IL6 and rheumatoid arthritis: IL-6 is a co-stimulator of vitro bone marrow mesenchymal stem cells.[18] Since IL-6 levels are significantly higher in MDS marrow than in comparable cells from healthy controls and the serum IL-6 concentrations are increased in RA patients, IL-6 antagonist (tocilizumab) would theoretically be ideal choice for the treatment of RA patients with MDS.[19] Therefore, we selected the therapy for RA with MDS and expected that tocilizumab simultaneously treat both inflammation and hematopoietic abnormality in this patient.