Granulocyte concentrates: how can we assess their quality?

The use of granulocyte transfusions to treat and prevent life-threatening infection in patients lacking neutrophil numbers or function may become increasingly important in aiding advances in the treatment of haematological malignancies. A critical factor in determining the outcome of granulocyte transfusion is the number of cells transfused, and collection of sufficiently high concentration of cells from donors remains challenging. A number of tests of granulocyte function can be performed in vitro to assess the quality of granulocyte concentrates, which may be useful in helping to optimize granulocyte collection, processing and storage methods. Studies that have examined neutrophil function in granulocyte concentrates to date have tended to focus on the assessment of viability, chemotaxis, phagocytosis and oxidative killing. How useful in vitro tests of neutrophil function are in predicting neutrophil function following granulocyte transfusion remains to be established in conjunction with well-designed clinical trials.

The use of stimulated granulocyte transfusions to prevent recurrence of past severe infections after allogeneic stem cell transplantation

The predictable neutropenia that follows allogeneic stem cell transplantation (ASCT) may be associated with recurrence of previous life-threatening infection. We describe nine patients with either previous invasive aspergillosis (IA) or considered to be at high risk of developing IA who underwent ASCT with prophylactic granulocyte transfusions. The study group, when compared with a control group, had a significant reduction in the incidence and duration of fevers (P < 0.05) and maximum C-reactive protein (P < 0.05). There were significantly fewer days of neutropenia (P < 0.05). There was also radiological improvement of pulmonary infiltrates in four out of seven assessable patients. No serious toxicity was encountered in donors or recipients. We conclude that prophylactic granulocyte donations can be given safely, and that they significantly reduce the number of days of neutropenia. Further investigation is warranted to determine whether granulocyte donations can prevent the recurrence of IA in patients at risk of fungal infection.

Donor CMV serostatus has no impact on CMV viremia or disease when prophylactic granulocyte transfusions are given following allogeneic peripheral blood stem cell transplantation

We studied the impact of donor cytomegalovirus (CMV) serologic status on CMV viremia and disease when prophylactic granulocyte colony-stimulating factor (G-CSF)-mobilized granulocyte transfusions (GTs) were given following allogeneic peripheral blood stem cell (AlloPBSC) transplantation. A cohort of 83 patients who received 2 prophylactic GTs from ABO-compatible stem cell donors following AlloPBSC transplantation was compared with a cohort of 142 patients who did not. AlloPBSC donors were eligible for granulocyte donation irrespective of their CMV serostatus. Recipients received no prophylactic therapy for CMV. Donor CMV serostatus had no impact on CMV viremia and disease in the 2 cohorts. Our data show that in an era of effective surveillance and preemptive therapy for CMV, AlloPBSC recipients can safely receive 2 transfusions of prophylactic G-CSF-mobilized granulocyte components from CMV-seropositive AlloPBSC donors. This knowledge may help expand the donor pool in areas with a high prevalence of CMV in the general population.

Immunomodulation of invasive fungal infections

Genetic and acquired (disease- or therapy- related) host immune factors increase the risk for IFIs. In addition to antifungal drug therapy, modulation of host defenses by the use of HGFs and IFN-gamma has been supported by extensive in vitro and in vivo preclinical data. Clinical studies on the prevention or the adjunctive therapy of IFIs in combination with antifungal agents are limited, however, and do not allow specific recommendations for their cost-effective use in most of the immunodeficient settings. There is an urgent need to push forward with well-structured, randomized clinical trials to determine optimal dose, duration, and timing for different combinations of immunotherapy and antifungal agents in high-risk patients.

Granulocyte transfusion therapy for treatment of infections after cytotoxic chemotherapy

Opportunistic fungal infections and antibiotic-refractory bacterial infections remain important causes of morbidity and mortality in neutropenic individuals. Furthermore, the expanding use of dose-intensive cancer treatment strategies has increased the frequency of prolonged neutropenia. Therefore, the transfusion of granulocytes should be a logical therapeutic approach. Substantial progress has been made in the field of granulocyte transfusion therapy during the past decade. Interest in granulocyte transfusion therapy has been rekindled by both the use of hematopoietic growth factors to mobilize neutrophils and modern leukapheresis techniques. Moreover, promising results were observed in the use of community donors and in granulocyte storage experiments, which could enhance the ability of blood banks for institution of granulocyte concentrates. Recent clinical trials suggest that granulocyte transfusion therapy may be effective and well-tolerated in the neutropenic patient affected by life-threatening infections. These results must be confirmed in controlled, clinical trials.

