Inclusion Criteria:
* Diagnosis of AS, RA, SLE according the mentioned criteria;
* Ability to provide informed consent;
* If entering the study on NSAIDs, tramadol, combination of paracetamol and codeine or hydrocodone, and/or non-opioid analgesics, subject must be on stable dose(s) for at least 14 days prior to the screening visit;
* If entering the study on oral corticosteroids, subject must be on a stable dose of prednisone (≤ 10 mg/day), or oral corticosteroid equivalents, for at least 14 days prior to the screening visit;
* If entering the study on MTX, leflunomide, SSZ, and/or hydroxychloroquine, subject must be on a stable dose of MTX (≤ 25 mg/week) and/or SSZ (≤ 3 g/day) and/or hydroxychloroquine (≤ 400 mg/day) or leflunomide (≤ 20 mg/day) for at least 28 days prior to the screening visit. A combination of up to two background csDMARDs is allowed;
* Subject is judged to be in good health as determined by the Principal Investigator based upon the results of medical history, laboratory profile, physical examination, x-Ray performed at the Screening Visit.
Exclusion Criteria:
* Current pregnancy or breastfeeding;
* Prior exposure to any biologic therapy;
* Intra-articular joint or tendon sheaths injections, spinal/paraspinal injection(s), or parenteral administration of corticosteroids within 28 days prior to the Baseline Visit. Inhaled or topical corticosteroids are allowed;
* Receipt of any live vaccine within 4 weeks prior to the screening visit;
* History of clinically significant (per Investigator\'s judgment) drug or alcohol abuse within the last 6 months;
* Subject has a history of inflammatory arthritis of different etiology other than AS, RA or SLE (including but not limited to PsA, mixed connective tissue disease, reactive arthritis, scleroderma, polymyositis, dermatomyositis, fibromyalgia), or any arthritis with onset prior to 17 years of age;
* Any uncontrolled medical condition (e.g., uncontrolled diabetes mellitus, unstable ischemic heart disease);
* History of any malignancy;
* Positive serology for hepatitis B, hepatitis C, or human immunodeficiency virus;
* Infections requiring hospitalization or intravenous treatment with antibiotics within 30 days or oral treatment with antibiotics within 14 days before enrollment;
* Note : Healthy Controls should be matched by gender and age. People with acute infections or injuries (in the last 6 months) or non-controlled chronic diseases (cardiac, metabolic, lung, neurologic, gastro-intestinal or renal) will be exclude. Family history of Auto-Immune diseases as diagnosed by a rheumatologist will be also excluded.
