Mapping the HLA association in Behçet's disease: a role for tumor necrosis factor polymorphisms?

Risk factors, clinical features and treatment of Behçet's disease uveitis

Behçet's disease is a systemic vasculitis frequently associated with intraocular inflammation. Recent findings identified independent clinical clusters in Behçet's disease, each involving distinct combinations of affected organs. Ocular Behçet's disease, mainly manifested as uveitis, is characterized as an independent cluster with a low likelihood of association with other system involvements, such as intestinal, cardiovascular, or central nervous system. A prevailing theory suggests that the pathogenesis of the disease is multifactorial, where a variety of genetic and infectious agents may interact with each other to cause the disease. Among sporadic cases, the human leukocyte antigen (HLA) genes, including HLA-B51, HLA-A26, HLA-B15, and HLA-B5701, have been found to be a key component conferring genetic susceptibility. Outside the HLA region, a set of susceptibility variants are identified, closely related to interleukin (IL)-23/IL-17 pathway, tumor necrosis factor (TNF) signaling, and pattern recognition receptor systems. Microbial infections, such as Streptococcus sanguinis, Mycobacterium tuberculosis, and Herpes simplex virus (HSV), are linked to play the triggering of disease in immunogenetically predisposed individuals. Clinically, due to the notable relapsing-remitting course of ocular Behçet's disease, the prevention of recurrent attack would be the primary treatment goal. Combination of corticosteroids and immunomodulatory drugs, such as anti-TNF agents, interferon, and conventional immunosuppressants (e.g. cyclosporine, azathioprine), have been the mainstream regimen for the disease. Future research may focus on comparing the effectiveness of immunomodulatory drugs and identifying the most suitable subgroups for a specific drug on the basis of the knowledge of the molecular heterogeneity of the disease.

Association of TNF-Alpha, MBL2, NOS2, and G6PD with Malaria Outcomes in People in Southern Ghana

Background

One major issue that has set back the gains of the numerous malaria control interventions that national malaria control programs have implemented is asymptomatic malaria. Certain host genetic factors are known to influence symptomatic malaria; however, not much is known about how host genetics influences the acquisition of asymptomatic malaria.

Methods

Genomic DNA was extracted from whole blood collected from 60 symptomatic and 149 nonfebrile (asymptomatic, N = 109, and uninfected, N = 40) volunteers aged between 2 and 69 years from a high (Obom) and a low (Asutsuare) malaria transmission setting in Southern Ghana. Restriction fragment length polymorphism (RFLP) was used to determine polymorphisms at the MBL2 54, TNF-α 308, NOS2 954, and G6PD 202/376 gene loci.

Results

Polymorphisms at the MBL2 54 and TNF-α 308 loci were significantly different amongst the three categories of volunteers in both Asutsuare (p = 0.006) and Obom (p=0.05). In Asutsuare, a low malaria transmission area, the allele G has significantly higher odds (3.15) of supporting asymptomatic malaria as against symptomatic malaria. There were significantly higher odds of TNF-α genotype GA being associated with symptomatic malaria as against asymptomatic malaria in both sites, Obom (p=0.027) and Asutsuare (p=0.027). The allele B of the G6PD gene was more prevalent in symptomatic rather than asymptomatic parasite-infected individuals in both Obom (p=0.001) and Asutsuare (p=0.003).

Conclusion

Individuals in Southern Ghana carrying the TNF-α 308 GA genotype are more likely to exhibit symptoms of malaria when infected with the malaria parasite as opposed to harboring an asymptomatic infection. Also, the B allele of the G6PD gene is likely to prevent a P. falciparum-infected person from exhibiting symptoms and thereby promote asymptomatic parasite carriage.

Behcet's Disease: An In-Depth Review about Pathogenesis, Gastrointestinal Manifestations, and Management

Background

Behcet's disease (BD) is a complex inflammatory vascular disorder that follows a relapsing-remitting course with diverse clinical manifestations. The prevalence of the disease varies throughout the globe and targets different age-groups. There are many variations of BD; however, intestinal BD is not only more common but has many signs and symptoms.

Summary

BD is a relapsing-remitting inflammatory vascular disorder with multiple system involvement, affecting vessels of all types and sizes that targets young adults. The etiology of BD is unknown but many factors including genetic mechanisms, vascular changes, hypercoagulability, and dysregulation of immune function are believed to be responsible. BD usually presents with signs and symptoms of ulcerative disease of the small intestine; endoscopy being consistent with the clinical manifestations. The mainstay of treatment depends upon the severity of the disease. Corticosteroids are recommended for severe forms of the disease and aminosalicylic acids are used in maintaining remission in mild to moderate forms of the disease.

Key Messages

In this review, we have tried to summarize in the present review the clinical manifestations, differential diagnoses, and management of intestinal BD. Hopefully, this review will enable health policymakers to ponder over establishing clear endpoints for treatment, surveillance investigations, and creating robust algorithms.

Interleukin-1 gene (IL-1) polymorphism in patients with Behçet’s Disease, and its relationship with disease manifestations

Objective

The objective of this study was to investigate whether interleukin-1 (IL-1) gene polymorphisms are associated with susceptibility to Behçet’s disease (BD) and clinical manifestations of the disease.

Methods

In this cross-sectional study, we enrolled 110 patients with BD and age-and gender-matched 120 healthy controls. Five polymorphic regions of the IL-1 gene including rs 1800587 (IL1A-889 C/T), rs 2234650 (IL1R1), rs 16944 (IL1B-511 C/T), rs 315952 (IL1RN), and rs1143634 (IL1B-3954 C/T) were analyzed by using the real-time polymerase chain reaction system. Allele frequencies and genotypes were compared between groups. p ≤ 0.05 was accepted as statistically significant.

Results

The mean age of the patients with BD was 41 ± 12.4 years. The two groups were similar in terms of the age and gender distribution. The vast majority of BD patients had mucocutaneous involvement. The mean disease duration was 83.7 ± 67.8 months among the patients. The frequencies of each polymorphism in the IL-1 gene were similar between patients with BD and healthy controls.

Conclusion

The frequencies of variable IL-1 gene polymorphisms were similar between patients with BD and healthy controls.

A Darwinian View of Behçet's Disease

Behçet's disease (BD) is a multisystem inflammatory disorder of unknown etiology, characterized by oral and genital ulceration, with other complications including eye, skin, joint, and central nervous system (CNS) lesions. Diagnosis is based on clinical findings, which may differ between patients. There is a strong genetic basis for BD; however, only a few genes have been associated with the disease across the geographical spread of BD. In this article, we discuss the history and combination of genes involved in this complex disease in relation to the geographical range and present our view that the disease has developed from a Darwinian perspective, with different gene polymorphisms that affect the same biological pathway. Moreover, these mutations individually are protective mechanisms against the disease relevant to each region, which affected both archaic and modern humans.

