FACTORS INFLUENCING PLATELET RECOVERY AFTER BLOOD-CELL TRANSPLANTATION IN MULTIPLE-MYELOMA

We sought to determine factors that impact on the recovery of platelet s after blood cell transplantation in patients with multiple myeloma, We performed retrospective analyses in 51 patients undergoing blood ce ll transplantation for multiple myeloma, The proportional-hazards mode l was applied to determine significant risk factors, Of 51 transplants , 14 patients failed to achieve a platelet count of 50 x 10(9)/l. Medi an time to a neutrophil count of 0.5 x 10(9)/l was 10.5 days, Median t ime to achieve a platelet count of 50 x 10(9)/l was 32 days. Multivari ate analysis revealed that cyclophosphamide and G-CSF priming before c ollection of hematopoietic precursors (P < 0.001) was a positive predi ctor of rapid engraftment and prior exposure to melphalan given orally (P = 0.02) was a negative predictor of subsequent platelet engraftmen t, The number of mononuclear cells collected, the patient's disease st atus at the time of transplant and the presence of circulating plasma cells in the harvested product did not have a significant impact on ti me to platelet engraftment, We conclude that cyclophosphamide and G-CS F priming shortened the time to achieve platelet engraftment compared with G-CSF alone, Prior exposure to melphalan delayed platelet engraft ment and can lead to complete failure of platelet recovery, Stem cells should be collected before melphalan administration in patients with multiple myeloma who are candidates for possible blood cell transplant ation.