Rheumatoid arthritis (RA) is a chronic inflammatory arthritis with many systemic 
manifestations. Several monoclonal antibodies targeting different components of 
the immune systems have been licensed for treatment of RA. Inflammatory 
cytokines such as interleukin-6 (IL-6) are found abundantly in the blood and the 
joints. The biologic effect of IL-6 on leukocyte, osteoclast, hepatocytes and 
bone marrow may mediate the articular and systemic inflammation in RA. Recently, 
an anti-IL-6 receptor monoclonal antibody, tocilizumab, has been licensed for 
the treatment as monotherapy or in combination with methotrexate of moderate to 
severe RA, when disease modifying anti-rheumatic drugs or anti-tumour necrosis 
factors (TNF) have failed. It improves symptoms and signs as well as reducing 
joint damage. Tocilizumab monotherapy has been shown to be superior to 
methotrexate. Its side-effects include infections, decrease in neutrophils, and 
increases in lipid and liver transaminases. Overall, tocilizumab has a 
well-defined and manageable safety profile that supports a favourable 
benefit/risk ratio for patients with RA.