Flares of immune-mediated inflammatory diseases, as Rheumatoid Arthritis (RA), are a major burden for patients in routine care. They occur unpredictably, adding to the physical and psychological burden of the condition. In this study we will deeply dissect the synovial tissue and peripheral blood signature of RA in sustained remission eligible to treatment discontinuation to better understand the individualized factors determining disease flare once biological treatment is discontinued. We expect that the combined study of synovial tissue, imaging and peripheral blood derived biomarkers, associated with disease flare after treatment discontinuation in RA in remission, will provide a tool for the routine assessment of RA eligible to treatment discontinuation reducing the relapse rate and increasing the optimization of the use of expensive pharmacological treatments only for patients still needing them.

Inclusion Criteria:

• Diagnosis of RA following the 2010 ACR/EULAR classification criteria
• Age ≥18 and ≤75 years
• Sustained remission (DAS<1.6 for at least 3 sequential evaluations 6months apart).
• Without evidence of ultrasound detected synovitis (Power Doppler negative in knee, wrist, II-V MCP, II-V PIP and II-V MTP bilaterally).
• Patients under treatment with stable dose of conventional, synthetic or biological DMARDs.
• Patients without steroid treatment in the last 6 months.

Exclusion Criteria:

• With other diagnosis of chronic joint diseases rather than RA.
• Unable to participate to the clinical outpatient follow-up.
• Exposed to steroid treatment within 6 months from study screening.
• With evidence of ultrasound detected synovitis (Power Doppler positivity) in other joints than the ones included in the screening visit.

Patients with Rheumatoid Arthritis in stable remission (DAS<1.6 for at least 6 months) and under treatment with stable dose of conventional, synthetic or biological DMARDs. All patients at the time of enrolment must fulfil the ultrasound criteria of Power Doppler negativity of knee, wrist, II-V MCP and II-V MTP bilaterally and any other reported painful joint not included in the screening ultrasound protocol.