[2018 update on chronic graft-versus-host disease]

Chronic graft-versus-host disease (GVHD) occurs in 30-40% of patients who undergo allogeneic hematopoietic cell transplantation. The symptoms of chronic GVHD resemble those of autoimmune diseases, and many sites, including the eyes, mouth, skin, gastrointestinal tract, liver, lungs, joints, and fascia, can be affected. Severe chronic GVHD increases patients' mortality and decreases their quality of life. The 2014 National Institutes of Health (NIH) Consensus has proposed a three-step model for classification of the mechanisms of chronic GVHD: early acute inflammation, chronic inflammation with dysregulated immunity, and tissue fibrosis. Many drugs targeting specific biological pathways for treating chronic GVHD are under development. The NIH Consensus has also clarified objective response measures, optimal endpoints, and clinical trial designs to be used for drug approval. More than 30 novel drugs for GVHD treatment are currently being tested in over 80 clinical trials worldwide.