Effect of the Inhibitors of the Way JAK-STAT on Regulatory B Cells

Inclusion criteria: * General criteria * Patient, of 18 and more years old * Subject affiliated to a social security system * Subject not being in period of exclusion with regard to another protocol * Absence of pregnancy in the inclusion (date of the last period, use of a contraceptive method, ß -HCG impulsive person in case of doubt) * Informed consent * Criteria of inclusion of the group rheumatoid arthritis (in vitro studies): * Rheumatoid arthritis, corresponding to the the classification ACR / EULAR 2010 criteria * Criteria of inclusion of the group arthritis (in vitro studies): * Spinal degenerative osteoarthritis or degenerative osteoarthritis of the members, according to the clinical and radiological elements. * Criteria of inclusion of the group rheumatoid arthritis, longitudinal study at the patients treated by JAK / STAT inhibitors : * Rheumatoid Polyarthritis, corresponding to the classification ACR / EULAR 2010 criteria * Patient to whom a treatment by inhibitor of the way JAK / STAT was proposed in current care of rheumatoid arthritis. Exclusion criteria: * General criteria * Corticosteroid therapy superior to 10 mg / j * Drip of corticoids in the previous month * Pregnant or breast-feeding Patients * Patient under protection(saving) of justice * Under guardianship Patient or guardianship * Current Infection * Criteria of non-inclusion of the group rheumatoid polyarthritis ( in vitro studies): * Treatment by immunomodulateur or biotherapics (anti-TNF alpha, tocilizumab, abatacept or rituximab) in the previous year * Criteria of non-inclusion of the group arthritis ( in vitro studies): * History of autoimmune disease or néoplasie * Treatment by immunomodulateur or biotherapics (anti-TNF alpha, tocilizumab, abatacept or rituximab) * Criteria of non-inclusion of the group rheumatoid arthritis, longitudinal study at the patients treated by JAK / STAT inhibitors : Treatment by rituximab in the previous year