Biological therapy in refractory cases of uveitis and scleritis: An analysis of 18 cases from a tertiary eye care center from South India

Purpose

To evaluate the effectiveness of biologic therapy in a cohort of patients with various types of refractory non-infectious uveitis and scleritis.

Methods

A retrospective observational study on patients with non-infectious uveitis and scleritis who were not responding or had a high recurrence rate with the conventional treatment and had received biologic therapy.

Results

We studied 18 patients (33 eyes) who received biological therapy between January 2017 and November 2019. The mean age was 30 ± 17 years and mean duration of uveitis was 36.8 months (range 1-120 months). Anterior uveitis (27.7%) was most commonly observed followed by scleritis, panuveitis, posterior, and intermediate uveitis. The most common etiology was Behçet's disease (4 patients, 22.2%) followed by juvenile idiopathic arthritis (3 patients, 16.6%), granulamotosis polyangitis, and idiopathic (2 patients each, 11.1%). Majority had trialled one or more immunosuppressive and were refractory in nature. Maximum patients had received adalimumab (61%) followed by infliximab (22%), rituximab (12%), and golimumab (6%). The median prednisolone dose was reduced from 30 mg (range 7.5-60 mg) to 5 mg (range 0-10 mg) after biological therapy (P = 0.002). Significant visual improvement was observed post biologic therapy (mean log mar VA 0.41 ± 0.62 improved to 0.23 ± 0.48 at the final visit, P = 0.008). Maximum number of patients (16 patients, 89%) responded well with biological therapy. Three patients developed recurrence and systemic complications were observed in two patients.

Conclusion

Biologic therapy is effective in non-infectious refractory uveitis who were resistant to conventional therapy and may prolong disease recurrence.

Next-generation sequencing and its application in diagnosis of retinitis pigmentosa

Retinitis Pigmentosa (RP) is a major cause of heritable human blindness with a high genetic heterogeneity. It is characterized by the initial degeneration of rod photoreceptors followed by cone photoreceptors. RP is also a prominent reason of visual impairment, by a global prevalence of 1:4000. RP is usually specified with nyctalopia in puberty, followed by concentric visual field loss, that reflects the main impairment of rod photoreceptors; later in the life, as disease progresses, because of cone dysfunction, central vision loss also occurs. A precise molecular diagnosis is crucial for disease characterization and clinical prognosis. DNA sequencing is a powerful tool for deciphering various causes of different human diseases. The arrival of next-generation sequencing (NGS) technologies has diminished sequencing cost and considerably augmented the throughput, making whole-genome sequencing (WGS) a conceivable way for obtaining comprehensive genomic data and a more precise clinical decision. Nevertheless, the advantages gained from NGS technologies are among a number of challenges that must be sufficiently addressed before this technique can be altered from an investigation tools to a helpful method in routine clinical practices. This article aims to provide an overview about NGS technology and its related platforms. The challenges in the analysis and choosing an appropriate NGS method likewise their potential applications in clinical diagnosis are also discussed. The merit of such technique has been reflected in some recent studies where it is shown that using NGS and molecular information could help with clinical diagnosis, providing potential treatment options or changes, up-to-date family counseling and management.

Tumor necrosis factor (TNF)-308, -1031, and angiotensin-converting enzyme (ACE) DD/II polymorphisms' role in Behcet's disease with and without uveitis: a meta-analysis

PURPOSE

There are conflicting results of studies investigating the association between the tumor necrosis factor (TNF) and angiotensin-converting enzyme (ACE) gene polymorphisms and Behcet's disease (BD). The aim of this meta-analysis is to assess the association between these gene polymorphisms and ocular involvement in BD.

METHODS

We identified relevant studies and reviewed the full-text manuscripts of the studies in order to select those for inclusion. Heterogeneity of studies was evaluated using Cochran Q-test and I-square index. To modify the heterogeneity in the variables we used random effects model. Meta-analysis was performed using STATA.

RESULTS

We analyzed TNF-1031, -308 and ACE DD/II genotype difference between BD patients with and without uveitis. Among these polymorphic genetic loci TNF-308 AA genotype has a statistically significant protective effect against BD uveitis (OR = 0.45 vs 1.23, p = .017). Such a statistically significant effect was not seen for other studied genotypes.

CONCLUSION

This meta-analysis revealed a significant protective effect of TNF-308 AA genotype against ocular involvement in Behcet's disease.

Association between tumor necrosis factor-α gene-1031T/C promoter polymorphism and endometriosis in a European population

Background Tumor necrosis factor-alpha (TNF-α) is a pro-inflammatory cytokine which plays an important role in the pathogenesis of many diseases. Endometriosis is one of the most common gynecological diseases. The purpose of this study was to investigate the association of TNF-α-1031T/C polymorphism with the genetic susceptibility of endometriosis in a European population. Materials and methods In this case-control study, 51 endometriosis patients and 67 healthy control women participated. We used endometrial tissue from the patients and peripheral blood from the healthy women to extract DNA. Polymerase chain reaction (PCR) analysis and the restriction enzyme Bbs I were used to analyze the -1031 T/C polymorphism in the TNF-α gene promoter region. Statistical analysis was performed using Fisher's exact test. We also calculated the odds ratios. Results In the group of patients, 66.7% of women were detected with the TT genotype, 33.3% with the TC genotype and 0% with the CC genotype while in the control group, 46.3% had the TT genotype, 47.8% had the TC genotype and 6% had the CC genotype. There was a significant association between the TT genotype with endometriosis (p = 0.03). There was no significant deviation from the Hardy-Weinberg equilibrium. Conclusions The TC and CC genotypes appeared more often in the healthy women than the endometriosis patients and this shows that the C allele might have a protective role in endometriosis in the Greek population. Further studies are needed to specify the role of this polymorphism in pathogenesis of endometriosis and the mechanisms that protect the patients from the disease.

Assessment of Cytokine Release against Oral Mucosal Cell Line Culture (TR146) Stimulated by Neutrophil Elastase Associated with Behcet's Disease

Aim

Cytokines and chemokines may be involved in the onset of oral ulcer in Behcet's disease. The aim of our study is to assess the cytotoxic effects of proinflammatory cytokines and chemokines on reconstructed oral mucosal cell line (TR146) when treated with different concentrations of neutrophil elastase (NE).

Objective

For this purpose, a culture of the oral mucosal model (OMM) prepared from a cell line derived from an oral squamous cell carcinoma of buccal mucosa (TR146) is treated with different concentrations of neutrophil elastase. The cultures were incubated for 4- and 24-hour intervals and designed as follows: culture + artificial saliva served as the negative control; culture + 0.01% SLS (sodium lauryl sulphate) served as the positive control; and culture + NE (10, 50, 100, and 200 nM) served as the treated group.

