Dosage and scheduling regimens for erythrocyte-sedimenting macromolecules

Granulocyte transfusions in the management of invasive fungal infections

Granulocyte transfusions have a long history of being used in patients with neutropenia or neutrophil dysfunction to prevent and treat invasive fungal infections. However, there are limited and conflicting data concerning its clinical effectiveness, considerable variations in current granulocyte transfusion practices, and uncertainties about its benefit as an adjunct to modern antifungal therapy. In this review, we provide an overview on granulocyte transfusions and summarize the evidence on their role in the prevention and treatment of invasive fungal infections.

Therapeutic transfusions of granulocytes collected by simple bag method for children with cancer and neutropenic infections: results of a single-centre pilot study

BACKGROUND AND OBJECTIVES

Granulocyte transfusion therapy (GTX) can be effective for life-threatening infections unresponsive to conventional antimicrobial therapies in severely neutropenic children with cancer. We developed a new granulocyte collection method, named the 'bag method', in which apheresis, hydroxyethyl starch (HES) or dexamethasone are not used. We undertook a pilot study to determine the feasibility and the safety of GTX collected by the bag method for children with cancer and life-threatening infections.

MATERIALS AND METHODS

A total of 25 GTX were administered to 13 patients (median age 3 years, range: 0.3-17; median weight 10.6 kg, range: 4.5-49.8) with neutropenia-related infections. Thirteen blood-relative donors received granulocyte colony-stimulating factor (G-CSF) (5-10 microg/kg), subcutaneously, 14 h before collection. Major end-points were granulocyte yields, post-transfusion absolute neutrophil counts (ANC) in patients, donor and patient safety, and clinical outcome on day 30.

RESULTS

The median yield of ANC per 400 ml of processed whole blood was 6.2 x 10(9) (range: 2.5-15.0 x 10(9)). Patients received a mean of 6.4 +/- 0.8 x 10(8) granulocytes per kg of body weight per transfusion. The 1-h and 24-h post-transfusion ANC rose to 607 +/- 124/microl and 704 +/- 300/microl, respectively, from the baseline of 21/microl before the first GTX. Adverse reactions were observed in five of 13 donors (bone pain, headache, vasovagal reaction; all < or = grade 2) and in two of 25 transfusions of 13 patients (transient hypoxia; grade 3). Ten patients had favourable responses, and infection resolved in nine patients.

CONCLUSIONS

The bag method without apheresis relieves the physical load of donors and enables patients with a low body weight to provide an adequate dose of granulocytes.

Collection by a Simple Bag Method and the Function of Granulocytes in Granulocyte Transfusion

Granulocyte transfusion is effective for treating some intractable infections. We have recently developed a simple bag method for collecting granulocytes without using apheresis. A recombinant human granulocyte colony-stimulating factor (G-CSF) (50, 100, 200, and 400 microg nartograstim) was administered to 5 healthy male adult volunteers. The quantity and quality of the collected granulocytes were evaluated. The G-CSF dose proportionally increased the collected neutrophil count. The count of collected neutrophils correlated strongly with the count before collection (r2 = 0.684; P < .001). The neutrophil counts collected from 200 mL whole blood were 0.90 x 10(9), 1.68 x 10(9), 2.40 x 10(9), and 2.99 x 10(9) at 50, 100, 200, and 400 microg G-CSF, respectively. There was no significant difference in neutrophil counts between the 200-microg and 400-microg doses. doses. Concerning granulocyte functions, active oxygen production and phagocytic capacity were not affected by irradiation with 15 Gy. Transient arthralgia occurred in 2 subjects. A single administration of 200 microg G-CSF enabled the collection of large quantities of granulocytes by the bag method. We consider that the collection of granulocytes by the bag method from 400 mL of whole blood drawn twice can theoretically provide 3 x 10(8)/kg of granulocytes for treating children weighing less than 30 kg.

Effect of intravenous hydroxyethyl starch on the accuracy of measuring hemoglobin concentration

STUDY OBJECTIVE

To determine if intravenous hydroxyethylstarch (HES) affects the accuracy of hemoglobin (Hb) measurements, as artificial colloids are known to increase red blood cell sedimentation rates.

