Association of HLA-B51 with clinical expression of Behçet's disease. Analysis of 201 Iranian patients

Prospective study of articular manifestations in Behçet's disease: five-year report

AIM

To evaluate different aspects of articular involvements (prevalence, types, relation to extra-articular manifestations, etc.) in Iranian patients with Behcet's disease (BD).

METHODS

In a prospective study, all patients with BD attending an outpatient BD clinic were enrolled. The type of articular involvements (peripheral or axial), involved joints, duration of attacks and their relation to extra-articular manifestations, human leukocyte antigen (HLA)-B5 and HLA-B27 were evaluated. Data analysis was done by using descriptive statistical indices such as mean and confidence interval. The comparisons were done by chi-square test.

RESULTS

In a 5-year period, 2312 patients were recruited. Musculoskeletal manifestations were recorded in 430 patients (190 without previous history of these involvements). The remaining 1882 patients showed no musculoskeletal involvements, of which 753 had past histories of musculoskeletal manifestations. The 5-year incidence rate was 18.6%, and the prevalence rate was 51.2%. History of previous musculoskeletal involvements has no effect in its new development (P = 0.2). Arthritis was the most common type of involvement (289/430, 67%). The most frequent pattern was monoarthritis (191/289, 66%), and the most frequent involved joints were knees (147/289, 50.9%). The arthritic attacks were unilateral in 82.4% of cases. Ankylosing spondylitis was seen in 44/430 (10.2%). There was no association between HLA-B5 or HLA-B27 and any type of musculoskeletal involvements (P > 0.5). Pseudofolliculitis was the only extra-articular manifestation related to arthritic attacks (P = 0.046).

CONCLUSION

Musculoskeletal involvement is a common manifestation of BD seen in more than half of patients. Acute knee monoarthritis was the most common pattern of articular involvement in BD.

Characterization of the major histocompatibility complex locus association with Behçet's disease in Iran

Introduction

The aim of this study was to characterize the association of human leukocyte antigen (HLA) B alleles and major histocompatibility complex (MHC) single nucleotide polymorphisms (SNPs) with Behçet’s disease (BD) in an Iranian dataset.

Methods

The association of three SNPs in the MHC region previously identified as the most associated in high-density genotyping studies was tested in a case–control study on 973 BD patients and 825 controls from Iran, and the association of HLA-B alleles was tested in a subset of 681 patients and 414 controls.

Results

We found that HLA-B*51 (P = 4.11 × 10⁻⁴¹, OR [95% CI] = 4.63[3.66-5.85]) and B*15 confer risk for BD (P = 2.83 × 10⁻², OR [95% CI] = 1.75[1.08-2.84]) in Iranian, and in B*51 negative individuals, only the B*15 allele is significantly associated with BD (P = 2.51 × 10⁻³, OR [95% CI] = 2.40[1.37-4.20]). rs76546355, formerly known as rs116799036, located between HLA-B and MICA (MHC class I polypeptide-related sequence A), demonstrated the same level of association with BD as HLA-B*51 (P_adj = 1.78 × 10⁻⁴⁶, OR [95% CI] = 5.46[4.21-7.09], and P_adj = 8.34 × 10⁻⁴⁸, OR [95% CI] = 5.44[4.20-7.05], respectively) in the HLA-B allelotyped subset, while rs2848713 was less associated (P_adj = 7.14 × 10⁻³⁵, OR [95% CI] = 3.73[2.97-4.69]) and rs9260997 was not associated (P_adj = 1.00 × 10⁻¹). Additionally, we found that B*51 genotype-phenotype correlations do not survive Bonferroni correction, while carriers of the rs76546355 risk allele predominate in BD cases with genital ulcers, positive pathergy test and positive BD family history (2.31 × 10⁻⁴ ≤ P ≤ 1.59 × 10⁻³).

Conclusions

We found that the HLA-B*51 allele and the rs76546355/rs116799036 MHC SNP are independent genetic risk factors for BD in Iranian, and that positivity for the rs76546355/rs116799036 risk allele, but not for B*51, does correlate with specific demographic characteristics or clinical manifestations in BD patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0585-6) contains supplementary material, which is available to authorized users.

Prevalence of celiac disease among patients with Behcet's disease in Iran

BACKGROUND

Behcet's disease and Celiac disease, both common in Iran, share many immunopathogenic and clinical features. Based on the possible association between these two diseases, this study is designed to determine the frequency of non-diagnosed celiac disease in patients with Behcet's disease.

METHODS

The sera of 288 consecutive patients with Behcet's disease were screened with anti-endomysial antibody and anti-tissue transglutaminase antibody for celiac disease. Those with a positive test underwent upper gastrointestinal endoscopy and duodenal biopsies to confirm the diagnosis of celiac disease. The patients with celiac disease were put on a gluten free diet to evaluate its efficacy on the improvement of their lesions.

RESULTS

Fourteen patients had positive anti-tissue transglutaminase antibody test (two with positive anti-endomysial antibody as well). Duodenal biopsies showed findings compatible with Marsh 3 in one and Marsh 1 in three other patients. All the diagnosed patients with celiac disease responded to the gluten free diet.

CONCLUSION

Our findings didn't support any association between celiac disease and Behcet's disease in Iranian patients compared to the general population of Iran.