Microbiome in Behcet's syndrome.

This review will discuss the current understanding of the role of microbiomes in Behcet's Syndrome, their influence on immune response and disease and potential future studies.

How to recognise a Behçet's ulcer from other types of oral ulceration? Defining Behçet's ulceration by an International Delphi Consultation.

OBJECTIVES: To define the clinical characteristics of oral ulceration (OU) in Behçet's disease (BD), to allow differentiation from other causes of OU, including aphthous ulcers, by an International Delphi consultation. To develop a clinical guideline on how to recognise BD ulcers. METHODS: Round 1. 40 clinical images of OU in BD, recurrent aphthous stomatitis (RAS), inflammatory bowel disease (IBD) and mucous membrane pemphigoid (MMP) were shown. Participants answered, independently, which images would be consistent with a BD ulcer. Round 2. The results from marking independently were shown. The panel remarked the questions through iteration process. The images not agreed to be a possible BD ulcer were discarded. Round 3. 10 clinical descriptors that may define BD ulcers were suggested. Participants ranked the level of importance for each descriptor on each image presented. Round 4. Participants re-ranked their level of agreement for each descriptor through iteration process. Whether the clinical pictures would be different from RAS was also explored. A final agreement was reached. RESULTS: This study has shown clear differentiation between BD, IBD and MMP ulcers when defining them by phenotype through clinical images only. On the other hand, no differentiation between RAS and BD ulcers was found. The most important clinical descriptors that define BD ulcers have been agreed. CONCLUSIONS: New clinical guidance for Health Care Professionals (HCP) on how to recognise a BD ulcer has been proposed. This should elucidate an earlier diagnosis, quicker access to treatment and control of the disease enhancing patient's quality of life.

KIR3DL1/S1 Allotypes Contribute Differentially to the Development of Behçet Disease.

Behçet disease is a chronic, relapsing-remitting autoinflammatory syndrome with a strong HLA-B*51 association. In this paper, we describe a human cohort of 267 individuals with Behçet disease and 445 matched controls from a tertiary referral center in the U.K. HLA-B*51 was confirmed as a genetic risk factor in this group (p = 0.0006, Bonferroni-Dunn correction for multiple testing [Pc] = 0.0192, odds ratio [OR] 1.92, 95% confidence interval [CI] 1.33-2.76). KIR3DL1/S1 allele-level analysis indicated that low-expressing KIR3DL1/S1 alleles in combination with KIR3DS1 increased the risk of developing Behçet disease (KIR3DL1LOW/KIR3DS1: p = 0.0004, Pc = 0.0040, OR 2.47, 95% CI 1.43-4.25), whereas high-expressing KIR3DL1/S1 alleles in combination with a null-expressing KIR3DL1 reduced the risk of disease (KIR3DL1HIGH/KIR3DL1NULL: p = 0.0035, Pc = 0.0350, OR 0.53, 95% CI 0.33-0.87). Behçet disease can manifest as a purely mucocutaneous disease or can involve other organ systems such as the eyes. In the U.K. cohort studied in this study, KIR3DL1LOW/KIR3DS1 increased the risk of ophthalmic disease (p = 1.2 × 10-5, OR 3.92, 95% CI 2.06-7.47), whereas KIR3DL1HIGH/KIR3DL1NULL reduced the risk of having purely mucocutaneous disease (p = 0.0048, OR 0.45, 95% CI 0.25-0.81). To our knowledge, this is the first analysis of KIR3DL1/S1 allelic variation in Behçet disease and may provide insight into the pathogenic role of HLA-B*51 and its interaction with KIR3DL1/S1.

Genetics of Behçet's disease.

