GRAFT-VERSUS-MYELOMA AFTER DONOR LEUKOCYTE INFUSION - MAINTENANCE OF MARROW REMISSION BUT EXTRAMEDULLARY RELAPSE WITH PLASMACYTOMAS

Adoptive immunotherapy with donor leukocytes has emerged as a promisin g strategy for the treatment of myeloma recurrence after allogeneic tr ansplantation. 2.9 x 10(8)/kg donor mononuclear cells containing 1.4% CD34(+) and 37% CD3(+) cells were administered to a 48-year-old patien t with non-secretory plasmablastic myeloma relapsing 9 months after a blood stem cell transplant from his HLA-identical sibling. In view of the extensive marrow infiltration and the aggressive behaviour of the disease, the donor cells were preceded by a course of EDAP chemotherap y. There was rapid clinical improvement, and CR was achieved on day 30 post infusion. However, three subcutaneous plasmacytomas showing anap lastic features developed within a few days. These failed to respond t o interferon-cu and continued to grow for 5 weeks in the absence of ma rrow plasmacytosis or other evidence of systemic disease. Grade 3 acut e liver GVHD developed on day 79 which was controlled with immunosuppr ession. Overt systemic relapse occurred on day 90 as the GVHD came und er control. The course of our case suggests highly proliferative malig nant cells may escape the graft-versus-tumour effect of immunocompeten t allogeneic cells in extramedullary sites subsequently resulting in o vert systemic relapse if left untreated. New approaches are needed to deal with the problem of extramedullary disease recurrence.