Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is vital in the treatment of high-risk hematologic cancers. Due to the immune system reconstitution process in the post-transplant period, infections are a leading cause of mortality and morbidity. Therefore, we aimed to investigate the efficacy of granulocyte transfusion (GT) therapy in patients who developed febrile neutropenia during allo-HSCT

This retrospective study included 22 patients who underwent allo-HSCT at the Erciyes University Bone Marrow Transplantation Unit between January 2016 and January 2024 and developed febrile neutropenia. Patient characteristics were recorded. GT was administered to patients with an absolute neutrophil count (ANC) <0.5 × 103/µL for at least three days, evidence of bacterial and/or fungal infection, and no response to appropriate antimicrobials for at least 48 hours.

The median age was 42 years (min-max, 19-66 years). The majority of patients were diagnosed with acute myeloid leukemia (AML) (50%)(11/22). The median CRP value was 168.5 mg/dl (min-max, 31.1-360 mg/dl). In 40.9 % of patients who received GT, their primary disease was in complete remission, while in 59.1 %, their primary disease was relapse. The infection etiologies included pneumonia (n=5), sepsis (n=2), pneumonia and sepsis (n=11), pneumonia + sepsis + catheter-associated infection (n=4), catheter-associated infection + mucositis (n=1), and abscess (n=1). Each patient received a median of 3 GTs (min-max, 1-6). The median transfused granulocyte dose per transfusion was 3.5 × 1010 (min-max, 0.8-9.4 × 1010). The median dose transfused, calculated based on the recipient&apos;s body weight, was 5.1 × 108/kg (min-max, 0.8-17 × 108/kg). On average, the median number of granulocytes transfused per patient was 5.3 × 108/kg (min-max, 1.9-11.3 × 108/kg). The median time from HSCT to the first GT was 192 days (min-max, 50-795 days). The median duration of fever before GT was three days (min-max, 2-6 days), and the time until the fever defervescence was 2 days (min-max, 1-5 days). The median duration of neutropenia before GT is 25 days (min-max, 8-30 days).

After GTX treatment, A favorable response was observed in 16 of 24 infection episodes (66.7%) regarding the resolution of infections. In 4 of the 8 infection episodes where the infection did not resolve, the patient also had a relapse of the disease. In 5 of 12 infection episodes that required intensive care, the need for intensive care was eliminated after GT. A statistically significant difference was found between the time of GT initiation and the ANC, TLC, and PLT counts on the fourth-day post-GT (p =0.001, p=0.001, p=0.003, separately for ANC, TLC, and PLT). The median follow-up in our cohort of patients is 600 days. The 30-day and 100-day OS were 67.7% and 50%, respectively. A mortality rate by day-28 was 3.8% and mortality rate by 100 was 19.2%. Acute, chronic GVHD, and CMV reactivation were not observed.

GT therapy may be effective in many critically ill patients with prolonged and profound neutropenia. It may be more beneficial in select patients, as it provides more time to overcome infections resistant to broad-spectrum antibiotics. Larger randomized trials are needed to confirm the effectiveness of GT in such patients.