DESIGN

Prospective, randomized study.

SETTING

Tertiary-care academic medical institution.

PATIENTS AND INTERVENTIONS

We randomized 40 surgical American Society of Anesthesiologists (ASA) physical status I and II patients undergoing preoperative autologous blood donation before elective orthopedic surgery. Patients were randomized to receive volume replacement with 500 mL of 6% HES 200,000/0.5 or 500 mL of electrolyte solution. Measurements of Hb concentration and leukocyte count were performed using an analyzer with a suction needle sampling from the bottom of the test tube. Measurements were performed after mixing and repeated after a 10-minute period of upright positioning of the tube (at rest).

MAIN RESULTS

In the study group that received HES, Hb levels were increased above baseline after resting (mean increase to 151% of baseline values, P < .01), whereas the leukocyte count was decreased (mean decrease to 39% of baseline values, P < .01). No difference between baseline and resting measurements were observed in patients who received intravenous crystalloids. In addition, we repeatedly measured the Hb concentration in an unstirred tube with and without the addition of HES. In blood samples containing HES, the Hb concentration was increased above baseline after 2.5 minutes of resting, compared with 30 minutes without HES addition (P < .05).

CONCLUSIONS

Mixing of test tube contents before sampling is critical for accurate measurement of the Hb concentration in the blood of patients who received intravenous HES.

Tolerance of granulocyte donors towards granulocyte colony-stimulating factor stimulation and of patients towards granulocyte transfusions: results of a multicentre study

Data of 507 granulocyte donations from 183 donors were evaluated. No severe granulocyte colony-stimulating factor (G-CSF)-related side-effects were observed. Three donors complained of severe itching following infusion of hydroxyethyl starch (HES). A high proportion (85%) of the donors stated that they would donate granulocytes again. The mean granulocyte yield was 4.3 x 10(10). High-molecular-weight HES resulted in a significantly higher yield compared with low-molecular-weight HES. Mild, but no severe, adverse transfusion reactions were observed in 16% of the recipients. A leucocyte alloimmunization rate of 24% was found. G-CSF stimulation and transfusion of G-CSF-mobilized granulocytes were well tolerated by donors and recipients, respectively.

Partial colloid starch replacement for therapeutic plasma exchange

Traditionally protein solutions have been used as the replacement solution of choice during therapeutic plasma exchange (TPE). Treatment protocols vary, but neurology patients, who exhibit autonomic instability, are typically replaced entirely with 5% protein solution. Due to sporadic product shortages and the increasing cost of protein solutions, we evaluated the use of 6% and 3% hetastarch (HES) as partial replacement during TPE. All adult neurology patients with normal liver, heart, and kidney function were evaluated for HES replacement. The first seven patients (33 procedures) received 1000 ml of 6% hetastarch as part of their replacement fluid and the next 42 patients (289 procedures) received 1000 ml of 3% HES as part of their replacement fluid. Three patients crossed over into both groups. Patients were evaluated for signs of peripheral edema, evidence of bleeding, skin rash, and any subjective changes. Total protein albumin, osmolality, PT, and aPTT were measured prior to each procedure in the first five patients in each group. In both groups there was a drop in total protein, but all other lab values returned to normal limits within 48 hours of treatment. One patient reported slight peripheral edema after two procedures. In the 3% HES group the BP and P remained stable in 97.3% (280) procedures. Two patients receiving 6% HES and 1 patient receiving 3% HES complained of severe transient back and head pain during HES infusion. There was no evidence of bleeding or subjective changes. Three percent HES is a safe and cost-effective partial replacement for albumin during TPE.

