Andreia Bettencourt, Clara Pereira, Luísa Carvalho, Cláudia Carvalho, José Vaz Patto, Marina Bastos, Ana Martins Silva, Rui Barros, Carlos Vasconcelos, Paulo Paiva, Luciana Costa, Paulo P Costa, Denisa Mendonça, João Correia, Berta Martins Silva
Background: Behçet’s disease (BD) is a systemic vasculitis of unknown aetiology. Genetic factors and infectious agents seem to be implicated in the aetiology and pathogenesis of the disease. Class I human leukocyte antigen (HLA)-B51 is a well known genetic factor associated with BD in many ethnic groups. Objectives: To analyse the influence of HLA-B*51 and other HLA class I alleles in BD susceptibility in a Portuguese population and its association with disease severity. Methods: The study groups consisted of 78 BD patients and 208 healthy controls. The patients were classified into two severity groups (mild [n=31], severe [n=47]) as described by Gul et al (Rheumatology, 2001). Results: As expected, a higher frequency of HLA-B*51 was found in BD patients when compared to controls (41.0% vs. 22.6%, OR=2.38, 95%CI=1.37-4.16). The frequencies of HLA-Cw*02, HLA-Cw*15 and HLA-Cw*16 alleles were significantly higher in patients than in controls (26.9% vs 13.5%, OR=2.37, 95%CI=1.25-4.49; 23.1% vs 10.6%, OR=2.54, 95%CI=1.28-5.04 and 17.9% vs 7.2%, OR=2.81, 95%CI=1.29-6.15, respectively). The HLA-B*07 and the HLA-Cw*07 alleles were underrepresented in the patients group (5.1% vs 17.3%, OR=0.258, p=0.014 and 21.8% vs 43.3%, OR=0.365, p=0.001 respectively). Regarding severity, HLA-B*27 frequency was higher in the severe group (17.0%) compared to controls (8.7%) and to the mild group (p=0.019). Conclusions: In this population of Portuguese BD patients, HLA-B*51 and HLA-Cw*16 seem to confer susceptibility to BD. The association of HLA-B*27 with disease severity suggests that this allele is important as a prognostic factor.
Key words: Behçet’s disease; HLA class I; Portugal; disease severity.
UMIB-ICBAS/University of Porto, Portugal – Phone: +351 22 2062255, Fax: +351 222062232
Department of Internal Medicine, Hospital Geral de Santo António, Porto, Portugal
Immunogenetics Laboratory- INSA- Dr. Ricardo Jorge, Porto, Portugal
Portuguese Institute of Rheumatology – Lisboa, Portugal
São Teotónio Hospital – Viseu, Portugal
Department of Neurology, Hospital Geral de Santo António, Porto, Portugal
Unidade de ID Immunology-INSA-Dr. Ricardo Jorge, Lisboa, Portugal
Department of Population Studies, Biometry Laboratory, ICBAS/IBMC Porto,
UMIB – Instituto de Ciências Biomédicas Abel Salazar
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