An Explorative Psoriasis Biomarker Study

Inclusion Criteria Healthy volunteers Eligible healthy volunteers must meet all of the following inclusion criteria at screening: 1. Male or non-pregnant female subjects, 18 to 75 years of age (inclusive); 2. Healthy as defined by the absence of any uncontrolled active or uncontrolled chronic disease following a medical and surgical history, documentation of general symptoms, and a symptom-directed physical examination including vital signs; 3. Willing to give written informed consent and willing and able to comply with the study protocol; Psoriasis patients Eligible psoriasis patients must meet all of the following inclusion criteria at screening: 1. Male or non-pregnant female subjects, 18 to 75 years of age (inclusive); 2. Diagnosed with plaque psoriasis at least 6 months prior to study participation 3. Willing to discontinue any psoriasis therapy other than emollients. 4. Having mild (PASI ≥1 and ≤ 5) or moderate-to-severe (PASI ≥ 10) plaque psoriasis; 5. Currently not using psoriasis medication and ≥ 2 plaques suitable for repeated biopsies and target lesion assessments. At least one of these lesions must be located on the extremities, preferably on the elbow or knee, with a minimal target lesion score between 6 and 9. Or, when currently using psoriasis medication and insufficient lesional skin is present, willing to discontinue treatment awaiting rescreening (see also exclusion criteria 3 for psoriatic patients); 6. Willing to give written informed consent and willing and able to comply with the study protocol; Exclusion Criteria Eligible healthy volunteers must meet none of the following exclusion criteria at screening: 1. History or symptoms of any uncontrolled, significant disease including (but not limited to), neurological, psychiatric, endocrine, cardiovascular, respiratory, gastrointestinal, hepatic, or renal disorder that may interfere with the study objectives, in the opinion of the Investigator; 2. History of immunological abnormality (e.g., immune suppression, severe allergy or anaphylaxis) that may interfere with study objectives, in the opinion of the Investigator; 3. Known infection requiring antibiotic therapy within the last three months prior to the study; 4. Immunosuppressive or immunomodulatory treatment within 30 days prior to the study; 5. Body mass index (BMI) ≤ 18.0 or ≥ 40.0 kg/m2; 6. Participation in an investigational drug study within 3 months prior to screening or more than 4 times a year; 7. Previous participation in an investigational drug study involving the dosing of an investigational compound targeting an immune pathway within one year prior to screening; 8. Loss or donation of blood over 500 mL within three months prior to screening; 9. The use of any medication or vitamin/mineral/herbal/dietary supplement within less than 5 half-lives prior to study participation, if the Investigator judges that it may interfere with the study objectives. The use of paracetamol (up to 4 g/day) is allowed; 10. History of alcohol consumption exceeding 5 standard drinks per day on average within 3 months of screening. Alcohol consumption will be prohibited from at least 12 hours preceding each study visit; 11. Any other condition that could interfere with the conduct of the study or the study objectives, in the opinion of the Investigator. Psoriasis patients Eligible psoriasis patients must meet none of the following exclusion criteria at screening: 1. Having primarily erythrodermic, pustular or guttate psoriasis; 2. Having medication-induced psoriasis; 3. Having previously failed on anti-IL23 therapy; 4. Having received treatments for psoriasis within the following intervals prior to the start of the study: 1. \< 2 weeks for topical treatment, e.g. retinoids, corticosteroids, vitamin D analogs 2. \< 4 weeks for phototherapy, e.g. PUVA, PDT 3. \< 4 weeks for non-biologic systemic treatment, e.g. retinoids, methotrexate, cyclosporine, fumaric acid esters 4. \< 4 weeks for etanercept 5. \< 8 weeks for adalimumab 6. \< 3 months for anti-IL17, anti-IL12(/23) and anti-IL23 treatments 5. History or symptoms of any significant uncontrolled disease including (but not limited to), neurological, psychiatric, endocrine, cardiovascular, respiratory, gastrointestinal, hepatic, or renal disorder that may interfere with the study objectives, in the opinion of the Investigator, excluding psoriasis and conditions that are related to psoriasis; 6. History of immunological abnormality (e.g., immune suppression, severe allergy or anaphylaxis) that may interfere with study objectives, in the opinion of the Investigator; 7. Known infection requiring antibiotic therapy within the last 3 months prior to the study, including latent tuberculosis; 8. Systemic immunosuppressive or immunomodulatory treatment within 30 days prior to the study; 9. Body mass index (BMI) ≤ 18.0 or ≥ 40.0 kg/m2; 10. Participation in an investigational drug study within 3 months prior to screening or more than 4 times a year; 11. Loss or donation of blood over 500 mL within three months prior to screening; 12. The use of any medication or vitamin/mineral/herbal/dietary supplement within less than 5 half-lives prior to study participation, if the Investigator judges that it may interfere with the study objectives. The use of paracetamol (up to 4 g/day) is allowed; 13. History of alcohol consumption exceeding 5 standard drinks per day on average within 3 months of screening. Alcohol consumption will be prohibited from at least 12 hours preceding each study visit; 14. Any other condition that could interfere with the conduct of the study or the study objectives, in the opinion of the Investigator.