Plasma collection and supply in Europe: Proceedings of an International Plasma and Fractionation Association and European Blood Alliance symposium.

At the symposium organized by the International Plasma and Fractionation Association and European Blood Alliance, experts presented their views and experiences showing that the public sector and its blood establishments may strengthen the collection and increase the supply of plasma using the right strategies in plasma donor recruitment, retention and protection, scaling-up collection by increasing the number of donors within improved/new infrastructure, supportive funding, policies and legislation as well as harmonization of clinical guidelines and the collaboration of all stakeholders. Such approaches should contribute to increased plasma collection in Europe to meet patients' needs for plasma-derived medicinal products, notably immunoglobulins and avoid shortages. Overall, presentations and discussions confirmed that European non-profit transfusion institutions are committed to increasing the collection of plasma for fractionation from unpaid donors through dedicated programmes as well as novel strategies and research.

Transferrin therapy ameliorates disease in beta-thalassemic mice.

Individuals with beta-thalassemia develop progressive systemic iron overload, resulting in high morbidity and mortality. These complications are caused by labile plasma iron, which is taken up by parenchymal cells in a dysregulated manner; in contrast, erythropoiesis depends on transferrin-bound iron uptake via the transferrin receptor. We hypothesized that the ineffective erythropoiesis and anemia observed in beta-thalassemia might be ameliorated by increasing the amount of circulating transferrin. We tested the ability of transferrin injections to modulate iron metabolism and erythropoiesis in Hbb(th1/th1) mice, an experimental model of beta-thalassemia. Injected transferrin reversed or markedly improved the thalassemia phenotype in these mice. Specifically, transferrin injections normalized labile plasma iron concentrations, increased hepcidin expression, normalized red blood cell survival and increased hemoglobin production; this treatment concomitantly decreased reticulocytosis, erythropoietin abundance and splenomegaly. These results indicate that transferrin is a limiting factor contributing to anemia in these mice and suggest that transferrin therapy might be beneficial in human beta-thalassemia.

Non-transferrin-bound iron in haematological patients during chemotherapy and conditioning for autologous stem cell transplantation.

Free iron induced hydroxyl radical formation is one possible mechanism for tissue injury during cytotoxic therapy. We studied the appearance of free, non-transferrin-bound iron (NTBI) at baseline and during the 20-d period after the onset of cytotoxic chemotherapy in patients with haematological malignancy undergoing intensive chemotherapy or conditioning for autologous stem cell transplantation (aSCT). NTBI was detected on average for 15.6 d in patients treated with chemotherapy only, and for 6.1 d in patients undergoing aSCT. The recovery of the bone marrow function coincided with the disappearance of NTBI. The type of the conditioning regimen was also associated with the appearance of NTBI. The timing of the presence of NTBI accords with the presence of the most important non-infectious complication of intensive chemotherapy and autologous transplantation, mucosal injury, and free iron is likely to contribute to this and probably other complications of the intensive treatments.

Effect of repeated apotransferrin administrations on serum iron parameters in patients undergoing myeloablative conditioning and allogeneic stem cell transplantation.

Myeloablative conditioning prior to allogeneic stem cell transplantation causes a rapid increase in transferrin saturation and potentially toxic non-transferrin-bound iron (NTBI) in plasma. We have studied the ability of repeatedly administered apotransferrin to maintain this iron in a transferrin-bound form. Twenty adult patients undergoing myeloablative conditioning and allogeneic stem cell transplantation were enrolled to receive apotransferrin with one of three dosage regimens. Ten consecutive patients with the same preconditioning were studied as controls. At the highest dose level, full transferrin saturation and appearance of NTBI were prevented in five of the eight patients. Serum iron increased significantly more in the patients receiving apotransferrin than in the controls and remained elevated until erythropoietic recovery. From the increment of iron saturation and the amount of endogenous and administered apotransferrin, an average 180 mumol of iron per day was bound to transferrin during the first 4 d after the start of the conditioning therapy. Thereafter, iron accumulation levelled off in most patients. The results suggested that about half of the amount of iron normally transported to erythropoiesis was initially released to plasma after induction of the erythroid arrest. Complete iron binding with apotransferrin would apparently require very high apotransferrin doses.

