• Relative variation(%)in apoptotic cells calculated according to the formula : (% of induced apoptotic cells - % of spontaneous apoptotic cells [ Time Frame: before treatment and 10 weeks after treatment ] [ Designated as safety issue: Yes ]
  

• lymphocytes activation markers and macrophages activation markers [ Time Frame: before treatment and 10 weeks after treatment ] [ Designated as safety issue: No ]
  

Crohn disease is an inflammatory disease; its frequency has been increasing over the last 25 years. The physiopathology involves a failure in the negative regulatory mechanisms of the inflammatory responses in the intestines, along with an excessive production TNF-α by T-lymphocytes and macrophages of the lamina propria.

Anti-TNF-α antibodies usually give good therapeutical results, in particular in patients who are resistent or dependant on steroids. Nevertheless, in Crohn disease, the destructive T-lymphocytes - macrophages interactions, their inhibition by anti-TNFα, and the impact of these antibodies on cellular signaling remain largely unknown.

Two groups de 10 patients with an active Crohn disease, with or without azathioprine, and requiring the beginning of anti-TNF treatment are included in this study. Rectosigmoïdal biopsies and blood tests will be done before starting the treatment, and after 10 weeks of treatment. Surface antigens, cytokines and cellular molecules and the number of apoptotic cells will be analyzed by FACS, and the quantification of RNA will be analyzed by RT-PCR.

This will therefore unable us to study, before and after anti-TNF-α, in patients treated or not with azathioprine, on intestinal and blood lymphocytes, the production of cytokines involved in the lymphocyte-macrophage interaction, and the potential role of regulatory T cells.