Granulocyte transfusions from G-CSF-stimulated donors for the treatment of severe infections in neutropenic pediatric patients with onco-hematological diseases

From March 1994 to January 2001, 15 courses of granulocyte transfusion (GTX) were administered to 13 neutropenic patients (6 male and 7 female patients; median age 7 years, range 3 months to 14 years) affected by: acute lymphoblastic leukemia (ALL) in 6 cases, acute myeloid leukemia (AML) in 5, very severe aplastic anemia in 1, and familial erythrophagocytic lymphohistiocytosis (FEL) in 1. Infections were classified as microbiologically defined and clinically defined infections in 8 and 7 episodes, respectively. Before the GTX transfusions, broad-spectrum antibacterial and antifungal therapy had been administered for a median of 12 (range 5-28) and 8 days (range 2-50), respectively, with no improvement. G-CSF was administered prior to GTX in 9 episodes of infection, with a median of 9 days of treatment (range 4-30). Leukapheresis was obtained from 15 related donors (father, 10; mother, 3; sister, 1; aunt, 1) after s.c. stimulation with G-CSF, 300 micro g daily, starting from day -3 (where day 0 was the day of the first granulocyte collection) and continuing throughout the period of GTX treatment. The donors' median white blood cell (WBC) count at leukapheresis was 31.6 x 10(9)/l (range 12-56), and the median yield was 31.39 x 10(9) WBC (range 2.96-64.73 x 10(9)), with a proportion of PMN of 90-95%. Overall, 70 GTX were administered, with a median of 4 GTX per episode of infection (range 2-11). The combination of GTX with antimicrobial therapy led to complete or partial recovery in 6 and in 3 of 15 episodes (60%), respectively. Priming of the donor with G-CSF was well tolerated, the most common side-effects being bone pain, malaise and paresthesia. All donors are alive and well after a median of 4.5 years (range 0.8-7.7) from donation. We conclude that GTX is potentially useful when the severity of the infection and the host's immunodeficiency make any other antimicrobial treatment ineffectual. Long-term safety data on the stimulation of donors with G-CSF have been reassuring to date. Further controlled studies are needed to assess the exact role of GTX in the outcome of neutropenic patients with severe infection and any criteria for patient selection and the timing of GTX administration.

Granulocyte transfusion as a treatment for enterococcal meningoencephalitis after allogeneic bone marrow transplantation from an unrelated donor

Bacterial meningoencephalitis occurring in the pre-engraftment period after bone marrow transplantation (BMT) is a rare complication, and the feasibility of granulocyte transfusion (GTX) in such cases remains to be elucidated. A 37-year-old man developed enterococcal meningoencephalitis during a severely granulocytopenic pre-engraftment period after BMT. Despite therapy with appropriate antibiotics, cultures of blood and cerebro-spinal fluid (CSF) continued to grow Enterococcus faecalis, and he developed rapid mental deterioration and seizure. Granulocytes were collected from his HLA-mismatched, ABO-matched sibling with subcutaneous injection of granulocyte colony-stimulating factor (G-CSF) and oral dexamethazone. Transfusion of 4.4 x 10(10) granulocytes resulted in a 12-h post-transfusion granulocyte increment of 2.0 x 10(9)/l, and maintained peripheral blood granulocyte counts above 0.5 x 10(9)/l for 3 days. A rapid increase of granulocytes in CSF was also observed, and cultures of blood and CSF became negative after GTX. A transient worsening of seizure was observed as a potential side effect of GTX. The patient subsequently developed septic shock because of Pseudomonas aeruginosa and died. Further studies are warranted to evaluate the clinical efficacy of GTX for the treatment of uncontrolled infections in granulocytopenic stem cell transplant recipients.

Granulocyte transfusions for neonates with confirmed or suspected sepsis and neutropaenia

BACKGROUND

Neonatal sepsis causes significant neonatal mortality and morbidity. Neonates, especially preterm infants, have an immaturity of granulopoeisis and have a limited capacity for progenitor cell proliferation. This results in the frequent occurrence of neutropaenia in septic neonates. Neutropaenic septic neonates have a higher mortality than neonates who are septic but not neutropaenic. Transfusion of granulocytes to septic neutropaenic neonates, therefore, may help reduce mortality and morbidity.

