Molecular monitoring of minimal residual disease in patients in long-term complete remission after allogeneic stem cell transplantation for multiple myeloma

In the present study, we used a polymerase chain reaction-based (PCR based) strategy to retrospectively analyze the presence of residual myeloma cells in serial posttransplant bone marrow samples obtained from 13 patients in remission after allogeneic hemopoietic stem cell transplantation (allo SCT) . For this purpose, patient-specific primers were generated from complement arity determining regions 2 and 3 of the rearranged IgH gene. The level of sensitivity of the PCR-based assay ranged from 1 in 10(5) to 1 in 10(6) nor mal marrow cells. Following transplantation, 9 of 12 patients who attained stringently defined complete remission (CR) remained persistently PCR- for a median of 36 months, and 4 of the patients remained PCR- up to the latest analysis, which was performed at 48, 72, 72, and 120 months, respectively, after allo SCT. None of the patients in the PCR- subgroup experienced a di sease relapse, and only 1 of 4 PCR+ patients experienced a relapse. It is c oncluded that allo SCT has the potential ability to induce sustained serolo gical and molecular CR in selected patients with multiple myeloma. (Blood. 2000;96:355-357) (C) 2000 by The American Society of Hematology.