Recently, various micro(mi)RNAs have been found deregulated in the setting of 
rheumatoid arthritis (RA), but their role in the pathogenesis of this disease 
remains a matter of debate. In the meanwhile, increasing evidence indicates a 
defective function of regulatory T cells (Tregs) in RA. This review discusses 
relevant studies addressing the function of Tregs and Cytotoxic T-Lymphocyte 
Antigen 4 in RA, provides recent data on the role of miRNAs for Tregs 
homeostasis, and focuses on the role of miR-155 in Tregs. In a final perspective 
section we discuss the potential impact of therapeutic miR-155 modulation in RA.