Biologic roles of the ABH and Lewis histo-blood group antigens part II: thrombosis, cardiovascular disease and metabolism.

The ABH and Lewis antigens were among the first of the human red blood cell polymorphisms to be identified and, in the case of the former, play a dominant role in transfusion and transplantation. But these two therapies are largely twentieth-century innovations, and the ABH and related carbohydrate antigens are not only expressed on a very wide range of human tissues, but were present in primates long before modern humans evolved. Although we have learned a great deal about the biochemistry and genetics of these structures, the biological roles that they play in human health and disease are incompletely understood. This review and its companion, which appeared in a previous issue of Vox Sanguinis, will focus on a few of the biologic and pathologic processes which appear to be affected by histo-blood group phenotype. The first of the two reviews explored the interactions of two bacteria with the ABH and Lewis glycoconjugates of their human host cells, and described the possible connections between the immune response of the human host to infection and the development of the AB-isoagglutinins. This second review will describe the relationship between ABO phenotype and thromboembolic disease, cardiovascular disease states, and general metabolism.

Biologic roles of the ABH and Lewis histo-blood group antigens Part I: infection and immunity.

The ABH and Lewis antigens were among the first of the human red blood cell polymorphisms to be identified and, in the case of the former, play a dominant role in transfusion and transplantation. But these two therapies are largely twentieth century innovations, and the ABH and related carbohydrate antigens are not only expressed on a very wide range of human tissues, but were present in primates long before modern humans evolved. Although we have learned a great deal about the biochemistry and genetics of these structures, the biological roles that they play in human health and disease are incompletely understood. This review and its companion, to appear in a later issue of Vox Sanguinis, will focus on a few of the biologic and pathologic processes which appear to be affected by histo-blood group phenotype. The first of the two reviews will explore the interactions of two bacteria with the ABH and Lewis glycoconjugates of their human host cells, and describe the possible connections between the immune response of the human host to infection and the development of the AB-isoagglutinins. The second review will describe the relationship between ABO phenotype and thromboembolic disease, cardio-vascular disease states, and general metabolism.

Massive Transfusion in Cardiac Surgery: The Impact of Blood Component Ratios on Clinical Outcomes and Survival.

BACKGROUND: Cardiac surgery is the most common setting for massive transfusion in medically advanced countries. Studies of massive transfusion after injury suggest that the ratios of administered plasma and platelets (PLT) to red blood cells (RBCs) affect mortality. Data from the Red Cell Storage Duration Study (RECESS), a large randomized trial of the effect of RBC storage duration in patients undergoing complex cardiac surgery, were analyzed retrospectively to investigate the association between blood component ratios used in massively transfused patients and subsequent clinical outcomes. METHODS: Massive transfusion was defined as those who had ≥6 RBC units or ≥8 total blood components. For plasma, high ratio was defined as ≥1 plasma unit:1 RBC unit. For PLT transfusion, high ratio was defined as ≥0.2 PLT doses:1 RBC unit; PLT dose was defined as 1 apheresis PLT or 5 whole blood PLT equivalents. The clinical outcomes analyzed were mortality and the change in the Multiple Organ Dysfunction Score (ΔMODS) comparing the preoperative score with the highest composite score through the earliest of death, discharge, or day 7. Outcomes were compared between patients transfused with high and low ratios. Linear and Cox regression were used to explore relationships between predictors and continuous outcomes and time to event outcomes. RESULTS: A total of 324 subjects met the definition of massive transfusion. In those receiving high plasma:RBC ratio, the mean (SE) 7- and 28-day ΔMODS was 1.24 (0.45) and 1.26 (0.56) points lower, (P = .007 and P = .024), respectively, than in patients receiving lower ratios. In patients receiving high PLT:RBC ratio, the mean (SE) 7- and 28-day ΔMODS were 1.55 (0.53) and 1.49 (0.65) points lower (P = .004 and P = .022), respectively. Subjects who received low-ratio plasma:RBC transfusion had excess 7-day mortality compared with those who received high ratio (7.2% vs 1.7%, respectively, P = .0318), which remained significant at 28 days (P = .035). The ratio of PLT:RBCs was not associated with differences in mortality. CONCLUSIONS: This analysis found that in complex cardiac surgery patients who received massive transfusion, there was an association between the composition of blood products used and clinical outcomes. Specifically, there was less organ dysfunction in those who received high-ratio transfusions (plasma:RBCs and PLT:RBCs), and lower mortality in those who received high-ratio plasma:RBC transfusions.