PURPOSE OF REVIEW: This article discusses recent genetic and epigenetic associations involved in the pathogenesis of Behçet's disease. RECENT FINDINGS: Genetic studies have supported the strong association of human leukocyte antigen-B and Behçet's disease, and high production of tumour necrosis factor and low production of interleukin (IL)-10, which have led to therapy based on controlling these effects. Polymorphisms that affect the response to pathogens (TLR and FUT2) are leading to increased interest in responses to microbiomes. Inflammation in Behçet's disease results in vascular damage and several single nucleotide polymorphisms in chemokine and adhesion molecules may be involved in this process. Increased levels of inflammatory cytokines including IL-1ß and IL-17 have been linked to altered expression of microRNAs, miR155, miR21 and miR23b. DNA methylation changes in monocytes and lymphocytes have been described that affect the function of these cells. SUMMARY: Genetic and epigenetic changes affecting cells and molecules involved in Behçet's disease offer new pathways for research, including cytoskeletal protein function, that will provide new targets for therapy, and potentially address the ethnic differences seen in validation of gene studies.

Ciprofloxacin and ceftriaxone alter cytokine responses, but not Toll-like receptors, to Salmonella infection in vitro.

OBJECTIVES: Antibiotics that enhance host natural defences to infection offer an alternative approach to treating infections. However, mechanisms underlying such processes are poorly understood. The aim of this study was to investigate the effects of clinically relevant concentrations of two antibiotics on bacterial interactions with murine macrophages. METHODS: Adhesion of Salmonella Typhimurium SL1344 to and invasion by Salmonella Typhimurium SL1344 of antibiotic-treated or untreated J774 murine macrophages were measured using a tissue culture infection model. Expression of genes central to the Toll-like receptor (TLR) signalling pathway of macrophages infected with Salmonella was analysed using the RT(2) Profiler PCR Array. Cytokine production was measured by ELISA. RESULTS: Adhesion of Salmonella Typhimurium SL1344 to J774 macrophage monolayers was increased when macrophages were exposed to ciprofloxacin and ceftriaxone, while invasion was decreased by ciprofloxacin. Expression of IL-1ß and TNF-α mRNA was greater in SL1344-infected macrophages that had been treated with ciprofloxacin or ceftriaxone than in macrophages exposed to antibiotics alone or SL1344 alone. TLR mRNA was down-regulated by SL1344 infection, a response that was not altered by antibiotic pretreatment. CONCLUSIONS: Clinically relevant concentrations of two antibiotics differentially enhanced the response of immune cells and their interaction with bacteria, increasing bacterial adhesion to macrophages and increasing cytokine production. As increased expression of IL-1ß fosters apoptosis of Salmonella-infected macrophages and clearance by neutrophils, the immunomodulatory potential of these antibiotics may explain, in part, why these two drugs continue to be used to treat salmonellosis successfully.

The Use of 1α,25-Dihydroxyvitamin D3 as an Anticancer Agent.

The notion that vitamin D can influence the incidence of cancer arose from epidemiological studies. The major source of vitamin D in the organism is skin production upon exposure to ultra violet-B. The very first observation of an inverse correlation between exposure of individuals to the sun and the likelihood of cancer was reported as early as 1941. In 1980, Garland and Garland hypothesised, from findings from epidemiological studies of patients in the US with colon cancer, that vitamin D produced in response to sun exposure is protective against cancer as opposed to sunlight per se. Later studies revealed inverse correlations between sun exposure and the occurrence of prostate and breast cancers. These observations prompted laboratory investigation of whether or not vitamin D had an effect on cancer cells. Vitamin D is not active against cancer cells, but the most active metabolite 1α,25-dihydroxyvitamin D3 (1,25D) has profound biological effects. Here, we review the anticancer action of 1,25D, clinical trials of 1,25D to date and the prospects of the future therapeutic use of new and low calcaemic analogues.

Progenitor cells are mobilized by acute psychological stress but not beta-adrenergic receptor agonist infusion.

