Risks of restrictive red blood cell transfusion strategies in patients with cardiovascular disease (CVD): a meta-analysis.

AIM: To evaluate the risks of restrictive red blood cell transfusion strategies (haemoglobin 7-8 g dL-1 ) in patients with and without known cardiovascular disease (CVD). BACKGROUND: Recent guidelines recommend restrictive strategies for CVD patients hospitalised for non-CVD indications, patients without known CVD and patients hospitalised for CVD corrective procedures. METHODS/MATERIALS: Database searches were conducted through December 2017 for randomised clinical trials that enrolled patients with and without known CVD, hospitalised either for CVD-corrective procedures or non-cardiac indications, comparing effects of liberal with restrictive strategies on major adverse coronary events (MACE) and death. RESULTS: In CVD patients not undergoing cardiac interventions, a liberal strategy decreased (P = 0·01) the relative risk (95% CI) (RR) of MACE [0·50 (0·29-0·86)] (I2  = 0%). Among patients without known CVD, the incidence of MACE was lower (1·7 vs 3·9%), and the effect of a liberal strategy on MACE [0·79, (0·39-1·58)] was smaller and non-significant but not different from CVD patients (P = 0·30). Combining all CVD and non-CVD patients, a liberal strategy decreased MACE [0·59, (0·39-0·91); P = 0·02]. Conversely, among studies reporting mortality, a liberal strategy decreased mortality in CVD patients (11·7% vs·13·3%) but increased mortality (19·2% vs 18·0%) in patients without known CVD [interaction P = 0·05; ratio of RR 0·73, (0·53-1·00)]. A liberal strategy also did not benefit patients undergoing cardiac surgery; data were insufficient for percutaneous cardiac procedures. CONCLUSIONS: In patients hospitalised for non-cardiac indications, liberal transfusion strategies are associated with a decreased risk of MACE in both those with and without known CVD. However, this only provides a survival benefit to CVD patients not admitted for CVD-corrective procedures.

Transfusion of recently donated (fresh) red blood cells (RBCs) does not improve survival in comparison with current practice, while safety of the oldest stored units is yet to be established: a meta-analysis.

BACKGROUND AND OBJECTIVES: Preclinical studies generated the hypothesis that older stored red blood cells (RBCs) can increase transfusion risks. To examine the most updated and complete clinical evidence and compare results between two trial designs, we assessed both observational studies and randomized controlled trials (RCTs) studying the effect of RBC storage age on mortality. MATERIALS AND METHODS: Five databases were searched through December 2014 for studies comparing mortality using transfused RBCs having longer and shorter storage times. RESULTS: Analysis of six RCTs found no significant differences in survival comparing current practice (average storage age of 2 to 3 weeks) to transfusion of 1- to 10-day-old RBCs (OR 0·91, 95% CI 0·77-1·07). RBC storage age was lower in RCTs vs. observational studies (P = 0·01). The 31 observational studies found an increased risk of death (OR 1·13, 95% CI 1·03-1·24) (P = 0·01) with increasing age of RBCs, a different mortality effect than RCTs (P = 0·02). CONCLUSION: RCTs established that transfusion of 1- to 10-day-old stored RBCs is not superior to current practice. The apparent discrepancy in mortality between analyses of RCTs and observational studies may in part relate to differences in hypotheses tested and ages of stored RBCs studied. Further trials investigating 1- to 10-day-old stored RBC benefits would seem of lower priority than studies to determine whether 4- to 6-week stored units have safety and efficacy equivalent to the 2- to 3-week-old stored RBCs commonly transfused today.

Peripheral expansion of pre-existing mature T cells is an important means of CD4+ T-cell regeneration HIV-infected adults.

