A group Crohn patients have long been in prolonged biochemical and conventional endoscopic remission, including patients treated with the biologic drug infliximab. These patients are also included in the study as a particularly interesting subgroup as CLE in a small study has suggested to contribute to the safe discontinuation of immunosuppressive therapy. The degree of healing of the mucous membrane including an intact barrier function is one of the most important prognostic factors for patients to develop a recurrence. Thus it will be of great clinical importance to clarify whether CLE can help to distinguish those patients who have an apparently normal endoscopy, yet unrealized discrete activity and defective barrier function from patients where there is no activity evaluated endoscopically and by CLE. Furthermore, a small number of patients will be included as a control group.