OBJECTIVES: Stimuli that activate the sympathetic nervous system, such as acute psychological stress, rapidly invoke a robust mobilization of lymphocytes into the circulation. Experimental animal studies suggest that bone marrow-derived progenitor cells (PCs) also mobilize in response to sympathetic stimulation. Here we tested the effects of acute psychological stress and brief pharmacological ß-adrenergic (ßAR) stimulation on peripheral PC numbers in humans. METHODS: In two studies, we investigated PC mobilization in response to an acute speech task (n=26) and ßAR-agonist (isoproterenol) infusion (n=20). A subset of 8 participants also underwent the infusion protocol with concomitant administration of the ßAR-antagonist propranolol. Flow cytometry was used to enumerate lymphocyte subsets, total progenitor cells, total haematopoietic stem cells (HSC), early HSC (multi-lineage potential), late HSC (lineage committed), and endothelial PCs (EPCs). RESULTS: Both psychological stress and ßAR-agonist infusion caused the expected mobilization of total monocytes and lymphocytes and CD8(+) T lymphocytes. Psychological stress also induced a modest, but significant, increase in total PCs, HSCs, and EPC numbers in peripheral blood. However, infusion of a ßAR-agonist did not result in a significant change in circulating PCs. CONCLUSION: PCs are rapidly mobilized by psychological stress via mechanisms independent of ßAR-stimulation, although the findings do not exclude ßAR-stimulation as a possible cofactor. Considering the clinical and physiological relevance, further research into the mechanisms involved in stress-induced PC mobilization seems warranted.

The immune response and antibacterial therapy.

The host's immune defence mechanisms are indispensable factors in surviving bacterial infections. However, in many circumstances, the immune system alone is inadequate. Since the 1940s, the use of antibacterial therapy has saved millions of lives, improving the span and quality of life of individuals. Unfortunately, we are now facing an era where antibacterial agents are threatened by resistance. In addition to targeting bacteria, some antibacterial agents affect various aspects of the immune response to infection. Since many antibacterial drugs are failing in efficacy due to resistance, it has been strongly suggested that any synergy between these drugs and the immune response be exploited in the treatment of bacterial infections. This review explores the influence of antibacterial therapy on the immune response and new approaches that could exploit this interaction for the treatment of bacterial infections.

Relaxation of mitochondrial hyperfusion in the diabetic retina via N6-furfuryladenosine confers neuroprotection regardless of glycaemic status.

The recovery of mitochondrial quality control (MQC) may bring innovative solutions for neuroprotection, while imposing a significant challenge given the need of holistic approaches to restore mitochondrial dynamics (fusion/fission) and turnover (mitophagy and biogenesis). In diabetic retinopathy, this is compounded by our lack of understanding of human retinal neurodegeneration, but also how MQC processes interact during disease progression. Here, we show that mitochondria hyperfusion is characteristic of retinal neurodegeneration in human and murine diabetes, blunting the homeostatic turnover of mitochondria and causing metabolic and neuro-inflammatory stress. By mimicking this mitochondrial remodelling in vitro, we ascertain that N6-furfuryladenosine enhances mitochondrial turnover and bioenergetics by relaxing hyperfusion in a controlled fashion. Oral administration of N6-furfuryladenosine enhances mitochondrial turnover in the diabetic mouse retina (Ins2Akita males), improving clinical correlates and conferring neuroprotection regardless of glycaemic status. Our findings provide translational insights for neuroprotection in the diabetic retina through the holistic recovery of MQC.

Genome-wide association study identifies GIMAP as a novel susceptibility locus for Behcet's disease.