The CD4+ T-cell pool in HIV-infected patients is in a constant state of flux as CD4+ T cells are infected and destroyed by HIV and new cells take their place. To study T-cell survival, we adoptively transferred peripheral blood lymphocytes transduced with the neomycin phosphotransferase gene between syngeneic twin pairs discordant for HIV infection. A stable fraction of marked CD4+ T cells persisted in the circulation for four to eighteen weeks after transfer in all patients. After this time there was a precipitous decline in marked cells in three of the patients. At approximately six months, marked cells were in lymphoid tissues in proportions comparable to those found in peripheral blood. In two patients, the proportion of total signal for the transgene (found by PCR analysis) in the CD4/CD45RA+ T-cell population relative to the CD4/CD45RO+ population increased in the weeks after cell infusion. These findings indicate that genetically-marked CD4+ T cells persist in vivo for weeks to months and that the CD4+ T-cell pool in adults is maintained mostly by the division of mature T cells rather than by differentiation of prethymic stem cells. Thus, after elements of the T-cell repertoire are lost through HIV infection, they may be difficult to replace.

Red blood cell transfusion in the treatment and management of anaemia: the search for the elusive transfusion trigger.

Therapeutic red blood cell (RBC) transfusion is widely utilized in the management of anaemia. Critically ill intensive care unit (ICU) patients in particular, as well as medical and haematology-oncology patients, are among the largest groups of users of RBC products. While anaemia is common in these patients, its treatment and management, including appropriate thresholds for RBC transfusion, remain controversial. We review here the function of RBCs in oxygen transport and physiology, with a view to their role in supporting and maintaining systemic tissue oxygenation. Adaptive and physiological compensatory mechanisms in the setting of anaemia are discussed, along with the limits of compensation. Finally, data from clinical studies will be examined in search of evidence for, or against, a clinically relevant transfusion trigger.

The relevance of practice misalignments to trials in transfusion medicine.

Practice misalignments can occur in any clinical trial investigating a pre-existing therapy that is typically adjusted based on clinical characteristics outside of the trial setting. To eliminate the heterogeneity in clinical practice, recent trials investigating titrated therapies have randomized patients to fixed-dose regimens without including a routine care control group receiving titrated therapy. In these trials, the normal relationships between clinically important characteristics and therapy titration are disrupted. Within each arm of the trial, randomization creates subgroups of patients receiving levels of therapy inconsistent with current practices outside of the trial. These practice misalignments may have outcomes worse than routine care and may compromise patient safety. In addition, comparisons of trial arms with practice misalignments have limited interpretability and generalizability. In this review, we use examples from the literature to discuss how practice misalignments can impact the safety, results and conclusions of clinical trials. In addition, we discuss methods to characterize relationships between therapy titration and clinical characteristics and trial design strategies that may minimize practice misalignments.

A preliminary comparison of the prevalence of transfusion reactions in recipients of platelet components from donors with and without human leucocyte antigen antibodies.

BACKGROUND: Human leucocyte antigen (HLA) antibodies have been implicated in transfusion-related acute lung injury, but the probability that the transfusion of a blood component containing HLA antibodies will cause a reaction is not known. This study compared the prevalence of reactions associated with the transfusion of platelet components with and without HLA antibodies. STUDY DESIGN AND METHODS: This retrospective study tested 96 consecutive apheresis platelet donors for HLA class I and II antibodies. Matched control donors without HLA antibodies were selected and records were reviewed to determine the proportion of components from each group that caused reactions. In addition, all apheresis platelet donors involved with two or more reactions were identified and tested for HLA class I antibodies. RESULTS: Five of the 96 donors had antibodies to class I or class II antigens and, of these, four had components transfused. The prevalence of reactions to components from these four donors with HLA antibodies and the 12 matched control donors without antibodies was similar (three reactions to 167 transfusions or 1.8% vs. three to 295 or 1.0%, respectively, P = 0.32). A retrospective review of the transfusion records from all platelet donors found that components from 22 caused two or more reactions and three (13.6%) had antibodies to HLA class I compared to 4.2% of the consecutively selected donors (P = 0.12). None of the patients experienced transfusion-related acute lung injury. CONCLUSION: Reactions associated with transfusion of apheresis platelets containing HLA antibodies are unusual.

Replacement therapy of alpha 1-antitrypsin deficiency. Reversal of protease-antiprotease imbalance within the alveolar structures of PiZ subjects.