Materials and Methods

We used sandwich ELISA technique to isolate IL-1β (interleukin 1β), IL-8, and TNF-α (tumor necrosis factor).

Results

We found no significant level of IL-8 and TNF-α when treated with different concentrations of neutrophil elastase after 4- and 24-hour incubation. The IL-1β level was slightly higher when treated with 100 and 200 nM NE after 24 hours of incubation although a significantly high level was observed at 100 nM NE after 4 hours of incubation. Hence, we found an increase in the level of IL-1β when stimulating the reconstructed oral mucosal model (OMM) with different concentrations of NE. This is a preliminary in vitro study; however, further research is required to evaluate the cytotoxic effects of cytokines and chemokines released when treated with NE. Moreover, high concentrations of NE are recommended to stimulate the release of cytokines and chemokines against the OMM.

The molecular and clinical evidence of vitamin D signaling as a modulator of the immune system: Role in Behçet's disease

Various tissues and cell types are the targets of vitamin D. However, the major targets of vitamin D in the immune system are monocytes/macrophages, dendritic cells (DCs), as well as B and T cells. Vitamin D plays an important role in the immune system modulation via regulating the expression of genes that generate pro-inflammatory mediators and inhibiting the proliferation of pro-inflammatory cells, both of which have been implicated in the pathophysiology of the inflammatory diseases. Recent studies have revealed the important relations between vitamin D and Behçet's disease (BD). Vitamin D function and its deficiency have been linked to a wide range of metabolic disorders including malignant, cardiovascular, infectious, neuromuscular, and autoimmune diseases. Here, we provide a brief analysis of the recent literature regarding immune-regulatory effects as well as clinical evidence of vitamin D influence on the molecular level in BD.

UVEOGENE: An SNP database for investigations on genetic factors associated with uveitis and their relationship with other systemic autoimmune diseases

Uveitis is an intraocular inflammatory disease which can lead to serious visual impairment. Genetic factors have been shown to be involved in its development. However, few databases have focused on the information of associations between single nucleotide polymorphisms (SNPs) and uveitis. To discover the exact genetic background of uveitis, we developed an SNP database specific for uveitis, “UVEOGENE,” which includes 370 genes and 918 SNPs covering 14 uveitis entities and 40 populations from 286 PubMed English‐language papers. Stratification analyses by gender, HLA status, and different clinical features were also extracted from the publications. As a result, 371 associations were judged as “statistically significant.” These associations were also shared with Global Variome shared Leiden Open Variation Database (LOVD) (https://databases.lovd.nl/shared/genes). Based on these associations, we investigated the genetic relationship among three widely studied uveitis entities including Behcet's disease (BD), Vogt–Koyanagi–Harada (VKH) disease, and acute anterior uveitis (AAU). Furthermore, “UVEOGENE” can be used as a reliable and informative resource to identify similarities as well as differences in the genetic susceptibility among uveitis and other autoimmune diseases. UVEOGENE is freely accessible at http://www.uvogene.com.

Behçet's disease: An immunogenetic perspective

Behçet's disease (BD) is a chronic and rare multisystemic disorder defined by autoimmunity and inflammatory characteristics, manifested by ocular lesions, recurrent genital and oral ulcers, skin symptoms and arthritis as well as neurological, intestinal, and vascular involvement. Despite the unknown cause of BD, there is some strong documentation for immunological, genetic, environmental, and infectious factors playing a role in the pathogenesis of BD. While the nature of the genetic variants remains unidentified, many genetic risk factors are considered to contribute to BD susceptibility. Along with human leukocyte antigen gene encoding B*51 (HLA-B*51) and areas including the major histocompatibility complex class I, genome-wide association studies have recognized numerous other BD susceptibility genes including those encoding interleukin (IL)-10, IL-12 receptor β 2 (IL-12RB2), IL-23 receptor (IL-23R), C-C chemokine receptor 1 gene, signal transducer and activator of transcription 4 (STAT4), endoplasmic reticulum aminopeptidase (ERAP1), and genes encoding killer cell lectin-like receptor family members (KLRC4-KLRK1). It is believed that BD could be considered as a disorder lying in between autoimmune and autoinflammatory syndromes. The positive responses to classical immunosuppressive agents like azathioprine and cyclosporine and involvement of autoantigens in the initiation of the disorder are the main BD features that reflect the autoimmune nature of the disorder. In this review, we address recent findings on the role of common cytokines, antibodies and immunogenetic factors in BD.

AIF-1 gene does not confer susceptibility to Behçet's disease: Analysis of extended haplotypes in Sardinian population

BACKGROUND

Behçet's disease (BD) is a polygenic immune-mediated disorder characterized by a close association with the HLA-B*51 allele. The HLA region has a strong linkage disequilibrium (LD) and carries several genetic variants (e.g. MIC-A, TNF-α genes) identified as associated to BD because of their LD with HLA-B*51. In fact, the HLA-B*51 is inherited as part of extended HLA haplotypes which are well preserved in patients with BD. Sardinian population is highly differentiated from other Mediterranean populations because of a distinctive genetic structure with very highly preserved HLA haplotypes.

PATIENTS AND METHODS

In order to identify other genes of susceptibility to BD within the HLA region we investigated the distribution of human Allograft Inflammatory Factor-1 (AIF-1) gene variants among BD patients and healthy controls from Sardinia. Six (rs2736182; rs2259571; rs2269475; rs2857597; rs13195276; rs4711274) AIF-1 single nucleotide polymorphisms (SNPs) and related extended haplotypes have been investigated as well as their LD within the HLA region and with HLA-B*51. Overall, 64 BD patients, 43 HLA-B*51 positive healthy controls (HC) and 70 random HC were enrolled in the study.

RESULTS

HLA-B*51 was the only allele with significantly higher frequency (pc = 0.0021) in BD patients (40.6%) than in HC (9.8%). The rs2259571T AIF-1 variant had a significantly reduced phenotypic, but not allelic frequency in BD patients (72.1%; pc = 0.014) compared to healthy population (91.3%). That was likely due to the LD between HLA-B*51 and rs2259571G (pc = 9E-5), even though the rs2259571G distribution did not significantly differ between BD patients and HC.

CONCLUSION

No significant difference in distribution of AIF-1 SNPs haplotypes was observed between BD patients and HC and between HLA-B*51 positive BD patients and HLA-B*51 positive HC. Taken together, these results suggest that AIF-1 gene is not associated with susceptibility to BD in Sardinia.

