Plasma-reduction for Apheresis Granulocyte transfusions in pediatric patients.

Granulocyte transfusion (GT) may be used to treat and prevent infections in patients with severe neutropenia or nonfunctioning granulocytes. For pediatric patients, the volume of granulocyte unit transfused is a crucial consideration given smaller blood volume and increased risk of volume overload compared to adults. There is limited literature on the optimal dosing or the maximum amount of granulocytes that can be tolerated, especially in pediatric patients. Additionally, no consensus exists regarding granulocyte collection method, frequency, or timing of GT initiation. Previous studies have described splitting or limiting collection volume for GT in pediatric patients, but these methods yield lower absolute neutrophil count (ANC) increment. Our blood supplier provides high-volume (0.5-1 L/unit), high-dose apheresis-collected granulocytes from donors stimulated with both granulocyte colony-stimulating factor and steroids. Here, we report cases of two pediatric patients with active infection undergoing bone marrow transplant with dramatic ANC increments (median one-hour ANC increment 5524/µL, interquartile range (IQR) 4417-10087; median 24-hour ANC increment 3880/µL, IQR 2550-5263) after infusing 100 mL plasma-reduced, apheresis collected GT. Our cases indicate that pediatric patients can tolerate 4-6 × 109/kg plasma-reduced GT and have detectable ANC with GT every 3 days.

Navigating the neutropenic abyss with granulocyte transfusions: Retrospective single-center analysis of effectiveness and safety in India.

BACKGROUND: Hemato-oncologic patients receiving intensive chemotherapy may develop severe neutropenia and serious bacterial and/or fungal infections. Granulocyte transfusions (GTs) may be beneficial as a bridging therapy in hemato-oncologic patients with febrile neutropenia. AIM: To evaluate the clinical effectiveness of GTs in hemato-oncologic patients with febrile neutropenia. MATERIALS AND METHODS: This retrospective study evaluated the effectiveness of 150 GTs in 88 hemato-oncologic patients. Donors were mobilized with granulocyte colony-stimulating factors and dexamethasone. Patients' hematological parameters (pre- and post-GT) and safety and effectiveness of GTs were analyzed. RESULTS: The safety and effectiveness of GTs were assessed in the patients with various underlying conditions, including 78% with acute myeloid leukemia. In total, 150 GTs were administered, mostly during the chemotherapy induction phase. The GTs were well-tolerated by the patients, and a significant increment in white blood cell count and absolute neutrophil count (ANC) was noticed in 95% of patients after the transfusion. The granulocyte dose was positively correlated with ANC after the transfusion. The average time to neutrophil recovery from the last day of GT was 6.7 days, and the 30-day survival rate was 77%. The donors were all men, and a significant increase in WBC count was observed post-mobilization. The median granulocyte yield was 2.28 × 1010 /unit. All granulocyte products were crossmatched and irradiated before the transfusion. CONCLUSION: GTs can be a useful adjunctive treatment for febrile neutropenia in hemato-oncologic patients with multidrug-resistant sepsis. However, additional studies are required for confirming their effectiveness and establishing guidelines for their use.

How are granulocytes for transfusion best used? The past, the present and the future.

Granulocyte transfusions continue to be used in clinical practice, predominantly for treatment of refractory infection in the setting of severe neutropenia. There is biological plausibility for effectiveness in these patients with deficiencies of neutrophils, either as a consequence of disease or treatment. However, there is a chequered history of conducting and completing interventional trials to define optimal use, and many uncertainties remain regarding schedule and dose. Practice and clinical studies are severely limited by the short shelf life and viability of current products, which often restricts the timely access to granulocyte transfusions. In the future, methods are needed to optimise donor-derived granulocyte products. Options include use of manufactured neutrophils, expanded and engineered from stem cells. Further possibilities include manipulation of neutrophils to enhance their function and/or longevity. Granulocyte transfusions contain a heterogeneous mix of cells, and there is additional interest in how these transfusions may have immunomodulatory effects, including for potential uses as adjuncts for anti-cancer effects.

Successful neutrophil engraftment supported by granulocyte transfusion in adult allogeneic transplant patients with peri-transplant active infection.