OBJECTIVES: To identify non-major histocompatibility complex susceptible genes that might contribute to Behçet's disease (BD). METHODS: We performed a genome-wide association study using DNA samples from a Korean population consisting of 379 BD patients and 800 controls. A replication study was performed in a Japanese population (363 BD patients and 272 controls). To evaluate the functional implication of the target single nucleotide polymorphisms (SNP), gene expression levels in peripheral T cells, allele-specific modulation of promoter activity and biological effect of mRNA knockdown were investigated. RESULTS: We found a novel association of BD to the GIMAP locus, mapped to chromosome 7q36.1 (rs1608157, p=6.01×10(-8) in a minor allele dominant model; rs11769828, allele based p=1.60×10(-6)). A fine mapping study identified an association with four additional SNP: rs1522596 (OR=1.45, p=7.70×10(-6)) in GIMAP4; rs10266069 (OR=1.32, p=2.67×10(-4)) and rs10256482 (OR=1.27, p=5.27×10(-4)) in GIMAP2; and rs2286900 (OR=1.61, p=3.53×10(-5)) in GIMAP1 areas. Replication study using DNA samples from the Japanese population validated the significant association between BD and the GIMAP locus. The GIMAP4 promoter construct plasmid with the minor allele of rs1608157 displayed significantly lower activity than one with the major allele. Moreover, CD4 T cells from BD patients showed a lower level of GIMAP4 mRNA, and GIMAP4 knockdown was protective against Fas-mediated apoptosis. CONCLUSIONS: These results suggest that a GIMAP cluster is a novel susceptibility locus for BD, which is involved in T-cell survival, and T-cell aberration can contribute to the development of BD.

Endogenous cortisol and TGF-beta in human aqueous humor contribute to ocular immune privilege by regulating dendritic cell function.

Aqueous humor (AqH) has been shown to have significant immunosuppressive effects on APCs in animal models. We wanted to establish whether, in humans, AqH can regulate dendritic cell (DC) function and to identify the dominant mechanism involved. Human AqH inhibited the capacity of human peripheral blood monocyte-derived DC to induce naive CD4(+) T cell proliferation and cytokine production in vitro, associated with a reduction in DC expression of the costimulatory molecule CD86. This was seen both for DC cultured under noninflammatory conditions (immature DC) and for DC stimulated by proinflammatory cytokines (mature DC). DC expression of MHC classes I/II and CD83 was reduced (mature DC only). Myeloid DC from peripheral blood were similarly sensitive to the effects of human AqH, but only under inflammatory conditions. The addition of α-melanocyte stimulating hormone and vasoactive intestinal peptide did not cause significant inhibition at physiological levels. However, the addition of exogenous cortisol at physiological levels recapitulated the AqH-induced reduction in CD86 and inhibition of DC-induced T cell proliferation, and blockade of cortisol in AqH partially reversed its suppressive effects. TGF-ß2 had an additional effect with cortisol, and although simultaneous blockade of cortisol and TGF-ß2 in AqH reduced its effectiveness, there was still a cortisol- and TGF-ß-independent component. In humans, AqH regulates DC maturation and function by the combined actions of cortisol and TGF-ß2, a pathway that is likely to contribute to the maintenance of immune privilege in the eye.

Conjunctival transcriptomics in ocular mucous membrane pemphigoid.

PURPOSE: Ocular Mucous Membrane Pemphigoid (OcMMP) is an orphan disease characterized by chronic autoimmune-driven conjunctival inflammation leading to progressive scarring, debilitating symptoms, and blinding sequelae. This feasibility study aims to demonstrate conjunctival genetic transcriptomic analyses as a putative tool for interrogation of pathogenic signaling pathways in OcMMP. METHODS: Conjunctival RNA profiling using the NanoString nCounter Human Fibrosis panel was undertaken on RNA extracted from conjunctival swabs obtained from 6 MMP patients (8 eyes; 4 M/2F; median age 78 [range 64-84] years); and 8 age-matched control participants (15 eyes; 3 M/5F; median age 69.5 [range 69-88] years). Data from 770 genes were analyzed with ROSALIND HyperScale architecture and stratified according to the level of clinically visible bulbar conjunctival inflammation. Normalization, fold-changes (≥+1.5-fold or ≤ -1.5-fold) and p-values adjustment (<0.05) using the Benjamini-Hochberg method were calculated. RESULTS: 93 differentially expressed genes (DEGs) were observed between OcMMP versus controls of which 48 were upregulated, and 45 downregulated. The top 4 upregulated DEGs represented fibrosis (COL3A1, COL1A1, FN1 and THBS1) while the key under-expressed genes (SCIN, HMGS2, XCL1/2) were indicative of ocular surface failure (goblet cell loss, keratinization, vulnerability to secondary infections). Forty-four pathways had a global significance score ≥2, the most significant being those related to extracellular matrix (ECM) remodeling, synthesis, and degradation. These pathways were accentuated in eyes with visible inflammation. CONCLUSIONS: NanoString methodology acquired via a simple conjunctival swab identifies profibrotic genes in OcMMP group and differentiates inflamed eyes. Longitudinal sampling and following investigative intervention will further mechanistic insight and development of novel biomarkers to monitor disease progression.

