1.3 Main objective and main judgement criteria. Determine predictive factors for relapse within one year after stopping infliximab. Main judgement criteria is the clinical relapse after stopping infliximab. Clinical relapse is defined either by a CDAI>250 or by a CDAI between 150 and 250 if this CDAI is confirmed over two consecutive weeks with an increase of at least 70 points over baseline for the two consecutive measures.