Active infection at the time of allogeneic hematopoietic stem cell transplantation (HSCT) is a risk for non-relapse mortality (NRM) after HSCT. Granulocyte transfusion (GTX) has been used to prevent or treat life-threatening infections in patients with severe neutropenia. However, data are limited on the clinical benefits of GTX during HSCT. We retrospectively analyzed the transplant outcomes of HSCT patients who had undergone GTX between 2012 and 2020. Altogether, 20 patients with documented infection had received 55 GTXs during HSCT. No adverse events were observed during the GTX infusion. The average number of granulocytes was 0.40 (range, 0.10-1.59) × 109/kg. The median neutrophil increment one day after GTX was 515 (range, -6 to 6630)/µl, which was significantly correlated with the infused granulocyte dose (p = 0.0007). A total of 17 of 20 patients achieved neutrophil engraftment. The number of infused granulocytes tended to higher in clinical responders (p = 0.12), and patients receiving ≥ 0.5 × 109/kg showed trend toward to better transplant outcomes (GTX-high vs. GTX-low, 1-year OS; 33% vs. 11%, p = 0.19. 1-year NRM; 44% vs.77%, p = 0.11). The type of red blood sedimenting agents was significantly correlated with the amounts of granulocyte collection. In conclusion, GTX, especially with a high amount of containing granulocytes, could be a safe bridging therapy for neutrophil engraftment after HSCT in patients with active infection.

Homing of granulocytes transfused in perineal cellulitis in a RAC2 deficiency child monitored by chimerism quantification methods.

Granulocyte transfusions can be used to treat infections when appropriate antibiotic and anti-fungal drugs have proved ineffective. We report a case of clinical efficacy of 18 granulocyte transfusions for perineal cellulitis in a 3-week-old RAC2-deficient newborn girl. This RAC2 deficiency is characterized by severe phagocyte defects including defective superoxide formation, adhesion and chemotaxis deficiency. In order to check that the granulocytes infused had reached the lesion site, the infiltration of donor cells was quantified by next generation sequencing (NGS) and digital droplet PCR after identification of DNA specific markers for donor and patient. After the 6th transfusion, 20% circulating cells and 55% cells isolated by swabbing from the lesion site were donor cells, confirming the infiltration of polynuclear cells in the perineal lesion site. These results strengthen the indication of granulocyte transfusions, and its continuation until the healing process of the skin is complete. This clinical case report highlights the potential efficacy of granulocyte transfusions to treat skin lesions in RAC2-deficient patients, a process which could be monitored by molecular biology tools for chimerism quantification.

Transfusable neutrophil progenitors as cellular therapy for the prevention of invasive fungal infections.

The use of mature neutrophil (granulocyte) transfusions for the treatment of neutropenic patients with invasive fungal infections (IFIs) has been the focus of multiple clinical trials. Despite these efforts, the transfusion of mature neutrophils has resulted in limited clinical benefit, likely owing to problems of insufficient numbers and the very short lifespan of these donor cells. In this report, we employed a system of conditionally immortalized murine neutrophil progenitors that are capable of continuous expansion, allowing for the generation of unlimited numbers of homogenous granulocyte-macrophage progenitors (GMPs). These GMPs were assayed in vivo to demonstrate their effect on survival in 2 models of IFI: candidemia and pulmonary aspergillosis. Mature neutrophils derived from GMPs executed all cardinal functions of neutrophils. Transfused GMPs homed to the bone marrow and spleen, where they completed normal differentiation to mature neutrophils. These neutrophils were capable of homing and extravasation in response to inflammatory stimuli using a sterile peritoneal challenge model. Furthermore, conditionally immortalized GMP transfusions significantly improved survival in models of candidemia and pulmonary aspergillosis. These data confirm the therapeutic benefit of prophylactic GMP transfusions in the setting of neutropenia and encourage development of progenitor cellular therapies for the management of fungal disease in high-risk patients.

Effect of Autoimmune Cell Therapy on Immune Cell Content in Patients with COPD: A Randomized Controlled Trial.