Genetics and immunodysfunction underlying Behçet's disease and immunomodulant treatment approaches

Behçet's disease (BD) is a chronic autoimmune condition primarily prevalent in populations along the Mediterranean Sea. The exact etiology of BD has not been fully explained yet, but the disease occurrence is associated with a genetic factor, human leukocyte antigen (HLA)-B51 antigen. Among the various immunodysfunctions that are found in BD, patients are increased neutrophil motility and superoxide production, as well as elevated production of tumor necrosis factor (TNF)-α and decreased production of interleukin (IL)-10. Elevated levels of inflammatory cytokines like IL-1 and IL-17 in BD have been found associated with aberrant expression of microRNA. Gene polymorphisms in BD patients have been observed in molecules involved in responses to pathogens that can ultimately modulate the host antimicrobial response. Moreover, several single nucleotide polymorphisms (SNPs) have been reported in genes encoding chemokines and adhesion molecules; many of these changes manifest as increases in vascular inflammation and vascular damage. Lastly, genetic and epigenetic changes have been suggested as involved in the pathogenesis of BD. Modifications in DNA methylation have been found in BD patient monocytes and lymphocytes, leading to adverse function of these cells. This review presents a comprehensive compilation of the literature with regard to the immunodysfunction underlying BD, as well as of the genetics, newly described clinical specifications and novel treatment strategies using immunomodulants based on the current understanding of BD.

Birmingham Behçet's service: classification of disease and application of the 2014 International Criteria for Behçet's Disease (ICBD) to a UK cohort

Background

This study reports on the analysis of the application and diagnostic predictability of the revised 2014 ICBD criteria in an unselected cohort of UK patients, and the ensuing organ associations and patterns of disease.

Methods

A retrospective cohort study was conducted using a database of electronic medical records. Three categories were recognised: clinically defined BD, incomplete BD and rejected diagnoses of BD. We applied the ISG 1990 and ICBD 2014 classification criteria to these subgroups to validate diagnostic accuracy against the multidisciplinary assessment.

Results

Between 2012 and 2015, 281 patients underwent initial assessment at an urban tertiary care centre: 190 patients with a confirmed diagnosis of BD, 7 with an incomplete diagnosis, and 84 with a rejected diagnosis. ICBD 2014 demonstrated an estimated sensitivity of 97.89% (95% CI: 94.70 to 99.42) and positive likelihood ratio of 1.21 (1.10 to 1.28). The strongest independent predictors were: Central nervous lesions (OR = 10.57, 95% CI: 1.34 to 83.30); Genital ulceration (OR = 9.05, 95% CI: 3.35 to 24.47); Erythema nodosum (OR = 6.59, 95% CI: 2.35 to 18.51); Retinal vasculitis (OR = 6.25, 95% CI: 1.47 to 26.60); Anterior uveitis (OR = 6.16, 95% CI: 2.37 to 16.02); Posterior uveitis (OR = 4.82, 95% CI: 1.25 to 18.59).

Conclusions

The ICBD 2014 criteria were more sensitive at picking up cases than ISG 1990 using the multidisciplinary assessment as the gold standard. ICBD may over-diagnose BD in a UK population. Patients who have an incomplete form of BD represent a distinct group that should not be given an early diagnostic label. Behçet’s disease is a complex disease that is best diagnosed by multidisciplinary clinical assessment. Patients in the UK differ in their clinical presentation and genetic susceptibility from the original descriptions. This study also highlights an incomplete group of Behçet’s patients that are less well defined by their clinical presentation.

Polymorphisms of Promoter Region of TNF-α Gene in Iranian Azeri Turkish Patients with Behçet's Disease

Behçet's disease (BD) is a complex chronic relapsing inflammatory disorder of unknown etiology. Alterations of the tumor necrosis factor (TNF) expression related to the polymorphic alleles of TNF gene may implicate a pathogenetic role in increased activity of this cytokine in BD. A current study aimed at investigating the possible association between BD and its clinical features in Iranian Azeri Turks with two functional TNF-α gene polymorphisms (at the positions of -238 and -857). A total number of 166 Iranian subjects were enrolled into two different groups; patients with BD (n = 64), and ethnically matched healthy controls (n = 101). The genotype distributions of BD patients and healthy controls were determined. The frequency of TNF-α -857C allele was significantly higher in Behçet's patients than that of healthy controls (P = 0.001; odds ratio [OR] = 2.616; 95% confidence interval [CI] = 1.129-6.160), whereas the frequency of TNF-α -238A allele was similar in both groups. The sole TNF-α haplotype-857C-1031C, was associated with an increase in the risk of developing BD. The TNF-α -857C allele was considerably associated with BD in this cohort. The findings of this study, collectively, indicate that TNF-α -857C-1031C haplotype located in the promoter region of the gene could exert major influence on the susceptibility to BD.

Tumour necrosis factor alpha promoter polymorphism, TNF-238 is associated with severe clinical outcome of falciparum malaria in Ibadan southwest Nigeria

Tumour necrosis factor (TNF) - α has been shown to play an important role in the pathogenesis of falciparum malaria. Two TNF promoter polymorphisms, TNF-308 and TNF-238 have been associated with differential activity and production of TNF. In order to investigate the association between TNF-308 and TNF-238 and the clinical outcome of malaria in a Nigerian population, the two TNF polymorphisms were analysed using Sequenom iPLEX Platform. A total of 782 children; 283 children with uncomplicated malaria, 255 children with severe malaria and 244 children with asymptomatic infection (controls) were studied. The distribution of TNF-308 and TNF-238 genotypes were consistent with the Hardy-Weinberg equilibrium. Distribution of both TNF polymorphisms differed significantly across all clinical groups (TNF-308: p=0.007; TNF-238: p=0.001). Further tests for association with severe malaria using genotype models controlling for age, parasitaemia and HbAS showed a significant association of the TNF-238 polymorphism with susceptibility to severe malaria (95% CI=1.43-6.02, OR=2.94, p=0.003237) The GG genotype of TNF-238 significantly increased the risk of developing cerebral malaria from asymptomatic malaria and uncomplicated malaria (95% CI=1.99-18.17, OR=6.02, p<0.001 and 95% CI=1.78-8.23, OR=3.84, p<0.001 respectively). No significant association was found between TNF-308 and malaria outcome. These results show thegenetic association of TNF-238 in the clinical outcome of malaria in Ibadan, southwest Nigeria. These findings add support to the role of TNF in the outcome of malaria infection. Further large scale studies across multiple malaria endemic populations will be required to determine the specific roles of TNF-308 and TNF-238 in the outcome of falciparum malaria infection.

Evaluation of Tumor Necrosis Factor Alpha Polymorphism Frequencies in Endometriosis

BACKGROUND

The pro-inflammatory cytokine, tumor necrosis factor-alpha (TNF-α), is a pathogenic element for a number of disorders. Previous studies have reported that the -1031 T/C and -238 G/A polymorphisms in the promoter region of the TNF-α gene are important factors in reproductive-related disorders. One of the most common gynecological diseases of women during the reproductive years is endometriosis. This study aims to assess an association between the -1031 T/C, -238 G/A and -308 G/A polymorphisms of the TNF-α gene promoter region to endometriosis.