OBJECTIVES

The primary objective of this review was to determine the efficacy and safety of granulocyte preparations (granulocyte and buffy coat transfusions) as adjuncts to antibiotics for the treatment of confirmed or suspected sepsis in neonates with neutropaenia in reducing all-cause mortality during hospital stay and adverse neurological outcome at a year of age or later. Secondary objectives were to determine the effects of granulocyte transfusions on length of hospital stay in survivors to discharge, adverse effects (fluid overload, transmission of blood borne infections, pulmonary complications and sensitisation to donor leukocyte antigens) and immunologic outcomes at a year of age or later.

SEARCH STRATEGY

Searches for eligible trials were made in September 2002 of the following electronic databases: The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2002), MEDLINE, EMBASE, CINAHL. The proceedings of the Pediatric Academic Societies, which were published in the journal, Pediatric Research, were searched from 1987 onwards. The Cambridge Database of Scientific Abstracts (1982 onwards) and Dissertation Abstracts on disc (1960 onwards) were also searched. Communications with prominent authors in the field and additional searches in the reference lists of identified trials were performed

SELECTION CRITERIA

Randomised and quasi-randomised studies were included, if the participants were neonates with suspected or confirmed sepsis and neutropaenia who received granulocyte preparations (granulocyte concentrates prepared by leukophoresis or buffy coat transfusions prepared by simple centrifugation of blood) at any dose or duration compared with placebo or no granulocyte transfusion, each as adjuncts to antibiotics or compared to other adjuncts to antibiotics to treat sepsis (e.g. intravenous immunoglobulin). Studies were included if any of the following outcomes were reported: all-cause mortality during hospital stay, neurological outcome at one year of age or later, length of hospital stay in survivors at discharge, adverse effects or immunological outcome at one year or later

DATA COLLECTION AND ANALYSIS

Trials identified by the search strategy were assessed for eligibility for inclusion in the review. Full text versions of the eligible trials were obtained. Data of interest were extracted on paper forms. Relative risk (RR) and risk difference (RD) with 95% confidence intervals using the fixed effects model were reported for dichotomous outcomes. Pre-specified subgroup analyses were done and reported.

MAIN RESULTS

Four eligible studies were identified. A total of 44 infants with sepsis and neutropaenia on antibiotics were randomised in three trials to granulocyte transfusions OR placebo/no transfusion. In another trial, 35 infants with sepsis and neutropaenia on antibiotics were randomised to granulocyte transfusion or intravenous immunoglobulin. When granulocyte transfusions were compared with placebo or no transfusion, there was no significant difference in all-cause mortality [typical RR 0.89 (95% CI 0.43, 1.86), typical RD -0.05 (95% CI -0.31, 0.21)]. There was no statistical heterogeneity in the results of the included trials. When granulocyte transfusions were compared with intravenous immunoglobulin, there was a reduction in all-cause mortality of borderline statistical significance [RR 0.06 (95% CI 0.00, 1.04), RD -0.34(95% CI -0.60, -0.09), NNT 2.9 (95% CI 1.7, 11.1)]. Pulmonary complication, seen in four infants (4%), was the only adverse effect reported. This adverse effect was noticed in the two trials which used buffy coat transfusions. None of the trials reported on neurological outcome at one year of age or later, length of hospital stay in survivors to discharge or immunological outcome at one year of age or later.

REVIEWER'S CONCLUSIONS

Currently, there is inconclusive evidence from RCTs to support or refute the routine use of granulocyte transfusions in neonates with sepsis and neutropaenia to reduce mortality and morbidity. Researchers can be encouraged to conduct adequately powered multicentre trials of granulocyte transfusions to clarify their role in neonates with sepsis and neutropaenia. Other adjuncts to antibiotics aimed at improving host defence mechanisms such as colony stimulating factors, IVIG and pentoxifylline should also be tested in RCTs.

Granulocyte transfusion in the G-CSF era

Granulocyte transfusions have been used since the 1960s with varying degrees of clinical success in the treatment of infection in patients with neutropenia or inherited granulocyte disorders. A number of studies have indicated that efficacy may well be associated with the dose of granulocytes delivered. Collection of granulocytes using modern apheresis machines and corticosteroid administration yields approximately 20 to approximately 30 x 10(9) neutrophils, unlikely to be adequate for treating an established infection. The administration of G-CSF to healthy donors has resulted in average granulocyte yields up to 8 x 10(10) cells. Normal or near normal blood neutrophil counts are often attained when these concentrates are transfused to neutropenic recipients, and these levels are sustained for up to 24 h. G-CSF-primed granulocytes appear to be functionally normal by both in vitro and in vivo measurements. Adverse effects experienced by recipients are similar to those seen with traditional doses of granulocytes. G-CSF administration to donors is well tolerated. Controlled clinical trials are needed to determine the therapeutic efficacy of G-CSF-primed granulocyte transfusions.