Alternatives to albumin: starch replacement for plasma exchange

Today, albumin, or a combination of saline and albumin, is used and widely accepted as a replacement for routine plasma exchange. However, decreased availability (due to market recalls secondary to Creutzfeld-Jacob or bacterial contamination risk) rising costs, recognition of drug interactions with albumin (i.e., ACE inhibitors) and a fear of disease transmission have led several groups to reconsider the use of colloid starches as partial or full replacement for plasma during plasma exchange. There are two hydroxyethyl starches: hetastarch (Hespan and Pentaspan) currently licensed for human use in the United States. While both are approved for granulocyte collection only Hespan is approved as a plasma volume expander. Anecdotal experience and limited reports in the literature with the use of starches as a replacement for plasma exchange suggest that such starch products are a reasonable replacement for albumin as an initial wash-out fluid or in combination with either albumin or saline. Kinetic modeling of the wash-out of starch used as a replacement fluid demonstrate that relatively little residual starch remains compared to the total amount infused. Hydroxyethyl starches are biochemically similar to glycogen, which likely explains the lack of immunogenicity and lack of adverse reactions. Substantial cost savings are associated with the substitution of starch for albumin. It is concluded that HES is well-tolerated and cost-effective as full or partial volume replacement with plasma exchange. It is anticipated that the use of HES will emerge as a standard of care in apheresis.

Hydroxyethyl starch reduces the chemotaxis of white cells through endothelial cell monolayers

BACKGROUND

Polymorphonuclear leukocytes (PMNs) play a tremendous role during inflammatory processes. PMNs have to pass a monolayer of endothelial cells to migrate into the extravascular space. Hydroxyethyl starch (HES) is frequently used as a volume expander in critically ill patients.

STUDY DESIGN AND METHODS

The aim of this study was to investigate whether HES influences the chemotaxis of PMNs through endothelial cell monolayers by using a test system that allows the simultaneous treatment of both cell types. Human umbilical endothelial cells were cultured on microporous membrane filters. PMNs were isolated and PMN chemotaxis was studied.

RESULTS

The number of untreated PMNs that migrated through untreated endothelial cell monolayers in response to a chemoattractant was used as a control and set as 100 percent. In clinically relevant concentrations, HES was able to significantly decrease PMN chemotaxis through endothelial cell monolayers, showing a dose-dependent effect (0.1 mg/mL: 99.6 +/- 10.9%, p = NS compared to control; 1 mg/mL: 82.4 +/- 8.3%, p<0.05 compared to control; 10 mg/mL: 62.9 +/- 11.7%, p<0.05). In this assay, both cell types (PMNs and endothelial cells in the monolayer) were treated simultaneously, which simulated the clinical situation after an intravenous injection of HES. The treatment of one cell type, PMNs (89.6 +/- 8.8%, p<0.05) or endothelial cells in the monolayer (76.2 +/- 9.4%, p<0.05), suggests that the influence on endothelial cells is greater.

CONCLUSION

HES is able to significantly reduce the chemotaxis of PMNs through endothelial cell monolayers. The possible clinical consequence of a moderate reduction in endothelium-mediated PMN chemotaxis in critically ill patients remains to be evaluated.

Transfusion and stem cell support in cancer treatment

Intensification of therapeutic regimens, improved patient survival, and advances in cytokine and cellular therapies have led to increasingly complex requirements for transfusion and stem cell support in cancer treatment. This article focuses on current and evolving issues in red blood cell, platelet, and granulocyte transfusion support, as well as measures to avoid increasingly important complications of transfusion therapy, such as alloimmunization, graft-versus-host disease, cytomegalovirus infection, and immunomodulation. Issues concerning current applications of hematopoietic stem cell transplantation and future prospects also are discussed.

Washout kinetics of colloidal starch as a partial or full replacement for plasma exchange

Colloidal starch has been used safely as a plasma expander and an erythrocyte sedimenting agent for over 25 years. However, there remains some concern in regard to the long term sequelae of the administration of large volumes of colloid starch such as would be administered if colloidal starch were used as a plasma replacement during serial plasma exchanges. We identified mathematical relations that allowed for the calculations of the theoretical circulating residual starch in a patient undergoing serial plasma exchanges and used it to model a variety of possible clinical scenarios. Following six one plasma volume exchanges, one would expect only 11, 13, 14, or 17% of the total infused starch to be remaining in the circulation. For example, in the case of a 4L exchange with full replacement, only the starch in 4.1 liters (4L x 6 exchanges x 17% = 4.1L) would be expected to remain in the circulation despite an infusion of 24 L (4L x 6 exchanges = 24L) of starch. The results suggest that relatively small amounts of starch would be expected to remain circulating relative to the large amounts infused following a series of plasma exchanges with partial or full starch replacement.