MATERIALS AND METHODS

In this case-control study, we enrolled 65 endometriosis patients and 65 matched healthy control women by simple sampling. Polymerase chain reaction (PCR) analysis was used to analyze -1031 T/C, -238 G/A and -308 G/A polymorphisms in the TNF-α gene promoter region. Statistical analysis was performed using the chi-square test. P values less than 0.05 were considered statistically significant.

RESULTS

We found a strong association between the -1031 T/C polymorphism in the promoter region of the TNF-α gene with endometriosis (P=0.001). There were no significant associations between the -238 G/A (P=0.243) and -308 G/A (P=1) polymorphisms with endometriosis and again endometriosis stages have no association with these polymorphisms.

CONCLUSION

The -1031 T/C polymorphism and CC genotype can be used as a relevant marker to identify women at risk of developing endometriosis.

Characteristics of patients with intestinal Behçet's disease requiring treatment with immunosuppressants or anti-TNFα antibody

OBJECTIVES

To identify the specific characteristics of patients with refractory intestinal Behçet's disease (BD) who required more than glucocorticoid (GC) and/or 5-aminosalicylic acid (5-ASA) treatment.

METHODS

A retrospective review of the patient records in a university hospital identified 34 patients with intestinal BD. The patients treated only with glucocorticoid and/or 5-ASA (n = 8) were compared with refractory cases which required additional immunosuppressants, anti-TNFα antibodies, or surgery (n = 12).

RESULTS

In the refractory group, ulcers were found outside the ileocecal region more often, and more active intestinal bleeding or melena was observed, than in the GC/5ASA-controlled group (75% vs 0%, p = 0.001), (58% vs 0%, p = 0.015). The refractory group also showed higher positivity for HLA-B51 (45% vs 0%, p = 0.044), higher blood C-reactive protein (CRP) levels (14.7 ± 8.74 vs 3.93 ± 6.33 mg/dL, p = 0.046), and a higher white blood cell or WBC count (14750 ± 6760 vs 7210 ± 1830/μl, p = 0.025) at onset. The existence of either HLA-B51, melena, or elevated CRP of more than 4 mg/dL predicted the refractory form of BD with 100% sensitivity and 85.7% specificity.

CONCLUSIONS

Refractory intestinal BD was distinguished from the non-refractory form by distinct clinical and laboratory findings. These findings will be useful in identifying patients who require intensive therapy (e.g., anti-TNFα antibodies) in addition to GC/5ASA.

Behçet syndrome: from pathogenesis to novel therapies

Behçet syndrome is a chronic disease hallmarked by inflammation of the blood vessels that is related to an autoimmune reaction caused by inherited susceptibility due to specific genes and environmental factors, probably components of infectious microorganisms, which turn on or get going the disease in genetically susceptible subjects. The more common clinical expression of the disease is represented by a triple-symptom complex of recurrent oral aphthous ulcers, genital ulcers, and uveitis, sometimes associated with inflammatory arthritis, phlebitis, iritis, as well as inflammation of the digestive tract, brain, and spinal cord. The treatment strategies used to manage the manifestations of Behçet syndrome have gradually progressed, and a number of new therapeutic resources have been implemented in recent years, allowing better control of pathogenic mechanisms, reducing symptoms and suffering, and ameliorating patient's outcome.

Immunopathogenesis of ocular Behçet's disease

Behçet's disease (BD) is a chronic recurrent systemic inflammatory disorder of unknown etiology characterized by oral and genital ulcerations, skin lesions, and uveitis. The ocular involvement of BD, or Behçet's uveitis (BU), is characterized by panuveitis or posterior uveitis with occlusive retinal vasculitis and tends to be more recurrent and sight threatening than other endogenous autoimmune uveitides, despite aggressive immunosuppression. Although pathogenesis of BD is unclear, researches have revealed that immunological aberrations may be the cornerstone of BD development. General hypothesis of BD pathogenesis is that inflammatory response is initiated by infectious agents or autoantigens in patients with predisposing genetic factors and perpetuated by both innate and acquired immunity. In addition, a network of immune mediators plays a substantial role in the inflammatory cascade. Recently, we found that the immunopathogenesis of BU is distinct from other autoimmune uveitides regarding intraocular effector cell profiles, maturation markers of dendritic cells, and the cytokine/chemokine environment. In addition, accumulating evidence indicates the involvement of Th17 cells in BD and BU. Recent studies on genetics and biologics therapies in refractory BU also support the immunological association with the pathogenesis of BU. In this review, we provide an overview of novel findings regarding the immunopathogenesis of BU.

MDR1 C3435T polymorphism associated with the development of clinical features in Behçet's disease in Iranian Azeri Turkish patients

BACKGROUND

Behçet's disease (BD) is a systemic vasculitis of unknown cause with a higher prevalence along the ancient Silk Road. Behçet's occasional familial aggregation and its close association with genes of major histocompatibility complexes justify that genetic factors play an important role in the development of the disease. In this study, we evaluated the association of multidrug resistance (MDR1) C3435T polymorphism with the severity of BD.

METHOD

We investigated the distribution of MDR1 C3435T polymorphism in 69 patients from the Iranian Azeri Turks group with BD and 92 ethnically sex-matched healthy controls, via the polymerase chain reaction-restriction fragment length polymorphism technique.

RESULT

Although there was no significant association of MDR1 C3435T polymorphism between two groups of patients and healthy controls, our data showed a substantial association of CC genotype with the development of several clinical features, including erythema nodosum (P = 0.001, OR = 2.686, 95%), pseudofolliculitis (P = 0.002, OR = 2.812, 95%), and skin lesions (P = 0.040, OR = 1.934, 95%).

CONCLUSION

These results suggest that CC genotype is a risk factor for the development of some clinical features of BD in patients from the Iranian Azeri Turk ethnic group.

Behçet disease-associated MHC class I residues implicate antigen binding and regulation of cell-mediated cytotoxicity

The HLA protein, HLA-B*51, encoded by HLA-B in MHC, is the strongest known genetic risk factor for Behçet disease (BD). Associations between BD and other factors within the MHC have been reported also, although strong regional linkage disequilibrium complicates their confident disentanglement from HLA-B*51. In the current study, we examined a combination of directly obtained and imputed MHC-region SNPs, directly obtained HLA-B locus types, and imputed classical HLA types with their corresponding polymorphic amino acid residues for association with BD in 1,190 cases and 1,257 controls. SNP mapping with logistic regression of the MHC identified the HLA-B/MICA region and the region between HLA-F and HLA-A as independently associated with BD (P < 1.7 × 10(-8)). HLA-B*51, -A*03, -B*15, -B*27, -B*49, -B*57, and -A*26 each contributed independently to BD risk. We directly examined rs116799036, a noncoding SNP upstream of HLA-B that was recently suggested to underlie the association of HLA-B*51 with BD, but we were unable to replicate that finding in our collection. Instead, we mapped the BD association to seven MHC class I (MHC-I) amino acid residues, including anchor residues that critically define the selection and binding of peptides to MHC-I molecules, residues known to influence MHC-I-killer immunoglobulin-like receptor interactions, and a residue located in the signal peptide of HLA-B. The locations of these variants collectively implicate MHC-I peptide binding in the pathophysiology of BD. Furthermore, several lines of evidence suggest a role for altered regulation of cellular cytotoxicity in BD pathogenesis.

