[Pathology and physiopathology of Behçet's disease]

The etiology of Behçet's disease, a multisystems disease, is unknown. Epidemiological, clinical and experimental data indicate that genetic factors and other environmental factors of viral or toxic origin, are necessary for the disease to develop. Sex, age of occurence, presence of familial forms, and frequency of the HLA-B5 gene form the immunogenetic support. The geographic distribution, the results of some virologic studies, and the fact that the disease may be reproduced in animals by organo-chlorinated derivatives, form the support of the environmental factor. Study of the interferon gamma system and T lymphocytes sub-populations is in favor of a viral etiology. Hormonal factors may modulate the clinical manifestations of the disease. Circulating immune complexes may be responsible for certain lesions: uveitis, arthritis, erythema nodosa, and central nervous system involvement. The lymphocytes cytotoxic activity and the increased chemotactile activity are supposed to be the physiopathological base of aphtha, papulo-pustulous skin lesions and the pathergic phenomenon.