2015 proceedings of the National Heart, Lung, and Blood Institute's State of the Science in Transfusion Medicine symposium.

On March 25 and 26, 2015, the National Heart, Lung, and Blood Institute sponsored a meeting on the State of the Science in Transfusion Medicine on the National Institutes of Health (NIH) campus in Bethesda, Maryland, which was attended by a diverse group of 330 registrants. The meeting's goal was to identify important research questions that could be answered in the next 5 to 10 years and which would have the potential to transform the clinical practice of transfusion medicine. These questions could be addressed by basic, translational, and/or clinical research studies and were focused on four areas: the three "classical" transfusion products (i.e., red blood cells, platelets, and plasma) and blood donor issues. Before the meeting, four working groups, one for each area, prepared five major questions for discussion along with a list of five to 10 additional questions for consideration. At the meeting itself, all of these questions, and others, were discussed in keynote lectures, small-group breakout sessions, and large-group sessions with open discourse involving all meeting attendees. In addition to the final lists of questions, provided herein, the meeting attendees identified multiple overarching, cross-cutting themes that addressed issues common to all four areas; the latter are also provided. It is anticipated that addressing these scientific priorities, with careful attention to the overarching themes, will inform funding priorities developed by the NIH and provide a solid research platform for transforming the future practice of transfusion medicine.

One size will never fit all: the future of research in pediatric transfusion medicine.

There is concern at the National Heart, Lung, and Blood Institute (NHLBI) and among transfusion medicine specialists regarding the small number of investigators and studies in the field of pediatric transfusion medicine (PTM). Accordingly, the objective of this article is to provide a snapshot of the clinical and translational PTM research considered to be of high priority by pediatricians, neonatologists, and transfusion medicine specialists. Included is a targeted review of three research areas of importance: (i) transfusion strategies, (ii) short- and long-term clinical consequences, and (iii) transfusion-transmitted infectious diseases. The recommendations by PTM and transfusion medicine specialists represent opportunities and innovative strategies to execute translational research, observational studies, and clinical trials of high relevance to PTM. With the explosion of new biomedical knowledge and increasingly sophisticated methodologies over the past decade, this is an exciting time to consider transfusion medicine as a paradigm for addressing questions related to fields such as cell biology, immunology, neurodevelopment, outcomes research, and many others. Increased awareness of PTM as an important, fertile field and the promotion of accompanying opportunities will help establish PTM as a viable career option and advance basic and clinical investigation to improve the health and wellbeing of children.

Strategies for more rapid translation of cellular therapies for children: a US perspective.

Clinical trials for pediatric diseases face many challenges, including trial design, accrual, ethical considerations for children as research subjects, and the cost of long-term follow-up studies. In September 2011, the Production Assistance for Cellular Therapies Program, funded by the National Heart, Lung, and Blood Institute of the National Institutes of Health, sponsored a workshop, "Cell Therapy for Pediatric Diseases: A Growing Frontier," with the overarching goal of optimizing the path of discovery in research involving novel cellular therapeutic interventions for debilitating pediatric conditions with few or no available treatment options. Academic and industry investigators in the fields of cellular therapy and regenerative medicine described the obstacles encountered in conducting a clinical trial from concept to conclusion. Patient and parent advocates, bioethicists, biostatisticians, regulatory representatives from the US Food and Drug Administration, and translational scientists actively participated in this workshop, seeking to identify the unmet needs specific to cellular therapies and treatment of pediatric diseases and propose strategies to facilitate the development of novel therapies. In this article we summarize the obstacles and potential corrective strategies identified by workshop participants to maximize the speed of cell therapy translational research for childhood diseases.

The role of comparative effectiveness research in transfusion medicine clinical trials: proceedings of a National Heart, Lung, and Blood Institute workshop.