Diversity of killer cell immunoglobulin-like receptor genes in uveitis associated with autoimmune diseases: ankylosing spondylitis and Behçet disease

PURPOSE

To determine whether the frequencies of specific killer cell immunoglobulin-like receptors (KIR) genotypes are associated with the incidence of uveitis in ankylosing spondylitis (AS) and Behçet disease (BD).

METHODS

The authors analyzed the frequency of 16 KIR genes in Koreans with either AS (110 patients, all HLA-B27-positive) or BD (86 patients), using polymerase chain reaction sequence-specific oligonucleotide probing.

RESULTS

The frequency of the inhibitory receptor KIR3DL1 was lower in AS patients affected by uveitis than that in the general population (p < 0.05). The frequency of the KIR3DL1(-)/2DS3(-) was significantly higher in AS patients with uveitis (odds ratio = 9.306, p = 0.007).

CONCLUSIONS

The study suggests that KIR3DL1 might associate with the resistance to AS-associated uveitis by influencing natural killer cell activity.

Association Analysis of IL10, TNF-α, and IL23R-IL12RB2 SNPs with Behçet's Disease Risk in Western Algeria

Objective: We have conducted the first study of the association of interleukin (IL)-10, tumor necrosis factor alpha (TNF-α), and IL23R-IL12RB2 region single nucleotide polymorphisms (SNPs) with Behçet’s disease (BD) in Western Algeria.

Methods: A total of 51 BD patients and 96 unrelated controls from West region of Algeria were genotyped by direct sequencing for 11 SNPs including 2 SNPs from the IL10 promoter [c.-819T > C (rs1800871), c.-592A > C (rs1800872)], 6 SNPs from the TNF-α promoter [c.-1211T > C (rs1799964), c.-1043C > A (rs1800630), c.-1037C > T (rs1799724), c.-556G > A (rs1800750), c.-488G > A (rs1800629), and c.-418G > A (rs361525)], and 3 SNPs from the IL23R-IL12RB2 region [g.67747415A > C (rs12119179), g.67740092G > A (rs11209032), and g.67760140T > C (rs924080)].

Results: The minor alleles c.-819T and c.-592A were significantly associated with BD [odds ratio (OR) = 2.18; 95% confidence interval (CI) 1.28–3.73, p = 0.003]; whereas, there was weaker association between TNF-α promoter SNPs or IL23R-IL12RB2 region and disease risk.

Conclusion: Unlike the TNF-α and the IL23R-IL12RB2 region SNPs, the two IL10 SNPs were strongly associated with BD. The -819T, and -592A alleles and the -819TT, -819CT, and -592AA and -592CA genotypes seem to be highly involved in the risk of developing of BD in the population of Western Algeria.

HLA and non-HLA genes in Behçet's disease: a multicentric study in the Spanish population

Introduction

According to genome wide association (GWA) studies as well as candidate gene approaches, Behçet’s disease (BD) is associated with human leukocyte antigen (HLA)-A and HLA-B gene regions. The HLA-B51 has been consistently associated with the disease, but the role of other HLA class I molecules remains controversial. Recently, variants in non-HLA genes have also been associated with BD. The aims of this study were to further investigate the influence of the HLA region in BD and to explore the relationship with non-HLA genes recently described to be associated in other populations.

Methods

This study included 304 BD patients and 313 ethnically matched controls. HLA-A and HLA-B low resolution typing was carried out by PCR-SSOP Luminex. Eleven tag single nucleotide polymorphisms (SNPs) located outside of the HLA-region, previously described associated with the disease in GWA studies and having a minor allele frequency in Caucasians greater than 0.15 were genotyped using TaqMan assays. Phenotypic and genotypic frequencies were estimated by direct counting and distributions were compared using the χ² test.

Results

In addition to HLA-B*51, HLA-B*57 was found as a risk factor in BD, whereas, B*35 was found to be protective. Other HLA-A and B specificities were suggestive of association with the disease as risk (A*02 and A*24) or protective factors (A*03 and B*58). Regarding the non-HLA genes, the three SNPs located in IL23R and one of the SNPs in IL10 were found to be significantly associated with susceptibility to BD in our population.

Conclusion

Different HLA specificities are associated with Behçet’s disease in addition to B*51. Other non-HLA genes, such as IL23R and IL-10, play a role in the susceptibility to the disease.

Macular hole in Behçet's disease

Objective:

To investigate the clinical features, prevalence, role of surgical intervention and the visual prognosis of macular holes (MH) in patients with Behcet's disease (BD).

Materials and Methods:

Retrospective study of patients with BD and MH from January 1998 to November 2008.

Results:

Out of 159 patients, 21 eyes of 17 patients were identified with MH. The mean age was 38.59 (range 23-61) years and the mean follow-up period was 5.1 years (range 13-164 months). The prevalence of MH was 7%. Visual acuity (VA) at the time of presentation ranged from 20/70 to hand-motion. Optical coherence tomography (OCT) findings revealed intraretinal cysts at the edge of the MH. The mean size of MH was 983.6 um; 52% had elevated edges, 43% had flat edges and only one eye (5%) was closed postoperatively. Fluorescein angiography (FA) was consistent with macular ischemia in 76% of the cases. Human leukocyte antigen (HLA) B51 association was found in 14 of the 15 patients investigated. Six patients (out of 17) underwent pars plana vitrectomy. The final VA on their last follow-up ranged from 20/70 to 2/200. Surgical intervention for MH did not result in any visual improvement as compared to non-operated eyes. One patient lost vision completely due to elevated intraocular pressure post vitrectomy and silicon oil tamponade.

Conclusions:

MH in patients with BD may lead to significant visual disability. Surgical intervention does not seem to have any potential beneficial effect on the VA, probably due to significant macular ischemia and sequelae from the ocular inflammation.