Low density neutrophils are increased in patients with Behçet's disease but do not explain differences in neutrophil function.

BACKGROUND: Behçet's disease (BD) is a multisystem autoinflammatory disease characterised by mucosal ulceration, ocular, neural, joint and skin inflammation. The cause of BD is not known but there is a strong genetic association with HLA-B*51, IL10 and IL23R. Neutrophils are a first line of defence against invading pathogens and have been described as activated in patients with BD. Neutrophils can now be separated into different subsets, such as low density (LDN) and normal density (NDN) that have diverse functional roles. We wished to address neutrophil heterogeneity in patients with BD. METHODS: Peripheral blood neutrophils were obtained from 32 BD patients and 37 healthy aged-matched controls. Percoll isolation was used to isolate all neutrophils, while Ficol-Hypaque was used to obtain LDN and NDN. Phagocytic capacity and production of reactive oxygen species (ROS), and neutrophil extracellular traps (NET) stimulated with phorbol 12-myristate 13-acetate (PMA) and Escherichia coli (E.coli) were assessed in both groups. RESULTS: We have demonstrated reduced phagocytic capacity and ROS production but greater NET production by total neutrophils stimulated with PMA or E.coli from BD patients in comparison with healthy controls. Patients with BD had elevated numbers of LDN and lower number of NDN compared with healthy controls. However, both neutrophil subsets showed the same reduced ROS production and phagocytic function as total neutrophils in both groups. CONCLUSION: Our novel findings indicate that the neutrophil population in BD is heterogeneous and the increased number of LDN in combination with greater NET production may contribute to the inflammatory response and pathogenesis.

The impact of the first United Kingdom COVID-19 lockdown on environmental air pollution, digital display device use and ocular surface disease symptomatology amongst shielding patients.

Worldwide lockdown reduced air pollution during the first phase of the COVID-19 pandemic. The relationship between exposure to ambient air pollution, digital display device use and dry eye symptoms amongst patients with severe ocular surface disease (OSD) were considered. Symptoms and air pollutant concentrations for three different time periods (pre, during and post COVID-19 lockdown) were analysed in 35 OSD patients who achieved an immunosuppression risk-stratification score > 3 fulfilling the UK Government criteria for 12-week shielding. OSDI symptoms questionnaire, residential postcode air pollution data obtained from the Defra Automated Urban and Rural monitoring network for concentrations of nitrogen dioxide (NO2), nitrogen oxides (NOx), particulate matter (PM) with diameters below 10 µm and 2.5 µm, and English Indices of Deprivation were analysed. Significant reductions in NO2 and NOx concentrations were observed between pre- and during-lockdown periods, followed by a reversal in the post-lockdown period. Changes were linked to the Living Environment outdoor decile. A 12% increase (p = 0.381) in symptomatology during-lockdown was observed that reversed post-lockdown by 19% (p = 0.144). OSDI scores were significantly correlated with hours spent on digital devices (r2 = 0.243) but not with air pollutant concentrations. Lockdown measures reduced ambient air pollutants whilst OSD symptomatology persisted. Environmental factors such as increased time indoors and use of bluescreen digital devices may have partly played a role.