Results of an international round robin for the quantification of serum non-transferrin-bound iron: Need for defining standardization and a clinically relevant isoform.

Non-transferrin-bound iron (NTBI) appears in the circulation of patients with iron overload. Various methods to measure NTBI were comparatively assessed as part of an international interlaboratory study. Six laboratories participated in the study, using methods based on iron mobilization and detection with iron chelators or on reactivity with bleomycin. Serum samples of 12 patients with hereditary (n=11) and secondary (n=1) hemochromatosis were measured during a 3-day analysis using 4 determinations per sample per day, making a total of 144 measurements per laboratory. Bland-Altman plots for repeated measurements are presented. The methods differed widely in mean serum NTBI level (range 0.12-4.32mumol/L), between-sample variation (SD range 0.20-2.13mumol/L and CV range 49.3-391.3%), and within-sample variation (SD range 0.02-0.45mumol/L and CV range 4.4-193.2%). The results obtained with methods based on chelators correlated significantly (R(2) range 0.86-0.99). On the other hand, NTBI values obtained by the various methods related differently from those of serum transferrin saturation (TS) when expressed in terms of both regression coefficients and NTBI levels at TS of 50%. Recent studies underscore the clinical relevance of NTBI in the management of iron-overloaded patients. However, before measurement of NTBI can be introduced into clinical practice, there is a need for more reproducible protocols as well as information on which method best represents the pathophysiological phenomenon and is most pertinent for diagnostic and therapeutic purposes.

Erratum to "Apotransferrin administration prevents growth of Staphylococcus epidermidis in serum of stem cell transplant patients by binding of free iron". [FEMS Immunol. Med Microbiol. 37 (2003) 45-51].

We investigated the effect of free, non-transferrin-bound iron occurring in haematological stem cell transplant patients on growth of Staphylococcus epidermidis in serum in vitro, and prevention of bacterial growth by exogenous apotransferrin. S. epidermidis did not grow in normal serum at inoculated bacterial densities up to 10(3) cfu ml(-1) but slow growth could be detected at higher initial inocula. Addition of free iron abolished the growth-inhibitory effect of serum, whereas addition of apotransferrin again restored it. Appearance of free iron and loss of growth inhibition coincided in patient serum samples taken daily during myeloablative therapy. Intravenously administered apotransferrin effectively bound free iron and restored the growth inhibition in patient sera. The results suggest that exogenous apotransferrin might protect stem cell transplant patients against infections by S. epidermidis and possibly other opportunistic pathogens.

Reduction of circulating redox-active iron by apotransferrin protects against renal ischemia-reperfusion injury.

BACKGROUND: Warm ischemia-reperfusion (I/R) injury plays an important role in posttransplant organ failure. In particular, organs from marginal donors suffer I/R injury. Although iron has been implicated in the pathophysiology of renal I/R injury, the mechanism of iron-mediated injury remains to be established. The authors therefore investigated the role of circulating redox-active iron in an experimental model for renal I/R injury. METHODS: Male Swiss mice were subjected to unilateral renal ischemia for 45 min, followed by contralateral nephrectomy and reperfusion. To investigate the role of circulating iron, mice were treated with apotransferrin, an endogenous iron-binding protein, or iron-saturated apotransferrin (holotransferrin). RESULTS: Renal ischemia induced a significant increase in circulating redox-active iron levels during reperfusion. Apotransferrin, in contrast to holotransferrin, reduced the amount of circulating redox-active iron and abrogated renal superoxide formation. Apotransferrin treatment did not affect I/R-induced renal apoptosis, whereas holotransferrin aggravated apoptotic cell death. Apotransferrin, in contrast to holotransferrin, inhibited the influx of neutrophils. Both apo- and holotransferrin reduced I/R-induced complement deposition, indicating that the effects of transferrin are differentially mediated by its iron and protein moiety. Finally, apotransferrin, in contrast to holotransferrin, dose-dependently inhibited the loss of renal function induced by ischemia. CONCLUSIONS: Redox-active iron is released into the circulation in the course of renal I/R. Reducing the amount of circulating redox-active iron by treatment with apotransferrin protects against renal I/R injury, inhibiting oxidative stress, inflammation, and loss of function. Apotransferrin could be used in the treatment of acute renal failure, as seen after transplantation of ischemically damaged organs.

