Behçet\'s disease is a chronic multisystemic inflammatory disorder of unknown origin. This disease occurs worldwide, but is more prevalent among Asian and Eurasian populations along the Silk Route. Peculiar geographic distribution supports that the disease might have a genetic basis. The etiology and pathogenesis have remained unclear, but it has long been assumed that immunological abnormalities, which are possibly induced by infectious agents in genetically susceptible individuals, are important in its pathogenesis.