Intercellular adhesion molecule-1 gene polymorphisms in Behçet's disease

Epigenetic alterations in chronic disease focusing on Behçet's disease: Review

OBJECTIVE

'Epigenetics' is specified as the inheritable changes in gene expression with no alterations in DNA sequences. Epigenetics is a rapidly overspreading scientific field, and the study of epigenetic regulation in chronic disease is emerging. This study aims to evaluate epigenetic changes including DNA methylation, histone modification, and non-coding RNAs (ncRNAs) in inflammatory disease, with focus on Behçet's disease. In this review, first we describe the history and classification of epigenetic changes, and then the role of epigenetic alterations in chronic diseases is explained.

METHODS

Systematic search of MEDLINE, Embase, and Cochrane Library was conducted for all comparative studies since 2000 to 2015 with the limitations of the English language.

RESULTS

For a notable period of time, researchers have mainly focused on the epigenetic pathways that are involved in the modulation of inflammatory and anti-inflammatory genes. Recent studies have proposed a central role for chronic inflammation in the pathogenesis of chronic disease, including Behçet's disease.

CONCLUSION

Studies have been reported on the epigenetic of BD showed the role of alterations in the methylation level of IRS elements; histone modifications such as H3K4me27 and H3K4me3; up regulation of miR-182 and miR-3591-3p; down regulation of miR-155, miR-638 and miR-4488 in the pathogenesis of the disease.

Analysis of ICAM1 gene polymorphism in Slovak multiple sclerosis patients

Infiltration of immune cells into CNS is one of the essential events in multiple sclerosis (MS) development. Adhesion molecules like the intercellular adhesion molecule 1 (ICAM-1) play critical role in this process. Therefore, the ICAM1 gene containing two important single-nucleotide polymorphisms (SNPs) belongs to candidate loci with possible involvement in MS susceptibility and/or severity. The objective of our case-control study was to analyze the association of two functional ICAM1 polymorphisms rs1799969 (or G241R) and rs5498 (or K469E) with susceptibility to MS and evaluate their influence on the age at disease onset, severity, neurological disability and progression rate. Two hundred forty-eight MS subjects (mean 39.2 years) and 208 age-matched controls (mean 35.6 years) were involved in the study. Genotyping of ICAM1 rs1799969 and rs5498 SNPs was performed by PCR-RFLP. Presence of the rs3135388 polymorphism tagging the major MS risk allele HLA-DRB1*15:01 allele was determined as well. Our analysis revealed no statistically significant association of ICAM1 polymorphisms with risk of MS development in the Slovak population. Stratification of study cohorts by gender, age at onset and presence of the HLA-DRB1*15:01 risk allele showed only moderate changes. Correlation of clinical findings as age at onset, Kurtzke Expanded Disability Status Scale, Multiple Sclerosis Severity Score and progression index with ICAM1 genotypes in MS patients revealed no significant association; however, patients with earlier onset of MS showed slightly higher frequencies of the homozygous G allele at rs5498 in comparison to other genotypes (P = 0.04), suggesting that GG carriers tend to induce MS at an earlier age.

The ICAM-1 Gly241Arg Polymorphism is Not Associated With Polycystic Ovary Syndrome - Results from a Case Control study in Kashmir, India

BACKGROUND

Polycystic ovary syndrome (PCOS) is considered to be a multifactorial disorder resulting from the interaction of several predisposing and protective genetic variants. PCOS is associated with low-grade chronic inflammation. Elevated levels of inflammatory markers including intercellular adhesion molecule-1 (ICAM-1) are demonstrated in women with PCOS. Recent evidence indicates a significant linkage between a locus on chromosome 19p13 and multifactorial diseases that have an inflammatory component. The aim of the study was to assess the possible association of Gly241Arg polymorphism of ICAM-1 gene located on chromosome 19p13 in determining risk of PCOS in Kashmiri women.

MATERIALS AND METHODS

Gly241Arg SNP in DNA from peripheral blood leukocytes of 220 PCOS cases and 220 age matched non-PCOS healthy controls was analysed using allel specific PCR.

RESULTS

The genotype and allele frequency distributions of Gly241Arg SNP showed insignificant difference between the PCOS cases and control women, indicating no role of this SNP in PCOS susceptibility. The odds ratio for Arg/Arg genotype was 0.87 (95% CI=0.32-2.3) [P=0.79], for Gly/Arg genotype was 0.98 (95% CI= 0.66-1.47) [P=1] and for Arg/Arg+Gly/Arg genotype was 0.97 (95% CI=0.65-1.45) [P=0.92]. The genotypic frequencies of ICAM-1codon 241 showed statistically insignificant difference between cases and controls (χ2=0.07; p=0.96) Nor the studied polymorphism was found to affect clinical and laboratory parameters significantly.

CONCLUSIONS

Although Gly241Arg polymorphism have not shown significant association with PCOS. Further, specifically designed studies on large cohorts are required to conclusively establish any role of ICAM-1 gene polymorphisms in PCOS in our study.

Association between Functional MICA-TM and Behcet's Disease: A Systematic Review and Meta-analysis

The relationships between polymorphisms of the trans-membrane(TM) region located in the major histocompatibility complex (MHC) class I chain-related gene A (MICA) and Behcet's disease (BD) have been discussed previously, however, the results were contradictory. In this study, we thoroughly assess whether MICA-TM gene variants are associated with BD by means of a systematic review and meta-analysis. Our study focused on the effects of polymorphisms of MICA-A4, A5, A5.1, A6, and A9 from the included articles. Sixteen previous original publications representing 1,555 BD patients and 2,086 unrelated healthy controls analyzed the association of BD with MICA-TM gene polymorphisms. For the five alleles, MICA-A6 showed a strongly positive correlation with BD patients and could be viewed as an increased risk factor of BD (OR = 2.34, 95%CI: 2.02-2.70). Furthermore, MICA-A4, A5, A5.1, and A9 exhibited negative associations with BD (OR = 0.71, 95%CI: 0.58-0.86; OR = 0.75, 95%CI: 0.63-0.90; OR = 0.63, 95%CI: 0.44-0.91; OR = 0.70, 95%CI: 0.58-0.84, respectively). Our meta-analysis confirmed MICA-A6 could be responsible for BD in three ethnic regions and should probably be treated as a risk factor for BD. MICA-A4, A5, A5.1, and A9 could be regarded as protective factors, especially in the Middle East and East Asia.

Intercellular adhesion molecule-1 polymorphisms in patients with Behçet disease: a meta-analysis

OBJECTIVES

To examine the association between the Intercellular adhesion molecule-1 (ICAM1) Polymorphisms and Behçet's disease.

