Abstract Background The innate immune receptor RIG-I detects viral RNA within the cytosol of infected cells. Activation of RIG-I leads to the induction of antiviral cytokines, in particular type I interferon, the inhibition of a T(H)17 response as well as to the suppression of tumor growth. Therefore, RIG-I is a promising drug target for the treatment of cancer as well as multiple sclerosis. A specific ligand for RIG-I is currently in preclinical testing. The first-in-human trial will need to be carefully designed to avoid an overshooting cytokine response. Therefore, the ResI study was set up to analyze the human immune response to standard treatment with recombinant interferon-beta to establish biomarkers for safety and efficacy of the upcoming first-in-human trial investigating the RIG-I ligand. Methods/Design ResI is a single center, prospective, open label, non-randomized phase I clinical trial. Three different cohorts (20 healthy volunteers, 20 patients with RRMS and ongoing interferon-beta treatment and 10 patients starting on interferon-beta) will receive standard interferon-beta-1a therapy for nine days. The study will be conducted according to the principles of the german medicinal products act, ICH-GCP, and the Declaration of Helsinki on the phase I unit of the Institute of Clinical Chemistry and Clinical Pharmacology and in the Department of Neurology, both University Hospital Bonn. Interferon-beta-induced cytokine levels, surface marker on immune cells, mRNA- and miRNA-expression as well as psychometric response will be investigated as target variables. Discussion The ResI study will assess biomarkers in response to interferon-β treatment to guide the dose steps within the first-in-human trial with a newly developed RIG-I ligand. Thus, ResI is a biomarker study to enhance the safety of the clinical development of a first-in-class compound. The data can additionally be used for the development of other therapies based on type I interferon induction such as TLR ligands. Moreover, it will help to understand the interferon-beta induced immune response in a controlled in vivo setting in the human system. Trial .