Anti-inflammatory therapy with monoclonal antibodies (mAbs) directed against tumour necrosis factor (TNF)-alpha has emerged as a major advancement in the treatment of various immune mediated diseases such as rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis and Crohn's disease. TNF-alpha seems to play a major pathogenic role in these chronic immune-mediated inflammatory diseases. Infliximab (Remicade), Centocor, Inc., Malvern, PA, USA), a chimaeric mAb, binds to soluble and membrane bound TNF-alpha, but not to TNF-beta. Infliximab is able to effectively regulate and mediate inflammatory processes involved in a number of different disease states. Many clinical trials in these diseases have demonstrated that biological therapy with mAbs directed against TNF-alpha is effective and relatively safe.