A study of HLA antigens in Behçet's syndrome

Advances in pathogenesis and treatment of ocular involvement in Behcet's disease

Behcet's disease (BD) is a chronic multi-systemic disease characterized by relapsing-remitting oral ulcers, genital ulcers, ocular inflammatory involvements, and numerous other systemic features. Ocular involvements are quite common in BD and may cause severe tissue damage and potentially blindness. Even though the pathogenesis of BD remains ambiguous, growing evidences have shown that genetic factors, environmental triggers and immunological abnormalities play significant roles in its development and progression. Novel biotherapies targeting IFN-γ, TNF-α and interleukins have been used in recent years. In this review, we mainly pay attention to the ocular involvement of BD, and discuss the current understanding of mechanisms and advances in therapeutic approaches, especially novel biologics. Finally, we discuss the management in patients with pregnancy.

Pathogenesis of Non-Infectious Uveitis Elucidated by Recent Genetic Findings

Uveitis is a generic term for inflammation of the uvea, which includes the iris, ciliary body, and choroid. Prevalence of underlying non-infectious uveitis varies by race and region and is a major cause of legal blindness in developed countries. Although the etiology remains unclear, the involvement of both genetic and environmental factors is considered important for the onset of many forms of non-infectious uveitis. Major histocompatibility complex (MHC) genes, which play a major role in human immune response, have been reported to be strongly associated as genetic risk factors in several forms of non-infectious uveitis. Behçet’s disease, acute anterior uveitis (AAU), and chorioretinopathy are strongly correlated with MHC class I-specific alleles. Moreover, sarcoidosis and Vogt-Koyanagi-Harada (VKH) disease are associated with MHC class II-specific alleles. These correlations can help immunogenetically classify the immune pathway involved in each form of non-infectious uveitis. Genetic studies, including recent genome-wide association studies, have identified several susceptibility genes apart from those in the MHC region. These genetic findings help define the common or specific pathogenesis of ocular inflammatory diseases by comparing the susceptibility genes of each form of non-infectious uveitis. Interestingly, genome-wide association of the interleukin (IL)23R region has been identified in many of the major forms of non-infectious uveitis, such as Behçet’s disease, ocular sarcoidosis, VKH disease, and AAU. The interleukin-23 (IL-23) receptor, encoded by IL23R, is expressed on the cell surface of Th17 cells. IL-23 is involved in the homeostasis of Th17 cells and the production of IL-17, which is an inflammatory cytokine, indicating that a Th17 immune response is a common key in the pathogenesis of non-infectious uveitis. Based on the findings from the immunogenetics of non-infectious uveitis, a personalized treatment approach based on the patient’s genetic make-up is expected.

A Rare Case of Vasculitis Patched Necrosis of Cecum due to Behçet's Disease

Isolated cecal necrosis is a rare form of acute ischemic colitis and a rare cause of surgical abdomen. Behçet's disease is a multisystemic autoimmune condition which can induce vasculitis. This can result in cecal necrosis while disease involves colon vessels. We describe a patient with complicated Behçet's disease and ischemic colitis admitted to our hospital. Patient was a 62-year-old female with more accompanying diseases. Histopathologic findings confirmed the diagnosis of ischemic colitis and regarding patient's vision problem and skin lesions, rheumatologic tests were performed which were positive for HLAB5 and HLAB51 suggestive of Behçet's disease; the patient was improved with surgery. Abdominal pain can indicate a disease with vascular involvement like Behçet's disease, especially in the presence of other clinical findings suggestive of the disease including blurred vision and skin lesions. An abdominal computerized tomography (CT) scan is very diagnostic in the same patients.

Relationships of HLA-B51 or B5 genotype with Behcet's disease clinical characteristics: systematic review and meta-analyses of observational studies

OBJECTIVE

To investigate comprehensively the relationships between Behçet's disease (BD) clinical features and HLA-B51 or HLA-B5 (HLA-B51/B5) status using meta-analyses.

METHODS

Relevant publications were identified by a systematic literature search. Eligible studies had to provide frequencies for one or more BD characteristics according to HLA-B51/B5 status. Pooled relative risks (RRs) were calculated by random-effects meta-analysis for those BD characteristics for which five or more relevant studies were identified. Between-study variability was assessed with I(2) and Q-statistics, and modelled using meta-regression.