Efficacy of pentastarch in granulocyte collection by centrifugal leukapheresis

The efficacy of 6% hydroxyethyl starch (hetastarch, HS) in enhancing granulocyte harvest by centrifugal leukapheresis has been described by a simple equation which predicts the granulocyte collection efficiency (GCE) based on an intrinsic donor variable, the erythrocyte sedimentation rate (ESR): GCE(%) = 1.3 ESR (mm/hr) + 45. Ten percent low molecular weight hydroxyethyl starch (pentastarch, PS) has been reported to be as effective as HS with potentially fewer adverse donor reactions (ADR). The derivation of an analogous equation for PS under conditions previously reported for HS may quantify PS efficacy and allow comparison to HS. We prospectively measured the in vitro and the in vivo effects of PS on the donor ESR in 53 granulocyte collections from 44 donors using the model CS-3000 Plus blood cell separator (CS). We then correlated the findings with the GCE of each procedure and derived an equation which expresses GCE in terms of baseline donor ESR. The in vitro addition of PS increased the donor ESR 2.4-fold, but its administration to a donor during a collection procedure did not appreciably change the ESR. Higher baseline donor ESR was more likely to result in more efficient cell collections: GCE (%) = 0.8 ESR (mm/hr) + 20; (r = 0.37). For granulocyte harvests using the CS and PS as the sedimenting agent 1) baseline donor ESR affects granulocyte harvests, but the poor correlation does not allow an accurate prediction of GCE and cell yield from the baseline donor ESR; 2) in comparison with HS (results from a previous study), PS may be less effective in vitro and not effective in vivo in elevating ESR, and may be less effective in enhancing granulocyte harvest; and 3) the parameters (slope, y-intercept, correlation coefficient) which define the linear relationship between baseline donor ESR and GCE may serve collectively as a quantitative measure of the effectiveness of different hydroxyethyl starch agents in enhancing granulocyte harvests. These parameters may be helpful in rapidly assessing the clinical efficacy of new, potentially useful hydroxyethyl starch agents prior to initiating a randomized, controlled clinical trial.

Blood center perspective of granulocyte transfusions: future applications

The role of the blood bank in provision of an optimal granulocyte concentrate is discussed. The importance of the granulocyte dose is emphasized, and recent developments permitting the collection of larger numbers of cells are reviewed. In particular, the administration of granulocyte colony-stimulating factor to normal donors has been reported to result in dramatically increased neutrophil yields. Recent data has also suggested that increased efficiencies of collection can be realized by the use of hetastarch as the red cell sedimenting agent.

A comparison of 10% pentastarch and 5% albumin in patients undergoing open-heart surgery

Colloids are useful in cardiac surgery to increase preload and improve cardiac output without the risks associated with blood transfusions. Pentastarch is a new low-molecular weight hydroxyethyl starch compound under investigation for this purpose. The authors compared, in a randomized fashion, 12 patients who received pentastarch and 17 patients who received albumin for volume expansion after open-heart surgery. During the 24-hour study period there was no significant difference between the two groups with respect to systemic blood pressure, mean arterial pressure, cardiac index, right atrial pressure, and pulmonary capillary wedge pressure, with the exception of a higher mean arterial pressure and systolic blood pressure at 4 hours in the albumin group and higher heart rate at 12 hours in the pentastarch group. In addition, postoperative prothrombin time, partial thromboplastin time, fibrinogen, platelets, and factor VIII levels were not significantly different between the two groups. There were no complications attributed to colloid administration. The hemodynamic parameters were further evaluated in a subset of 6 pentastarch and 9 albumin patients who received the first 500 mL of colloid in a similar time frame and under similar clinical conditions. The patients who received pentastarch showed a significantly greater increase in cardiac index than did the patients who received albumin. No significant change in other parameters were noted between the two groups. The authors conclude that pentastarch is as safe as albumin and may be a more effective volume expander than albumin when used in open-heart surgery patients.