PB2358 THE IMPACT OF THE NUMBER OF CD34 + CELLS TRANSPLANTED IN ENGRAFTMENT AFTER AUTOLOGOUS TRANSPLANTATION OF HEMATOPOIETIC PROGENITORS

Background: Despite the emergence of new therapeutic options, autologous hematopoietic stem‐cell transplantation (AHCT) is still one of the pillars in the treatment of patients with multiple myeloma (MM), especially in younger and fit patients. However, the ideal number of transplanted CD34 + cells to maximize post‐transplant results is still under discussion. Aims: Verify the corelation between the number of cell CD34 + infused and the outcomes in neutrophils and platelets recovery and transfusional requirements. Methods: Prospective analysis of 243 autologous transplants in patients with multiple myeloma for 10 years from January 2007 to December 2017,in a single institution. For this study, where analysed: the myeloma subtype, the age of diagnosis, the time from diagnosis to transplantation, the conditioning used, the number of days of hospitalization, number of cells infused, the number of days of engraftment, number of days with neutrophils< 0,5 × 10 9 /L, number of days with platelets< 20 × 10 9 , number of transfused platelets pools, number of transfused red blood cells (RBC). The statistical treatment of the data was done in SPSS version 24. Results: In this sample 217 patients were analysed, of whom 79 were females (36,4%) and 138 were males (64%). The medium age of diagnosis was 54.28 years (27 – 77 years) and of transplantation was 58.42 years (28 – 72 years). The most frequent subtype of MM was IgG kappa (45,7%), IgA kappa and IgG lambda (both with 13,2%). The median time from diagnosis to transplant was 533 days. The conditioning regimen used in the majority of the patients was melphalan 200 (97%), and the mean time of hospitalization was 19 days (12 – 77). The number of cells CD34 + infused ranged from 1.40 to 13 × 10 6 cells/kg, with a average of 3.49 cells/kg. In this study, no correlation was verified between the number of cells CD34 + infused and the number of days with neutrophils< 0,5 × 10 9 /Lor with the transfusion need for RBC. The average number of days of engraftment was 13 days (9 – 28), and there is also no correlation between the number of cells CD34 + infused. However, there is an inversely proportional and statistically significant correlation (p < 0.01 and p < 0.05, respectively) related to the number of days with platelets< 20 × 10 9 /L as well as to the number of transfused platelets pools. Summary/Conclusion: An increased number of transplanted CD34 + cells was shown to have a significant impact in time until recovery of the number of platelets, and was associated with lower transfusion dependencepost‐AHCT. The remaining variables evaluated did not show to be dependent on the number of transplanted cells.