Purified granulocytes in extracorporeal cell therapy: A multifaceted approach to combat sepsis-induced immunoparalysis.

BACKGROUND: Immune cell dysfunction plays a central role in sepsis-induced immunoparalysis. Targeted treatment using healthy donor immune cell transfusions, particularly granulocyte concentrates (GC) potentially induces tissue damage. Initial trials using GC in an extracorporeal immune cell perfusion system provided evidence for beneficial effects with fewer side effects, by separating patient and donor immune cell compartments. A multicenter clinical trial is exploring feasibility and effects of a 6-h treatment (NCT06143137). This ex vivo study examines technical feasibility and cellular effects of an extended treatment interval up to 24 h. METHODS: Standard GC were purified to increase the potential storage time and subsequently implemented in the extracorporeal immune cell perfusion system. Parameters assessed included cell viability, phagocytosis activity, oxidative burst, cytokine release, and metabolic parameters of purified. GC during an extended circulation time of up to 24 h. RESULTS: After storage of 72 h granulocytes were viable throughout the study period and exhibited preserved functionality and metabolic activity. The findings highlight a time-dependent nature of cytokine release by neutrophils in the extracorporeal circuit, as cytokine secretion patterns showed IL-8 peaking within 6 h, while MCP-1, IL-6, IL-1ß, and TNF-α increased after 24 h of circulation. CONCLUSION: Purified GC remain functional after 72 h of storage and additional 24 h in the circulating treatment model. Cytokine secretion patterns revealed a significant increase, especially between 10 and 24 h of treatment. Extending treatment time holds promise for enhancing immune response against sepsis-induced immunoparalysis. These findings provide valuable insights for optimizing immune-targeted therapeutic interventions.

Extracorporeal therapy of sepsis by purified granulocyte concentrates: ex vivo circulation model.

BACKGROUND: Immune cell dysfunction is a central part of immune paralysis in sepsis. Granulocyte concentrate (GC) transfusions can induce tissue damage via local effects of neutrophils. The hypothesis of an extracorporeal plasma treatment with granulocytes is to show beneficial effects with fewer side effects. Clinical trials with standard GC have supported this approach. This ex vivo study investigated the functional properties of purified granulocyte preparations during the extracorporeal plasma treatment. METHODS: Purified GC were stored for up to 3 days and compared with standard GC in an immune cell perfusion therapy model. The therapy consists of a plasma separation device and an extracorporeal circuit. Plasma is perfused through the tubing system with donor immune cells of the GC, and only the treated plasma is filtered for re-transfusion. The donor immune cells are retained in the extracorporeal system and discarded after treatment. Efficacy of granulocytes regarding phagocytosis, oxidative burst as well as cell viability and metabolic parameters were assessed. RESULTS: In pGC, the metabolic surrogate parameters of cell functionality showed comparable courses even after a storage period of 72 h. In particular, glucose and oxygen consumption were lower after extended storage. The course of lactate dehydrogenase concentration yields no indication of cell impairment in the extracorporeal circulation. The cells were viable throughout the entire study period and exhibited preserved phagocytosis and oxidative burst functionality. CONCLUSION: The granulocytes demonstrated full functionality in the 6 h extracorporeal circuits after 3 days storage and in septic shock plasma. This is demonstrating the functionality of the system and encourages further clinical studies.

Therapeutic granulocyte infusion for patients with severe neutropaenia and neutrophilic dysfunction: New Zealand experience.

BACKGROUND AND OBJECTIVES: Studies have shown granulocyte transfusions (GTXs) may be beneficial in neutropaenic patients with severe systemic infections. New Zealand Blood Service has a policy for provision of granulocytes to New Zealand's District Health Boards. We set out to explore utilization of therapeutic granulocyte infusions in New Zealand. MATERIALS AND METHODS: Patients who received GTXs in the 16-year period between 2000 and 2016 were identified by the New Zealand electronic blood management system, eProgesa. Information pertaining to recipient demographics, disease-related factors, methods of granulocyte collection and clinical outcomes was obtained by the review of electronic transfusion and clinical records. RESULTS: Forty-five septic patients received granulocyte support for a total of 263 days. The median age of the recipients was 16 (range 0-74) years. Seventy-nine percent of the recipients had an underlying haematological malignancy with 50% having acute leukaemia. The median neutrophil count on the last day of GTX was 0.02 × 109 /L (range 0-16.32). Sixty-three percent (27/43 patients with available data) had persisting severe neutropaenia when the GTXs were stopped. The median duration of support was 3 (range 1-32) days. Forty-six percent of granulocyte collections were performed via apheresis. Of the 44 patients, for whom survival outcome was available, 18 (41%) survived the acute illness. CONCLUSION: GTXs were infrequently used, most commonly in the setting of an underlying haematological malignancy. This may be explained by the current weak evidence base supporting this therapeutic modality. Procuring a sufficiently large dose of granulocytes for infusion remains an issue for adult recipients.

Granulocyte concentrates prepared from residual leukocyte units produced by the Reveos automated blood processing system.

BACKGROUND: Granulocyte concentrates are mainly derived by apheresis technique from donors stimulated with granulocyte colony-stimulating factor and steroids. The automated blood processing system Reveos, which is now increasingly used across the world, separates whole blood into four components, including a residual leukocyte unit containing granulocytes. The aim of this study was to produce an alternative granulocyte concentrate from leukocyte units produced by the Reveos system, and to assess the function of the granulocytes. METHODS: The number of granulocytes was measured in residual leukocyte units, derived from whole blood donations, with different volumes ranging from 10 to 40 ml. After deciding the optimal volume of the leukocyte unit (30 ml), ten ABO-matched units were pooled to form a granulocyte concentrate. The function of the granulocytes from residual leukocyte units was assessed by analyzing surface markers, phagocytosis of yeast, and production of reactive oxygen species. RESULTS: Residual leukocyte units with a volume of 30 ml contained a median number of 0,7 × 109 granulocytes, and granulocyte concentrates prepared from ten pooled 30 ml-leukocyte units contained a median number of 6,3 × 109 granulocytes. Granulocytes derived from residual leukocyte units displayed surface markers associated with granulocyte function, and capability to phagocytose yeast and produce reactive oxygen species. CONCLUSIONS: Granulocyte concentrates prepared from residual leukocyte units contain in vitro functional granulocytes and may be considered as an alternative product in acute situations before regular granulocyte concentrates from stimulated donors are available.