Comparative effectiveness research (CER) is the study of existing treatments or ways to deliver health care to determine what intervention works best under specific circumstances. CER evaluates evidence from existing studies or generates new evidence, in different populations and under specific conditions in which the treatments are actually used. CER does not embrace one research design over another but compares treatments and variations in practice using methods that are most likely to yield widely generalizable results that are directly relevant to clinical practice. Treatments used in transfusion medicine (TM) are among the most widely used in clinical practice, but are among the least well studied. High-quality evidence is lacking for most transfusion practices, with research efforts hampered by regulatory restrictions and ethical barriers. To begin addressing these issues, the National Heart, Lung, and Blood Institute convened a workshop in June 2011 to address the potential role of CER in the generation of high-quality evidence for TM decision making. Workshop goals were to: 1) evaluate the current landscape of clinical research, 2) review the potential application of CER methods to clinical research, 3) assess potential barriers to the use of CER methodology, 4) determine whether pilot or vanguard studies can be used to facilitate planning of future CER research, and 5) consider the need for and delivery of training in CER methods for researchers.

Developments in clinical cell therapy.

Immunotherapy has become an important part of hematopoietic stem cell (HSC) transplantation and cancer therapy. Regenerative and reparative properties of somatic cell-based therapies hold tremendous promise for repairing injured tissue, preventing and reversing damage to organs, and restoring balance to compromised immune systems. The principles and practices of the diverse aspects of immune therapy for cancer, HSC transplantation and regenerative medicine have many commonalities. This meeting report summarizes a workshop sponsored by the National Heart, Lung and Blood Institute (NHLBI) and Production Assistance for Cellular Therapies (PACT), held on 23-24 April 2009 at the National Institutes of Health (NIH, USA). A series of scientific sessions and speakers highlighted key aspects of the latest scientific, clinical and technologic developments in cell therapy, involving a unique set of cell products with a special emphasis on converging concepts in these fields.

Production Assistance for Cellular Therapies (PACT): four-year experience from the United States National Heart, Lung, and Blood Institute (NHLBI) contract research program in cell and tissue therapies.

BACKGROUND: In 2002, the US National Heart, Lung, and Blood Institute (NHLBI) conducted a workshop to determine needs of the cell therapy community. A consensus emerged that improved access to cGMP facilities, regulatory assistance, and training would foster the advancement of cellular therapy. STUDY DESIGN AND METHODS: A 2003 NHLBI request for proposals resulted in four contracts being awarded to three cell-manufacturing facilities (Baylor College of Medicine, University of Minnesota, and University of Pittsburgh) and one administrative center (The EMMES Corporation). As a result, Production Assistance for Cellular Therapies (PACT) was formed. RESULTS: As of October 1, 2008, PACT has received 65 preliminary applications of which 45 have been approved for product manufacture. A variety of cell therapies are represented including T-regulatory cells, natural killer cells, adipose-derived stem cells, cardiac progenitor cells for cardiac disease, hematopoietic progenitor cells (HPCs) for central nervous system applications, cytotoxic T lymphocytes, and dendritic cells. A total of 169 products have been administered under 12 applications and 2 reagents were manufactured and delivered. Fourteen peer-reviewed publications and 15 abstracts have resulted from the PACT project to date. A cell therapy textbook is nearly complete. PACT technical projects have addressed assay development, rapid endotoxin testing, shipping of cell products, and CD34+ HPC isolation from low-volume marrow. Educational Web seminars and on-site training through workshops have been conducted. CONCLUSIONS: PACT is an active and successful cell therapy manufacturing resource in the United States, addressing research and training while forging relationships among academia, industry, and participating institutions.

Pediatric transfusion medicine: development of a critical mass.

Many significant events have occurred in the recent past that beg a broad audience to address the question "What is pediatric transfusion medicine?" Herein, we list some of these events and their relevance below and attempt to provide an answer for this question. Indeed, several issues regarding the subspecialty of pediatric transfusion medicine (PTM) are particularly timely, and it appears that a critical mass, or a nidus capable of becoming a critical mass, is developing in PTM.

Cold temperatures reduce the sensitivity of stored platelets to disaggregating agents.