RESULTS

Among the 859 publications evaluated, 72 (representing 74 study populations) met eligibility criteria. Pooled RRs (95% CIs) of the association of HLA-B51/B5 with the 14 analysed clinical characteristics were male sex 1.14 (1.05, 1.23); eye involvement 1.13 (1.06, 1.21); genital ulcers 1.07 (1.01, 1.14); skin involvement 1.10 (1.03, 1.16); erythema nodosum 1.11 (0.96, 1.29); pseudofolliculitis 1.07 (0.93, 1.23); positive pathergy test 1.05 (0.94, 1.17); joint involvement 0.94 (0.86, 1.04); neurological involvement 0.95 (0.71, 1.27); gastrointestinal involvement 0.70 (0.52, 0.94); thrombophlebitis 1.17 (0.77, 1.76); vascular involvement 1.00 (0.68, 1.47); chest involvement 1.55 (0.75, 3.20) and orchiepididymitis 1.13 (0.59, 2.15). For most of the analysed outcomes, between-study heterogeneity was low or absent and most of the meta-regression models were statistically non-significant.

CONCLUSION

The results of these meta-analyses showed that, in BD, HLA-B51/B5 carriage predominates in males and is associated with moderately higher prevalences of genital ulcers, ocular and skin manifestations, and a decreased prevalence of gastrointestinal involvement.

HLA-B51/B5 and the risk of Behçet's disease: a systematic review and meta-analysis of case-control genetic association studies

OBJECTIVE

To quantify by meta-analysis the genetic effect of the HLA-B5 or HLA-B51 (HLA-B51/B5) allele on the risk of developing Behçet's disease (BD) and to look for potential effect modifiers.

METHODS

Relevant studies were identified using the PubMed Medline database and manual searches of the literature. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated by using the random-effects model. Subgroup meta-analyses and meta-regression analyses were undertaken to investigate the effects of selected study-level parameters on the pooled OR. Heterogeneity was assessed using the I2 statistic. Pooled results were used to calculate population-attributable risks (PAR) for BD in relationship to HLA-B51/B5.

RESULTS

A total of 4,800 patients with BD and 16,289 controls from 78 independent studies (published 1975-2007) were selected. The pooled OR of HLA-B51/B5 allele carriers to develop BD compared with noncarriers was 5.78 (95% CI 5.00-6.67), with moderate between-study heterogeneity (I2 = 61%). The subgroup analyses stratifying studies by geographic locations (Eastern Asia, Middle East/North Africa, Southern Europe, Northern/Eastern Europe) yielded consistent OR ranges (5.31-7.20), with I2 ranges of 52-70%. Univariate random-effects meta-regression indicated the percentage of male BD cases (P = 0.008) as a source of heterogeneity. The PAR within the various geographic areas were estimated at 32-52%.

CONCLUSION

The strength of the association between BD and HLA-B51/B5, and its consistency across populations of various ethnicities, lends further support to this allele being a primary and causal risk determinant for BD. Variations according to sex support an interaction of this allele with BD characteristics.

Association of the MIC-A gene and HLA-B51 with Behçet's disease in Arabs and non-Ashkenazi Jews in Israel

BACKGROUND

Behçet's disease is known to be strongly associated with HLA-B51 in many different ethnic groups. Recently, it was suggested that MIC-A (major histocompatibility complex class I related gene A) is the pathogenic gene after strong association was found between the MIC-A A6 allele of the transmembrane region and the disease in Japanese and Greek patients, although in Greek patients this association was found to be due to linkage disequilibrium with HLA-B51.

OBJECTIVES

To investigate microsatellite polymorphism in Arab and non-Ashkenazi Jewish (NAJ) patients in Israel, to determine whether this association occurs in these groups with Behçet's disease, and elucidate the associated HLA allele of the disease.

METHODS

Forty four Israeli patients with Behçet's disease, including 20 Arabs and 24 NAJ, and 130 ethnically matched healthy controls were examined for MIC-A microsatellite polymorphism of the transmembrane region using polymerase chain reaction, autoradiography, and sequence analysis.

RESULTS

The MIC-A A6 allele was significantly more frequent in the Arab patient group (19/20 (95%)) than in healthy Arab controls (25/42 (60%)) (p(corr)=0.015, OR=12.92), but not in the NAJ patients (16/24 (67%)) compared with NAJ healthy controls (48 /88 (55%)) (p(corr)=1.02, OR=1.667). In stratification analysis of the Arab subgroup, on the confounding effect of MIC-A A6 on HLA-B51 association and vice versa, Behçet's disease was distinctly associated only with HLA-B51.

