Rheumatoid arthritis (RA) is a common autoimmune disease characterized by chronic inflammation of synovial joints. RA is presented as the malfunction of immune system especially mediated by Th1 cells. B lymphocytes are also closely associated with RA in the process of antigen presentation, antibody generation and cytokine secretion. Besides, γδ T lymphocytes, Th17 cells, interleukin (IL)-4 and IL-10 also function in different stages of RA. This paper discusses the correlation of cells, antibodies and cytokines with the development, diagnosis and treatment of RA.