This study aims to study the inflammatory response in various forms of arthritis.

Arthritis, a significant heald burden is characterized by joint inflammation that severely impacts patients' quality of live. Despite advancements in treatment, many individuals with conditions like rheumatoid arthritis (RA), osteoarthritis (OA), and spondyloarthritis (SpA) do not achieve satisfactory outcomes, underscoring the need for more precise therapeutic strategies.

The project aims to characterize the inflammatory response in various form of arthritis by collecting and analyzing synovial tissue-the connective tissue lining joints. Biopsies will be collected through ultrasound-guided biopsies (UGSB), a minimally invasive and well-tolerated procedure. Presence of immune and stromal cells in the tissue, their interactions, and their relationship to clinical symptoms are characterized by histological and molecular methods. By comparing these features across different forms of arthritis, the study aims to identify molecular pathways and biomarkers that distinguish these diseases and their subtypes. The study hopes to contribute to a broader understanding of arthritis pathophysiology, ultimately translating into novel therapeutic targets and tailored clinical strategies.

Inclusion Criteria:

• Age >18 years
• Clinically relevant arthritis in one or more joints as assessed by the treating rheumatologist, including RA, SpA, connective tissue disease and OA.

Exclusion Criteria:

• Known allergies to local anesthetics
• Family history of bleeding, history of increased bleeding tendency or prolonged bleeding, current treatment with oral anticoagulants or platelet aggregation inhibitors; Quick < 65%, international normalised ratio (INR) ≥ 1.3, thrombocyte count < 100'000/μl, activated partial thromboplastin time (aPTT) > 37 sec
• Inability or insufficient knowledge of project language to understand the information given in the informed consent form

arthritis patients