Granulocytapheresis with modified fluid gelatin versus high-molecular-weight hydroxyethyl starch: a matched-pair analysis

Granulocyte concentrate splitting does not affect phenotype and function

BACKGROUND

More granulocyte concentrates (GCs) could be produced for more patients from the same donor if apheresis bags were split and stored for longer periods of time. Hence, we tested the hypothesis that splitting and extension of storage of GCs do not impair granulocyte function or viability.

STUDY DESIGN AND METHODS

Granulocyte apheresis concentrates were produced using modified fluid gelatin as a separation enhancer, split into two portions, and stored for 24 and 48 h. Granulocyte function, represented by cell migration, reactive oxygen species (ROS) production, and neutrophil extracellular trap formation (NETosis), was measured by live-cell imaging. ROS production, adhesive surface protein expression, and viability were measured by flow cytometry.

RESULTS

Splitting had no effect on any of the tested parameters. After 24 h of storage, live-cell imaging showed no significant difference in migration, time to maximum ROS production, time to half-maximum NETosis, viability, or CD11b expression, but ROS production induced by phorbol 12-myristate 13-acetate (PMA) decreased from an initial median fluorescence intensity of 1775-590 artificial units. After 48 h, PMA-induced ROS production, viability, and migration declined, as reflected by decreases in median total distance (119 vs. 63.5 μm) and median Euclidean distance (30.75 vs. 14.3 μm).

CONCLUSION

Splitting GC products has no effect on granulocyte viability or function, but extended storage >24 h does compromise granulocyte function. The findings confirm that GCs should be transfused within 24 h of collection. Longer storage cannot be recommended.

Granulocyte transfusions made with modified fluid gelatin in pediatric and adolescent patients with prolonged neutropenia

BACKGROUND

Granulocyte transfusions (GT) are used to treat progressive systemic or local infections in prolonged neutropenic patients with antibiotic or antifungal resistance. Granulocytes are most commonly collected from whole blood by apheresis using hydroxyethyl starch (HES) as the red blood cell (RBC) sedimentation agent. This is the first study on the safety and efficacy of transfusing granulocytes collected with modified fluid gelatin (MFG) instead of HES to pediatric patients.

METHODS

Clinical data from 46 pediatric and adolescent patients receiving at least one MFG-based granulocyte transfusion and in total 295 granulocyte concentrates from July 2013 to August 2019 at our local university medical center were evaluated retrospectively.

RESULTS

Forty-one patients (89%) survived at least 21 days after their last granulocyte transfusion. These survivors had lower CRP values and higher leukocyte counts after GT than non-survivors (mean delta of -5.34 mg/dl vs. -11.99 mg/dl and + 0.62 × 10³ /μl vs. +0.18 × 10³ /μl of all GT, respectively). The neutrophil corrected count increment (CCI) was 68.72 mm² /ml in survivors versus 28.00 mm² /ml in non-survivors. There were no major or severe adverse events.

CONCLUSION

This study suggests that modified fluid gelatin is a safe and effective alternative to hydroxyethyl starch for the collection of granulocytes for transfusion to prolonged neutropenic patients with progressive systemic or local infections refractory to antibiotic or antifungal therapy.

Prolonged storage of purified granulocyte concentrates: Introduction of a new purification method

BACKGROUND

Use of donor granulocyte concentrate (GC) has been limited due to its short storage time of 6-24 h, which is partially due to residual red blood cells (RBCs) and platelets and the resulting lactate production leading to an acidotic milieu. To increase this storage time, we developed a closed system procedure compatible with standard blood bank technologies to remove RBC and platelets and to enrich the GC.

METHODS

Standard GCs (sGCs) were sedimented, washed twice with 0.9% sodium chloride (NaCl), and resuspended in blood group-identical fresh frozen plasma. The resulting purified GCs (pGCs) were then stored in platelet bags at a cell concentration of about 5 × 10⁷  ± 1.8 × 10⁷ leukocytes/ml without agitation at room temperature for up to 72 h. Cell count and viability, pH, blood gases, phagocytosis, and oxidative burst were monitored daily.

RESULTS

A significant reduction in RBC (98%) through sedimentation, and platelets (96%) by washing, purified the white blood cell (WBC) population and enriched the granulocytes to 96% of the WBC in the pGC. After 72 h of storage, over 90% of the initial WBC count of pGC remained, was viable (≥97%), and the granulocytes exhibited a high phagocytosis and oxidative burst functionality, comparable to sGC after 24 h.