OBJECTIVE: To explore the effect of autoimmune cell therapy on immune cells in patients with chronic obstructive pulmonary disease (COPD) and to provide a reference for clinical treatment of COPD. METHODS: Sixty patients with stable COPD were randomly divided into control group and treatment group (n = 30). The control group was given conventional treatment, and the treatment group was given one autoimmune cell therapy on the basis of conventional treatment. The serum levels of CD3+ T cells, CD4+ T cells, CD8+ cells, B cells, and NK cells in the peripheral blood were detected by flow cytometry. Possible adverse reactions were detected at any time during treatment. RESULTS: There were no significant differences in the contents of CD3+ T cells, CD4+ T cells, CD8+ cells, B cells, and NK cells in the serum of the control group (P > 0.05). Compared with before treatment, the contents of CD3+ T cells, CD4+ T cells, CD8+ cells, B cells, and NK cells in the serum of the treatment group were significantly increased (P < 0.05). The ratio of CD4 + /CD8+ T cells in both control and treatment groups did not change significantly during treatment (P > 0.05). There were no significant differences in serum CD3+ T cells, CD4+ T cells, CD8+ cells, B cells, and NK cells in the treatment group at 30 days and 90 days after treatment (P > 0.05), but they were significantly higher than those in the control group (P < 0.05). CONCLUSION: Autoimmune cell therapy can significantly increase the level of immune cells in the body and can be maintained for a long period of time, which has certain clinical benefits for recurrent respiratory tract infections and acute exacerbation in patients with COPD.

Survival among children and adults treated with granulocyte transfusions: Twenty years' experience at a Brazilian blood center.

BACKGROUND: It remains controversial whether granulocyte transfusions as a supportive treatment improve survival in patients with febrile neutropenia or granulocyte dysfunctions. We describe survival rates subsequent to granulocyte transfusions in pediatric and adults patients treated at a major blood center in Brazil. MATERIAL AND METHODS: We retrospectively reviewed the clinical charts of pediatric and adult patients treated with granulocyte transfusions at our institution from January 2000 to October 2019. We assessed demographic characteristics, clinical features, indications for transfusion, units transfused, dose of granulocytes administered and survival rates 30 and 100 days after the initial transfusion. RESULTS: We identified 64 pediatric and 67 adult patients treated with 262 granulocyte transfusions. An optimal dose (> 0.6 × 109 granulocytes per kilogram per transfused unit) was available for transfusion in 80.4 % of pediatric patients but in only 19.6 % of adults (p = 0.017). Thirty days after their first granulocyte transfusion, 38 (59.4 %) pediatric and 61 (91 %) adult patients had died. Patients receiving the optimal dose of granulocytes had better survival outcomes, but even among this sub-group, adults were more likely to die than were children either at 30 days (OR = 8.67, 95 %CI 2.69-34.9) or 100 days (OR = 6.27, 95 %CI 1.86-25.9) after their initial granulocyte transfusion. CONCLUSION: Survival rates following granulocyte transfusion varied by the dose transfused and were higher in children than in adults.

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.

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 Transfusion: Clinical Updates and a Practical Approach to Transfusion.

Neutrophils are an integral component of the innate immune system and key regulators of cell-mediated defense against bacterial and fungal pathogens. The potential of granulocyte transfusions has been investigated to temporarily replenish innate immune function to prevent and/or treat infections in patients with severe neutropenia or neutrophil dysfunction. However, evidence has been largely theoretical, experimental, and/or inconclusive. Clinical efficacy has yet to be confirmed by large-scale randomized controlled clinical trials. Performing such trials has been hampered by low granulocyte collection yield and poor patient accrual. We provide a practical summary of the current literature surrounding the practice of granulocyte transfusion.

Targeting multiple cell death pathways extends the shelf life and preserves the function of human and mouse neutrophils for transfusion.

Clinical outcomes from granulocyte transfusion (GTX) are disadvantaged by the short shelf life and compromised function of donor neutrophils. Spontaneous neutrophil death is heterogeneous and mediated by multiple pathways. Leveraging mechanistic knowledge and pharmacological screening, we identified a combined treatment, caspases-lysosomal membrane permeabilization-oxidant-necroptosis inhibition plus granulocyte colony-stimulating factor (CLON-G), which altered neutrophil fate by simultaneously targeting multiple cell death pathways. CLON-G prolonged human and mouse neutrophil half-life in vitro from less than 1 day to greater than 5 days. CLON-G-treated aged neutrophils had equivalent morphology and function to fresh neutrophils, with no impairment to critical effector functions including phagocytosis, bacterial killing, chemotaxis, and reactive oxygen species production. Transfusion with stored CLON-G-treated 3-day-old neutrophils enhanced host defenses, alleviated infection-induced tissue damage, and prolonged survival as effectively as transfusion with fresh neutrophils in a clinically relevant murine GTX model of neutropenia-related bacterial pneumonia and systemic candidiasis. Last, CLON-G treatment prolonged the shelf life and preserved the function of apheresis-collected human GTX products both ex vivo and in vivo in immunodeficient mice. Thus, CLON-G treatment represents an effective and applicable clinical procedure for the storage and application of neutrophils in transfusion medicine, providing a therapeutic strategy for improving GTX efficacy.

