Follow-up of healthy donors receiving granulocyte colony-stimulating factor for peripheral blood progenitor cell mobilization and collection. Results of the Spanish Donor Registry.

Background: Information about the long-term follow-up and safety of granulocyte colony-stimulating factor administration to healthy donors is limited. The aims of this study were to analyze the side effects of granulocyte colony-stimulating factor administration in donors included in a Spanish Registry of hematopoietic stem cell donors and to determine the long-term outcome of these donors.

Design And Methods: The Spanish National Donor Registry was developed to record the short- and long-term results of granulocyte colony-stimulating factor administration to mobilize peripheral blood progenitor cells in normal donors. To date, 1436 donors (771 males, 665 females) with a median age of 37 years (range, 1 to 74 years) have been registered. Granulocyte colony-stimulating factor was the only cytokine administered. A baseline investigation was performed in every donor before granulocyte colony-stimulating factor administration and follow-up investigations (controls) were planned at 4 weeks and annually thereafter for up to 5 years after the mobilization.

Results: At least one of the scheduled controls was performed in 736 donors, while 320 donors have been followed for 2 years or more. The peripheral white blood cell count decreased significantly from 6.8 x 10(9)/L at baseline to 5.9 x 10(9)/L at 4 weeks after leukapheresis (p<0.0001) and remained at values lower than those observed premobilization until 2 years after mobilization. In contrast, hemoglobin concentration and platelet count returned to normal values within 1 year after mobilization. Bone pain (90%) and headache (33%) were the most frequently reported granulocyte colony-stimulating factor-related side effects. Five patients (0.68%) were diagnosed as having solid tumors (lung cancer in two patients and thyroid carcinoma, choroid melanoma, and colon carcinoma in one patient each) between 10 and 64 months after administration of granulocyte colony-stimulating factor. No hematologic malignancies have been reported.

Conclusions: The clinical side effects of granulocyte colony-stimulating factor administration in healthy donors are generally mild. Changes in blood counts were minimal and mainly affected white blood cell counts, which returned to normal values within 2 years after granulocyte-colony stimulating factor administration. No patient developed a hematologic malignancy. A larger number of donors and longer follow-up are needed to determine the safety of granulocyte colony-stimulating factor administration definitively.