The impact of red blood cell storage duration on tissue oxygenation in cardiac surgery.

OBJECTIVE: Although storage alters red blood cells, several recent, randomized trials found no differences in clinical outcomes between patients transfused with red blood cells stored for shorter versus longer periods of time. The objective of this study was to see whether storage impairs the in vivo ability of erythrocytes to traverse the microcirculation and deliver oxygen at the tissue level. METHODS: A subset of subjects from a clinical trial of cardiac surgery patients randomized to receive transfusions of red blood cells stored ≤10 days or ≥21 days were assessed for thenar eminence and cerebral tissue hemoglobin oxygen saturation (StO2) via the use of near-infrared spectroscopy and sublingual microvascular blood flow via side-stream darkfield videomicroscopy. RESULTS: Among 55 subjects, there was little change in the primary endpoint (thenar eminence StO2 from before to after transfusion of one unit) and the change was similar in the 2 groups: +1.7% (95% confidence interval, -0.3, 3.8) for shorter-storage and +0.8% (95% confidence interval, -1.1, 2.9) for longer-storage; P = .61). Similarly, no significant differences were observed for cerebral StO2 or sublingual microvascular blood flow. These parameters also were not different from preoperatively to 1 day postoperatively, reflecting the absence of a cumulative effect of all red blood cell units transfused during this period. CONCLUSIONS: There were no differences in thenar eminence or cerebral StO2, or sublingual microcirculatory blood flow, in cardiac surgery patients transfused with red blood cells stored ≤10 days or ≥21 days. These results are consistent with the clinical outcomes in the parent study, which also did not differ, indicating that storage may not impair oxygen delivery by red blood cells in this setting.

Effects of red-cell storage duration on patients undergoing cardiac surgery.

BACKGROUND: Some observational studies have reported that transfusion of red-cell units that have been stored for more than 2 to 3 weeks is associated with serious, even fatal, adverse events. Patients undergoing cardiac surgery may be especially vulnerable to the adverse effects of transfusion. METHODS: We conducted a randomized trial at multiple sites from 2010 to 2014. Participants 12 years of age or older who were undergoing complex cardiac surgery and were likely to undergo transfusion of red cells were randomly assigned to receive leukocyte-reduced red cells stored for 10 days or less (shorter-term storage group) or for 21 days or more (longer-term storage group) for all intraoperative and postoperative transfusions. The primary outcome was the change in Multiple Organ Dysfunction Score (MODS; range, 0 to 24, with higher scores indicating more severe organ dysfunction) from the preoperative score to the highest composite score through day 7 or the time of death or discharge. RESULTS: The median storage time of red-cell units provided to the 1098 participants who received red-cell transfusion was 7 days in the shorter-term storage group and 28 days in the longer-term storage group. The mean change in MODS was an increase of 8.5 and 8.7 points, respectively (95% confidence interval for the difference, -0.6 to 0.3; P=0.44). The 7-day mortality was 2.8% in the shorter-term storage group and 2.0% in the longer-term storage group (P=0.43); 28-day mortality was 4.4% and 5.3%, respectively (P=0.57). Adverse events did not differ significantly between groups except that hyperbilirubinemia was more common in the longer-term storage group. CONCLUSIONS: The duration of red-cell storage was not associated with significant differences in the change in MODS. We did not find that the transfusion of red cells stored for 10 days or less was superior to the transfusion of red cells stored for 21 days or more among patients 12 years of age or older who were undergoing complex cardiac surgery. (Funded by the National Heart, Lung, and Blood Institute; RECESS ClinicalTrials.gov number, NCT00991341.).

A Man with Paraneoplastic Retinopathy plus Small Fiber Polyneuropathy Associated with Waldenström Macroglobulinemia (Lymphoplasmacytic Lymphoma): Insights into Mechanisms.

PURPOSE: To report a well-characterized Waldenström's macroglobulinemia (WM) case that provides insight into the mechanisms of two paraneoplastic complications -- cancer-associated retinopathy (CAR) and small fiber polyneuropathy (SFPN). METHODS: Retrospective medical chart review. RESULTS: A 58-year old man with WM developed vision loss and bilateral lower extremity pain. CAR was diagnosed by history, a depressed electroretinogram (ERG) and positive anti-retinal antibodies. SFPN diagnosis was based on abnormal autonomic nerve function testing and a distal-leg skin biopsy that demonstrated absent epidermal small-fiber innervation, IgM and complement deposition and microvasculopathy. Plasma exchange (PLEX) led to dramatic pain relief and subjective improvement in eye symptoms along with improvement of some ERG parameters. Repeat skin biopsy after treatment showed less microvascular abnormalities and decreased complement deposition. CONCLUSIONS: The concurrence of CAR and SFPN in this patient suggest that both were complications of WM and their common response to PLEX suggests co-mediation by humoral factors that accessed target antigens through IgM-triggered, complement-mediated vascular damage.

