Discrepancy between serological complete remission and concomitant new bone lytic lesions after infusion of escalating low doses of donor lymphocytesin multiple myeloma: a case report

A graft-versus-myeloma effect has been previously induced by infusing high numbers of donor lymphocytes after allogeneic stem cell transplantation in relapsed/refractory multiple myeloma (MM) patients. A 43-year-old patient w ith MM refractory to standard chemotherapy and autologous transplantation r eceived an allogeneic HLA-matched T cell-depleted marrow transplant from hi s sister after conditioning with single dose total-body irradiation, melpha lan and cyclophosphamide, Twenty-four months after transplant neither a sig nificant reduction of serum M protein nor evidence of acute or chronic graf t-versus-host disease (GVHD) were observed. The patient was then treated wi th four escalating low doses of donor lymphocyte infusions (DLI) (0.1, 1.0, 5.0 and 5.0 x 10(6) CD3(+) T cells/kg, respectively) over a 13 month perio d, Following the second infusion a mild liver acute GVHD and a partial, but transient, response occurred. After the last DLI the patient achieved a co mplete remission and developed extensive chronic GVHD. However, concomitant with the disappearance of clonal plasma cells from the marrow and of serum M protein, two new bone lytic lesions appeared requiring treatment with ra diotherapy, In conclusion, escalating low doses of DLI may be effective in MM and may prevent severe acute but not chronic GVHD, However, the efficacy of DLI in extramedullary MM lesions is still unclear.