(OH)D level, was examined using data of genome-wide association study (GWAS) on 999 Behçet's disease and 4417 healthy individuals of Chinese ancestry and validated using data of GWAS on 1215 Behçet's disease and 1278 controls of Turkish ancestry. The primary outcome was the risk of Behçet's disease, evaluated by an inverse variance weighted average of the associations with genetically determined 25(OH)D levels., Results: The inverse variance weighted estimate showed that genetically increased 25(OH)D level was associated with a higher risk of Behçet's disease. In the Chinese cohort, the odds ratio for Behçet's disease in one standard deviation increase of natural log-transformed 25(OH)D level was 3.82 (95% CI: 1.27-11.42). Data from Turkish cohort confirmed the association with Behçet's disease (OR, 95% CI: 4.18, 1.15-15.12). In overall combination of Chinese and Turkish cohorts, the odds ratio for Behçet's disease per standard deviation increase of natural log-transformed 25(OH)D level was estimated to be 3.96 (95% CI: 1.72-9.13; P = 0.001). No significant evidence of pleiotropy and heterogeneity was detected., Conclusions: On the basis of evidence in 7909 human beings, this study provides the newest indication that a lifelong higher 25(OH)D level is associated with an increased risk of Behçet's disease. Special attention should be paid to the potential harm of long-term or high-dose use of vitamin D supplements in clinical practice., Competing Interests: Conflicts of interest The authors declare no conflict of interests., (Copyright © 2020 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)

Purpose: To investigate the associations of single nucleotide polymorphisms (SNPs) of three genes (IL-12B, IL-12Rβ1 and IL-12Rβ2) in Behcet's disease (BD) and Vogt-Koyanagi-Harada (VKH) syndrome in a Chinese Han population., Methods: A total of 806 BD cases, 820 VKH patients, and 1600 healthy controls were involved in this study. The first investigation included 400 BD patients, 400 VKH cases, and 600 healthy individuals. A second confirmatory study included a separate set of 406 BD patients, 420 VKH cases and another 1000 normal controls. Genotyping was carried out by PCR-restriction fragment length polymorphism assay and results were validated by using direct sequencing. The χ2 test was performed to compare the allele and genotype frequencies between cases and healthy controls., Results: This study comprised two phases. In the first phase study, a significantly increased frequency of the rs3212227/IL-12B genotype CC and C allele was found in BD patients as compared to controls (Bonferroni corrected p value (pc) = 0.009, OR 1.8; pc = 0.024, OR 1.3, respectively). Moreover, the frequency of the C allele of rs3212227/IL-12B was also significantly increased in VKH patients (pc = 0.012, OR 1.3, 95% CI 1.1 to 1.6). No associations were found for the other seven tested SNPs either in BD or VKH disease. The second study as well as the combined data confirmed the significant association of rs3212227/IL-12B with BD (CC genotype: combined pc = 6.3×10(-7), OR = 1.8; C allele: combined pc = 2.0×10(-5), OR = 1.3, respectively) and the C allele frequency of rs3212227/IL-12B as the risk factor to VKH patients (combined pc = 2.5×10(-5), OR 1.3, 95% CI 1.2 to 1.5)., Conclusions: Our study revealed that the IL-12B gene is involved both in the susceptibility to BD as well as VKH syndrome.

Aim: MicroRNA-146a (miR-146a) is involved in certain immune-mediated diseases. Transcription factor Ets-1 strongly affects miR-146a promoter activity and directly regulates miR-146a expression. This study was performed to investigate the association of miR-146a and Ets-1 gene polymorphisms with Behçet's disease (BD) and Vogt-Koyanagi-Harada (VKH) disease in a Chinese Han population., Methods: A total of 809 patients with BD, 613 patients with VKH and 1132 normal controls were genotyped for miR-146a/rs2910164, rs57095329 and rs6864584, Ets-1/rs1128334 and rs10893872 using a PCR restriction fragment length polymorphism assay. miR-146a expression was examined in peripheral blood mononuclear cells (PBMCs) by real-time PCR. Cytokine production by PBMCs was measured by ELISA., Results: A significantly decreased frequency of the homozygous rs2910164 CC genotype and C allele was observed in patients with BD compared with controls (pc(a)=1.24×10(-5), OR 0.61; pc(a)=1.33×10(-4), OR 0.75, respectively). MiR-146a expression in GG cases was 2.45-fold and 1.99-fold higher, respectively, than that in CC cases and GC cases. There was no association of the other four single nucleotide polymorphisms (SNPs) with BD. There was also no association of these five SNPs with its main clinical features. No associations were found with the five SNPs tested or with its clinical manifestations in VKH disease. Interleukin (IL)-17, tumour necrosis factor (TNF)α and IL-1β production from rs2910164 CC cases was markedly lower than that in GG cases. No effect of genotype was observed on IL-6 and monocyte chemoattractant protein (MCP)-1 production and IL-8 expression was slightly higher in CC cases., Conclusions: Our study identified a strong association of rs2910164 of miR-146a with BD in a Chinese population and decreased expression of miR-146a and certain proinflammatory cytokines in individuals carrying the CC genotype.

