Inflammatory bowel disease (IBD) and psoriasis (Ps) are common, chronic, immune- mediated barrier diseases with shared inflammatory pathways. Current therapeutic interventions with anti-cytokine antibodies (TNF-α, IL-23/IL-12) reflect the intent to disrupt specific pathways of inflammatory immunopathology. Individual responses to biological treatment can be thereby be exploited in a systems biology approach that employs a targeted mechanism of action (MOA) to decipher molecular signatures of therapeutic responses in the context of a distinct disease entity. Using a translational approach to investigate clinical and molecular phenotypes during therapeutic interference with cytokine signaling and leukocyte trafficking, the investigators aim to trace common and unique signatures of drug- and therapy-specific responses.

Patients will undergo endoscopic evaluation of the mucosal surface and gastrointestinal wall by conventional HD-colonoscopy, endoscopic ultrasound and confocal laser endomicroscopy prior to and during specific therapies with biologicals. In parallel, mucosa samples will be obtained to define molecular phenotypes during the course of therapy.

Inclusion Criteria:

• inflammatory bowel disease
• indication for biological therapy

Exclusion Criteria:

• pregnancy, breast feeding
• no written informed consent to participate in the study