Current treatment options for chronic granulomatous disease

Chronic granulomatous disease is a rare inherited disorder of phagocytic cells which results in a susceptibility to infections of catalase-positive bacteria and fungi (especially Aspergillus species), as well as granuloma formation. The mainstay of therapy is antibacterial and antifungal prophylaxis. Trimethoprim sulfamethoxazole is the drug of choice for the prevention of bacterial infection, while itraconazole is most widely used for the prevention of fungal infection. Immunomodulatory agents, such as IFN-phi, have a role in the prevention and treatment of intractable infection. New antifungal agents provide the promise of improved cure rates for invasive Aspergillus, while bone marrow transplants and gene therapy may offer the promise of complete cure.

Granulocyte transfusion: a review

Neutrophils are the body's main defence against invasion by bacteria and fungi and, below a level of 1 x 10(9)/l, there is a direct relationship between their circulating number and the risk of systemic infection. Despite advances in supportive care, such as improved broad-spectrum antibiotics and the haemopoietic growth factors, neutropenia following myelosuppressive chemotherapy for malignant disease remains the most important cause of treatment-related morbidity and mortality and its most important dose-limiting toxicity. Although there is clear theoretical, experimental and anecdotal clinical evidence supporting the use of transfused granulocytes to prevent and treat infection in neutropenia, early attempts at exploiting this clinically were unsuccessful, mainly because of difficulties in collecting a sufficient number of cells. Improvements in the technology of collection, including the use of red cell sedimenting agents, glucocorticoids and, more recently, granulocyte-colony-stimulating factor, now allow granulocyte doses within the therapeutic range to be routinely collected. Preliminary evidence suggests clinical efficacy. However, well-designed trials with clinically relevant end-points will be required before granulocyte transfusion can become part of routine clinical practice.

[Granulocytes transfusion for neutropenic patients]

A renewed interest in the transfusion of granulocytes for support of patients afflicted by severe and prolonged neutropenia has resulted from improved methods of mobilization and collection that provide cellular products superior in number and functions as compared with historical experiences of the 70's. In this review we discuss the clinical experience reported in the literature over the past three decades, the progress made in donor selection, the use of growth factors and mechanical apheresis. We comment on adverse effects, emphasize present indications and our own experience for the use of granulocyte transfusions. Hopefully, the progress made in this area will justify the consideration of granulocyte transfusions in the management of the severely neutropenic patient and provide proper documentation to avoid repeating the disappointment experienced in the previous two decades.

Granulocyte transfusion therapy: update on potential clinical applications

The clinical usefulness of granulocyte transfusions for treatment or prevention of life-threatening bacterial and fungal infections remains controversial. Clinical benefit has long been limited by insufficient donor stimulation regimens and suboptimal leukapheresis techniques. Methodologic progress, in particular mobilization of neutrophils in healthy donors by administration of G-CSF, has significantly enhanced leukapheresis yields. A newly published study indicates that unrelated community donors can be effectively and safely used as an alternative to related family donors. Furthermore, several recent studies suggest that it may be possible to store granulocyte concentrates for 24 to 48 hours with adequate preservation of neutrophil function. This review summarizes the current role of granulocyte transfusion therapy in infectious diseases and highlights important recent advances.

Successful treatment of invasive aspergillosis in chronic granulomatous disease by granulocyte transfusions followed by peripheral blood stem cell transplantation

Chronic granulomatous disease (CGD) is a primary immunodeficiency disorder characterized by impaired microbial killing and susceptibility to bacterial and fungal infections. Cure of the disease can be achieved by stem cell transplantation when performed early in its course, and before severe infections have developed. Invasive aspergillosis constitutes a very high risk for transplantation. We report a 4-year-old boy with X-linked CGD who underwent successful HLA-identical peripheral blood stem cell (PBSC) transplantation during invasive pulmonary aspergillosis and osteomyelitis of the left fourth rib, which was unresponsive to antifungal treatment. During the 2 months prior to the transplant he received G-CSF-mobilized granulocyte transfusions (GTX) from unrelated donors three times a week in addition to the antifungal treatment. This resulted in clinical improvement in his respiratory status. He also received GTX during the aplastic period after the conditioning regimen, until he had engrafted. Post-transplant superoxide generation test revealed that neutrophil function was within normal range. One year post transplant the CT scan showed almost complete clearance of the pulmonary infiltrates and a marked improvement in the osteomyelitic process. Based on other reports and our own experience, GTX can serve as important treatment in patients with CGD who have failed conventional anti-fungal treatment and for whom stem cell transplantation is the only chance for cure.