Deep Metagenomic Sequencing for Endophthalmitis Pathogen Detection Using a Nanopore Platform.

PURPOSE: To evaluate the utility of nanopore sequencing for identifying potential causative pathogens in endophthalmitis, comparing culture results against full-length 16S rRNA nanopore sequencing (16S Nanopore), whole genome nanopore sequencing (Nanopore WGS), and Illumina (Illumina WGS). DESIGN: Cross-sectional diagnostic comparison. METHODS: Patients with clinically suspected endophthalmitis underwent intraocular vitreous biopsy as per standard care. Clinical samples were cultured by conventional methods, together with full-length 16S rRNA and WGS using nanopore and Illumina sequencing platforms. RESULTS: Of 23 patients (median age 68.5 years [range 47-88]; 14 males [61%]), 18 cases were culture-positive. Nanopore sequencing identified the same cultured organism in all of the culture-positive cases and identified potential pathogens in two culture-negative cases (40%). Nanopore WGS was able to additionally detect the presence of bacteriophages in three samples. The agreements at genus level between culture and 16S Nanopore, Nanopore WGS, and Illumina WGS were 75%, 100%, and 78%, respectively. CONCLUSIONS: Whole genome sequencing has higher sensitivity and provides a viable alternative to culture and 16S sequencing for detecting potential pathogens in endophthalmitis. Moreover, WGS has the ability to detect other potential pathogens in culture-negative cases. Whilst Nanopore and Illumina WGS provide comparable data, nanopore sequencing provides potential for cost-effective point-of-care diagnostics.

Gut Dysbiosis in Ocular Mucous Membrane Pemphigoid.

Mucous Membrane Pemphigoid is an orphan multi-system autoimmune scarring disease involving mucosal sites, including the ocular surface (OcMMP) and gut. Loss of tolerance to epithelial basement membrane proteins and generation of autoreactive T cell and/or autoantibodies are central to the disease process. The gut microbiome plays a critical role in the development of the immune system. Alteration in the gut microbiome (gut dysbiosis) affects the generation of autoreactive T cells and B cell autoantibody repertoire in several autoimmune conditions. This study examines the relationship between gut microbiome diversity and ocular inflammation in patients with OcMMP by comparing OcMMP gut microbiome profiles with healthy controls. DNA was extracted from faecal samples (49 OcMMP patients, 40 healthy controls), amplified for the V4 region of the 16S rRNA gene and sequenced using Illumina Miseq platform. Sequencing reads were processed using the bioinformatics pipeline available in the mothur v.1.44.1 software. After adjusting for participant factors in the multivariable model (age, gender, BMI, diet, proton pump inhibitor use), OcMMP cohort was found to be associated with lower number of operational taxonomic units (OTUs) and Shannon Diversity Index when compared to healthy controls. Within the OcMMP cohort, the number of OTUs were found to be significantly correlated with both the bulbar conjunctival inflammation score (p=0.03) and the current use of systemic immunotherapy (p=0.02). The linear discriminant analysis effect size scores indicated that Streptococcus and Lachnoclostridium were enriched in OcMMP patients whilst Oxalobacter, Clostridia uncultured genus-level group (UCG) 014, Christensenellaceae R-7 group and butyrate-producing bacteria such as Ruminococcus, Lachnospiraceae, Coprococcus, Roseburia, Oscillospiraceae UCG 003, 005, NK4A214 group were enriched in healthy controls (Log10 LDA score < 2, FDR-adjusted p <0.05). In conclusion, OcMMP patients have gut dysbiosis correlating with bulbar conjunctival inflammation and the use of systemic immunotherapies. This provides a framework for future longitudinal deep phenotyping studies on the role of the gut microbiome in the pathogenesis of OcMMP.

Age, gender and disease-related platelet and neutrophil activation ex vivo in whole blood samples from patients with Behçet's disease.