Tumour necrosis factor gene polymorphism and disease prevalence

Tumour necrosis factor (TNF), an important proinflammatory cytokine, plays a role in the regulation of cell differentiation, proliferation and death, as well as in inflammation, innate and adaptive immune responses, and also implicated in a wide variety of human diseases. The presence of DNA sequence variations in regulatory region might interfere with transcription of TNF gene, influencing the circulating level of TNF and thus increases the susceptibility to human diseases (infectious, cancer, autoimmune, neurodegenerative and other diseases). In this review, we have comprehensively analysed various published case-control studies of different types of human diseases, in which TNF gene polymorphism played a role, and computationally predicted several single nucleotide polymorphisms (SNPs) lie in transcription factor-binding sites (TFBS) of transcription factors (TFs). It has been observed that TNF enhancer polymorphism is implicated in several diseases, and TNF rs1800629 and rs361525 SNPs are the most important in human disease susceptibility as these might influence the transcription of TNF gene. Thirty-two SNPs lies in TFBS of 20 TFs have been detected in the TNF upstream region. It has been found that TNF enhancer polymorphism influences the serum level of TNF in different human diseases and thus affects the susceptibility to diseases. The presence of DNA sequence variation in TNF gene causes the modification of transcriptional regulation and thus responsible for association of susceptibility/resistance with human diseases.

Ocular Behçet disease: current therapeutic approaches

PURPOSE OF REVIEW

To alert physician to timely recognition and current treatment of recurrent hypopyon iridocyclitis or panuveitis in ocular Behçet disease (OBD).

RECENT FINDINGS

Interferon-α, rituximab, intravitreal triamcinolone, and biological response modifiers by tumor necrosis factor inhibitors such as infliximab and adalimumab are being used increasingly for the treatment of severe sight-threatening ocular inflammation including retinal vasculitis and cystoid macular edema (CME).

SUMMARY

Biological agents offer tremendous potential in the treatment of OBD. Given that OBD predominantly afflicts the younger adults in their most productive years, dermatologist, rheumatologist, internist, or general practitioners supervising patients with oculo-articulo-oromucocutaneous syndromes should be aware of systemic Behçet disease. Early recognition of ocular involvement is important and such patients should strongly be instructed to visit immediately an ophthalmologist, as uveitis management differs from extraocular involvements with high ocular morbidity from sight-threatening complications due to relapsing inflammatory attacks in the posterior segment of the eye. A single infliximab infusion should be considered for the control of acute panuveitis, whereas repeated long-term infliximab infusions were proved to be more effective in reducing the number of episodes in refractory uveoretinitis with faster regression and complete remission of CME.

The promoter -1031(T/C) polymorphism in tumor necrosis factor-alpha associated with polycystic ovary syndrome

BACKGROUND

A tumor necrosis factor-alpha is a multifunctional pro-inflammation cytokine, which has been considered as one of pathogenic factors for various diseases. The promoter -1031(T/C) polymorphism in the tumor necrosis factor-alpha gene was reported that it plays a part in reproduction-related diseases. Among these, polycystic ovary syndrome (PCOS) is known to be a common gynecological disease of women in reproductive age women. Here, we performed a comparative study of -1031(T/C) polymorphism of TNF-alpha gene with PCOS in a Korean population.

METHODS

The -1031(T/C) polymorphism of TNF-alpha gene was analyzed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) in a total of 217 PCOS patients and 144 matched female controls of healthy women. And statistical analysis was performed using HapAnalyzer. X2 test and logistic regression were utilized analyze the association between two groups. A p-value under 0.05 was considered statistically significant.

RESULTS

The genotype and allelic frequencies were in Hardy-Weinberg equilibrium (HWE). There was strong association between the -1031(T/C) polymorphism in the promoter region of TNF-alpha gene and PCOS (p-value = 0.0003, odd ratio (OR) = 2.53). In addition, the frequency of C allele was significantly higher in PCOS patients compared with controls. Sequence analyses also showed the -1031(T/C) polymorphism of TNF-alpha gene.

CONCLUSION

This is the first study on the -1031(T/C) polymorphism of TNF-alpha gene in PCOS. We concluded that the -1031(T/C) polymorphism of TNF-alpha gene is associated with PCOS in a Korean population. Therefore, it is possible that it may be considered as a clinical biomarker to diagnose for PCOS, and is helpful in understanding the etiology for the pathogenesis of PCOS.

Genetics in ocular inflammation--basic principles

The ability to identify individuals at risk of ocular disease, or to determine the potential severity of disease or response to therapy is the current focus of much research. These studies are being led by genetic analysis of individuals to determine associations with alterations in gens that may explain manifestations of particular diseases. In this review we consider the basic principles behind genetic studies in general and of ocular disease in particular. We address the methodologies being utilised, and the results derived so far. The potential and pitfalls of such studies are relevant to the concept of personalised medicine and better defined clinical trials.

Genetic susceptibility to Behcet's disease: role of genes belonging to the MHC region

OBJECTIVE

To review the progress in the field of MHC-related genetic susceptibility to Behçet's disease (BD).

METHOD

Systematic review of the English literature between 1 January 1980 and 31 January 2010 using Medline. Case-control, population-based, observational cohort studies investigating the association between BD and HLA-B*51 subtypes, classical and non-classical HLA alleles and other HLA-related genes were selected. The geographical distribution of BD and these susceptibility genes was also taken into consideration. Case and familial case reports were excluded except for case series with more than two patients.

RESULTS

Ninety articles plus 17 obtained from other sources were included in the systematic review. We have found high evidence that a core component of genetic susceptibility to BD is within the MHC region being primarily related to an HLA-B*51 subtype: HLA-B*5101/B*510101. Moreover, HLA-A*26, HLA-B*15, HLA-B*5701 and TNF-α -1031C were independently associated with BD. Data suggest that other HLA (HLA-C, HLA-DR) and HLA-related [MHC Class I chain-related gene A (MIC-A), TNF-α] genes may play a role in BD co-susceptibility or pathogenesis. Finally, the distinctive geographical distribution of BD suggested an evolutionary selection of HLA-B*51 subtypes as the major susceptibility factors for BD.

CONCLUSION

Further studies must be addressed to clarify the functional relevance of the different genes found to be associated with disease susceptibility and the potential interactions between genes located within and outside the MHC region.

Evaluation of current therapeutic strategies in Behçet's disease

Behçet's disease (BD) is a chronic relapsing vasculitis with multifunctional pathogenesis. The mucocutaneous and ocular lesions are the commonest manifestations, but BD also affects the musculoskeletal, intestinal, cardiac, and central nervous system. BD therapy is based on the suppression of the inflammatory process, using immunomodulating and immunosuppressive agents. In selected cases, invasive procedures may be required.

Etiopathogenesis of Behçet's disease with emphasis on the role of immunological aberrations

Behçet's disease (BD) is a chronic multisystemic inflammatory disorder of unknown origin consisting of oral aphthous ulcers, ocular symptoms, skin lesions, and genital ulcerations. It has many features in common with systemic vasculitides and is more prevalent in countries along the ancient Silk route. Immune-mediated mechanisms play a major role in the pathogenesis of the disease, and inflammatory mediators are also involved. BD is not considered to be an autoimmune disorder, and the character of the disease needs to be clarified. Immunological aberrations in BD have been extensively studied by many investigators; genetic factors have been related to disease susceptibility, but their exact role in the development of disease is uncertain. Environmental factors such as infectious agents have also been implicated in the etiology of BD. However, the etiopathogenesis of the disease remains to be elucidated. Factors involved in the immunopathogenesis of BD with emphasis on the role of immunological aberrations are analyzed in this review.