In this study, we compared the effect of signal transduction inhibitors on fibrinogen binding, aggregation, the activation state of GPIIb-IIIa, and cytosolic calcium levels in cold and room temperature-stored platelets. Cold-stored platelets have a higher sensitivity to agonist-induced aggregation when compared to room temperature-stored platelets. We also found that cold-stored platelets had a significantly higher aggregation response to ADP and epinephrine, while platelets stored at room temperature responded poorly to these agonists (mean values of 61 vs. 18%, n = 14). Four inhibitors were selected to target various signaling pathways. Cold-stored platelets were more resistant to disaggregation by promethazine, prostaglandin D2, yohimbine, and echistatin. The effects of cold temperatures on stored platelets are targeted to activation pathways as there was no spontaneous aggregation or spontaneous fibrinogen binding as measured in this study. PAC-1 binding was not inhibited to the same degree as aggregation or fibrinogen binding responses, suggesting that the disaggregation was not caused by a change in the conformation of GPIIb-IIIa. Cytosolic calcium levels did not decrease in cold-stored platelets after inhibitor addition. The inhibitors are likely acting after the establishment of the GPIIb-IIIa activation state and may affect the post-occupancy signaling by the fibrinogen-occupied integrin. Differences between aggregation and disaggregation responses of cold- and room temperature-stored platelets suggest that cold-stored platelets may have different mechanisms to stabilize platelet aggregates during their formation.

Toxicity of a first-generation adenoviral vector in rhesus macaques.

We constructed a first-generation adenovirus vector (AVC3FIX5) that we used to assess the rhesus macaque as a nonhuman primate model for preclinical testing of hemophilia B gene therapy vectors. Although we succeeded in our primary objective of demonstrating expression of human factor IX we encountered numerous toxic side effects that proved to be dose limiting. Following intravenous administration of AVC3FIX5 at doses of 3.4 x 10(11) vector particles/kg to 3.8 x 10(12) vector particles/kg, the animals in our study developed antibodies against human factor IX, and dose-dependent elevations of enzymes specific for liver, muscle, and lung injury. In addition, these animals showed dose-dependent prolongation of clotting times as well as acute, dose-dependent decreases in platelet counts and concomitant elevation of fibrinogen and von Willebrand factor. These abnormalities may be caused by the direct toxic effects of the adenovirus vector itself, or may result indirectly from the accompanying acute inflammatory response marked by elevations in IL-6, a key regulator of the acute inflammatory response. The rhesus macaque may be a useful animal model in which to evaluate mechanisms of adenovirus toxicities that have been encountered during clinical gene therapy trials.

Adenoviral vectors do not induce, inhibit, or potentiate human platelet aggregation.

Adenoviruses are commonly used as vectors in human clinical gene therapy trials. High doses of intravenous adenovirus vectors have been associated with development of thrombocytopenia of undetermined origin. Viral internalization requires the presence cell surface integrins, alpha(v)beta(3) or alpha(v)beta(5), that can blind ligands with a arginine-glycine-aspartic acid (RGD) sequence. This sequence is found in the adenovirus penton base. Platelets express the alpha(v)beta(3) integrin and other integrins that bind the RGD sequence of ligands such as fibrinogen, laminin, vitronectin, and von Willebrand factor (vWF). Platelet aggregation is mediated, in part, by the binding of the RGD sequence of fibrinogen to a platelet surface integrin, glycoprotein IIb/IIIa (GP IIb/IIIa). We investigated whether adenovirus particles could interfere with or potentiate agonist-induced platelet aggregation. Incubation of platelet-rich plasma with adenovirus under stirred conditions did not promote spontaneous aggregation. The addition of physiological platelet agonists, ADP, collagen, or epinephrine, induced platelet aggregation. However, the presence of adenovirus in a wide range of concentrations did not inhibit or potentiate agonist-induced aggregation. These results suggest that the adenovirus-associated thrombocytopenia observed in vivo is independent of a direct effect of the virus on platelet aggregation.