The emphysema associated with the inherited serum deficiency of alpha 1-antitrypsin appears to result from an imbalance between neutrophil elastase and its major inhibitor within the alveolar structures. In the present study we assessed the feasibility of reversing this biochemical defect within the lung via parenteral replacement therapy with an alpha 1-antitrypsin concentrate of normal plasma. A 20--40% polyethylene glycol precipitate of pooled human donor plasma was used to obtain an enriched alpha 1-antitrypsin concentrate devoid of hepatitis B antigen and immunoglobulins. Using this material, five individuals with severe serum alpha 1-antitrypsin deficiency (PiZ phenotype) and advanced emphysema received 4 g of alpha 1-antitrypsin intravenously at weekly intervals for four doses. During this period of weekly replacement therapy alpha 1-antitrypsin serum levels were maintained at greater than or equal to 70 mg/dl, the level likely required for effective antielastase protection of the lung. In addition, assessment of lower respiratory tract antielastase activity by bronchoalveolar lavage demonstrated that parenteral replacement of alpha 1-antitrypsin resulted in establishment of effective antielastase activity within the alveolar structures. There were no untoward side effects consequent to this approach to the replacement therapy of alpha 1-antitrypsin. These results demonstrate that the parenteral replacement of alpha 1-antitrypsin provides a means of obtaining elastase-antielastase balance within the lung of individuals with this serum protease inhibitor deficiency.

Two different allelic mutations in the lecithin-cholesterol acyltransferase gene associated with the fish eye syndrome. Lecithin-cholesterol acyltransferase (Thr123----Ile) and lecithin-cholesterol acyltransferase (Thr347----Met).

We have elucidated the genetic defect in a 66-yr-old patient with fish eye syndrome (FES) presenting with severe corneal opacities and hypoalphalipoproteinemia. The patient's plasma concentration of high density lipoprotein (HDL) cholesterol was reduced at 7.7 mg/dl (35.1-65.3 mg/dl in controls) and the HDL cholesteryl ester content was 31% (60-80% in controls); however, total plasma cholesteryl esters were similar to normal (60% of total cholesterol vs. a mean of 66% in controls). The patient's plasma cholesterol esterification rate was slightly reduced at 51 nmol/ml per h (control subjects: 61-106 nmol/ml per h), whereas lecithin-cholesterol acyltransferase (LCAT) activity, assayed using a HDL-like exogenous proteoliposome substrate, was virtually absent (0.9 nmol/ml per h vs. 25.1-27.9 nmol/ml per h in control subjects). DNA sequence analysis of the proband's LCAT gene revealed two separate C to T transitions resulting in the substitution of Thr123 with Ile and Thr347 with Met. The mutation at codon 347 created a new restriction site for the enzyme Nla III. Analysis of the patient's polymerase chain reaction-amplified DNA containing the region of the Thr347 mutation by digestion with Nla III confirmed that the proband is a compound heterozygote for both defects. The patient's daughter, who is asymptomatic despite a 50% reduction of LCAT activity, is heterozygous for the Thr123----Ile mutation. Our data indicate that the regions adjacent to Thr123 and Thr347 of LCAT may play an important role in HDL cholesterol esterification, suggesting that these regions may contain a portion of the LCAT binding domain(s) for HDL.

Fish eye syndrome: a molecular defect in the lecithin-cholesterol acyltransferase (LCAT) gene associated with normal alpha-LCAT-specific activity. Implications for classification and prognosis.