The tumor necrosis factor alpha-inducible protein 3 (TNFAIP3) gene polymorphisms have recently been reported to be associated with the susceptibility to several immune-related diseases. This study was performed to evaluate the potential association of TNFAIP3 polymorphisms with Behcet's disease (BD) in a Chinese Han population. Five single-nucleotide polymorphisms (SNPs), rs10499194, rs610604, rs7753873, rs5029928, and rs9494885 of TNFAIP3 were genotyped in 722 BD patients and 1,415 healthy controls using a PCR-restriction fragment length polymorphism assay. Allele and genotype frequencies were compared between patients and controls using the χ (2) test. The results showed a significantly increased prevalence of the rs9494885 TC genotype and C allele in BD patients compared with controls (Bonferroni corrected p (p (c)) = 1.83 × 10(-10), odds ratio (OR) [95% CI] 2.03 [1.65-2.49]; p (c) = 8.35 × 10(-10), OR [95% CI] 1.81 [1.51-2.18], respectively).The frequency of the TT genotype and T allele of rs9494885 was markedly lower in BD patients than that in controls (p (c) = 1.23 × 10(-10), OR [95% CI] 0.50 [0.40-0.61]; p (c) = 8.35 × 10(-10), OR [95% CI] 0.55 [0.46-0.66], respectively). For rs10499194, a higher frequency of the CC genotype (p (c) = 0.015, OR [95% CI] 1.96 [1.30-2.97]) and C allele (p (c) = 0.005, OR [95% CI] 1.92 [1.28-2.90]), and a lower frequency of the TC genotype (p (c) = 0.015, OR [95% CI] 0.51 [0.34-0.77]) and T allele (p (c) = 0.005, OR [95% CI] 0.52 [0.35-2.97]) were found in BD patients. Concerning rs7753873, a higher frequency of the AC genotype (p (c) = 0.015, OR [95% CI] 1.49 [1.17-1.91]) and C allele (p (c) = 0.025, OR [95% CI] 1.39 [1.11-1.76]), and a lower frequency of the AA genotype (p (c) = 0.03, OR [95% CI] 0.68 [0.53-0.87]) and A allele (p (c) = 0.025, OR [95% CI] 0.72 [0.57-0.91]) were observed in BD patients. This study identified one strong risk SNP rs9494885 and two weak risk SNPs rs10499194 and rs7753873 of TNFAIP3 in Chinese Han BD patients.

Purpose: Behçet's disease (BD) is a chronic systemic inflammatory disorder of unknown etiology. Toll-like receptors (TLRs) are critical in the innate immune response to microbial invaders. In this study we investigated the role of TLRs in the pathogenesis of BD., Methods: TLR2/4 expression and IL-1β and reactive oxygen species (ROS) production were studied in monocyte-derived macrophages (MDMs) obtained from BD patients, acute anterior uveitis (AAU) patients, and healthy controls using real-time PCR, flow cytometry, and ELISA. The NLRP3 inflammasome of MDMs was downregulated by RNA interference. The levels of phosphorylated P38, Erk1/2, and JNK MAPK were evaluated using flow cytometry., Results: TLR2/4 expression was significantly increased in MDMs from active BD patients. IL-1β and ROS production of peptidoglycan (PGN)/lipopolysaccharide (LPS)-induced MDMs from active BD patients was significantly increased compared with inactive BD patients, AAU patients, and healthy controls. ROS activator and inhibitor significantly increased and decreased the production of IL-1β, respectively. The production of IL-1β was significantly decreased after the NLRP3 inflammasome was downregulated. The phosphorylation levels of p38 and ERK1/2 in MDMs from BD patients and controls were increased following stimulation with either PGN or LPS. Both SB203580 (p38 inhibitor) and PD98059 (ERK1/2 inhibitor) significantly decreased the production of IL-1β., Conclusions: The results suggest that TLR2/4 expression in MDMs from active BD patients is significantly increased. Interaction of TLR2/4 with their ligands PGN/LPS is involved in BD pathogenesis, possibly by the induction of IL-1β through a ROS-NLRP3-dependent pathway.

