Long-Term Follow up of Healthy Donors Receiving G-CSF for Peripheral Blood Progenitor Cell Mobilization and Collection.

Background: Peripheral blood progenitor cells (PBPC) are a common source of hematopoietic stem cells for allogeneic transplantation. Information about long-term follow up and donor safety is, however, very limited.

Study design and methods: A National Donor Registry was developed in Spain in 1999 directed to know the short and long-term effects of G-CSF administration on healthy donors for PBPC mobilization. A total of 1287 donors (590 M/697 F; median age, 37 years, range 1–74) have been registered. G-CSF, either filgrastim (1041 cases) or lenograstim (291 cases) was the only cytokine administered. Median (range) dose of G-CSF was 10 (5–23) mcg/kg/day, for a median of 4 days. Sixty-five donors underwent more than one mobilization procedure. A baseline investigation was performed in every donor 2–4 weeks before G-CSF administration and follow up investigations were planned at 4 weeks, and thereafter annually up to 5 years after mobilization.

Results: In 588 donors at least one of the scheduled controls have been done, and 187 donors have been followed for more than two years. The peripheral white blood cell (WBC) count decreased significantly 4 weeks after leukaphereses, from 6.4 x10⁹/L at baseline to 5.9 x10⁹/L (P <0.0001). WBC were normal 1 year after mobilization and maintained similar values during the remaining follow up. Four weeks after PBPC collection, hemoglbin presented lower values than that observed before mobilization (14.3 vs. 13.8 g/dL; P <0.0001). As with WBC, hemoglobin one year after G-CSF administration was similar to baseline values. Regarding short-tem complications, 740 donors complained of some side-effect during G-CSF administration, being bone pain (89%) and headache (31%) the symptoms most commonly observed. One donor presented with a splenic rupture 12 hours after last leukapheresis that required splenectomy. During follow up, three donors (0.23%) have developed neoplastic diseases (colon carcinoma, lung cancer, and melanoma in choroidal region of the left eye) at 3, 5 and 6 years following G-CSF administration. Finally, one donor developed thrombocytopenia 1 month after mobilization. The bone marrow study excluded myelodysplastic syndrome and was diagnosed as having idiopatic thrombocytopenic purpura.

Conclusion: Our analysis represents the larger study of follow up of donors receiving G-CSF for PBPC mobilization and reveals that clinically side-effects of G-CSF administration in healthy donors are generally mild. Changes in blood counts were minimal and restored normal values within one year after G-CSF. With longer follow up, isolated neoplastic diseases have been detected, although no hematologic malignancy has been reported and no other unusual diseases have been observed. Greater number of donors and longer follow-up are, however, needed to definitively guarantee the safety of the procedure.