We have identified the molecular defect in two siblings presenting with classical clinical and biochemical features of Fish Eye disease (FED), including corneal opacities, HDL cholesterol < 10 mg/dl, normal plasma cholesteryl esters, and elevated triglycerides. In contrast to previously reported patients with FED who are unable to esterify HDL-associated cholesterol, our patients' plasma lecithin-cholesterol acetyltransferase (alpha-LCAT)-specific activities assayed using an HDL-like proteoliposome substrate were 12.7-25.7 nmol/micrograms (19.5 +/- 1.8 in controls). In addition, significant residual cholesterol esterification was present in VLDL/LDL-depleted plasma, confirming the presence of HDL-associated alpha-LCAT activity. DNA sequence analysis of the proband's LCAT gene identified deletion of the triplet coding for leu300, which resulted in the loss of a restriction site for MlnI. Digestion of PCR-amplified DNA using MlnI established that both siblings are homozygous for this defect. Expression of LCAT300-del. in human embryonic kidney-293 cells revealed normal mRNA and intracellular LCAT concentrations. However, reduced amounts of LCAT300-del., which had a normal specific alpha-LCAT activity, were present in the media. In summary, we report the first case of FED associated with a mutant enzyme that has a normal alpha-LCAT-specific activity. The functional significance of this LCAT gene defect has been established in an in vitro expression system, which demonstrates that very small amounts of this functional LCAT mutant enzyme accumulate in the media. Characterization of LCAT300-del. established that selective alpha-LCAT deficiency is not a prerequisite for the development of FED. On the basis of our combined results, we propose that the residual amounts of total plasma LCAT activity and not its distribution on lipoproteins primarily determines the heterogeneity in phenotypic expression observed in familial LCAT deficiency syndromes.

Intraoperative hemolysis. The initial manifestation of glucose-6-phosphate dehydrogenase deficiency.

Unexpected intraoperative hemolysis suggestive of a hemolytic transfusion reaction was the initial clinical manifestation of Mediterranean type glucose-6-phosphate dehydrogenase (G-6-PD) deficiency in a 50-year-old Indian man. There was no evidence for immune mediated hemolysis since no unexpected RBC antibodies were found, and results of the direct antiglobulin test remained negative. Analysis of preoperative blood specimens demonstrated complete absence of G-6-PD activity. No etiologic agent clearly associated with G-6-PD hemolysis could be identified. Testing for G-6-PD deficiency should be considered when unexpected hemolysis occurs intraoperatively.

Traumatic cardiac hemolytic anemia: a late complication of a Starr-Edwards mitral valve prosthesis.

Severe, traumatic, cardiac, hemolytic anemia developed in a patient nine years after mitral valve replacement with a Starr-Edwards model 6120 prosthesis. Cardiac catheterization failed to demonstrate a perivalvular leak or prosthetic malfunction. Transfusion on two occasions resulted in accelerated hemolysis and failed to maintain an appreciable elevation of the hemoglobin level. At operation, a perivalvular leak was found. Replacement of the valve led to complete resolution of the hemolytic problem. The case demonstrates that cardiac hemolysis may be a good indicator of valve dysfunction.

Autoantibody formation in the alloimmunized red blood cell recipient: clinical and laboratory implications.

Alloimmunization to erythrocyte antigens is a well-characterized complication in heavily transfused patients. Less well recognized, however, is the frequency of autoantibody formation in these previously alloimmunized patients. The autoantibodies are heterogeneous and of variable clinical significance. We describe the clinical history, laboratory evaluation, diagnosis, and treatment in 4 patients who developed autoantibodies in temporal association with alloantibody formation. In one case, the autoantibody found on routine screening had no clinical significance. In another case, the autoantibody made accurate blood typing and subsequent transfusion exceedingly difficult. Two patients experienced hemolysis as a consequence of the autoantibody. The management of both patients included supportive measures, while one patient required glucocorticosteroids and red blood cell transfusion. We review the published literature concerning autoimmunization in the transfused alloimmunized host. The spectrum of clinical consequences is important for the general practitioner to recognize, as these complications may occur during routine blood transfusions.

Blood substitutes: how close to a solution?