CONCLUSION

Purification extends the maximum storage period of GC from 24 to 72 h and may therefore improve the availability of GC and its clinical use.

Total platelet donation count and donation frequency are determinants of plateletpheresis-associated lymphopenia

BACKGROUND

Plateletpheresis using a leukocyte reduction system (LRS) traps donor WBCs in the LRS chamber, which may lead to lymphopenia, especially in frequent plateletpheresis donors. It seems plausible that this might cause adverse effects. However, current knowledge about potential confounders and donor health impacts is incomplete.

DONORS AND METHODS

Recent platelet donors and donations collected at University Hospital Regensburg from 2016 to 2019 using the Terumo BCT Trima Accel LRS system were retrospectively analyzed and compared with historical platelet donors and donations collected mainly with Fresenius Kabi Amicus non-LRS system from 2010 to 2013. Additionally, recent donors were prospectively surveyed using a health-related topics questionnaire.

RESULTS

Analysis of 819 recent donors with 11,254 blood counts and 1464 questionnaires and 1011 historical donors with 12,848 blood counts revealed that increased annual platelet donation frequencies were associated with decreased lymphocyte counts in both groups. Median lymphocyte counts in recent donors with no versus ≥24 previous annual donations declined from 2.0 to 1.2 × 10³ /μL (p < 2.2 × 10^-16 ), and those in historical donors with no versus ≥24 previous annual donations decreased from 2.0 to 1.5 × 10³ /μL (p = 6 × 10^-4 ), respectively. The questionnaire results showed that donation frequency and lymphopenia were not associated with upper respiratory tract infection (URTI) incidence or duration, but platelet donors who concomitantly donated granulocytes had significantly shorter URTI durations than those who did not (p = .008).

CONCLUSION

This study confirmed that plateletpheresis-associated lymphopenia occurs in LRS and to a lesser degree in non-LRS platelet donors, but revealed no evidence of a negative impact on donor health.

Granulocyte collection by polymorphonuclear cell-targeting apheresis with medium-molecular-weight hydroxyethyl starch

Granulocyte transfusion (GTX) is a therapeutic option for patients with prolonged neutropenia suffering from severe infections. Efficient granulocyte collection by apheresis from donors requires clear separation of granulocytes from red blood cells (RBCs), and infusion of high-molecular-weight (MW) hydroxyethyl starch (HES) facilitates RBC sedimentation. Recent research has shown that apheresis with medium-MW HES may prevent adverse effects of high-MW HES on donors, but the rationale for collection with medium-MW HES has yet to be evaluated. To validate the use of medium-MW HES, we first performed experiments with whole blood samples to determine how efficiently high-, medium- and low-MW HES separated granulocytes from RBCs, and found that medium-MW HES was just as efficient as high-MW HES. We also reviewed clinical data of granulocyte apheresis at our institution to evaluate granulocyte yields. Retrospective analysis of granulocyte collection revealed that apheresis with medium-MW HES yielded sufficient granulocytes for GTX and that donor anemia reduced collection efficiency. These results collectively may help us to establish a safer method for apheresis targeting polymorphonuclear granulocytes as an alternative to high-MW HES.

Impact of the use of hydroxyethyl starch in granulocyte apheresis using Spectra Optia

OBJECTIVES

To determine the impact of the use of hydroxyethyl starch (HES) in granulocyte apheresis using Spectra Optia.

BACKGROUND

Granulocyte transfusion (GT) is a therapeutic option for neutropenic patients with severe bacterial or fungal infections. Recent studies in emergency medicine have shown the potential risk of using HES, which is routinely used in granulocyte apheresis to increase yield by sedimenting red blood cells. We hypothesized that the use of a newer device (Spectra Optia) would spare the need for HES.

METHODS

We retrospectively compared granulocyte apheresis with HES (HES group, n = 89) and without HES (non-HES group, n = 36) using Spectra Optia.

RESULTS

The granulocyte yield was significantly higher in the HES group (7.3 × 10¹⁰ vs. 2.0 × 10, p < 0.01) and was attributed to the difference in collection efficiency (36% vs. 7.7%, p < 0.01). The absolute neutrophil count on the following morning of GT was significantly higher in the HES group than in the non-HES group (2460/μl vs. 505/μl, p < 0.01). There were no significant differences in the occurrence of adverse events between the HES and non-HES groups. The renal function was unchanged in both groups after apheresis.

