G-CSF-induced spleen size changes in peripheral blood progenitor cell donors

BACKGROUND: PBPC donors given G-CSF experience splenic enlargement and, rarely, spontaneous rupture of the spleen. This study evaluated the incidence and time course of splenic enlargement in PBPC concentrate donors and assessed factors affecting size changes. STUDY DESIGN AND METHODS: Twenty healthy adults were given G-CSF (10 mug/kg/day) for 5 days and a PBPC concentrate was collected by apheresis. Ultrasound was used to assess craniocaudal spleen length before giving G-CSF, on the day of apheresis and 3 or 4 days after apheresis. The effects of donor age, gender, race, and changes in blood chemistries, blood counts, and CD34+ cell counts on spleen length change were assessed. RESULTS: Spleen length increased in 19 of 20 donors. Mean length changed from 10.9 +/- 2.0 cm before G-CSF to 12.3 +/- 2.1 cm on the day of apheresis (p < 0.001). The mean increase in length was 1.5 +/- 0.9 cm or 13.8 +/- 9.1 percent. Spleen length increased 20 percent or more in six subjects. The spleen length fell to 11.3 +/- 1.8 cm (p < 0.001) 3 or 4 days after apheresis, but it remained greater than baseline levels (p = 0.03). Spleen length change was not affected by donor gender, race, or age. There was no relationship between changes in spleen length and 1) baseline and apheresis-day blood counts and chemistries, or 2) changes in blood counts and chemistries. CONCLUSIONS: Spleen size increases in almost all PBPC donors. Enlargement is transient but may be marked in some donors and may place them at risk for splenic rupture.