Absolute Neutrophil Counts Before HSCT Have Prognostic Value in Aplastic Anemia

Before they perform allogeneic hematopoietic stem cell transplantation (HSCT) when managing aplastic anemia (AA), clinicians should measure patients’ absolute neutrophil counts (ANCs) as a prognostic factor, according to a retrospective study of the relationship between ANC before allogeneic HSCT and outcomes in adults with AA.

The study group was comprised of 883 patients with AA who underwent allogeneic HSCT as their first transplantation between 2008 and 2020. They were then sorted into three groups based on their pretransplant ANCs, where 116 patients had ANC of 0/µL, 210 with ANCs of 1 to 199/µL, and 557 whose ANCs were 200/µL or higher.

Multivariate analysis in the study found a significant association between pretransplant ANC and a five-year overall survival (OS), this outcome being better in patients with higher pretransplant values. Those with values of 0/µL had a 64.4% five-year OS, those with values of 1 to 199/µL a 71.7% five-year OS, and those with values of 200/µL or higher had an 80.3% five-year OS. However, patients with a pretransplant ANC of 0/µL did have a marked OS benefit if they were younger, had a shorter duration from diagnosis to transplantation, a hematopoietic cell transplantation comorbidity index (HCT-CI) of 0, or bone marrow from a related donor as their stem cell source.

The researchers found patients with pretransplant ANCs of less than 200 to be older, have a shorter duration from diagnosis to transplantation, and higher HCT-CIs. They further noted that “[t]he cumulative incidence of bacterial infection, invasive fungal disease, and early death before engraftment were significantly higher in the low ANC groups.”

Other patient factors the analysis found to be significantly associated with five-year OS were age, previous antithymocyte globulin (ATG) treatment, and stem cell source. Among patients with pretransplant ANCs of less than 200, use of prior ATG treatments or ATG-based conditioning was infrequent but there was frequent use of peripheral blood stem cells from related donor and cord blood.

Reference

Nakamura Y, Zaimoku Y, Yamaguchi H, et al. Significance of absolute neutrophil count before allogeneic hematopoietic stem cell transplantation in adult patients with aplastic anemia. Ann Hematol. 2024. doi:10.1007/s00277-024-05800-1