The investigators propose to identify changes in cytokines like adipocytokines and microRNA (miR) expression (for example miR-9, miR-16, miR-125, miR-132, miR-146a, miR-150, miR-155, miR-181 and miR-223) in peripheral blood leukocytes and in serum samples obtained from rheumatoid arthritis (RA) patients before and after tocilizumab treatment. The results obtained will be compared to gender- and age-matched healthy controls, and will help the investigators define one or more miRNAs as biomarkers for treatment effectiveness.