The term "blood substitute" is commonly misused when "red cell substitute (RCS) is meant. The ideal RCS should deliver (i) oxygen; (ii) require no compatibility testing; (iii) cause few side effects; (iv) have prolonged storage qualities; (v) persist in the circulation and (vi) be available at reasonable cost. While no drug with all these qualities is on the near horizon, several early generation RCS are approaching submission for licensing, at least for limited indications. Haemoglobin-derived RCS from human, bovine and recombinant sources, as well as perfluorochemicals that dissolve 02 are in different stages of development. While each formulation has its own physical characteristics, biological activities, and adverse reaction profile, all share one characteristic: the physiological consequences of delivering 02 with small molecules is poorly understood and may both account for problems seen in the clinical trials and provide therapeutic opportunities for the cancer patient. Those RCS in phase III trials all have a half-life measured in hours and are unlikely to replace transfusions or drugs that stimulate erythropoiesis for chronic anaemia, but they may play a role (i) in military and civilian trauma as resuscitation solutions, (ii) as a bridge to transfusion when no compatible blood is immediately available, (iii) as an adjunct to the autologous haemodilution management of surgery, or even (iv) in radiation therapy or the management of cancer-related vascular occlusive syndromes.

Dual PI3K/mTOR inhibition shows antileukemic activity in MLL-rearranged acute myeloid leukemia.

In acute myeloid leukemia (AML), several signaling pathways such as the phosphatidylinositol-3-kinase/AKT and the mammalian target of rapamycin (PI3K/AKT/mTOR) pathway are deregulated and constitutively activated as a consequence of genetic and cytogenetic abnormalities. We tested the effectiveness of PI3K/AKT/mTOR-targeting therapies and tried to identify alterations that associate with treatment sensitivity. By analyzing primary samples and cell lines, we observed a wide range of cytotoxic activity for inhibition of AKT (MK-2206), mTORC1 (rapamycin) and PI3K/mTORC1/2 (BEZ-235) with a high sensitivity of cells carrying an MLL rearrangement. In vivo PI3K/mTOR inhibition delayed tumor progression, reduced tumor load and prolonged survival in an MLL-AF9(+)/FLT3-ITD(+) xenograft mouse model. By performing targeted amplicon sequencing in 38 MLL-AF9(+) and 125 cytogenetically normal AML patient samples, we found a high additional mutation rate for genes involved in growth factor signaling in 79% of all MLL-AF9(+) samples, which could lead to a possible benefit of this cohort. PI3K/mTOR inhibition for 24 h led to the cross-activation of the ERK pathway. Further in vitro studies combining PI3K/mTOR and ERK pathway inhibition revealed highly synergistic effects in apoptosis assays. Our data implicate a possible therapeutic benefit of PI3K/mTOR inhibition in the MLL-mutated subgroup. Inhibiting rescue pathways could improve the therapeutic efficacy of PI3K-targeted therapies in AML.

Immunologic aspects of blood transfusion.

For 20 years, clinical reports and laboratory observations have suggested that allogeneic blood transfusion effects important changes in the recipient's immune response. The seminal clinical studies involved dose-dependent improvement in renal allograft survival in patients transfused with allogeneic whole blood, red blood cells, and buffy coat preparations. Subsequently, a burgeoning, but unclear literature proposed that allogeneic blood transfusion decreases survival or tumor-free survival of patients who undergo operations for a variety of different malignancies. Similar studies suggest that the risk of postoperative infection increases when patients receive allogeneic blood. Transfusion reportedly improves some patients with Crohn's disease. In summary, these findings have been interpreted as evidence for an immunosuppressive effect of allogeneic blood transfusion. A small prospective study showed that paternal buffy coat infusion decreases the rate of fetal loss in a subset of women with recurrent abortion. These data suggest induction of "tolerance." Laboratory studies confirm changes in lymphocyte subsets, lymphocyte activation, natural killer cell activity, antigen-presenting function, and phagocytic cell function in patients and animals that receive allogeneic blood. The clinical relevance of these observations remains controversial. Allogeneic leukocytes induce expression of latent cell-associated viruses (human immunodeficiency virus, cytomegalovirus, Epstein-Barr virus), suggesting further immune-mediated adverse effects of transfusion. The mechanisms and clinical importance of these observations have become areas of intense interest and investigation for transfusion medicine.

Development of an automated closed system for generation of human lymphokine-activated killer (LAK) cells for use in adoptive immunotherapy.