METHODS

MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials for original studies up to July 31, 2012 were searched for relevant studies. All pooled odds ratios (ORs) were derived from either fixed or random-effects model with its 95% confidence intervals (CI).

RESULTS

Five studies met the inclusion criteria. Overall, ICAM1 E469 (OR = 1.45, 95% CI = 1.06-1.97), genotype ICAM1 469 E/E (OR = 1.45, 95% CI = 1.09-1.94), ICAM1 241 G/R (OR = 3.65, 95% CI = 1.69-7.89), had significant associations with Behçet's disease. A significant association was found between the presence of skin lesions and genotype ICAM1 469 E/E (OR = 3.52, 95% CI = 1.62-7.66).

CONCLUSIONS

Behçet's disease was associated with the ICAM1 E469, genotype ICAM1 469 E/E, ICAM1 241 G/R polymorphisms in different ethnic groups. Among patients, genotype ICAM1 469 E/E had a significant association with skin lesion.

Association between Rho-kinase (ROCK2) gene polymorphisms and Behçet's disease

Behçet's disease (BD) is a multi-systemic vasculitis. The aim of this study was to investigate the association between Rho-kinase (ROCK2) gene polymorphisms and patients with BD in a Turkish population. A total of 194 BD patients and 276 healthy controls with similar age and sex were included to this study. Polymorphisms were analyzed in genomic DNA using a BioMark 96.96 dynamic array system. mRNA from blood samples was extracted, and real-time polymerase chain reaction was performed for ROCK2 gene expression. There were marked changes in both genotype (TT, 41.8%; TA, 30.3%) and allele (T, 57%; A, 43%) frequencies for the rs35768389 (Asp601Val) polymorphism in patients compared with controls (TT, 64.6%; TA, 9.4%, P < 0.0001; T, 69.3%; A, 30.7%, P = 0.0004). Although CC genotype (52.0%) of rs1515219 polymorphism were more frequent, CT genotype (27.7%) were less frequent among the patients than controls (CC, 31.7%, CT, 44.6%, P = 0.0001). There was an increase in C allele (65.8% vs 54.0%) and decrease in T allele frequencies (34.2% vs 46.0%, P = 0.001) in patients. However, no associations were found with rs726843, rs2290156, rs965665, rs10178332, rs2230774, rs6755196, rs10929732, and rs34945852 polymorphisms. There was an increase in peripheral blood mRNA ROCK2 expressions in patients. This is the first study to examine the involvement of ROCK2 gene variation in the risk of incident BD. The results strongly suggest that ROCK2 gene polymorphisms may modify individual susceptibility to BD in the Turkish population.

The intercellular adhesion molecule-1 (ICAM-1) gene polymorphism K469E in end-stage renal disease patients with cardiovascular disease

The intercellular adhesion molecule-1 (ICAM-1) mediates interaction of activated endothelial cells with leukocytes. It plays an important role in the pathogenesis of atherosclerosis. A functionally important polymorphism of the ICAM-1 gene, K469E, has been described. We investigated whether this polymorphism influences the risk of CVD in end-stage renal disease (ESRD) patients. The groups of 1016 ESRD patients and 824 healthy individuals were genotyped by PCR and allele specific oligonucleotide technique. The T allele of the K469E polymorphism was significantly more frequent in ESRD CVD+ patients than CVD- and controls (OR 2.26, 95% CI 1.87-2.72 and 1.82, 95% CI 1.55-2.11, respectively). The TT genotype was also more frequent in CVD+ patients (OR 9.90, 95% CI 6.17-15.88 vs. CVD- subgroup). When patients were stratified according to clinical outcome of CVD, there was a tendency towards higher frequencies of the T allele and TT genotype in patients with myocardial infarction (OR for T allele 1, 57, 95% CI 1.12-2.18 vs. patients without MI). In the multivariate regression analysis the carrier status of T allele of K469E was an independent risk factor of susceptibility to CVD. Our data suggest that the ICAM-1 K469E polymorphism is associated with CVD in ESRD patients.

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.

New insights into the pathogenesis of Behçet's disease

Behçet's disease (BD) is a recurrent systemic inflammatory disorder of unknown origin characterized by oral and genital mucous ulcer, uveitis, and skin lesions. Involvement of large vessels, central nervous system (CNS), gastrointestinal tract and thrombotic events are less frequent but can be life threatening. The aim of this review is to provide new insights into the pathogenesis of BD. Over the past year substantial advances have been done in the understanding of the genetic [1,2] and immunology [3] of BD. BD is at the crossroad between autoimmune and autoinflammatory syndromes. In common with autoimmune diseases BD shares class I MHC association. However, in contrast to autoimmune disorders, BD has clinical features that seem to be mostly autoinflammatory. The pathogenesis of BD is still unknown, but major determinants of the genetic and immune system abnormalities have been reported recently. Triggering infectious factors are supposed to participate in the outbreak of BD in genetically predisposed patients. Two recent large genome-wide association study (GWAS) conducted in Turkey and Japan reported association between single nucleotide polymorphism (SNP) of interleukin (IL)-10 and IL-23R/IL-12RB2 genes and BD. New insights into the perturbations of T cell homeostasis of BD recently emerged. We have recently demonstrated the promotion of Th17 responses and the suppression of regulatory T cells (Tregs) that were driven by interleukin (IL)-21 production and that correlates with BD activity. Inflammatory cells within BD inflammatory lesions included mostly neutrophils, Th1 and Th17 cells, and cytotoxic CD8+ and γδ T cells. Altogether, the recent progresses in the knowledge of BD pathogenesis pave the way for innovative therapy.

Intercellular adhesion molecule-1 gene polymorphisms in patients with familial mediterranean fever

Familial Mediterranean fever (FMF) is a disease of unknown etiology characterized by recurrent attacks of polyserositis and fever. Intercellular adhesion molecule-1 (ICAM-1) is known to contribute inflammatory conditions by regulating leukocyte localization at inflammatory sites. The aim of this study was to evaluate the probable association of ICAM-1 G/R 241 and ICAM-1 E/K 469 polymorphisms according to susceptibility with FMF. Sixty-seven FMF patients and 83 healthy volunteers were included in the study. Genomic DNA was extracted from EDTA-preserved whole blood of whole series of patients and controls, and genotyped by polymerase chain reaction (PCR) and allele-specific oligonucleotide techniques for ICAM-1 polymorphisms G/R at codon 241 and E/K at codon 469. The ICAM-1 241 genotype and allele frequencies of FMF patients and healthy volunteers were similar. The frequency of ICAM-1 K469 homozygosity was significantly lower in FMF patients than in the controls (32.8% vs 50.7% subsequently, p=0.03). Moreover, ICAM-1 E469 allele was more frequent in FMF patients than in controls (44.8% vs 32.3%, p:0.03). Our results showed that ICAM-1 469 gene polymorphism could contribute to the pathogenesis of FMF.

