Granulocyte transfusions in children and adults with hematological malignancies: benefits and controversies

GRAIN Study - Granulocytes Against Infections - Use of granulocyte transfusion in haematopoietic stem cell transplant

Granulocyte transfusions (GTx) combat infections in neutropenic patients. However, immune-mediated off-target effects in transplant settings are unknown. Between January 2020 and December 2021, all transplants that used GTx during the peri-transplant period were analysed. Engraftment, infections, and days to clearance were retrieved from clinical records. Overall survival is compared with the mean total PMN count and the different products. Pooled buffy coat was used in 110 patients (98 %), of which 38 (34 %) additionally received an apheresed product. The median days of GTx was 4. The median bags pooled to prepare a single buffy coat product was 4. The mean total PMN count was 0.98 × 1010/ L granulocytes per pooled buffy coat and 1.93 × 1010/L granulocytes per apheresis product. A higher PMN count (>1 × 1010/L) was achieved in 48 % with pooled buffy coat versus 85 % with apheresis. Respiratory worsening occurred in 39 % receiving GTx. All patients who received granulocytes had engrafted with a median time of 14 days for neutrophil and 20 days for platelet engraftment. Blood cultures cleared in 81 %, whereas only 28 % cleared other cultures. Fungal pneumonia cleared in 25 %, and invasive fungal sinusitis or otitis cleared in 50 %. Overall survival was 47 %, non-significantly higher (57 % vs 39 %, P = 0.1) with a higher PMN dose. The pooled buffy coat is an affordable alternative to apheresis for an effective PMN dose. Ease of availability and low cost of pooled buffy coat, with comparable overall survival points toward a safe and efficacious product, in the peri-transplant period.

Use of Granulocyte Transfusions in the Management of Severe Infections Among Children with Neutropenia

Background/Objectives: Infections remain the leading cause of mortality among neutropenic patients with haematologic malignancies, making effective infection management crucial. Achieving a sufficient neutrophil count is essential for the elimination of pathogens. Granulocyte concentrate (GC) can be a treatment option for neutropenic patients with severe infections. This study aimed to evaluate the efficacy, safety, and impact on survival of GC transfusions in neutropenic children with severe infections treated over the past 13 years in a single centre. Methods: The retrospective study analysed clinical data from 60 children (median age 9.5 years) who received GC transfusions at our centre. Granulocytes were collected by apheresis from donors stimulated with granulocyte colony-stimulating factor. The majority of the patients (70%) were diagnosed with acute leukaemia. The main indications for GC were severe pneumonia (45%) and bacterial sepsis (38.33%). Results: The patients received 1 to 29 GC transfusions for 1 to 70 days, with a median time of administration of 3 days. Neutrophil counts increased to >1000/µL within a median of 5 days. GCs were well tolerated by most patients. One patient presented symptoms of anaphylaxis, the other acute lung injury related to transfusions, and alloimmunisation was reported in one patient. Of the patients analysed, 78.33% survived the infection that justified GC administration. We did not observe significant differences in survival depending on the aetiology of the infection. Conclusions: Based on our research, GC appears to be a beneficiary for neutropenic children with severe infections and reduces infection mortality rates. However, further well-designed randomised trials are needed to define its role in this setting.

