[Certain immune-genes may affect Crohn disease. Advances in diagnosis, pathogenesis and treatment].

Despite extensive research, the cause of Crohn's disease remains unknown. No specific infectious agent has been identified, though interest has been focused on the possible involvement of mycobacteria, and recently on child hood measles as a possible aetiological factor. Both hereditary and environmental factors seem to contribute to development of the disease. The clinical picture may be dependent upon individual HLA subtypes, as they appear to differ from each other regarding the secretion of inflammatory cytokines. Non-invasive scintigraphy and computerised tomography are used to determine the extent of disease, and to localise such complications as abscesses and fistulas. Endoscopic ultrasonography and magnetic resonance imaging have proved particularly valuable in diagnosing rectal and rectovaginal fistulas. New 5-ASA (5-aminosalicylic acid) preparations, steroids with fewer systemic side effects, and azathioprine-induced immunosuppression constitute the cornerstones of medical treatment, further developments in pharmacological immunoregulation being a future treatment possibility.