Role of ICAM-1 and E-selectin gene polymorphisms in pathogenesis of PAOD in Egyptian patients

Background:

Intercellular adhesion molecule-1 (ICAM-1) and E-selectin have been shown to predict cardiovascular disease (CVD) such as myocardial infarction, stroke, and peripheral arterial occlusive disease (PAOD).

Methods:

Two mutations, S128R in E-selectin and K469E in ICAM-1, were investigated in 156 patients with PAOD and 100 control subjects using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis in an Egyptian population.

Results:

The distribution of E-selectin genotypes in patients affected by PAOD was 84.6% for the AA genotype and 15.4% for the AC genotype. In the control arm the distribution was 97% for the AA genotype and 3% for the AC genotype. There was a statistically significance difference in the distribution of the AC genotype in PAOD patients when compared with the control subjects. Additionally, the distribution of ICAM-1 genotypes in patients affected by PAOD was 30.8% with the EE, 48% with the EK, and 21.2% with the KK genotypes. The distribution of ICAM-1 genotypes in control subjects was 13% EE, 33% EK and 54% KK. The EE genotype was significantly more common in PAOD patients than in the controls.

Conclusion:

S128R and K469E polymorphisms were associated with increased risk in PAOD. Early detection of these polymorphic genes helps in early prophylaxis against PAOD.

Behçet's disease--a contemporary review

Behçet's disease (BD) is a systemic vasculitis disorder of unknown etiology, characterized by relapsing episodes of oral aphthous ulcers, genital ulcers, skin lesions and ocular lesions. It can affect other systems including vascular, gastrointestinal and neurological systems. It occurs most frequently in an area that coincides with the Old Silk Route (between latitudes 30 degrees and 45 degrees north in Asia and Europe). BD is slightly more frequent and has a worse clinical course in men. It is believed to be due to an auto-immune process triggered by an infectious or environmental agent in a genetically predisposed individual. HLA-B51 is the most strongly associated risk factor. The International Study Group (ISG) for Behçet's Disease created a set of criteria for the diagnosis of BD. Available treatments include corticosteroids, azathioprine, cychlophosphamide, cyclosporine A, interferon-alpha, anti-tumour necrosis factor alpha agents, among others. BD has a variable course characterized by relapses and remissions. Prognosis depends on the clinical involvement. Loss of visual acuity and neurological disease are major causes of morbidity and disability.

ICAM-1 (Lys469Glu) and PECAM-1 (Leu125Val) polymorphisms in diffuse astrocytomas

Cell adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) and platelet-endothelial cell adhesion molecule-1 (PECAM-1) play an important role in glioma invasion and angiogenesis. The aim of this study was to investigate whether specific genetic polymorphisms of ICAM-1 and PECAM-1 could be associated with glioma development and progression. Single-nucleotide polymorphism in codon 469 of ICAM-1 and codon 125 of PECAM-1 were examined in 158 patients with astrocytomas and 162 controls using polymerase chain reaction and restriction enzyme analysis. The distribution of PECAM-1 polymorphic genotypes in astrocytomas did not show any significant difference. However, a specific ICAM-1 genotype (G/G, corresponding to Lys469Glu) exhibited higher frequency in grade II astrocytomas compared to controls, grade III, and grade IV astrocytomas; suggesting that this polymorphism could be involved in the development of grade II astrocytomas.

Intercellular adhesion molecule-1 K469E polymorphism in Korean patients with spontaneous preterm delivery

OBJECTIVES

To investigate the association between intercellular adhesion molecule-1 (ICAM-1) gene K469E polymorphism and spontaneous preterm delivery in a Korean population.

METHODS

Genomic DNA was extracted from whole blood from 55 women experiencing preterm labor and 153 multiparous women (control group) with a history of at least 2 term deliveries. DNA samples were analyzed by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

The spontaneous preterm delivery (SPD) group carried the 469E allele significantly more frequently than those in the control group (odds ratio [OR], 1.62; 95% CI, 1.04-2.53). The EE genotype was significantly associated with increased risk of SPD (OR, 2.84; 95% CI, 1.17-6.89; P = 0.02). Allelic frequencies in women with abnormal C-reactive protein levels (K = 0.48; E = 0.52) were significantly different from frequencies in the controls (K = 0.68; E = 0.32) (P = 0.006).

CONCLUSIONS

ICAM-1 gene K469E polymorphism may be a candidate region and useful predictor of susceptibility to SPD in the Korean population.

Susceptibility to active decompensated cirrhosis is associated with polymorphisms of intercellular adhesion molecule-1 (ICAM-1) in chronic HBV carriers

Intercellular adhesion molecule-1 (ICAM-1) plays an important role in the pathogenesis of viral hepatitis B. Several inflammatory diseases are associated with distinct polymorphisms of the ICAM-1 gene. The aims of this study were to analyse the association of ICAM-1 polymorphisms G241R and K469E with susceptibility to active decompensated cirrhosis in chronic hepatitis B virus (HBV) carriers. The polymorphisms at codons G241R and K469E of ICAM-1 were analysed by sequence-specific primer polymerase chain reaction (PCR-SSP) in 572 unrelated chronic HBV carriers and 157 unrelated healthy HBV non-infected blood donors. There were significantly increased frequencies of R at codon 241 and E at codon 469 in patients with active decompensated cirrhosis (38.3% and 58.3%), compared with patients with chronic hepatitis B (CHB; 21.9% and 46.5%) and chronic asymptomatic HBV carriers (AsC; 12.6% and 40.3%). The frequencies of R241-E469 haplotype and genotypes carrying at least one R241-E469 haplotype were significantly higher in patients with active decompensated cirrhosis than those in patients with CHB (38.3% and 63.3%vs 21.9% and 36.7%), and significantly higher in patients with CHB than those in AsC (21.9% and 36.7%vs 12.6% and 23.3%). The ICAM-1 polymorphisms at codons G241R and E469K were associated with the disease susceptibility, and susceptibility to active decompensated cirrhosis is significantly increased in chronic HBV carriers carrying at least one R241-E469 haplotype.