Granulocyte transfusions in severe aplastic anemia

Patients with severe aplastic anemia (SAA) are at high risk of morbidity and mortality due to severe infections. We aimed to characterize the role of granulocyte transfusions (GT) in SAA. Primary outcomes were survival after the first GT, including overall survival (OS) at last follow up, survival to discharge, and receipt of a hematopoietic stem cell transplant (HSCT) Secondary outcomes included evaluation of clinical response at 7 and 30 days after initiation of GT, using a clinical scoring system incorporating microbiological and radiographic response. Twenty-eight SAA patients underwent 30 GT courses with a per-dose median of 1.28x109 granulocytes/kilogram (range, 0.45-4.52x109). OS from initial GT to median last follow up (551 days) was 50%, with 39% (11/28) alive at last follow up. Sixty-four percent (18/28) of all patients survived to hospital discharge. Patients with a complete or partial response, or stable infection, at 30 days had significantly better OS compared to non-responders (P=0.0004). Eighty-six percent (18/21) of patients awaiting HSCT during GT underwent a transplant and 62% (13/21) survived to post-HSCT discharge. Sex, type of infection, and percentage of days with absolute neutrophil count >0.2x109/L during the course of GT were not predictive of survival (P=0.52, P=0.7 and P=0.28, respectively). Nine of 28 (32%) patients developed new or increased human leukocyte antigen alloimmunization during their GT course. GT in SAA may have an impact on survival in those patients with improvement or stabilization of their underlying infection. Alloimmunization can occur and OS in this population remains poor, but GT may be a useful tool to bridge patients to curative treatment with HSCT.

Granulocyte transfusions in life-threatening infections of children with hemato-oncological diseases

Granulocytes are the most important cells for host defense during infections. Granulocyte suspension transfusions (GTx) may be given as additional treatment in severely neutropenic patients with life-threatening infections when antimicrobial therapy is inadequate. The aim of this study was to evaluate the effectiveness and safety of GTx for the treatment of children with hemato-oncological disease, febrile neutropenia and serious life-threatening infections. Patients who underwent GTx between July 2020 and September 2022 were evaluated retrospectively. Hematologic and clinical response rates, adverse effects, characteristics of infection episodes and survival data of the patients were analyzed. During the study period, 60 patients received a total of 313 GTx for 81 infection episodes with a median number of GTx/infection episode of 3 (range 1-29). The median neutrophil count per bag was 20.8 (range 7.9-68.3) × 109 and the median neutrophil count per kg body weight was 0.82 (range 0.17-9.2) × 109. Clinical response was 85 %. Clinical response decreased significantly as the duration of neutropenia increased (p = 0.002). Hematologic response was calculated in 198 GTx (GTx given with pre-transfusion neutrophil count ≤ 0.5 × 109/L); hematologic response rate was 34 %. The infection-related mortality was 15 % and overall survival rate was 87 % and 70 % on days 30 and 90, respectively. No serious side effects were observed in any patient. Granulocyte transfusions appear to be safe and effective supportive treatment in neutropenic children with hematologic/oncologic diseases and severe infections.

Risk stratification by 30-day prognostic factors of clinical outcomes after granulocyte transfusion in acute myeloid leukemia: A single-center retrospective study

Background

Granulocyte transfusions (GTs) have been used to treat infections in neutropenic patients undergoing chemotherapy or hematopoietic stem cell transplantation. However, there is persistent controversy regarding their outcomes. We aimed to analyze accumulated clinical and laboratory data from patients with acute myeloid leukemia (AML) who underwent GT at our institution in the last 10 years to determine optimal parameters to estimate the GT effect. We hypothesized that patients grouped according to prognostic factors would have inconsistent clinical outcomes.

Materials and methods

In this single-center retrospective study, we collected medical records of 219 GT-treated patients diagnosed with AML from 2009 to 2019. Prognostic factors, including clinical and laboratory parameters, were assessed. Serial measurements of laboratory parameters before and after GT were collected, and the area under the curve of the white blood cells (AUC-WBC) was calculated using the trapezoidal method. A prognostic scoring system using 8 factors from multivariate analysis was analyzed. The primary outcome was survival at 30 days (D30) after GT initiation.

Results

The 8 factors for the prognosis scoring system included secondary AML, mean AUC-WBC, prothrombin time, and levels of blood urea nitrogen (BUN), bilirubin, alanine aminotransferase (ALT), phosphorus, and lactate dehydrogenase (LDH). Patients were grouped into 4 risk groups (low, medium, high, and very high), and the D30 survival rates for each group were as follows: 87.6% (99/113), 55.9% (33/59), 21.1% (4/19), and 0% (0/19), respectively. Hematopoiesis, liver, and renal function affected the outcome. FLT3 mutation acted as a favorable factor for D30 survival.

