Outcomes of Neutropenic Patients with Severe Infections Treated with Granulocyte Transfusions: The USC Experience

Introduction Despite major progress in antimicrobial and supportive measures, prolonged disease-associated or treatment-related neutropenia is a leading cause of mortality and morbidity in patients after stem cell transplantation or with hematologic malignancies or bone marrow failure. Intuitively, a granulocyte transfusion should be as effective as a platelet or red cell transfusion. However, efforts to prove the effectiveness of granulocyte transfusions have been disappointing. Due to the lack of adequately powered randomized controlled trials, it is difficult to prove or refute the effectiveness of granulocyte transfusions in neutropenic patients. Therefore, they are likely underutilized or used inappropriately as a last resort. To better understand the utility of this treatment modality, we reviewed the outcomes of patients with hematologic conditions who received granulocyte transfusions at our institutions during the treatment of neutropenic sepsis. Methods We identified 20 patients with severe neutropenia who received a granulocyte transfusion at Norris Comprehensive Cancer Center or Keck Hospital of USC in Los Angeles, California between 2014-2022. 19 of these patients received a total of 166 transfusions for treatment of suspected or confirmed sepsis. One patient received a prophylactic dose of granulocytes and was excluded from this study. Granulocyte donors were mobilized with 480 mcg G-CSF and a minimum yield of 4 x 10 10 granulocytes was obtained. The primary outcome was attainment of “clinical improvement” defined as either safe discharge from the hospital or resolution of symptoms. Descriptive statistics were presented as counts and percentages for categorical variables and as means with standard deviations for continuous variables. Categorical variables were accessed by Chi-square test or Fischer's exact test when appropriate. For continuous variables, Kruskal-Wallis test was used. P-values of ±0.05 were regarded as significant and all tests were two-tailed and analyzed with SAS (9.4). Results In our cohort, 47.4% were male, ages ranged from 20-70, and 57.9% identified as Hispanic. The most common diagnosis was acute myeloid leukemia (AML) (n=13), followed by aplastic anemia (n=3), myelodysplastic syndrome (MDS) (n=2), and acute lymphoblastic leukemia (ALL) (n=1). The most common infections were fungal or presumed fungal (n=9) and mixed fungal and bacterial (n=7). Prior to the start of granulocyte transfusions, 63.2% of patients were neutro