Granulocyte Concentrates From a Single High-Yield Apheresis Can Be Split to Support Multiple Patients
Authors: Aung Fleur M. , Reddy Virgil M , Lichtiger Benjamin 
Published: October 2019

Abstract
Abstract 4373

Introduction
Granulocyte transfusion has evolved as an accepted therapeutic approach for immunocompromised, severely neutropenic, myelosuppressed leukemic patients or hematopoietic stem cell transplant (HSCT) with life-threatening infections despite appropriate antibiotic therapy. The combination of Growth-stimulating colony factor (G-CSF) and dexamethasone to stimulate granulopoiesis in normal donors has facilitated the collection of larger cell doses of granulocyte concentrations (GCs) via automated apheresis and the use of Hespan-sodium citrate/anticoagulant solution has enhanced the harvesting of GCs yield as high as 800–900 mL ready for infusion.
To our knowledge GCs harvested via collection from G-CSF/dexamethasone stimulated donors have been transfused only to single patients. Here we describe the process in splitting the GCs for transfusion to 2 or more patients when the designated patient has volume restrictions. This practice is similar to the double and triple splitting of apheresis platelet concentrates a practice routinely performed at Blood Donor Centers in the USA.

METHODS
This retrospective study was approved by the Institutional Review Board, written informed consent was obtained and all split GCs between 01/2010 and 12/2011 were reviewed.
Donors were recruited from relatives/friends of patients or were community volunteers who underwent screening for infectious diseases according to current regulatory requirements for allogeneic donors. Other eligibility criteria included a biochemical profile (alanine aminotransferase, alkaline phosphatase, total bilirubin, hemoglobin S) and a urine pregnancy test for all female donors. Potential hematopoietic stem cell (HSC) donors were deferred.
All eligible donors first underwent a platelet apheresis donation to evaluate their vascular access and to determine whether they could withstand a 2-hour collection via two-arm continuous-flow apheresis. GCs were collected via donor stimulation with a single subcutaneous injection of G-CSF (600 μg; Amgen) and in first-time donors an oral dose of dexamethasone (8 mg) 12 hours prior to the granulocyte collection was also given.GCs were harvested via Hespan-sodium citrate solution (6% hetastarch in 0.9% sodium chloride; Braun, Inc. containing 30 cc of triCitrasol anticoagulant sodium citrate concentrate (46.7% trisodium citrate; Citra Labs) 12 hours after stimulation. Approximately 1.5 × whole blood volumes from each donor was processed via a two-arm peripheral venous access procedure with a COBE Spectra continuous-flow cell separator (CaridianBCT) and COBE Spectra WBC tubing set (CaridianBCT).
The decision to split each GC unit was made after determination of the total absolute WBC count upon completion of the granulocyte apheresis. Each GC unit was sterilely connected to a second 600 mL sterile bag via a Terumo sterile tubing welder (TSCD SC-201A, Terumo Medical Corporation) outfitted with TSCD wafers (Terumo Medical Corporation) and then half of the volume was expressed into the second 600-mL bag (Fenwal, Inc.) with the first half remaining in the original bag. The GC units with ABO incompatible red cells with the recipient were filtered via gravity drainage. All GCs were crossmatched, labeled, irradiated (2500 cGy, Cesium-I37 irradiator, IS Bio International) and released for transfusion.

RESULTS
GCs were collected from 93 donors [67 Males: 26 Females; median age 40 (19–73 years); total volume median 718 mL (range 538–860), original wbc yield median 9.7 10∧10e (range 5.1–17.2) and split GC yield, median 4.48 10∧10e (range 2.70–7.72)]. Split GCs were transfused to 51 patients [31 Males: 20 Females; median age 58 (range 19–83 years); diagnosis-AML/MDS 32 (63%), ALL/CLL 12 (24%), CML 5 (10%), others 2 (3%)]. The patients received median 3.5 split GCs (range 1–18) with a WBC increment median 0.02 × 10∧3/μL (range 0.00 to 8.3). Donors with post stimulation WBC counts 30 K/UL or greater were able to provide GCs volumes sufficient for splitting.

DISCUSSION
The practice of splitting GCs based on yield and WBC count is a safe process and the product transfused without any patient adverse effects. This approach has allowed maximum use of all collected GCs and has provided GCs to patients who otherwise would not have received GCs. The transfusion of GCs is a complex lengthy process which must be well organized by the blood bank/Blood Donor Center/Apheresis Unit and the oncology team.

Disclosures:
No relevant conflicts of interest to declare.