CONCLUSIONS

These results imply strong association between the MIC-A A6 allele and the disease in Israeli Arabs, but not in Israeli NAJ patients. The stratification analysis indicates that this association results secondarily from a strong linkage disequilibrium with HLA-B51, and the real disease susceptibility gene which plays a part in the development of Behçet's disease is most probably the HLA-B51 allele itself.

Clinical analysis of Behçet disease: arthritic manifestations in Behçet disease may present as seronegative rheumatoid arthritis or palindromic rheumatism

OBJECTIVES

To analyze arthritic manifestations in Behcet disease, which is one of the most common manifestations of Behcet disease.

METHODS

Among the patients who visited the Rheumatology Division, Keimyung University Dongsan Medical Center, Taegu, Korea from March 1997 to February 1998, 35 patients, with more than 3 months follow-up, were compatible for the diagnosis of Behcet disease according to the Shimizu criteria, after exclusion of uncertain or possible Behcet cases. The presence of various manifestations was evaluated. Regarding the joint manifestations, the involved joint, signs and the pattern of the articular symptoms were examined. Basic laboratory tests, HLA studies and simple radiologic studies were done.

RESULTS

All 35 patients had evident, recurrent, painful oral ulcers by the study definition. Genital ulcers were found in 29%, skin lesions in 77%, uveitis in 9%, gastrointestinal ulcerations in 6% and vascular manifestations in 6%. Joint manifestations appeared in 97%. Knee(91%), proximal interphalangeal (53%) and metacarpophalangeal joints(21%) were the main sites. Tenderness was prominent in 91% and swelling in 44%. Polyarticular presentation was found in 47%. In most cases (76.4%), the articular symptom was short-lasting. C-reactive protein was likely to be positive in active Behcet disease. HLA B51 was positive in 46%.

CONCLUSIONS

In Behcet disease, various manifestations can be found. The arthritic manifestation seems quite common. It may present as seronegative rheumatoid arthritis. Otherwise, it may present as palindromic rheumatism.

Microsatellite polymorphism within the MICB gene among Japanese patients with Behçet's disease

Behçet's disease (BD) is known to be associated with HLA-B51. In order to investigate the influence of the MICB gene, located about 120 kb centromeric of the HLA-B gene, on the susceptibility to BD, (CA/TG) dinucleotide repeat microsatellite polymorphism in intron 1 of the MICB gene was investigated among 77 Japanese patients with BD, 60 randomly selected controls and 28 HLA-B51-positive unrelated healthy controls. There was no significant difference in the phenotype frequency of the microsatellite polymorphism between the BD patients and controls. This result suggests that the MICB gene itself is not responsible for the development of BD, and that the candidate gene(s) for BD is located between the MICA and HLA-C genes.

Primary association of HLA-B51 with Behçet's disease in Ireland

AIMS/BACKGROUND

While a primary association of HLA-B51 with Behçet's disease (BD) in Japanese and Mediterranean patients supports an immunogenetic predisposition, this link is unclear in north western Europe. This study assessed HLA associations with BD, and HLA-B51 with certain clinical characteristics, in the Republic of Ireland, which has an ethnically homogeneous population.

METHODS

HLA-A, HLA-B, and HLA-DR typing was performed in 24 BD patients, conforming to International Study Group criteria, and in blood donors, as controls. Patient records were retrospectively reviewed and patients reassessed clinically.

RESULTS

A highly significant HLA-B51 association (corrected exact p value = 0.002, relative risk = 6.3) with BD was determined, despite a low B51 prevalence (25%) in patients. No other HLA type was associated. There was a significant B51 link with male sex in BD patients but no association with age at first manifestation/diagnosis, eye involvement, cyclosporin A therapy, or poor visual acuity was determined.

CONCLUSIONS

This study supports a HLA-B51 immunogenetic predisposition, similar to Japanese patients, in Irish BD in an ethnically homogeneous population in north western Europe. However, owing to a low prevalence of B51 positivity in BD patients in Ireland, a multifactorial pathogenesis is suggested.