Adverse effects of hemorrhagic shock resuscitation with stored blood are ameliorated by inhaled nitric oxide in lambs*.

OBJECTIVES: Transfusion of stored RBCs is associated with increased morbidity and mortality in trauma patients. Plasma hemoglobin scavenges nitric oxide, which can cause vasoconstriction, induce inflammation, and activate platelets. We hypothesized that transfusion of RBCs stored for prolonged periods would induce adverse effects (pulmonary vasoconstriction, tissue injury, inflammation, and platelet activation) in lambs subjected to severe hemorrhagic shock and that concurrent inhalation of nitric oxide would prevent these adverse effects. DESIGN: Animal study. SETTING: Research laboratory at the Massachusetts General Hospital, Boston, MA. SUBJECTS: Seventeen awake Polypay-breed lambs. INTERVENTIONS: Lambs were subjected to 2 hours of hemorrhagic shock by acutely withdrawing 50% of their blood volume. Lambs were resuscitated with autologous RBCs stored for 2 hours or less (fresh) or 39 ± 2 (mean ± SD) days (stored). Stored RBCs were administered with or without breathing nitric oxide (80 ppm) during resuscitation and for 21 hours thereafter. MEASUREMENTS AND MAIN RESULTS: We measured hemodynamic and oxygenation variables, markers of tissue injury and inflammation, plasma hemoglobin concentrations, and platelet activation. Peak pulmonary arterial pressure was higher after resuscitation with stored than with fresh RBCs (24 ± 4 vs 14 ± 2 mm Hg, p < 0.001) and correlated with peak plasma hemoglobin concentrations (R = 0.56, p = 0.003). At 21 hours after resuscitation, pulmonary myeloperoxidase activity was higher in lambs resuscitated with stored than with fresh RBCs (11 ± 2 vs 4 ± 1 U/g, p = 0.007). Furthermore, transfusion of stored RBCs increased plasma markers of tissue injury and sensitized platelets to adenosine diphosphate activation. Breathing nitric oxide prevented the pulmonary hypertension and attenuated the pulmonary myeloperoxidase activity, as well as tissue injury and sensitization of platelets to adenosine diphosphate. CONCLUSIONS: Our data suggest that resuscitation of lambs from hemorrhagic shock with autologous stored RBCs induces pulmonary hypertension and inflammation, which can be ameliorated by breathing nitric oxide.

The concentration of CD44 is increased in hematopoietic stem cell grafts of patients with acute myeloid leukemia, plasma cell myeloma, and non-Hodgkin lymphoma.

CONTEXT: In autologous hematopoietic stem cell transplantation (autoHSCT), malignant cells remaining in the graft may re-engraft leading to relapse of the original disease. CD44 is known to play a role in the engraftment of leukemia-initiating cells and is shed from the surface of malignant cells. Soluble CD44 is a cleaved fragment, which is found in the serum of patients with metastasized epithelial and hematologic malignancies and in some other cancers, and has been demonstrated to be correlated with clinical outcome. OBJECTIVES: To investigate (1) a possible correlation between the concentration of CD44 in an autoHSCT graft and the type of hematologic malignancy and (2) a possible correlation between the concentration of CD44 in the autoHSCT graft with clinical outcome after autoHSCT. DESIGN: We measured CD44 in 157 hematopoietic stem cell grafts from patients with hematologic malignancies and from 43 healthy donors by enzyme-linked immunosorbent assay. RESULTS: Levels of CD44 were almost 2-fold higher in the patients' grafts. Highest levels were found in the grafts of patients with acute myeloid leukemia, diffuse large B-cell lymphoma, and plasma cell myeloma, congruent with known CD44 expression levels in these malignancies. The survival advantage among patients with CD44 levels less than 22 000 ng/mL was highly statistically significant. CONCLUSION: These results show that CD44 levels in an autoHSCT graft may be linked to clinical outcome after autoHSCT.

An open-label, randomized, parallel-group study of perioperative epoetin alfa versus standard of care for blood conservation in major elective spinal surgery: safety analysis.