Rapid detection of intercellular adhesion molecule 1 (G241R and K469E) polymorphisms by a novel PCR-SSP assay

Intercellular adhesion molecule 1 (ICAM-1) is a cell surface glycoprotein member of the immunoglobulin superfamily and is actively involved in immune and inflammatory responses. We introduce a novel polymerase chain reaction-sequence-specific primers (PCR-SSP) method for rapid and simultaneous genotyping of ICAM-1 G241R and K469E polymorphisms. In a total of 184 DNA samples that have been previously analyzed for these polymorphisms using polymerase chain reaction-restriction fragment length polymorphism technique, re-genotyping of all samples with this new assay showed accurate and reproducible results. As PCR-SSP-based genotyping protocols are more convenient and cost-effective to do, it could therefore offer a valuable tool for assessment of ICAM-1 polymorphisms to which more confirmatory studies are needed.

Analysis of CD28 and CTLA-4 gene polymorphisms in Turkish patients with Behcet's disease

In this study we aimed to investigate IVS3 +17T/C single nucleotide polymorphism (SNP) of CD28 gene, +49A/G and -318C/T SNPs of CTLA-4 gene in patients with Behçet's disease (BD) and their potential association to the main clinical features of the disease. These polymorphisms were investigated in a Turkish population of 123 patients with BD and 179 healthy controls, by using PCR-RFLP technique. HLA-B*51 genotype was also studied in both groups by using PCR-SSP. The frequency of IVS3 +17TC genotype of the CD28 gene was significantly increased in BD patients compared to controls (43.6% vs. 31.2%, OR = 1.663, 95% CI = 1.033-2.679, P = 0.039). CTLA-4 +49GG genotype frequency was found to be significantly lower in patients with BD than those of healthy controls (4% vs. 10.6%, OR = 0.357, 95% CI = 0.130-0.983, P = 0.05). Genotype and allele frequencies of the CTLA-4-318C/T polymorphism between the BD and healthy control groups were not significantly different (12.2% vs. 10.6%, OR = 1.170, 95% CI = 0.570-2.402, P = 0.713). There were no associations between the studied polymorphisms and the main clinical features of BD. The frequencies of HLA-B*51 were 60.3% and 30.7% in BD and control groups, respectively (OR = 3.429, 95% CI = 2.115-5.559, P = 0.0001). Association between HLA-B*51 and each studied polymorphism did not reach to significant levels (OR = 0.479, 95% CI = 0.228-1.004, P = 0.064 for CD28 IVS3 +17TT genotype; OR = 2.180, 95% CI = 1.025-4.639, P = 0.061 for TC genotype; OR = 1.570, 95% CI = 0.870-2.836, P = 0.146 for C allele). These results may suggest that CD28 IVS3 +17TC genotype may be a risk factor for the development of BD, on the contrary CTLA-4 +49GG genotype may be protective in the studied Turkish population.

Analysis of MAdCAM-1 and ICAM-1 polymorphisms in 365 Scandinavian patients with primary sclerosing cholangitis

BACKGROUND/AIMS

Mucosal addressin cellular adhesion molecule-1 (MAdCAM-1) has been implicated in the aberrant homing of intestinal lymphocytes to the liver in primary sclerosing cholangitis (PSC). Intercellular adhesion molecule-1 (ICAM-1) has also been implicated in the pathogenesis of PSC and the E/E genotype of the K469E polymorphism has been reported to be associated with PSC susceptibility. The aims of this study were to determine if MAdCAM-1 polymorphisms or the K469E polymorphism of ICAM-1 are associated with PSC in Scandinavia.

METHODS

Seven single nucleotide polymorphisms (SNPs) in MAdCAM-1 and the G421R and K469E ICAM-1 SNPs were genotyped in 365 PSC patients from Norway and Sweden. 327 Norwegian ulcerative colitis (UC) patients and 368 Norwegian bone marrow donors served as controls.

RESULTS

No significant association with PSC was found for any of the MAdCAM-1 or ICAM-1 SNPs. Allele frequencies for these polymorphisms were not significantly different between PSC patients with UC, UC patients and healthy controls.

CONCLUSIONS

Polymorphisms in MAdCAM-1 are not likely to significantly affect PSC susceptibility. In addition, the E/E genotype of the K469E in ICAM-1 does not influence PSC susceptibility in Scandinavia.

Physiopathologie de la maladie de Behçet

SUBJECT

Pathophysiology of Behçet's disease (BD) is complex. Recent experimental data shed new light on the mechanisms leading to organ lesions.

MAIN ISSUES

Neutrophils and cytotoxic lymphocytes are now recognized as key effector cells in BD. Genetic susceptibility, environmental factors (virus and/or bacterial infections), inflammatory response abnormalities (heat shock proteins, dysregulated NO production) and abnormal immune response play also a major role in BD pathogeny.

PERSPECTIVES

Better understanding of the BD pathophysiology will allow the development of new therapies more specific of BD.

NOD2/CARD15, NOD1/CARD4, and ICAM-1 gene polymorphisms in Turkish patients with inflammatory bowel disease

PURPOSE

The genetic susceptibility of people with certain NOD2/CARD15, NOD1/CARD4, and ICAM-1 gene variants to inflammatory bowel disease is still under investigation. The aim of this study was to investigate polymorphisms in the NOD2/CARD15 (R702W, G908R, and 3020insC), NOD1/CARD4 (E266K, D372N), and ICAM-1 (G241R, K469E) genes, which are known to be associated with inflammation, in Turkish patients with inflammatory bowel disease and healthy control groups.

METHODS

The genotypes of 70 patients with endoscopically and histopathologically diagnosed Crohn's disease (38 men, 32 women; mean age, 38.8 +/- 1.3), 120 patients with ulcerative colitis (67 men, 53 women; mean age, 41.7 +/- 1.3) and 106 healthy control subjects (37 men, 69 women; mean age, 35.7 +/- 1.4), who stated that they had never had any prior bowel disease history, were compared. A polymerase chain reaction-restriction fragment length polymorphism analysis was performed for two variants of the ICAM-1 gene, the three main variants of the NOD2/CARD15 gene, and the E266K variant of the NOD1/CARD4 gene, and DNA sequencing was used for the D372N polymorphism of the NOD1/CARD4 gene.

RESULTS

In this study, the three previously described Crohn's disease-predisposing variants of the NOD2/CARD15 gene and the polymorphisms examined in the NOD1/CARD4 and ICAM-1 genes were not found to be associated with ulcerative colitis or Crohn's disease.

CONCLUSIONS

These findings suggest that the polymorphisms observed in the NOD2/CARD15, NOD1/CARD4, and ICAM-1 genes are not genetic susceptibility factors for Crohn's disease or ulcerative colitis in Turkey.