Feasibility and recent improvement of autologous stem cell transplantation for acute myelocytic leukaemia in patients over 60 years of age: importance of the source of stem cells

A total of 193 patients with acute myelocytic leukaemia (AML) [147 in first complete remission (CR1)], ranging from 60 years to 75 years of age (median 63 years), were autografted between January 1984 and December 1998. The source of stem cells was peripheral blood (PB) in 128 patients, bone marrow in 51 patients and a combination of both in 14 patients. Total body irradiation (TBI) was used in 34 cases. Ninety-seven per cent of patients had successful engraftment of neutrophils on day 15 (range days 7-71) and of platelets on day 30 (range days 9-894). In patients autografted in CR1, the transplant-related mortality (TRM) was 15 +/- 4%, the relapse incidence (RI) was 58 +/- 5%, the leukaemia-free survival (LFS) was 36 +/- 5% and the overall survival was 47 +/- 5% at 3 years. The source and dose of stem cells were studied in particular; in patients transplanted in CR1, the RI was 44 +/- 11% in those receiving marrow compared with 63 +/- 6% in those receiving PB (P = 0.04). Patients autografted in CR1 who received higher granulocyte-macrophage colony-forming units (CFU-GM) doses (above the median) had a lower RI (47 +/- 11% vs. 79 +/- 9%, P = 0.009). There was a significant improvement in patients transplanted after March 1996; for those in CR1, the RI was 41 +/- 8% vs. 65 +/- 6% (P = 0.01), the LFS was 53 +/- 8% vs. 28 +/- 5% (P = 0.01) and the overall survival was 72 +/- 7% vs. 36 +/- 6% (P = 0.02). By multivariate analyses, significant factors for the outcome were the date of transplant with recent improvement and the source of stem cells, with a lower RI for marrow. Autologous stem cell transplantation (ASCT) is a potential therapeutic approach in patients with AML over 60 years of age; results have improved recently.

Storage of G-CSF-mobilized granulocyte concentrates

BACKGROUND

Current standards limit granulocyte storage to 24 hours. Since G-CSF inhibits granulocyte apoptosis, it may be possible to store G-CSF-mobilized granulocytes for longer periods while maintaining cell viability and function. However, G-CSF mobilization increases the yield of granulocytes several times, and the resulting higher cell concentrations may diminish viability during storage and significant levels of pyrogenic cytokines may be produced.

STUDY DESIGN

Ten granulocyte donors were given dexamethasone (8 mg PO), G-CSF (5 microg/kg SQ), or both and on the next day granulocyte concentrates were collected using a blood cell separator. Component cell counts, cell viablilities, pH, and IL-1beta, IL-6, IL-8 and TNF levels were measured at 2 to 4 (2), 20 to 28 (24), and 44 to 52 hours (48 hours).

RESULTS

Significantly more granulocytes were collected when donors were given G-CSF (4.2 +/- 2.3 x 10(10)) or G-CSF plus dexamethasone (6.4 +/- 2.5 x 10(10)) compared with that collected with dexamethasone alone (2.2 +/- 1.2 x 10(10)); p = 0.03 and p = 0.002, respectively. Storage had little effect on WBC count. Slight but significant increases in IL-1beta and IL-8 occurred after 24 and 48 hours as compared to the levels at 2 hours' storage. Levels of IL-6 and TNF did not change. The pH dropped significantly with time in granulocytes mobilized with each regimen. Granulocytes mobilized with G-CSF plus dexamethasone were acidic immediately after collection, and pH was below 6.0 after 24 hours. To assess the effect of cell concentrations on pH, serial dilutions were performed on 13 granulocyte concentrates in autologous plasma prior to storage. The pH remained above 7.0 only when dexamethasone-mobilized granulocytes were diluted 1-in-8 and when the G-CSF plus dexamethasone-mobilized granulocytes were diluted 1-in-16.

CONCLUSIONS

To optimize storage pH, mobilized granulocyte concentrates require a 1-in-8 to 1-in-16 dilution, which is operationally impractical. Clinical-grade granulocyte preservative solutions are needed to maintain pH during storage.