Polymerase chain reaction reveals herpes simplex virus DNA in saliva of patients with Behçet's disease

The etiology of Behçet's disease is unclear, but viral infection is thought to be one etiologic factor. The aims of this study were to detect herpes simplex virus (HSV) DNA in the saliva of patients with Behçet's disease and of healthy persons, to determine whether the presence of HSV in saliva is associated with the presence of intraoral ulcer, and to investigate the relationship between HSV and Behçet's disease. The polymerase chain reaction (PCR) was used to detect HSV DNA sequences in DNA extracted from the saliva of patients with Behçet's disease and of healthy control subjects. Of 66 patients with Behçet's disease diagnosed clinically, 19 were diagnosed as complete type, 29 as incomplete type and 18 as suspected type. Of 66 DNA preparations from the saliva of the patients, 26 (39.4%) showed the 289-bp band. This contrasts with 12 of 87 preparations (13.8%) from healthy controls (P < 0.01). There were no significant differences among the three patient groups. All the 289-bp bands analyzed by restriction endonuclease digestion yielded the expected 158-bp and 131-bp fragments when digested with PstI.HSV DNA was detected in 12 of 33 Behçet's disease patients (36.4%) with oral ulceration and 14 of 33 patients (42.4%) without oral ulceration at the time of testing. There was no statistically significant correlation in the PCR results between the two groups.

Clinical analysis of 40 cases of childhood-onset Behçet's disease

Behçet's disease is a chronic, relapsing, idiopathic, multi-system condition characterized by mucocutaneous, ocular, gastrointestinal, articular, vascular, urogenital, and neurologic involvement. Usually the onset occurs between 20 and 30 years of age; it is very uncommon in children. We analyzed 40 cases of childhood-onset Behçet's disease. The male:female ratio was 0.67. The most frequent major sign was oral ulceration, appearing in all patients. Other major signs were genital ulcers (33 patients), skin lesions (29), and ocular lesions (11). The average time interval between the initial oral ulceration and the second major manifestation was 8.8 years. After the second major manifestation, the third and fourth features rapidly developed within one to two years. The most frequent minor sign was arthritis, occurring in 11 of 40 patients. Intestinal, neurologic, and renal involvement was also present. From our results, we concluded that oral ulceration, which is the most common initial manifestation, should not be neglected in children, since it may signal Behçet's disease.

HLA-DR and DQ antigens in Chinese patients with Behçet's disease

The frequencies of HLA-DR and DQ antigens in 24 Chinese patients with Behçet's disease (BD) were calculated and compared with those in 130 healthy control Chinese and those in 80 Chinese patients with recurrent oral ulcers (ROU). Although an increased trend of DRw6 and DRw8 antigens in patients with BD was noted, there was no significant difference in frequencies of HLA-DR and DQ antigens between patients with BD and healthy control subjects or patients with ROU after correction of P values (Pc > 0.05). Further analysis of our data of the phenotype frequencies of DRw6 and DRw8 antigens according to the subtypes of BD also showed the increased frequencies of DRw6 and DRw8 antigens in patients with mucocutaneous type of BD as compared with those in healthy control subjects. However, only the phenotype frequency of DRw8 antigen in patients with mucocutaneous type of BD was significantly higher than that in patients with ROU (P < 0.005, Pc < 0.05, relative risk = 17.7, and etiologic fraction = 0.30). This significant increase of the phenotype frequency suggests that the gene coding for HLA-DRw8 antigen in patients with ROU was only partially (30%) responsible for susceptibility to the mucocutaneous type of BD.

Association of HLA-B51 and lack of association of class II alleles with Behcet's disease

Eighty-one Behcet's disease patients have been studied for HLA association by HLA-DRB1, -DQA1, -DQB1 and -DPB1 genotyping with the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique and for NcoI RFLP in the tumor-necrosis factor (TNF beta) gene by Southern hybridization in addition to serological typing. In serological typing, the frequency of HLA-B51 was significantly increased in the patients. In PCR genotyping, there was a significant increase in the HLA-DRB1*0802, DQA1*0301 and DQB1*0303 alleles, whereas the frequencies of DRB1*1502, DQA1*0103, DQA1*0101, DQB1*0601 and DQB1*0501 showed a significant decrease in the patients. No significant difference was observed in any HLA-DPB1 alleles. Among them, B51 was found to be a genetic marker most strongly associated with Behcet's disease (p less than 0.00005, chi 2 = 46.47, pc[corrected p] less than 0.005). The positive and negative associations of class II alleles with the disease can be explained by linkage disequilibrium with B51, and do not reach statistical significance by the corrected p-value test. In NcoI RFLP typing in the TNF beta gene, 250 kb centromeric of the HLA-B gene, the frequency of a 5.5 kb fragment was considerably decreased in the patients when compared to the controls, although the decrease was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)