No Association Between Selected Candidate Gene Polymorphisms and Severe Chronic Periodontitis

BACKGROUND

Chronic periodontitis (CP) risk is influenced by environmental and genetic factors. Using a case-control design, we tested for associations between CP and selected DNA sequence variations (single nucleotide polymorphisms [SNPs]) in or near genes coding for proteins that play a role in the pathogenesis of this disease.

METHODS

DNA was analyzed from 219 whites who were examined clinically. Cases (N=137) were >or=35 years of age with eight or more teeth having >or=5 mm of proximal clinical attachment loss. Controls (N=82) were >or=45 years of age with minimal or no proximal attachment loss or pocketing. Nine diallelic polymorphisms (gene and SNP descriptor) were studied in subjects: cytotoxic T-lymphocyte antigen-4 (CTLA-4, 49 A>G), human beta-defensin-1 (DEFB1, 692 G>A), intercellular adhesion molecule-1 (ICAM-1, 1548 A>G), Fas ligand (fasL, -844 C>T), inducible costimulator (ICOS, 3990 G>T), interleukin-6 (IL-6, -174 G>C), cysteine-cysteine chemokine receptor-5 (CCR5, 59653 C>T), osteoprotegerin (OPG, 245 T>G), and osteopontin (OPN, 707 C>T). Genotypes were determined using an automated fluorogenic 5'-nuclease, polymerase chain reaction-based assay. Gender and smoking history (pack-years) were included as covariates in logistic regression analyses.

RESULTS

Heavy smoking (>10 pack-years) and male gender were significantly associated with disease (P<0.001). For all SNPs tested, the allele frequencies and distributions of genotypes did not differ between cases and controls (P>0.05). No unadjusted or adjusted odds ratios (comparing genotypes in cases versus controls) were significantly different than 1.0 (P>0.05) under any additive, dominant, or recessive inheritance model.

CONCLUSIONS

None of the SNPs tested were strongly associated with generalized severe chronic periodontitis in North American whites. A potentially more fruitful approach in future studies will be to test for associations between periodontitis and haplotype blocks constructed from either multiple SNPs in candidate gene regions or from panels of markers that span the entire genome.

Association study of endometriosis and intercellular adhesion molecule-1 (ICAM-1) gene polymorphisms in a Japanese population

OBJECTIVE

Endometriosis is an immune-related, chronic inflammatory disease with polygenic predisposition. Cell adhesion molecules are expressed in endometriotic lesions, and in cells and tissues that are involved in the development and progression of the disease. In this study, we investigated the possible association between endometriosis and the G241R and K469E polymorphisms in the intercellular adhesion molecule-1 (ICAM-1) gene in a Japanese population.

METHODS

We compared the distribution of the G241R and K469E polymorphisms in the ICAM-1 gene in 126 endometriosis patients and 172 controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis in a Japanese population.

RESULTS

There were no significant differences between the cases and controls in the allele frequencies or genotype distributions of either the G241R or K469E polymorphisms in the ICAM-1 gene. The endometriosis patients were divided into a subgroup of women with severe disease only. However, no significant differences were observed in the allele frequencies and genotype distributions of the ICAM-1 K469E polymorphisms between this subgroup and the controls. In contrast, only one in 169 controls was heterozygous (G/A genotype), and the A allele in the G241R polymorphism was not found in any of the 126 endometriosis patients.

CONCLUSION

Our findings suggest that the G241R and K469E polymorphisms in the ICAM-1 gene are unlikely to be associated with an increased risk of endometriosis in the Japanese population.

ICAM-1 polymorphisms and development of cutaneous malignant melanoma

Tumour growth in cutaneous malignant melanoma (CMM) is mediated by cell adhesion molecules, including intercellular adhesion molecule-1 (ICAM-1). ICAM-1 expression is associated with increasing Breslow thickness of vertical growth-phase tumours and, in patients with stage 1 disease, may be associated with disease free and patient survival. In this study we have investigated whether two single nucleotide polymorphisms (SNPs) in the ICAM-1 gene encoding amino acid substitutions in codons 241 and 469 of the expressed ICAM-1 molecule are associated with susceptibility to and markers of prognosis (including tumour Breslow thickness) in CMM. A total of 164 CMM patients and 264 cancer-free controls were genotyped for these SNPs by the 5' nuclease assay for allelic discrimination (TaqMan). No genotypes showed any significant associations with CMM susceptibility, although there was a non-significant increase in frequency of the ICAM-1 469 AA genotype among CMM patients vs. controls (38.4% vs. 29.9%; P = 0.11). However, the ICAM-1 241 GG genotype was significantly decreased in frequency among patients with primary invasive tumours of greater Breslow thickness (72.5% vs. 91.2%; P = 0.013; OR = 0.25 (0.072-0.85)). These results provide no evidence for a role for the ICAM-1 codon 241 and 469 SNPs in determining susceptibility to CMM, but provide preliminary evidence that the role of ICAM-1 polymorphism in modulating tumour growth in CMM requires further investigation in a larger study group.

Intercellular adhesion molecule-1 and childhood asthma

We investigated the role of intercellular adhesion molecule-1 in childhood asthma by examining associations of functional variants at codons 29 (A --> T), 241 (G --> A), and 469 (A --> G) in Children's Health Study participants. Among African-Americans, 469G carriers had lower risk for asthma (ever asthma OR = 0.4, 95% CI 0.2-0.9) but increased risk among 29T carriers (early onset active asthma OR = 2.2, 95% CI 1.0-4.9). Protective associations with the 241A allele were observed among non-Hispanic and Hispanic whites (ever asthma OR = 0.7, 95% CI 0.6-0.9; early onset active asthma OR = 0.5, 95% CI 0.4-0.8), and these associations were not confounded by population stratification. To gauge the potential impact of confounding by population stratification, we performed analyses by ethnic group and in an independent family-based sample. Regional associations were stable across analyses. Haplotype associations of the four common haplotypes (29A/241G/469A, AGG, TGA, and AAG) with asthma showed that Hispanics with the AAG haplotype had lower asthma risk compared to carriers of two copies of AGA haplotype (OR = 0.6, 95% CI 0.4-0.9). Among non-Hispanic whites, the AAG haplotype was associated with reduced risk for active asthma. For African-Americans, who had a low frequency of the AAG haplotype, carrying one copy of the AGG haplotype was associated with a lower risk of asthma (OR = 0.3, 95% CI 0.1-0.8), as compared with two copies of the AGA haplotype. Consistent with information on variant function, the 241A and 469G variants may indicate haplotypes that are associated with reduced risk for asthma.