Conclusions

GT response in patients with AML seemed to be reflected by 8 score markers, and GT was significantly effective in the low-risk group. We suggest that it is important to evaluate the risk assessment of patients before GT to achieve better outcomes.

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.

Open-Label Phase II Prospective, Randomized, Controlled Study of Romyelocel-L Myeloid Progenitor Cells to Reduce Infection During Induction Chemotherapy for Acute Myeloid Leukemia

PURPOSE

Standard cytotoxic induction chemotherapy for acute myeloid leukemia (AML) results in prolonged neutropenia and risk of infection. Romyelocel-L is a universal, allogeneic myeloid progenitor cell product being studied to reduce infection during induction chemotherapy.

PATIENTS AND METHODS

One hundred sixty-three patients with de novo AML (age ≥ 55 years) receiving induction chemotherapy were randomly assigned on day 0 (d0), of whom 120 were evaluable. Subjects received either romyelocel-L infusion on d9 with granulocyte colony-stimulating factor (G-CSF) starting daily d14 (treatment group) or G-CSF daily alone on d14 (control) until absolute neutrophil count recovery to 500/µL. End points included days in febrile episode, microbiologically defined infections, clinically diagnosed infection, and days in hospital.

RESULTS

Mean days in febrile episode was shorter in the treatment arm from d15 through d28 (2.36 v 3.90; P = .02). Similarly, a trend toward decreased microbiologically defined infections and clinically diagnosed infection in the treatment arm was observed from d9 to d28 (35.6% v 47.5%; P = .09), reaching a statistically significant difference from d15 to d28 (6.8% v 27.9%; P = .002). Because of this, antibacterial or antifungal use for treatment of an infection was significantly less in the treatment group (d9-d28: 44.1% v 63.9%; P = .01). Significantly fewer patients in the treatment arm received empiric antifungals from d9 tod28 (42.4% v 63.9%; P = .02) and d15-d28 (42.4% v 62.3%; P = .02). Patients in the treatment arm also had 3.2 fewer hospital days compared with control (25.5 v 28.7; P = .001). Remission rates and days to absolute neutrophil count recovery were similar in the two groups. No patients in the romyelocel-L plus G-CSF group died because of infection compared with two patients in the control arm. No graft-versus-host disease was observed.

CONCLUSION

Subjects receiving romyelocel-L showed a decreased incidence of infections, antimicrobial use, and hospitalization, suggesting that romyelocel-L may provide a new option to reduce infections in patients with AML undergoing induction therapy.

Insights into the toll-like receptors in sexually transmitted infections

Toll-like receptors (TLRs) are like soldiers of an innate immune system, which protects vital biological processes against invading pathogens. TLR signalling pathways help in the removal of pathogens and mediate well-established inflammatory processes. However, these processes may also aid in the development or augmentation of an infection or an autoimmune disease. Recent studies have delineated TLR polymorphism's role in the loss of function, making hosts more resistant or vulnerable to the development of an infection. In this review, we have discussed the association of TLRs with sexually transmitted infections (STIs), especially to the pathogen-specific ligands. We have also assessed the impact on TLR downstream signalling and the maintenance of cellular homeostasis during immune responses. Besides, we have discussed the role of TLRs single nucleotide polymorphisms in various STIs. Since TLRs are known to play a part in defence mechanisms and in aiding infections therefore, a thorough understanding of TLRs structure and molecular mechanisms is required to explain how they can influence the outcome of an STI. Such a strategy may lead to the development of novel and useful immunotherapeutic approaches to control pathogen progression and prevent transmission.