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.

Use of granulocyte transfusion in early period in life-threatening infections of pediatric hematology and oncology patients: A single-center experience.

Despite all the developments in medicine, infections continue to be one of the most important causes of mortality in pediatric hematology and oncology patients. The more severe the degree of neutropenia develops after intensive chemotherapy in cancer patients, and the longer the neutropenia duration, the higher the risk of infection. Granulocyte transfusion (GT) is used as supportive therapy in cases where the bone marrow needs time to recover in invasive bacterial or fungal infections along with severe neutropenia. The patients who had granulocyte transfusions in our clinic between June 2019 and June 2020 were reviewed retrospectively. A total of 15 units of granulocyte concentrate were used in 11 febrile neutropenia attacks of 9 patients. The demographic characteristics of the patients and features belonging to the period of GT were recorded. In our study, the clinical response rate after GT was 90.9 %, while the hematological response rate was 40 %. Most of the patients were treated succesfully, the mortality rate was 9%. We think that the most critical factor for success with GTs is determining the neutropenic patient in particular with a combination of high-risk malignancy and acute life-threatening infection for using GT. Also, early use of GT in those patients who do not recover despite appropriate antimicrobial and supportive treatment may contribute to improvement of the clinical conditon in a shorter period of time and reduction of repeated GTs.

Effects of ultrasound guided leukocyte-rich platelet-rich plasma (LR-PRP) injection in patients with pes anserinus tendinobursitis.

OBJECTIVES: To demonstrate the efficacy and safety of ultrasound guided leukocyte-rich platelet-rich plasma (LR-PRP) injection in patients with pes anserinus tendinobursitis (PATB). METHODS: A prospective, randomized and single-blinded study of 60 patients with PATB were randomly assigned into 2 groups. Whereas 2 mL LR-PRP injection was applied to one grup, once accompanied by ultrasonography (USG), 2 mL LR-PRP injection was applied to the other group accompanied by USG twice with a one-week interval. Visual Analog Scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), 6-minute walking test (6MWT), Likert Scale were evaluated pre-treatment, at the 4th and 12th weeks after treatment. RESULTS: There was no statistical difference between the two groups in terms of age, gender, body mass index, duration of symptoms, affected side. When both groups are compared within themselves before and after treatment, there was a significant improvement in all VAS, in all WOMAC subgroups, 6MWT, at the 4th and 12th weeks after treatment. When the two groups are compared with each other, there was no statistical difference. In addition, when all patients were evaluated with Likert scale in the 12th week after treatment, complete healing in 22(36.7 %) patients, significant relief in 25(41.7 %) patients, mild relief in 4(6.7 %) patients, 5(8.3 %) same as before treatment patients, and worsened pain in 4(6.7 %) patients were seen. CONCLUSION: Both single-dose and double-dose local LR-PRP is a safe and effective treatment option for patients with PATB syndrome. We believe that once LR-PRP injection may be sufficient for the treatment efficacy in PATB.

Optimizing leukapheresis product yield and purity for blood cell-based gene and immune effector cell therapy.

PURPOSE OF REVIEW: A critical common step for blood-based ex-vivo gene and immune effector cell (IEC) therapies is the collection of target cells for further processing and manufacturing, often accomplished through a leukapheresis procedure to collect mononuclear cells (MNCs). The purpose of this review is to describe strategies to optimize the apheresis product cell yield and purity for gene and IEC therapies. Relevant data from the conventional bone marrow transplant literature is described where applicable. RECENT FINDINGS: Product yield is affected by three main factors: the peripheral blood concentration of the target cell, optimized by mobilizing agents, donor interventions or donor selection; the volume of peripheral blood processed, tailored to the desired product yield using prediction algorithms; and target cell collection efficiency, optimized by a variety of device and donor-specific considerations. Factors affecting product purity include characteristics of the donor, mobilizing agent, device, and device settings. SUMMARY: Strategies to optimize product yield and purity for gene and IEC therapies are important to consider because of loss of target cell numbers or function with downstream steps and detrimental effects of nontarget cells on further manufacturing and patient outcome.

Immunodeficient mice are better for modeling the transfusion of human blood components than wild-type mice.