Influence of cytokine and ICAM-1 gene polymorphisms on susceptibility to chronic pancreatitis

AIMS

To test the hypothesis that single nucleotide polymorphisms (SNPs) within genes (or their promoter regions) encoding cytokines, growth factors, and intercellular adhesion molecules modulate the risk of development of chronic pancreatitis (CP).

METHODS

DNA was extracted from peripheral blood leucocytes or formalin fixed, paraffin wax embedded tissue from 53 patients with CP and 266 healthy controls. SNPs within the interleukin 1beta (IL-1beta), IL-6, IL-8, tumour necrosis factor alpha (TNFalpha) and vascular endothelial growth factor (VEGF) gene promoter regions and the transforming growth factor beta1 (TGFbeta1) and intercellular cell adhesion molecule 1 (ICAM-1) genes were genotyped by the amplification refractory mutation system polymerase chain reaction or 5' nuclease (Taqman) techniques. Patient-control comparisons were made using 2 x 2 contingency tables and chi2 analyses.

RESULTS

A non-significant decrease in the frequency of the IL-8 -251 AA genotype and a non-significant increase in the frequency of the ICAM-1 +469 GA genotype was seen in patients compared with controls. No associations were identified between SNPs in the promoter regions of the IL-1beta, IL-6, or TNFalpha proinflammatory cytokines genes or the TGFbeta1 and VEGF genes and susceptibility to CP.

CONCLUSIONS

This preliminary study suggests that genetic polymorphism within several cytokine genes is unlikely to influence susceptibility to CP, but the possible role of IL-8 and ICAM-1 polymorphisms in the development of this disease requires further investigation.

The K469E polymorphism of the intercellular adhesion molecule-1 gene is associated with plasma fibrinogen level in type 2 diabetes

Intercellular adhesion molecule-1 (ICAM-1) is involved in inflammation and development of atherosclerotic change of vascular endothelium. The aim of the present study is to investigate whether K469E polymorphism of the ICAM-1 gene is associated with various clinical factors including plasma fibrinogen in patients with type 2 diabetes. ICAM-1 gene polymorphism was examined using polymerase chain reaction and restriction enzyme analysis in 360 type 2 diabetic patients. Plasma fibrinogen levels and other clinical variables were measured as well as circulating soluble ICAM-1 (sICAM-1) levels by enzyme-linked immunosorbent assay. The distribution of ICAM-1 genotypes, EE, EK, and KK, was not significantly different between type 2 diabetes and 152 healthy control subjects. Among 3 groups according to ICAM-1 genotypes in type 2 diabetes, no difference was found in adiposity, glycemic control, lipid profile, insulin sensitivity evaluated by homeostasis model assessment, or sICAM-1. Regarding fibrinogen, the patients with E allele showed significantly lower plasma fibrinogen levels in a dose-dependent manner (P = .033). Spearman rank correlation analyses revealed that ICAM-1 genotype showed significant correlation with plasma fibrinogen level (P < .001). In multiple regression analysis, ICAM-1 genotype was independent contribution factor of plasma fibrinogen level as well as high-density lipoprotein-cholesterol and urinary albumin excretion (R2 = 0.148, P < .001). In conclusion, K469E polymorphism of the ICAM-1 gene had impact on plasma fibrinogen level independently of other clinical factors in 360 type 2 diabetic patients, suggesting that fibrinogen is a candidate which links the ICAM-1 gene polymorphism to atherosclerosis.

Intercellular adhesion molecule-1 polymorphisms in Korean patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is characterized by synovial proliferation and the accumulation of inflammatory cells in the affected joints. Intercellular adhesion molecule-1 (ICAM-1) is readily detected in RA synovial tissues and helps recruit inflammatory cells to the joint. ICAM-1 shows genetic polymorphisms at codons 241 (R241G) and 469 (K469E). In order to investigate the association between ICAM-1 gene polymorphisms and RA, we genotyped ICAM-1 R241G and ICAM-1 K469E polymorphisms in 143 Korean patients with RA, and in 138 healthy controls, by using the polymerase chain reaction-restriction fragment length polymorphism method. No polymorphism of R241G was found in Korean subjects. However, the frequency of the K469 allele was found to be significantly lower in RA patients than in healthy controls. Allele frequency of K469 was lower in RA patient group, compared to that in healthy controls, regardless of the shared epitope status. Distribution of K469E allele frequencies was not different whether the patient had rheumatoid factor, radiographic erosion or extra-articular complications. In conclusion, this study shows lower frequency of the ICAM-1 K469E allele in Korean patients with RA than that in healthy controls.

Single-nucleotide polymorphism g.1548G > A (E469K) in human ICAM-1 gene affects mRNA splicing pattern and TPA-induced apoptosis

The single-nucleotide polymorphism (SNP) g.1548G > A (E469K) in the human intercellular adhesion molecule-1 (ICAM-1) gene has been suggested to have an association with several types of inflammatory diseases. The polymorphism is located at the three-base position upstream of the splice donor site that produces an alternatively spliced short isoform (ICAM-1-S). To clarify its functional relevance, we studied RNA splicing patterns by comparing cells with different genotype (G/G cells and A/A cells). G/G cells expressed a lower amount of ICAM-1-S mRNA than A/A cells. Since ICAM-1-S has no transmembrane or intracellular domain, ICAM-1 signal transduction and cell-cell contact including Fas-FasL interaction may be influenced. In addition, we studied the effect of this change on FLIP-L mRNA and apoptosis. FLIP-L mRNA tended to decrease, while cell death induced by phorbol 12-myristate 13-acetate was increased. These results suggest that the g.1548 polymorphism modifies inflammatory immune responses by changing cell-cell interaction and then regulating apoptosis.

Inflammatory bowel disease is linked to 19p13 and associated with ICAM-1

Genome-wide scans have implicated several susceptibility loci, but linkage of 19p13 (IBD6) to Crohn's disease (CD) has not been fully replicated. We report a replication study of IBD6 in a UK Caucasian population. Two hundred eighty-four affected sibling pairs from 234 families were used for the linkage study. Linkage between IBD6 linkage and CD was replicated (LOD score = 1.59). Two candidate genes (DDXL and ICAM-1) within the IBD6 locus were examined in a case/control study with a total of 228 CD and 243 ulcerative colitis (UC) patients and 407 healthy controls. No association to either UC or CD was found in three novel intronic single nucleotide polymorphisms (SNPs) in DDXL. For ICAM-1, a significant association was found between K469 homozygosity and CD overall (39.9% vs 29.4%; Pc = 0.0096) and between E469 and fistulating disease (21.8% vs 10.0%, Pc = 0.030). In the UC group, limited disease extent was associated with homozygosity of the G241 allele (82.7% vs 64.7%, Pc = 0.0040). These data support linkage for CD at 19p13 and suggest that the amino acid polymorphisms in ICAM-1 may be associated with IBD.

