This is a prospective, multicenter, double-blind, placebo controlled interventional study to evaluate the safety and efficacy of allogeneic mesenchymal stem cells (MSCs) in 20 patients with new onset Rheumatoid Arthritis (RA). The study is a single dose, phase I clinical trial and is the first time that this product will be infused in RA patients. The study duration is approximately fourteen months from time of screening to completion.