Treatment of steroid-resistant graft-versus-host disease after allogeneic bone marrow transplantation with anti-CD3/TCR monoclonal antibodies.

Acute graft-versus host disease (GVHD), one of the major complications of allogeneic bone marrow transplantation (BMT), occurs in 30-50% of all patients transplanted from HLA-identical sibling donors and in 50-80% of all patients transplanted from an unrelated or HLA-mismatched family donor, despite GVHD prophylaxis with methotrexate and cyclosporin. We report our experience with OKT3/BMA031 treatment in 14 patients with severe steroid-resistant GVHD following allogeneic BMT. Three of 5 patients treated in the early post-transplant period with OKT3 remitted and 2 of 3 became long-term survivors. Two patients treated for extensive chronic GVHD showed only minor responses. Five of 7 patients treated with BMA031 showed a partial remission; no complete remission was seen after treatment with this antibody. Shortly after the introduction of OKT3 or BMA031 therapy a rapid decline of the lymphocyte count, especially the CD3+ subset, was observed coinciding with a relative increase of CD56+ lymphocytes and of gamma/delta TCR+ T cells. Increasing numbers of CD3+ lymphocytes preceded recurrence of acute GVHD in three patients. In contrast, persisting CD3-lymphocytopenia was associated with complete clearance of acute GVHD. The incidence of infectious complications following OKT3 or BMA031 therapy was high (42%). Thus, to improve treatment results of severe acute GVHD, prophylactic or pre-emptive strategies are required to reduce the rate of fatal viral and fungal infections.