Analysis of the CC chemokine receptor 5 (CCR5) Delta32 polymorphism in Behcet's disease

Chemokines are important determinants of the early inflammatory response. The CC chemokine receptor 5 (CCR5) Delta32 variant results in a non-functional form of the chemokine receptor, and has been implicated in a variety of immune-mediated diseases. To investigate its role in the pathogenesis of Behçet's disease, we studied 350 patients and 519 healthy controls from three ethnic groups. While significant inter-ethnic variation in allele frequency was observed, no association was identified with disease, even when data were stratified by the known susceptibility gene HLA-B*51.

Behçet's disease: from Hippocrates to the third millennium

Behçet's disease (BD) is characterised by recurrent episodes of orogenital aphthae, systemic vasculitis, and systemic and retinal venous thrombosis. An association between HLA-B51 and BD was first identified over 20 years ago, but recently identified gene associations implicate regions both within and without the MHC in the immunological events underlying the lesions in BD. These include allelic variants within the tumour necrosis factor gene region and within the MHC class I chain related gene region, the factor V Leiden mutation, which is associated with retinal vascular occlusion, and alleles of the intercellular adhesion molecule gene. No single causative gene for BD has emerged; the evidence indicates that the underlying immune events in BD are triggered by a microbial antigen and subsequently driven by genetic influences which control leucocyte behaviour and the coagulation pathways. Knowledge of these risk factors may permit a more accurate prognosis for a given patient, and identify new pathways for more targeted intervention than is currently available.

Association between Gly241Arg ICAM-1 gene polymorphism and serum sICAM-1 concentration in the Stanislas cohort

Intracellular adhesion molecule-1 (ICAM-1), a cellular adhesion molecule that mediates the interaction of activated endothelial cells with leukocytes, is involved in various inflammatory and cardiovascular disorders. The relation between these markers and genetic polymorphism, however, remains to be elucidated. The aim of this study is to estimate the effect of a single-base polymorphism at codon 241 in exon 4 of ICAM-1 gene on serum sICAM-1 concentration in a healthy population, taking into account other biological determinants of sICAM-1 level. Serum sICAM-1 levels and the G/R241 polymorphism of the ICAM-1 gene were measured in a large healthy population consisting of 413 children aged 6-21 years and 363 adults aged 38-55 years extracted from the Stanislas cohort. The R241 allele was significantly associated with lower sICAM-1 levels and explained 3.4 and 1.9% of the sICAM-1 variability in children and adults, respectively. A codominant pattern contributed better to the model after adjustment for covariates as the RR homozygote effect was higher than that of the GR heterozygote. Moreover, significant independent associations were found between sICAM-1 and smoking, insulin resistance index (HOMA IR), interleukin-6 level, and alkaline phosphatase and aspartate aminotransferase activities. In conclusion, this study revealed a significant association between the G/R241 ICAM-1 polymorphism and serum sICAM-1 levels, probably due to the impairment in binding of ICAM-1 to leukocyte integrin Mac-1 protein.

The pathology and pathogenesis of retinal vasculitis

Retinal vasculitis is a rare, but potentially blinding intraocular inflammatory condition with diverse aetiology. Although commonly idiopathic, it has a strong association with systemic inflammatory diseases known to involve other areas of the central nervous system, most notably Behcet's disease, sarcoidosis, systemic lupus erythematosis and multiple sclerosis. This article describes the clinicopathologic features of retinal vasculitis and its visually damaging sequelae, reviewing available human histopathologic studies and work with experimental models to discuss the pathogenesis and immunopathology. Evidence indicates that noninfective retinal vasculitis is an autoimmune condition that may be induced by antecedent infection with microbes cross-reacting with putative autoantigens, influenced by genetic susceptibility of both HLA associations and cytokine polymorphisms. The growing understanding of the cellular mechanisms involved in the effector immune response is already providing a rationale for more specific therapeutic approaches.

C/T polymorphism of the intercellular adhesion molecule-1 gene (exon 6, codon 469). A risk factor for coronary heart disease and myocardial infarction

BACKGROUND

The intercellular adhesion molecule-1 (ICAM-1) mediates the interaction of activated endothelial cells with leukocytes and plays a fundamental role in the pathogenesis of coronary atherosclerosis. ICAM-1 single-base C/T polymorphism, which determines an amino acid substitution in the ICAM-1 protein in exon 6 codon 469, has been described. Our purpose was to determine whether this C/T polymorphism influences the risk of coronary heart disease (CHD) and myocardial infarction (MI) in humans.

METHODS AND RESULTS

We enrolled 349 patients with angiographically documented CHD, including a sub-group of 179 patients with acute or chronic MI. The control group consisted of 213 patients with normal left ventricular function and no documented evidence of CHD. All patients and controls were Germans genotyped by polymerase chain reaction and allele-specific oligonucleotide techniques for the ICAM-1 polymorphism. In the patients with CHD and MI the frequencies of the T genotype (TT+TC) were significantly higher than the CC genotype compared to the control subjects (P<0.001). With the additional use of multivariable logistic regression analysis for CHD (TT+TC versus CC; P=0.011, odds ratio 2.21, 95% CI 1.20-4.07), we found a significant association between CHD and MI and the TT and TC genotype of the ICAM-1 gene polymorphism.

CONCLUSIONS

These results suggest that the TT and TC genotype of the ICAM-1 gene polymorphism in codon 469 is a genetic factor that may determine an individual's susceptibility for CHD and MI.

Intercellular adhesion molecule-1 (ICAM-1) polymorphism is associated with diabetic retinopathy in Type 2 diabetes mellitus

AIMS

Leucocyte adhesion to the diabetic retinal vasculature has been implicated in the pathogenesis of diabetic retinopathy. We evaluated the relationship between genetic polymorphisms in leucocyte and endothelial cell adhesion molecules and diabetic retinopathy in Type 2 diabetes mellitus.

METHODS

We determined ICAM-1, platelet endothelial cell adhesion molecule-1 (PECAM-1), and leucocyte endothelial adhesion molecule-1 (LECAM-1) genotypes in 81 patients with and 50 without diabetic retinopathy.

