The clinical spectrum of acute graft-versus-host disease.

Acute graft-versus-host disease (GVHD), initiated by the reaction of donor T lymphocytes against nonshared recipient antigens, typically leads to a clinical syndrome characterized by cutaneous eruptions and intestinal and hepatic dysfunction. These three organ systems are considered in the clinical grading of acute GVHD. However, other targets may be involved. With conventional transplant conditioning regimens and in vivo prophylaxis, GVHD becomes clinically manifest within 2 to 4 weeks. With reduced-intensity conditioning, the onset of acute GVHD may be delayed until 2 to 3 months after transplantation. Hyperacute GVHD may occur within a week of transplantation after severely human leukocyte antigen (HLA)-mismatched transplants or transplants without GVHD prophylaxis. There is no reliable laboratory test for acute GVHD, and the diagnosis is based on clinical assessment.