OBJECTIVES: Behçet's disease (BD) is more severe among young males and disease severity decreases with age. Therefore, the effect of disease activity, gender and age on platelet and neutrophil activation in whole blood taken from patients with BD was investigated. METHODS: Using an anti-coagulant Tripotassium ethylenediaminetetra acetic acid (K3EDTA) plus citrate-theophylline-adenosine-dipyridamole (CTAD) (K3EDTA/CTAD) that preserves the degree of platelet activation that exists in vivo, we assessed neutrophil and platelet activation, microparticles, and monocyte and neutrophil-platelet aggregate formation in 43 BD patients using flow cytometry. This is the first description of platelet activation and microparticles in BD patients using this methodology. RESULTS: Inactive [2.78 (0.56)%, P = 0.0009; 3.11 (0.78)%, P < 0.0001] and active [2.28 (0.84)%, P < 0.0001; 3.071 (0.67)%, P = 0.0031] BD patients had significantly higher percentages of CD62P-expressing platelets and CD62P+ platelet microparticles as compared with healthy controls (HCs) [0.84 (0.1)% and 1.23 (0.14)%], respectively. The percentages of CD62P+ platelets and CD62P+ platelet microparticles in female and male BD patients were also significantly higher than those expressed by female and male HCs. The percentages of CD62P+ microparticles were significantly increased in the 20-30-(P = 0.0301) and 31-50-(P < 0.0162) year age ranges, but not in the >50-year age group of BD patients. CONCLUSION: BD is a rare, chronic multi-systemic vasculitis and interaction of activated platelets with leucocytes has been linked to pathological disorders associated with vascular inflammation. Importantly, this study demonstrates that platelet microparticle activation is increased in BD. Also, this is the first report in which changes in platelet activation in BD are concordant with the observations that BD disease activity diminishes with age.

TIRAP Ser180Leu polymorphism is associated with Behcet's disease.

OBJECTIVES: The initiating cause of Behçet's disease (BD) is unknown, but an aberrant response to infection has been suggested. In this study, single nucleotide polymorphisms in Toll-like receptors (TLRs) and associated molecules that have a sentinel function at mucosal surfaces were analysed in patients with BD. METHODS: TLR expression was determined by immunohistochemistry in buccal mucosal tissue from patients with BD, in tissue from patients with lichen planus (LP) or pyogenic granuloma (PG) as disease controls, or from healthy individuals. Using SSP-PCR we analysed SNP in CD14, TLR2, TLR4 and TIRAP (TIR domain-containing adaptor protein) in patients with BD from different geographical regions. RESULTS: TLR expression was increased in buccal lesions from patients with BD compared with healthy controls; however, a similar increase was seen in lesion tissue from patients with LP or PG, suggesting that this was a generalized inflammatory response as opposed to a BD-specific response. SNP analysis showed no association between CD14, TLR2 or TLR4 polymorphisms. However, TIRAP 180Leu was significantly associated with BD in UK, but not Middle Eastern, patients. CONCLUSION: TLR expression showed no difference in tissue from patients with BD compared with either disease or healthy controls. Likewise, SNPs in TLR genes were no different from healthy controls. The association with the increased function variant of TIRAP suggests that encounter with a pathogen at mucosal sites will lead to increased cytokine production and tissue damage with persistence of mucosal lesions.

Behçet's Disease-Do Microbiomes and Genetics Collaborate in Pathogenesis?

Behçet's disease (BD) is a multisystem autoinflammatory condition characterized by mucosal ulceration, breakdown of immune privilege sites and vasculitis. A genetic basis for BD has been described in genome-wide and validation studies. Similarly, dysbiosis of oral and gut microbiomes have been associated with BD. This review will describe links between genetic polymorphisms in genes encoding molecules involved in gut biology and changes seen in microbiome studies. A potential decrease in bacterial species producing short chain fatty acids linked to mutations in genes involved in their production suggests a potential therapy for BD.