Factors that influence long-term hematopoietic function following autologous stem cell transplantation

The aim of the present study was to assess which factors influence hematopoietic function long term after transplantation. For this purpose, we have analyzed a series of 79 patients who underwent autologous transplantation. None of them received any further chemotherapy or radiotherapy after transplant. All patients were disease-free 1 year after autologous transplantation. Late impairment of hematopoietic function was defined as the presence of non-transient peripheral blood cytopenias, detected 6 and 12 months after autografting. Before transplantation, 38.7% of patients showed peripheral blood cytopenias. Six and 12 months after transplantation, cytopenias presented in 44.2% and 42.4% of patients, respectively. Cases displaying cytopenias 6 months after transplantation had received a significantly lower dose of CFU-GM and CD34+ cells than patients without cytopenias (P = 0.012 and P = 0.04, respectively). The same correlation, with even higher statistical significance, was observed 12 months after transplant (P = 0.007 and P = 0.005). Alkylating agents and radiotherapy administered prior to transplantation and age did not seem to influence the presence of permanent cytopenias. The incidence did not vary significantly according to the stem cell source (bone marrow or peripheral blood). The number of CFU-GM and CD34+ cells infused was the most important factor for maintenance of adequate hematopoiesis.