Behçet's syndrome: from aetiology to treatment.

Abstract

Behcet’s syndrome is an inflammatory disorder of unknown cause‚ pathologically characterised by a vasculitis‚ with a predilection for small venules. A T-helper 1 polarisation of the immune response has been suggested. Hulusi Behcet himself suggested herpes simplex as an aetiological agent and more recently‚ superantigens‚ heat shock proteins and streptococcal antigens have been suggested as putative aetiological factors. Clustering of cases along the ancient Silk Road is often cited to support a genetic basis for Behcet’s syndrome‚ but that is clearly not the whole story. The prevalence of Behcet’s syndrome amongst Turks in Germany is lower than that of Turks in Turkey‚ but is higher than that in the indigenous German population‚ suggesting a strong environmental influence. Similarly‚ the rarity of Behcet’s syndrome in Japanese migrants in Hawaii and California contrasts with the higher incidence in mainland Japan. A family history is present in up to 12% of non-caucasoid cases‚ and a sibling risk ratio of 11.2 is reported . The genetic susceptibility to Behcet’s syndrome has been linked with HLA-B51‚ MIC-A6 and more recently‚ 6p22-23. However‚ HLA-B51 is not the elusive “Behcet’s gene”‚ as there is a marked geographical variation in relative risk‚ up to 75% of patients worldwide are HLA-B51 negative‚ and HLA-B51 transgenic mice do not develop the Behcet’s phenotype. Nevertheless‚ these disease markers are all adjacent to suggesting a key role for this cytokine. This is supported by the efficacy of anti-TNF