Immunotherapy utilizing the adoptive transfer of lymphokine-activated killer (LAK) cells in conjunction with recombinant interleukin-2 (IL-2) can mediate tumor regression in some patients with advanced cancer. The activation of large numbers of LAK cells was performed in roller bottles in a research laboratory setting and required meticulous aseptic technique, at least one skilled technician per patient and one laminar flow hood per patient. To reduce the complexity and expense of LAK cell generation for human immunotherapy trials we have developed a closed-system automated procedure using a continuous flow blood cell separator. PBL were obtained by standard apheresis techniques. Platelets and plasma were elutriated using countercentrifugal flow of saline in the cell separator machine. The washed PBL were underlaid with Ficoll-Hypaque (FH) in the original separation bag. Lymphocytes were then flushed into a collection bag where they were concentrated and washed with 2 liters of saline. Mean recovery from the automated FH technique was 54.6 +/- 4.3% compared to 62.3 +/- 4.0% using manual methods in 50 ml tubes (P greater than 0.05). Cells were diluted in the collection bag with RPMI 1640 +/- 2% human AB serum and could be dispensed in an automated fashion to polyolefin bags via a sample port with 1000-1500 U/ml IL-2. After 3-4 days of culture in 5% CO2 at 37 degrees C, activated cells from the bags were harvested and washed in a closed system using the continuous flow cell separator. Cell yield from the harvest was 79.2 +/- 5.4% in the automated system compared to 64.9 +/- 5.0% in the standard procedure using manual harvest of roller bottles (P less than 0.01). Lytic capacity of the cells against fresh human tumor in a 4 h 51Cr release assay was equivalent in cells processed either by the automated or the conventional manual method. The advantages of a closed system include decreased potential for microbial contamination and reduced labor and capital equipment costs. This technique may be easily adapted for use with other cell collection and culture systems.

New insights into the management of anemia in the surgical patient.

Although the safety of allogeneic blood transfusion has increased dramatically in recent decades, some risks remain. Contamination with infectious agents-including viruses, bacteria, spirochetes, and parasites-is still possible, although recent advances in blood screening and testing have decreased the risk. The principal noninfectious complication of blood transfusion is immunomodulation. Clinical manifestations of transfusion-related immunomodulatory activity include hemolytic and allergic reactions, graft-versus-host disease, the possible decreased survival in patients with cancer, as well as increased susceptibility to postoperative infection, activation of latent infection, improvement in organ allograft survival, decreased frequency of spontaneous abortion, and moderation of immune inflammatory disease. The cause of transfusion-related immunosuppression is not yet known, but possible contributing factors are the development of a suppressor cell network, formation of anti-idiotype antibodies, clonal deletion, macrophage paralysis, up-regulation of cells with latent infections, cytokine infusion, and contamination by infectious and noninfectious agents.

Transfusion in transplant patients: the good, the bad, and the ugly.

Several transfusion-related complications have particular relevance to the transplant setting. Transfusions reportedly improve solid organ graft survival, especially when the donor and recipient share at least one HLA-DR antigen. Whereas the mechanism for this effect is unclear, less favorable "immunomodulating" effects of transfusion may increase postoperative infections and shorten survival time and disease-free intervals in patients with a variety of malignancies who are undergoing surgery. The contribution of the different components of the blood transfusion to these outcomes remains speculative. Directed donations, especially from relatives and in the setting of a recipient who is immunosuppressed, may give rise to a severe but under-appreciated immunologic consequence of transfusion: graft-versus-host disease. Although still rarely reported, transfusional graft-versus-host disease is almost invariably fatal. This complication is entirely avoidable if the transfused blood product is appropriately gamma-irradiated. Infectious complications remain the most feared consequence of transfusion; the cytomegalovirus, the human immunodeficiency virus, and hepatitis B and C may run a more fulminant course in transplant patients who are immunosuppressed. Red cell substitutes, hematopoietic growth factors, and autologous transfusion are among the strategies for preventing complications of blood transfusion. With the advent of cyclosporine and more potent and specific immunosuppressive therapies, the desirability of preoperative transfusion for organ grafts warrants reevaluation.