TNF polymorphisms in patients with Behçet disease: a meta-analysis

BACKGROUND AND AIMS

Polymorphisms in the tumor necrosis factor (TNF) gene at the locations -308, -238, -863, -857 and -1031 have been studied in various ethnic groups for possible association with Behçet's disease. The aim of this meta-analysis is to examine the association between polymorphism in the TNF gene at the locations -308, -238, -863, -857 and -1031 and Behçet's disease.

METHODS

A literature review was performed using MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials for original studies published in English up to October 31, 2009 and that examined the association of the TNF-alpha promoter polymorphisms with Behçet's disease. All pooled odds ratios (OR) were derived from random-effects model with its 95% confidence intervals (CI). We assessed statistical heterogeneity among studies using Cochrane Q test and by calculating I(2). The Cochrane collaboration's software program, RevMan 5 was used to prepare and complete this review.

RESULTS

The literature search resulted in 13 studies. Ten studies met the included criteria and thus were selected. Overall, -1031C (OR = 1.35, 95% CI = 1.09-1.68), -238A (OR = 1.51, 95% CI = 1.12-2.04) and -857T (OR = 0.76, 95% CI = 0.58-0.98) had a significant association with Behcet's disease. The pooled estimates for the other polymorphisms were not statistically significantly associated with Behcet's disease; -308A and -863A.

CONCLUSIONS

Behcet's disease was associated with the -1031C, -238A and the -857T promoter polymorphisms in various ethnic groups.

Analyses of functional IL10 and TNF-α genotypes in Behçet's syndrome

We aim to ascertain the possible involvement of functional IL10 and TNF-α promoter polymorphisms on the susceptibility to Behçet's syndrome (BS), to examine whether IL10 and TNF-α genotypes might work synergistically influencing susceptibility to BS. IL10 -1082G/A, -819C/T and -592C/A and TNF -308G/A polymorphisms were analyzed in 102 Turkish patients with BS and 102 healthy subjects by using amplification refractory mutation system-polymerase chain reaction (ARMS-PCR). We have found no significant associations between IL10 -1082G/A, -819C/T, -592C/A, TNF-α -308G/A polymorphisms and BS. Also, no significant correlation was found between IL10 GCC, ACC, ATA haplotypes, GCC(+)/GCC(+), GCC(+)/GCC(-), GCC(-)/GCC(-) genotypes. There was no significant association between combined TNF-α/IL10 genotypes and BS. Our study indicates that functional TNF-α, IL10 genotypes or combined TNF-α, IL10 genotypes do not play a role in BS susceptibility in Turkish BS patients.

Immune response genes in uveitis

Uveitis is defined as an intraocular inflammation induced by different etiologies. Though the precise pathogenesis is still unknown, accumulating evidence shows that both innate and adaptive immune responses may be predominant mechanisms involved in the development of uveitis. Toll-like receptors have been shown to be expressed in the human eye and play an important role in infectious uveitis. The NOD proteins, expressed mainly in the cytosol by APCs, recognize the products of bacteria and participate in the development of uveitis. HLA genes have been associated with some uveitis entities, including acute anterior uveitis (HLA-B27), Behcet disease (HLA-B51), birdshot retinochoroidopathy (HLA-A29), Vogt-Koyanagi-Harada syndrome (HLA-DR4), sarcoidosis, sympathetic ophthalmia, juvenile idiopathic arthritis, tubulointerstitial nephritis and uveitis (TINU) syndrome, and pars planitis (HLA-DR15). The exact mechanism whereby certain HLA genes predispose to a certain uveitis entity has not yet been elucidated. In addition, several studies have demonstrate that polymorphisms in certain immune response genes, such as tumor necrosis factor (TNF), MHC class I polypeptide-related sequence A (MICA), interleukin-1 (IL-1), and some chemokines, may contribute to the development of human uveitis. Polymorphisms in the gene coding for the costimulatory molecule known as cytotoxic T-lymphocyte antigen 4 (CTLA-4) were recently found in Chinese patients with VKH syndrome but not in patients with Behcet disease. Further developments in the unraveling of immune response genes may lead to a better understanding of human uveitis and will hopefully allow the development of novel treatment regimes.

Immunogenetics of drug-induced skin blistering disorders. Part I: Perspective

The overall immunopathogenesis relevant to a large series of disorders caused by a drug or its associated hyperimmune condition is discussed based upon the examination of the genetics of severe drug-induced bullous skin problems (sporadic idiosyncratic adverse events, including Stevens-Johnson syndrome and toxic epidermal necrolysis). An overarching pharmacogenetic schema is proposed. Immune cognition and early-effector processes are focused upon and a challenging synthesis around systems evolution is explained by a variety of projective analogies. Etiology, human leukocyte antigen-B, immune stability, dysregulation, pharmacomimicry, viruses and an aggressive ethnically differentiated 'karmic' response are discussed.

The novel –G646A polymorphism of the TNFα promoter is associated with the HLA‐B51 allele in Korean patients with Behçet's disease

OBJECTIVE

This study was performed to examine the influence of tumour necrosis factor-alpha (TNFalpha) promoter polymorphisms on disease susceptibility and clinical features of Behçet's disease (BD) and the association between TNFalpha polymorphisms and human leucocyte antigen (HLA)-B51.

METHODS

We examined 115 patients with BD and 114 healthy subjects. Six single nucleotide polymorphisms (SNPs) of the TNFalpha promoter at positions -1031, -863, -857, -308, -238, and -646 were analysed using automated sequencing. We compared the frequencies of alleles and genotypes in patients with BD and controls using the chi(2)-test or Fisher's exact test. Haplotype frequency was also assessed using the chi(2)-test.

RESULTS

We found no significant differences in the frequencies of polymorphic genotypes and alleles of the TNFalpha promoter region between BD patients and controls. The resulting haplotype frequencies of the BD patients were also not significantly different from those of controls. None of the TNFalpha promoter polymorphisms analysed here were associated with clinical features. Patients with the novel -646A allele of the TNFalpha promoter region were significantly associated with the expression of the HLA-B51 allele (p(corr) = 0.006), although this novel polymorphic allele was not associated with BD susceptibility.

CONCLUSION

The novel -646A TNFalpha allele was associated with the expression of HLA-B51 in Korean BD, although we found no genetic role of TNFalpha promoter polymorphisms in the susceptibility to BD. Further studies to examine the contributions of this gene polymorphism and HLA-B51 to the susceptibility to BD in large populations are required.