Apotransferrin administration prevents growth of Staphylococcus epidermidis in serum of stem cell transplant patients by binding of free iron.

We investigated the effect of free, non-transferrin-bound iron occurring in haematological stem cell transplant patients on growth of Staphylococcus epidermidis in serum in vitro, and prevention of bacterial growth by exogenous apotransferrin. S. epidermidis did not grow in normal serum at inoculated bacterial densities up to 10(3) cfu ml(-1) but slow growth could be detected at higher initial inocula. Addition of free iron abolished the growth-inhibitory effect of serum, whereas addition of apotransferrin again restored it. Appearance of free iron and loss of growth inhibition coincided in patient serum samples taken daily during myeloablative therapy. Intravenously administered apotransferrin effectively bound free iron and restored the growth inhibition in patient sera. The results suggest that exogenous apotransferrin might protect stem cell transplant patients against infections by S. epidermidis and possibly other opportunistic pathogens.

Effective binding of free iron by a single intravenous dose of human apotransferrin in haematological stem cell transplant patients.

Myeloablative treatment results in iron accumulation and the appearance of non-transferrin-bound iron (NTBI) in the circulation, which may contribute to treatment-related organ damage and susceptibility to infections. The aim of this study was to investigate the efficacy of human apotransferrin in the binding of NTBI in patients receiving an allogeneic stem cell transplant after myeloablative conditioning. A single intravenous 100 mg/kg dose of apotransferrin was given to six adult patients on d 3 after the transplantation. Initially, all patients had serum transferrin saturation above 80% and NTBI in their serum. After the apotransferrin injection, serum NTBI became undetectable in all patients and transferrin saturation decreased to 30-50%. Serum transferrin increased by an average of 1.95 g/l. The administered apotransferrin was subsequently converted into monoferric and diferric transferrin forms. NTBI reappeared and transferrin saturation again exceeded 80% 12-48 h after the injection in four patients and after 6 d in one patient. NTBI remained non-detectable for the whole 12 d follow-up period in one patient. The apotransferrin injection was well tolerated and no adverse events with probable association with the apotransferrin were observed. Repeated apotransferrin infusions might completely eliminate NTBI and iron-induced toxicity during myeloablative therapy.

Bleomycin-detectable iron assay for non-transferrin-bound iron in hematologic malignancies.

BACKGROUND: A microwell modification of the bleomycin assay for determining non-transferrin-bound iron (NTBI) was evaluated and compared with a chelation method. METHODS: The bleomycin assay reagent and sample volumes were halved, and measurements were done in microwell plates. Samples from patients treated for hematologic malignancies were studied. The chelation method was based on mobilization of NTBI with a chelator and measurement of the ultrafiltered iron-chelator complex. NTBI results were also compared with transferrin saturation and the distribution of transferrin iron forms by urea-polyacrylamide gel electrophoresis. RESULTS: The bleomycin assay intraassay imprecision (CV) was 7.7% and 8.2% and the interassay imprecision was 18% and 9.8% for a low (0.2 micromol/L) and a high (1.5 micromol/L) contrtrol, respectively. Hemolysis increased measured NTBI. A detection limit of 0.1 micromol/L was established based on the interference of nonvisible hemolysis and on accuracy studies. In patient samples, NTBI exceeded the detection limits only when transferrin saturation was >80%. Compared with the chelation method, the bleomycin assay gave clearly lower NTBI concentrations. The chelation method also gave positive results at <80% transferrin saturation. The recovery of iron added as ferric nitrilotriacetate to serum was 33% by the bleomycin assay and 64% by the chelation assay. CONCLUSIONS: The microwell version of the bleomycin assay is reproducible. When hemolyzed samples were excluded, bleomycin-detectable iron was found only when the transferrin saturation was >80%, suggesting high specificity. Bleomycin-detectable iron constitutes only a portion of the NTBI measured by the chelation method.