STUDY DESIGN: Prospective, open-label, randomized, parallel-group study at 80 centers. OBJECTIVE: To demonstrate there is no clinically important additional risk for deep vein thrombosis with perioperative use of epoetin alfa versus standard of care in spine surgery without prophylactic anticoagulation. SUMMARY OF BACKGROUND DATA: Trials of epoetin alfa in orthopedic surgery that demonstrated no additional risk of thrombovascular events included perioperative pharmacologic anticoagulation. METHODS: Subjects received epoetin alfa 600 U/kg subcutaneously once weekly starting 3 weeks before spinal surgery plus standard of care for blood conservation, or standard of care alone. Perioperative anticoagulation therapy was not permitted; mechanical deep vein thrombosis prophylaxis was allowed. Doppler imaging for deep vein thrombosis was done on postoperative day 4 (or day of discharge), or for suspected deep vein thrombosis. Deep vein thrombosis was diagnosed by Doppler result or adverse event report. The criterion for no additional risk of deep vein thrombosis was a 1-sided 97.5% upper confidence limit < or =4% between groups. RESULTS: Of the 680 subjects analyzed (340 in each treatment group), 16 (4.7%) in the epoetin alfa group and 7 (2.1%) in the standard of care group had a diagnosis of deep vein thrombosis either by Doppler or by adverse event report with normal Doppler. The between-group difference was 2.6% (97.5% upper confidence limit, 5.4%). Deep vein thrombosis confirmed by Doppler (4.1% vs. 2.1%), other clinically relevant thrombovascular events (1.5% vs. 0.9%), and all adverse events combined (76.5% vs. 73.2%) occurred with similar frequency in the 2 treatment groups. CONCLUSION: This study documented a higher incidence of deep vein thrombosis and similar rates of other clinically relevant thrombovascular events with epoetin alfa versus standard of care for blood conservation in subjects who did not receive prophylactic anticoagulation before spinal surgery. Antithrombotic prophylaxis should be considered when erythropoietin is used in the surgical setting.

Therapy with immunoglobulin: applications for monoclonal antibodies.

The ability of antibodies to recognize specific antigenic targets and trigger responses from the immune system has made them attractive candidates as therapeutic agents. Monoclonal and recombinant technology have made possible the development of a new class of therapeutic and diagnostic agents that combine the exquisite specificity of antibodies with biologic compatibility and protracted half-lives. This technology is just beginning to be explored and considerable evolution may be expected in the next few decades.

Immunization using autologous dendritic cells pulsed with the melanoma-associated antigen gp100-derived G280-9V peptide elicits CD8+ immunity.

PURPOSE: To determine the toxicity, maximal tolerated dose, and clinical and immunologic response to autologous dendritic cells pulsed with melanoma-associated antigen gp100-derived G280-9V peptide. PATIENTS AND METHODS: Twelve HLA-A*0201(+) patients with advanced melanoma were administered dendritic cells pulsed with G280-9V peptide. Cohorts of three patients were administered 5 x 10(6), 15 x 10(6), and 50 x 10(6) cells i.v. every 3 weeks for six doses according to a dose escalation scheme. Three additional patients were treated at the highest dose. No additional cytokines or therapies were coadministered. The immunogenicity of G280-9V-pulsed dendritic cells was measured by IFN-gamma ELISPOT assay, tetramer assay, and (51)Cr release assay comparing prevaccination to postvaccination blood samples. Response to treatment was assessed by Response Evaluation Criteria in Solid Tumors. RESULTS: CD8(+) immunity to the native G280 was observed in 8 (67%) patients as measured by ELISPOT and in 12 (100%) patients as measured by tetramer assay. Of the 9 patients tested, 9 (100%) had measurable high-avidity CTL activity as defined by lysis of allogeneic melanoma lines, which coexpress HLA-A*0201 and gp100. The median follow-up of the entire cohort is 43.8 months. Two (17%) partial responses were observed and 3 (25%) patients had stable disease. The median survival of the treated population was 37.6 months. At this time, three patients are alive, including one patient who continues to respond without additional treatment. CONCLUSION: The high rate of immunization as measured by three independent assays and the occurrence of clinical regression support continued investigation of G280-9V peptide as a candidate epitope in melanoma vaccine formulations.

Prion diseases: recent developments toward diagnostic tests.

Concerns about the large-scale European crisis of bovine spongiform encephalopathy, the finding of 1 infected cow in Alberta, Canada, in 2003, and the theoretical concern of prion transmissibility in blood have renewed interest in the development of rapid, minimally invasive diagnostic assays for prion diseases. Herein we review the pathologic features, clinical manifestations, diagnostic criteria, and recent developments that may lead to new diagnostic screening assays for prion diseases.