Objective: Interleukin (IL)-22 has been reported to be involved in the development of autoimmune diseases. This study aimed to analyze the expression and potential role of IL-22 in the pathogenesis of Behcet's disease (BD)., Methods: The levels of IL-22 in patient sera or supernatants of cultured peripheral blood mononuclear cells (PBMCs) and CD4(+)T cells were detected by enzyme-linked immunosorbent assay (ELISA). Flow cytometry was used to evaluate the frequency of IL-22-producing CD4(+) T cells. IL-22 mRNA from erythema nodosum skin lesions was examined using real time quantitative RT-PCR., Results: BD patients with active uveitis showed a significantly higher expression of IL-22 in the supernatants of stimulated PBMCs and CD4(+)T cells compared with BD patients without active uveitis and normal controls. An increased frequency of IL-22-producing CD4(+)T cells was also found in BD patients with active uveitis. IL-22 mRNA expression was elevated in erythema nodosum skin lesions. In BD patients, a high IL-22 level in the supernatant of stimulated PBMCs correlated with the presence of retinal vasculitis and erythema nodosum., Conclusions: IL-22 was associated with disease activity in BD and correlated with the presence of small vessel inflammation, suggesting that it may be involved in its pathogenesis.

Objective: To identify susceptibility loci for Behçet's disease (BD) and elucidate their functional role., Methods: A genome-wide association study (GWAS) and functional studies were conducted. A total of 149 patients and 951 controls were enrolled in the initial GWAS, and 554 patients and 1,159 controls were enrolled in the replication study. Real-time polymerase chain reaction, luciferase reporter assay, and enzyme-linked immunosorbent assay were performed., Results: Our GWAS and replication studies identified a susceptibility locus around STAT4 (single-nucleotide polymorphisms [SNPs] rs7574070, rs7572482, and rs897200; P = 3.36 × 10(-7) to 6.20 × 10(-9) ). Increased expression of STAT4 was observed in individuals carrying the rs897200 risk genotype AA. Consistent with the idea that STAT4 regulates the production of interleukin-17 (IL-17) and interferon-γ, IL17 messenger RNA and protein levels were increased in individuals carrying the rs897200 risk genotype AA. Interestingly, the risk allele A of rs897200 creates a putative transcription factor binding site. To test whether it directly affects STAT4 transcription, an in vitro luciferase reporter gene assay was performed. Higher transcription activity was observed in individuals carrying the risk allele A, suggesting that rs897200 is likely to directly affect STAT4 expression. Additionally, 2 SNPs, rs7574070 and rs7572482, which are tightly linked with rs897200, were cis-expression quantitative trait loci (eQTL) SNPs, suggesting that SNP rs897200 is an eQTL SNP. Most importantly, the clinical disease severity score was higher in individuals with the rs897200 risk genotype AA., Conclusion: These findings strongly suggest that STAT4 is a novel locus underlying BD. We propose a model in which up-regulation of STAT4 expression and subsequent STAT4-driven production of inflammatory cytokines, such as IL-17, constitute a potential pathway leading to BD., (Copyright © 2012 by the American College of Rheumatology.)

Purpose: MicroRNAs (miRNAs) have emerged as a class of gene expression regulators involved in immune regulation. In the present study, we investigated the role of miRNA in two uveitis entities: Behcet's disease (BD) and Vogt Koyanagi Harada syndrome (VKH)., Methods: The expression of five miRNAs was studied in PBMCs, DCs, and CD4(+) T cells from BD patients with active and inactive uveitis, VKH patients with active uveitis, and healthy controls using real-time PCR. MiR-155 mimics and inhibitor were transfected to DCs to evaluate the effect on DC maturation and cytokine production by these cells and CD4(+) T cells. Luciferase reporter assays and Western blotting were performed to identify the target gene of miR-155., Results: Only miR-155 expression was significantly decreased in PBMCs and DCs from BD patients with active uveitis and no differences were observed in the miRNA expression in cells from patients with VKH as compared with controls. Overexpression of miR-155 in DCs was shown to inhibit the production of IL-6 and IL-1β, and to promote the expression of IL-10 by these cells. MiR-155 transfected DCs significantly inhibited intracellular IL-17 expression in allogeneic CD4(+) T cells; however, it did not influence the expression of cell surface markers CD80, CD40, CD83, CD86, and HLA-DR. Luciferase reporter assays revealed that TAB2 was a target gene of miR-155, which was confirmed by Western blotting., Conclusions: The present results suggest that miR-155 expression is decreased in active BD but not in VKH patients. Downregulated miR-155 may be involved in BD pathogenesis by targeting TAB2.