Educational Case: Granulocyte Transfusion

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, seehttp://journals.sagepub.com/doi/10.1177/2374289517715040.¹

Lentiviral gene therapy and vitamin B3 treatment enable granulocytic differentiation of G6PC3-deficient induced pluripotent stem cells

Induced pluripotent stem cells (iPSCs) from patients with genetic disorders are a valuable source for in vitro disease models, which enable drug testing and validation of gene and cell therapies. We generated iPSCs from a severe congenital neutropenia (SCN) patient, who presented with a nonsense mutation in the glucose-6-phosphatase catalytic subunit 3 (G6PC3) gene causing profound defects in granulopoiesis, associated with increased susceptibility of neutrophils to apoptosis. Generated SCN iPSC clones exhibited the capacity to differentiate into hematopoietic cells of the myeloid lineage and we identified two cytokine conditions, i.e., using granulocyte-colony stimulating factor or granulocyte-macrophage colony stimulating factor in combination with interleukin-3, to model the SCN phenotype in vitro. Reduced numbers of granulocytes were produced by SCN iPSCs compared with control iPSCs in both settings, which reflected the phenotype in patients. Interestingly, our model showed increased monocyte/macrophage production from the SCN iPSCs. Most importantly, lentiviral genetic correction of SCN iPSCs with a codon-optimized G6PC3 transgene restored granulopoiesis and reduced apoptosis of in vitro differentiated myeloid cells. Moreover, addition of vitamin B3 clearly induced granulocytic differentiation of SCN iPSCs and increased the number of neutrophils to levels comparable with those obtained from healthy control iPSCs. In summary, we established an iPSC-derived in vitro disease model, which will serve as a tool to test the potency of alternative treatment options for SCN patients, such as small molecules and gene therapeutic vectors.

Acute respiratory failure and the kinetics of neutrophil recovery in pediatric hematopoietic cell transplantation: a multicenter study

In this multicenter study, we investigated the kinetics of neutrophil recovery in relation to acuity and survival among 125 children undergoing allogeneic hematopoietic cell transplantation (allo-HCT) who required invasive mechanical ventilation (IMV). Recovery of neutrophils, whether prior to or after initiation of IMV, was associated with a significantly decreased risk of death relative to never achieving neutrophil recovery. A transient increase in acuity (by oxygenation index and vasopressor requirements) occurred among a subset of the patients who achieved neutrophil recovery after initiation of IMV; 61.5% of these patients survived to discharge from the intensive care unit (ICU). Improved survival among patients who subsequently achieved neutrophil recovery on IMV was not limited to those with peri-engraftment respiratory distress syndrome. The presence of a respiratory pathogen did not affect the risk of death while on IMV but was associated with an increased length of IMV (p < 0.01). Among patients undergoing HCT who develop respiratory failure and require advanced therapeutic support, neutrophil recovery at time of IMV and/or presence of a respiratory pathogen should not be used as determining factors when counseling families about survival.

Granulocyte transfusions collected after steroid priming for severe infections during neutropenia: A single center experience

BACKGROUND

There is no universally accepted opinion on the use of granulocyte transfusions collected using apheresis (GTA) in neutropenic patients and severe infection.

PATIENTS AND METHODS

The efficacy and safety of GTAs transfused at a single center over 10 years were analyzed retrospectively. GTAs were harvested from voluntary unrelated donors after priming with methylprednisolone using continuous apheresis and hydroxyethylstarch as sedimentation agent.

RESULTS

41 patients with neutropenia and hematologic malignancy (15 females and 26 males aged 22-69 (median 45.5)) were given a median 3.5 GTAs per patient (range: 1-17) containing a median 1.39×10¹⁰ granulocyte/GTA (range: 0.65-2.81). The indications for GTA use were soft tissue inflammation, sepsis, and pneumonia in 30, 22, and 14 cases, respectively. After GTA complete (30 patients: 73.2%) or partial (6 patients: 14.6%) healing of the infection was achieved. The success rate was 91.7% in soft tissue infections, 66.7% in invasive fungal infections, and 68% in sepsis. Septic shock (documented in 12 cases) was associated with a poor response (P<0.03; Chi-square test). Clinical worsening was observed in six cases (14.6%); four patients died. No significant short-term side effects of GTA treatment were recorded.