RESULTS

The frequency of ICAM-1 469KK genotype and K allele were significantly higher in the patients with diabetic retinopathy than in those without retinopathy (genotype 42% vs. 20%, chi2 = 6.70, P = 0.035; allele 66% vs. 50%, chi2 = 6.49, P = 0.011). With regard to the PECAM-1 V125L and LECAM-1 P213S polymorphisms, there were no significant associations between the distribution of genotypes or allele frequencies and the presence of diabetic retinopathy. Independent of other risk factors, the ICAM-1 469KK genotype was associated with a 3.51-fold increased risk for retinopathy.

CONCLUSIONS

These data suggest that the ICAM-1 469KK genotype could be a genetic risk factor for retinopathy in Type 2 diabetes mellitus.

Clinical overview of leukocyte adhesion and migration: where are we now?

This article discusses the potential for clinical translation of the large amount of information on the molecular basis of leukocyte-endothelial cell interactions that has been collected over the last twenty years. Areas of current interest include the identification of adhesion molecule expression in inflammation by diagnostic imaging, understanding variability in inflammatory responsiveness and disease susceptibility through identification of adhesion molecule and chemokine polymorphisms and the application to the treatment of inflammatory diseases of monoclonal antibodies and conventional drugs with specific actions on leukocyte adhesion and migration.

Polymorphisms of the ICAM-1 gene are associated with inflammatory bowel disease, regardless of the p-ANCA status

The intercellular adhesion molecule-1 (ICAM-1) is of paramount importance for the initiation and propagation of various inflammatory conditions. An increased frequency of allele R241 of the ICAM-1 gene was previously described in p-ANCA-negative as compared to p-ANCA-positive ulcerative colitis and vice versa in Crohn's disease. One hundred sixteen healthy unrelated controls, 121 patients with ulcerative colitis, and 96 patients with Crohn's disease were genotyped for two polymorphisms of the ICAM-1 gene (R/G241, exon 4; and K/E469, exon 6), employing dot-blot hybridization and stratified according to their p-ANCA status. When compared with the control group the frequency of the allele R241 (P = 0.024) and the heterozygous genotype R/G241, P = 0.032) were significantly increased in ulcerative colitis, whereas the homozygous genotype G/G241 was found less frequently (P = 0.022). The heterozygous genotype K/E469 was observed less frequently (P = 0.001 and 0.037, resp.) than the homozygous genotype E/E469, which was more frequent in Crohn's disease and ulcerative colitis (P = 0.002 and 0.012, respectively). Further significant differences concerning the allele or genotype distribution were not observed. After stratification for the p-ANCA status significant differences concerning the frequencies of both the R241 and the E469 alleles were not detected when p-ANCA-positive inflammatory bowel disease and p-ANCA-negative inflammatory bowel disease were compared. Ulcerative colitis and Crohn's disease are associated with polymorphisms of the ICAM-1 gene, which might therefore represent a functional candidate gene. However, the observed associations are independent of the p-ANCA status.

Immunopathology of the noninfectious posterior and intermediate uveitides

The posterior and intermediate uveitides share an underlying immune etiology; however, they can be clinically and immunopathologically distinguished. Although the initiating stimuli for posterior and intermediate uveities are not known, it is believed that an exogenous agent (such as a bacterium or a virus) or an endogenous molecule may induce disease. In either case, T-helper lymphocytes in conjunction with human leukocyte antigens are likely to be involved. This review examines the epidemiology, histology, immunopathology, and theories of pathogenesis of several posterior and intermediate uveitides, including sympathetic ophthalmia, Vogt-Koyanagi-Harada syndrome, Behçet's disease, sarcoidosis, intermediate uveitis, white dot syndromes, and birdshot retinochoroidopathy.

A candidate gene analysis of three related photosensitivity disorders: cutaneous lupus erythematosus, polymorphic light eruption and actinic prurigo

BACKGROUND

Polymorphic light eruption (PLE) is a common inherited photosensitivity disorder, which may predispose to several related but distinct conditions, including subacute cutaneous lupus erythematosus (SCLE), discoid lupus erythematosus (DLE) and actinic prurigo (AP).

OBJECTIVES

To examine specific candidate genes for shared susceptibility alleles between these related phenotypes.

METHODS

Eighty-five caucasian patients with annular SCLE or DLE were recruited, in addition to 102 first-degree relatives. The prevalence of PLE in both the patient and relative groups was determined by detailed interview and clinical examination. Eighty-five patients with pure PLE and 59 patients with AP were also recruited. Candidate genes were analysed by typing of single nucleotide polymorphisms of IL10 (-1082 G/A and -819 C/T), FCGR2A (131 R/H), SELE (128 S/R), ICAM1 (241 G/R and 469 E/K), IL1A (+ 4845 G/T), IL1B (-511 C/T and + 3954 C/T), IL1RN (+ 2018 T/C) and TNF (-308 G/A) using polymerase chain reaction (PCR) with sequence-specific primers and 5'-nuclease PCR.

RESULTS

A significant association was found between SCLE and the rare TNF -308 A allele when compared with patients with DLE (P = 0.043), PLE (P = 0.001), AP (P < 0.001) and healthy controls (P < 0.001). However, there was strong linkage disequilibrium between TNF -308 A and the HLA A*01, B*08, DRB1*0301 haplotype. A negative association was also found between SCLE and the IL1B + 3954 T allele (P = 0.039), but the significance was lost on correction for multiple testing.

CONCLUSIONS

We have demonstrated the association of SCLE with the rare TNF -308 A allele, which may be pathogenic or, alternatively, a marker allele for the extended HLA A*01, B*08, DRB1*0301 haplotype that is associated with a number of autoimmune conditions. Although many of the other loci that we chose failed to demonstrate an association, a candidate gene approach remains the most logical one, and the most likely to yield positive results in the future.

Behçet disease

Behçet's disease is a multisystem inflammatory disorder of unknown origin, characterized by recurrent oral and genital ulcerations, ocular and cutaneous lesions, arthritis, central nervous system, and vascular disease. There is no pathognomonic laboratory test, but there are clinical criteria to assist in establishing the diagnosis. Behçet's is most common along the Silk Road. It is particularly common among persons who have the HLA-B51 major histocompatibility type. Cutaneous lesions include pustules, erythema nodosum-like lesions, Sweet's-like lesions, pyoderma gangrenosum-ike lesions, and pathergy. The major cutaneous findings may be classified as neutrophilic vascular reactions. There is considerable morbidity resulting from Behçet's disease, most notably a high risk of blindness from ocular involvement. Mortality may occur as a result of neurologic or vascular disease or gastrointestinal perforation.