Serum Ferritin Levels Prior to Mobilization and Collection May Not Influence Stem Cell Yield

Background

Bone marrow transplantation requires collecting an adequate number of hematopoietic stem cells to ensure successful engraftment. Ferritin, a key iron storage protein, is routinely evaluated during pre-collection visits, as low levels often indicate iron deficiency, which may impact stem cell capture. In some practices stem cell collection may be delayed to correct ferritin deficiencies. However, the level at which such intervention is necessary is not well known. Furthermore, delaying stem cell collection can have many implications including risk of infection, psychological stress, increased cost, and logistical challenges. The present study seeks to describe the impact of relative ferritin status on stem cell collection prior to bone marrow transplantation.

Methods

In a retrospective chart review of 183 patients at our center, 155 patients undergoing autologous transplantation from 2016-2018 and 2022-2023 as well as 28 allogeneic transplant donors between 2016-2023 were included. Patients and donors (n=13) who were missing ferritin levels at pre-collection or stem cell capture data in the electronic medical record (EMR) were excluded from analysis. Patient demographics, ferritin level (FL) at the pre-collection evaluation visit, total stem cell capture (TC), stem cell capture on the first day of apheresis (FC), and the total number of days of apheresis (DOA) were retrieved from the EMR. We classified patients into three groups: FL-1 had a ferritin level less than 50 ng/ml, FL-2 had a level between 50.1-500 ng/ml, and FL-3 had a level greater than 500 ng/ml. The Allogeneic donor cohort had an insufficient number of patients with high ferritin for analysis. A general linear model was used to assess the relationship between TC, DOA, and FC compared to ferritin status while covarying for age, sex, and race.

Results

In the allogeneic donor population, DOA (p=0.666), TC (p=0.938), and FC (p=0.961) were not statistically significant between groups FL-1 and FL-2. Additionally, there were no statistically significant differences in DOA, TC, or FC when our low ferritin cut off includes levels up to 100 ng/ml. In the autologous transplant population, there were no statistically significant differences between groups FL-1 and FL-2 regarding DOA (p=0.254) or TC (p=0.139), albeit FL-2 had a marginally higher FC (p=0.024). FL-2 had marginally lower FC (p=0.003) and TC (p=0.003) than FL-3, but DOA was not significantly different (p=0.783). Those observations held true when our low ferritin cut off includes levels up to 100 ng/ml.

Conclusion

Our results suggest that ferritin levels below 50 or 100 ng/ml may not warrant delaying stem cell collection in related allogeneic donors. For autologous transplants, the groups with normal ferritin levels showed slightly better first-day capture; however, the difference was not substantial enough to justify delaying collection because of its lack of effect on days of apheresis and total capture. On the other hand, high ferritin slightly increased the total and first day capture, so high levels should not delay collection either. This retrospective analysis adds valuable data to the relatively under-researched area of ferritin status in stem cell mobilization and offers insight to physicians considering collection delays.