CONCLUSIONS

In our study GTAs collected after steroid priming and used for the treatment of infection during severe neutropenia have shown comparable efficacy with several previously reported trials. However retrospective fashion of our study and inhomogeneous group of patients do not allow any firm conclusions. Prospective studies (including patients' registries) are needed for the better clarification of the role and the dose of GTAs necessary for the successful infection management during neutropenia.

Is there a standard-of-care for transfusion support of patients with haematological malignancies?

PURPOSE OF REVIEW

Patients with haematological malignancies are a high-user group for blood transfusions. Here, we describe the current evidence on transfusion policies in patients with haematological malignancies, based on recent systematic reviews of RCTs.

RECENT FINDINGS

Results from six RCTs (1195 participants) suggest that prophylactic platelet transfusions reduce bleeding compared with therapeutic-only use, although the effects varied according to patient diagnosis/treatment plan. A meta-analysis of seven RCTs (1814 participants) reported that low-dose platelet transfusions (1.1 × 10/m ± 25%) were noninferior to standard dose (2.2 × 10/m ± 25%), or high dose (4.4 × 10/m ± 25%). Three RCTs (499 participants) reported that restrictive platelet count thresholds (less than 10 × 10/l) were noninferior to liberal thresholds counts (less than 20-30 × 10/l). For red-cell transfusions, the data from completed RCTs was less advanced. A recent meta-analysis with four RCTs (240 participants) suggested that restrictive thresholds (less than 70-90 g/l) are noninferior to liberal thresholds (less than 80-120 g/l), but with more uncertainty for clinical outcomes.

SUMMARY

There is support from randomised trials for using prophylactic platelet transfusions, in low-dose, and with restrictive thresholds. No large completed studies have been published for red-cell transfusions. Many studies overall were arguably underpowered and only offered low-to-medium grade level evidence.

Granulocyte transfusions: A concise review for practitioners

Granulocyte transfusions (GTXs) have been used to treat and prevent infections in neutropenic patients for more than 40 years, despite persistent controversy regarding their efficacy. This narrative review attempts to complement recent systematic reviews by the Cochrane Collaboration and provide both historical context and critical assessment of the most significant clinical studies published over the years. The data suggest that properly collected and promptly infused granulocytes are active against infections, both bacterial and fungal. The most important question that remains unanswered is in which patients the administration of granulocytes will be beneficial. The preponderance of evidence suggests that granulocyte transfusions may be efficacious in few select cases as a temporizing measure to control an infection that is expected (or proven) to be refractory to optimal antimicrobial treatment, and that could otherwise be controlled by marrow recovery, which is expected to happen. In this regard, they are best considered a "bridge" that grants enough time for the recipient to develop their own response to the infection. The challenges to use GTXs successfully are both clinical, in terms of timely identifying the patients who may benefit, and logistical, in terms of optimal selection of donors and collection technique.

Granulocyte Transfusion Therapy in Childhood

Despite the use of new broad-spectrum anti-bacterial and anti-fungal agents, infections still represent the major cause of morbidity and mortality in patients with prolonged neutropenia after intensive chemotherapy. The aim of this study is to assess the effect and safety of granulocyte transfusions (GTs) for the treatment of severe life-threatening infections in pediatric patients with febrile neutropenia. In this study, 13 pediatric patients with high-risk febrile neutropenia, who received 24 GTs, were included. GTs were well tolerated in all patients. Upon 24 h post-transfusion, neutrophil and platelet counts increased significantly, when compared to the baseline values. The clinical response and hematologic response rates were 69.2 % respectively. In conclusion, GT is safe and effective in controlling life-threatening infections. Furthermore, randomized controlled studies with long-term follow-up are needed to assess the exact role of GT in the outcome of patients with neutropenia.

