Anti-cytokine therapy for the treatment of graft-versus-host disease.

Acute graft-versus-host disease (GVHD) and chronic GVHD remain the major barriers to successful hematopoietic cell transplantation. The induction of GVHD may be divided into three phases--(I) recipient conditioning, (II) donor T cell activation, and (III) effector cells mediating GVHD. Cytokines have been shown to be extremely important in the initiation and propagation of GVHD. Of note, IL-2 and TNF-alpha lead to cellular activation as well as local tissue damage. There has been a major development in the last few years of monoclonal antibodies that target cytokines. Drugs that target the IL-2 receptor (daclizumab and basiliximab) are now commonly used to prevent renal transplant rejection. Furthermore, drugs that target TNF-alpha (infliximab and etanercept) are used in rheumatoid arthritis and Crohn's disease but are also being tested for a number of other autoimmune diseases. These agents are very selective immunosuppressants that have different mechanisms of action than the calcineurin inhibitors and therefore are potentially promising for treatment or prevention of GVHD. The authors present up-to-date data regarding the use and development of anti-cytokine therapy for GVHD. The most effective approach to GVHD prevention will likely be a combination regimen where the three phases of the GVHD cascade are disrupted. Once GVHD has occurred, all three phases of the cascade are activated. Developments of combination therapy for treatment of both acute and chronic GVHD will likely yield better results than monotherapy. The numerous new treatment modalities presented should improve the outlook for acute and chronic GVHD.