CONCLUSIONS

We demonstrated that the advantage of using HES remained unchanged in granulocyte apheresis using Spectra Optia.

Granulozytentransfusion: Update 2020

Die therapeutische Anwendung von Granulozytenkonzentraten erfolgt im klinischen Alltag im Gegensatz zu der anderer Blutprodukte nur selten und unregelmäßig. Der zurückhaltende Einsatz beruht unter anderem auf dem Fehlen einer breiten Evidenz, logistischen und wirtschaftlichen Problemen und dem Vorhandensein anderer potenter Therapieoptionen neutropener Infektionen. Dennoch gab es in den letzten Jahren neue wissenschaftliche Erkenntnisse nicht nur zu Physiologie und Pathophysiologie der Granulozyten, wie neu charakterisierten zellulären Verteidigungsstrategien oder deren Mitwirkung bei thrombotischen oder malignen Ereignissen, sondern auch zu deren therapeutischem Effekt. Dieser wird von einer Vielzahl an Parametern, wie der Art der Infektion, dem Transfusionszeitpunkt und der Dosis, beeinflusst. Das macht die Indikationsstellung zu einer komplexen Einzelfallentscheidung und es gilt, die heterogene Datenlage systematisch zusammenzufassen. Außerdem wurden die etablierten Indikationen neutropener bzw. neutropathischer Infektionen um experimentelle, mögliche neue Anwendungsgebiete wie die Mukositis oder Leukämiebehandlung erweitert. Die erfolgreiche Anwendung setzt eine geeignete, moderne Herstellungsweise voraus. Neben der Apherese, bei der eine relativ hohe Spenderbelastung unter anderem durch Nebenwirkungen von Mobilisationsregime und Sedimentationsbeschleunigern berücksichtigt werden muss, existieren weitere Verfahren wie die Gewinnung von Granulozyten aus Buffy Coats von Vollblutspenden. Diese versprechen eine Reduktion logistischer Probleme und unerwünschter Wirkungen auf den Spender. Unerwünschte Wirkungen bei Empfängern von Granulozytentransfusionen sollten nach wie vor berücksichtigt und gegen einen erhofften therapeutischen Effekt abgewogen werden.

Impact of hydroxyethyl starch and modified fluid gelatin on granulocyte phenotype and function

BACKGROUND

Patients with neutropenia or granulocyte dysfunction may require granulocyte transfusions for adequate immune restoration. High-molecular-weight hydroxyethyl starch (HES) is the most commonly used sedimentation agent to enhance granulocyte collection efficiency. However, authorities recently restricted the use of HES due to its unfavorable risk-benefit profile. As modified fluid gelatin (MFG) is already used as an alternative sedimentation agent, we tested the hypothesis that MFG is not inferior to HES in terms of the functionality and viability of granulocytes.

STUDY DESIGN AND METHODS

Granulocytes from ten healthy donors were isolated, aliquoted and incubated in parallel for 2 hours with either 0% (control), 7.5%, 15%, or 30% MFG (Gelafundin) or HES (Hespan), respectively, and granulocyte migration, chemotaxis, reactive oxygen species (ROS) production, neutrophil extracellular trap formation (NETosis), antigen expression, and viability were subsequently investigated in vitro.

RESULTS

Relative to the controls, all three concentrations of HES compared to only 15% and 30% MFG lowered migration distances, and the 15% and 30% concentrations of both sedimentation agents reduced track straightness. HES resulted in lower CD11b expression and higher CD62L expression compared to MFG and the controls, whereas the differences for CD66b did not reach statistical significance. No significant differences in the timing of ROS production or NETosis, or in neutrophil viability or respiratory burst were observed.

CONCLUSION

These results indicate that MFG is not inferior to HES in terms of granulocyte function in vitro when used at equal concentrations, and that potential impairment of granulocyte function can occur with HES.

Matched Molecular Pair Analysis on Large Melting Point Datasets: A Big Data Perspective

A matched molecular pair (MMP) analysis was used to examine the change in melting point (MP) between pairs of similar molecules in a set of ∼275k compounds. We found many cases in which the change in MP (ΔMP) of compounds correlates with changes in functional groups. In line with the results of a previous study, correlations between ΔMP and simple molecular descriptors, such as the number of hydrogen bond donors, were identified. In using a larger dataset, covering a wider chemical space and range of melting points, we observed that this method remains stable and scales well with larger datasets. This MMP-based method could find use as a simple privacy-preserving technique to analyze large proprietary databases and share findings between participating research groups.