Erythrocyte sialoglycoproteins engage Siglec-9 on neutrophils to suppress activation

Healthy blood neutrophils are functionally quiescent in the bloodstream, have a short lifespan, and exit the circulation to carry out innate immune functions, or undergo rapid apoptosis and macrophage-mediated clearance to mitigate host tissue damage. Limitation of unnecessary intravascular neutrophil activation is also important to prevent serious inflammatory pathologies. Because neutrophils become easily activated after purification, we carried out ex vivo comparisons with neutrophils maintained in whole blood. We found a difference in activation state, with purified neutrophils showing signs of increased reactivity: shedding of l-selectin, CD11b upregulation, increased oxidative burst, and faster progression to apoptosis. We discovered that erythrocytes suppressed neutrophil activation ex vivo and in vitro, including reduced l-selectin shedding, oxidative burst, chemotaxis, neutrophil extracellular trap formation, bacterial killing, and induction of apoptosis. Selective and specific modification of sialic acid side chains on erythrocyte surfaces with mild sodium metaperiodate oxidation followed by aldehyde quenching with 4-methyl-3-thiosemicarbazide reduced neutrophil binding to erythrocytes and restored neutrophil activation. By enzyme-linked immunosorbent assay and immunofluorescence, we found that glycophorin A, the most abundant sialoglycoprotein on erythrocytes, engaged neutrophil Siglec-9, a sialic acid-recognizing receptor known to dampen innate immune cell activation. These studies demonstrate a previously unsuspected role for erythrocytes in suppressing neutrophils ex vivo and in vitro and help explain why neutrophils become easily activated after separation from whole blood. We propose that a sialic acid-based "self-associated molecular pattern" on erythrocytes also helps maintain neutrophil quiescence in the bloodstream. Our findings may be relevant to some prior experimental and clinical studies of neutrophils.

Granulocyte transfusions in critically ill children with prolonged neutropenia: side effects and survival rates from a single-center analysis

Granulocyte transfusions for neutropenic patients have been used for over 40 years, although effectiveness, indications, and both patient and donor safety remain debated. This single-center study assessed the side effects, clinical course, and survival of granulocyte transfusions in critically ill pediatric patients, with underlying hemato-oncological disorders, prolonged neutropenia, and proven or suspected severe infection. Donor-specific side effects and influence of donor-specific characteristics on patient outcome were also investigated. A median of 4.02 × 10(10) cells was collected from 39 healthy donors for 118 granulocyte concentrates. Donors reported no significant side effects. Complications for patients were frequent but mostly minor and included vomiting, hypotension, and dyspnea. In one episode of life-threatening dyspnea, association with the granulocyte transfusion could not be ruled out. Overall survival on day 100 was 61.9 %. Patients received a median of 0.13 × 10(10) cells per kg body weight. Doses above this median were associated with a significantly better survival. Lower patient weight and age-/sex-adjusted weight were also associated with better survival.

CONCLUSION

Granulocyte mobilization and collection is a safe practice. Transfusions are well tolerated in critically ill patients. Patient weight and transfused cells per kg bodyweight are major determinants of survival in pediatric patients.

WHAT IS KNOWN

• Granulocyte transfusions for neutropenic patients have been used for over 40 years • The effectiveness of the technique remains controversial • Patient and donor safety remain debated • New mobilization protocols generate higher yields of granulocytes What is new: • Granulocyte collection can safely be performed • Granulocytes can safely be administered to patients • Lower patient weight and age-/sex-adjusted weight are associated with better survival rates • Patients receiving above 0.13 × 10 (10) cells per kg body weight had an excellent outcome • Further standardized, prospective studies are warranted.