Contribution of Hla-B51 in the susceptibility and specific clinical features of Behcet's disease in Tunisian patients.

Background: Many researchers have tried to investigate the association of HLA-B51 with the severity and the clinical features of BD with conflicting results.

Methods: We aimed at investigating the association of HLA-B51 with demographical and clinical manifestations as well as the severity of BD, by studying 178 native Tunisian BD patients, fulfilling the International Study group criteria for the BD classification recruited from the Department of Internal Medicine, Rabta Hospital in Tunis and compared with 125 native Tunisian healthy age and sex matching volunteers.

Results: According to our findings, the frequency of HLAB 51 was significantly higher in BD patients than in controls (p<0.001). Positive pathergy test (PPT) (p = 0.01) and retinal vasculitis (p = 0.045), were significantly more frequent in HLA B51(+) patients, while the frequency of arterial aneurysms (p = 0.009) and neurological involvement, especially the parenchymal involvement (p<0.001), were significantly and clearly higher in HLA B51(-) patients. The patients without HLA B51 had a significantly less severe disease (p = 0.001). Discussion/conclusion We conclude that HLA B51 is a predisposing marker for BD in our population as in most ethnic groups. It seems to be associated with a subgroup of BD patients characterized by a higher frequency of ocular involvement and PPT, but a lower frequency of arterial aneurysm and neurological involvement, and a less severe disease course.