Treatment of marrow graft recipients with thymopentin

Four adult patients with acute non-lymphocytic leukemia were given marrow grafts from HLA-identical siblings following 120 mg/kg cyclophosphamide and 10-12 Gy total body irradiation. All received intermittent intravenous methotrexate as prophylaxis against graft-versus-disease (GVHD). In an attempt to accelerate immune recovery and prevent GVHD, each patient received thymopentin (TP5) for 100 days after grafting. No adverse effects were seen with TP5 administration. All four patients developed acute GVHD (one grade I, one grade II, and two grade III). Two patients died of late infections: one at 6 months from Pneumocystis carinii pneumonia and one at 11 months from disseminate Pseudomonas, Candida and cytomegalovirus infection. Two patients survive more than 3.9 years after transplantation with Karnofsky scores of 100%. One required treatment for chronic GVHD and recovered. Delayed-type hypersensitivity, antibody production to specific antigen in vivo, and results of in vitro immunologic studies were not altered by TP5 treatment. We conclude that while the administration of TP5 in these patients as described was not harmful, it did not prevent opportunistic infection, improve immunologic reconstitution or lower the incidences of acute or chronic GVHD from that of our previous experiences without thymopentin.