T-cell chimerism prior to graft-versus-host disease.

Graft-versus-host disease (GVHD), a serious complication of haematopoietic stem cell transplantation, can occur following solid organ transplantation. However, diagnosing solid organ transplantation-associated GVHD is difficult, and its risk factors are not fully understood. Here, we report a GVHD case in a 59-year-old woman with dermatomyositis-associated interstitial pneumonia, who took immunosuppressants including corticosteroids before receiving right lung transplantation from a 13-year-old brain-dead male donor. She developed systemic erythema with desquamation and pancytopenia by day 20. Mixed chimerism with donor- and recipient-type cells in the bone marrow and skin led to the diagnosis of GVHD. Corticosteroid pulse therapy reduced the symptoms and decreased donor-type cell percentage. On day 50, the patient developed donor lung injury and was diagnosed with acute rejection, which was treated using steroid pulse therapy again. Although the granulocytes were recipient type, donor chimerism of peripheral blood T cells exacerbated on day 68. Subsequent deterioration of liver function and pulmonary injury in the patient's own lung led to the diagnosis of relapsing GVHD. The patient died of multiple organ failure despite treatment with anti-thymocyte globulin. Thus, repeated steroid pulse therapy and age difference between donors and recipients may predispose to GVHD and T-cell mixed chimerism can be an important diagnostic indicator of GVHD.