Animal models are vital to the study of transfusion and development of new blood products. Post-transfusion recovery of human blood components can be studied in mice, however, there is a need to identify strains that can best tolerate xenogeneic transfusions, as well as to optimize such protocols. Specifically, the importance of using immunodeficient mice, such as NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice, to study human transfusion has been questioned. In this study, strains of wild-type and NSG mice were compared as hosts for human transfusions with outcomes quantified by flow cytometric analyses of CD235a+ erythrocytes, CD45+ leukocytes, and CD41+CD42b+ platelets. Complete blood counts were evaluated as well as serum cytokines by multiplexing methods. Circulating human blood cells were maintained better in NSG than in wild-type mice. Lethargy and hemoglobinuria were observed in the first hours in wild-type mice along with increased pro-inflammatory cytokines/chemokines such as monocyte chemoattractant protein-1, tumor necrosis factor α, keratinocyte-derived chemokine (KC or CXCL1), and interleukin-6, whereas NSG mice were less severely affected. Whole blood transfusion resulted in rapid sequestration and then release of human cells back into the circulation within several hours. This rebound effect diminished when only erythrocytes were transfused. Nonetheless, human erythrocytes were found in excess of mouse erythrocytes in the liver and lungs and had a shorter half-life in circulation. Variables affecting the outcomes of transfused erythrocytes were cell dose and mouse weight; recipient sex did not affect outcomes. The sensitivity and utility of this xenogeneic model were shown by measuring the effects of erythrocyte damage due to exposure to the oxidizer diamide on post-transfusion recovery. Overall, immunodeficient mice are superior models for xenotransfusion as they maintain improved post-transfusion recovery with negligible immune-associated side effects.

Characteristics of autologous protein solution and leucocyte-poor platelet-rich plasma for the treatment of osteoarthritis of the knee.

Recently, platelet-rich plasma (PRP) has received attention as a treatment for patients with osteoarthritis of the knee (OAK), a chronic degenerative disease, to bridge the gap between conservative and surgical treatments. Here, we investigated the differences in the humoral factors present in two types of PRP purified using the Autologous Protein Solution (APS) kit (group Z; leucocyte-rich PRP) or the Cellaid Serum Collection Set P type (group J; leucocyte-poor [LP]-PRP). Differences in humoral factors between healthy subjects (n = 10) and OAK patients (n = 12; group Z = 6, group J = 6), and the relationship between humoral factors and clinical outcome scores were investigated. Both anti-inflammatory and inflammatory cytokines were highly enriched in APS. The concentrations of tumour necrosis factor (TNF)-α, platelet-derived growth factor, fibroblast growth factor, soluble TNF-receptor 2, soluble Fas and transforming growth factor-ß1 were higher in group Z, while the total amounts were higher in group J. The concentration of interleukin-1 receptor antagonist was positively correlated with the magnitude of change in the clinical outcome score and may contribute to improving knee-joint function. This is the first description of the humoral factors in APS and LP-PRP prepared from healthy subjects or OAK patients of Asian descent.

In canine bacterial pneumonia circulating granulocyte counts determine outcome from donor cells.

BACKGROUND: In experimental canine septic shock, depressed circulating granulocyte counts were associated with a poor outcome and increasing counts with prophylactic granulocyte colony-stimulating factor (G-CSF) improved outcome. Therapeutic G-CSF, in contrast, did not improve circulating counts or outcome, and therefore investigation was undertaken to determine whether transfusing granulocytes therapeutically would improve outcome. STUDY DESIGN AND METHODS: Twenty-eight purpose-bred beagles underwent an intrabronchial Staphylococcus aureus challenge and 4 hours later were randomly assigned to granulocyte (40-100 × 109 cells) or plasma transfusion. RESULTS: Granulocyte transfusion significantly expanded the low circulating counts for hours compared to septic controls but was not associated with significant mortality benefit (1/14, 7% vs. 2/14, 14%, respectively; p = 0.29). Septic animals with higher granulocyte count at 4 hours (median [interquartile range] of 3.81 3.39-5.05] vs. 1.77 [1.25-2.50]) had significantly increased survival independent of whether they were transfused with granulocytes. In a subgroup analysis, animals with higher circulating granulocyte counts receiving donor granulocytes had worsened lung injury compared to septic controls. Conversely, donor granulocytes decreased lung injury in septic animals with lower counts. CONCLUSION: During bacterial pneumonia, circulating counts predict the outcome of transfusing granulocytes. With low but normal counts, transfusing granulocytes does not improve survival and injures the lung, whereas for animals with very low counts, but not absolute neutropenia, granulocyte transfusion improves lung function.