Colonic graft-versus-host disease

Purpose of review: Graft-versus-host disease (GVHD) is a common, potentially life-threatening complication of allogenic hematopoietic stem cell transplantation. Gastrointestinal GVHD frequently involves the colon and complicates management of these seriously ill patients. This review updates the diagnosis and management of colonic GVHD. Recent findings: Conditions are primed for development of GVHD when the pretransplant conditioning regimen generates substantial proinflammatory cytokines, This "cytokine storm" then acts on T cells in the graft, prompting them to attack host antigens. In its acute form, GVHD focuses on the skin, liver, and gastrointestinal tract. Gastrointestinal manifestations include diarrhea, bleeding, vomiting, and abdominal pain. Endoscopic biopsy can readily diagnosis GVHD. However, risk of endoscopy is higher in these ill patients and frequent thrombocytopenia complicates mucosal biopsy. Apoptosis is required to make the diagnosis of GVHD but is not a specific finding. Although gastrointestinal symptoms are common after the acute phase, chronic GVHD of the gut does not appear to be a major etiologic factor. Systemic steroids are the first line of therapy for GVHD. Infliximab or oral budesonide are helpful in patients with steroid-refractory disease, particularly in those with gastrointestinal tract involvement. Summary: Although colonic GVHD is readily diagnosed, advances in management await greater understanding of pathogenesis and more specifically targeted therapies.