EHA Library - The official digital education library of European Hematology Association (EHA)

Anneke Brand - Chair Introduction

This year selected topics consist of novel and/or urgent transfusion questions: the significance of extracellular vesicles (EV) in blood products, red blood cell (RBC) cross-match problems and possible solutions in myeloma patients after anti-CD38 treatment and the lack of data to recommend RBC transfusion triggers in hematology patients. The session starts with an overview of EV in blood products. Besides the physiological generation of EV in vivo resulting from shear stress in the circulation, blood withdrawal, preparation and storage of donor blood, affects the amount and size of EV in blood products. The measurement of quantity and nature of EV in blood products and unravelling their possible role in unwanted transfusion complications such as TRALI and TRIM (transfusion related immune suppression) are suspected but not yet studied. The session continues with cross-match problems caused by therapeutic (monoclonal) antibodies intended to target antigens expressed by malignant cells such as CD38 expressed, but not exclusive, on malignant plasma cells. The company producing anti-CD38 provides warnings and solutions for haematologist which cannot always performed by the transfusion laboratory. The last lecture reveals the shocking situation, that hematologist who use circa one-third of available blood products, in contrast to most other medical disciplines use no evidence –based indications. Attempts to investigate evidence –based RBC transfusion triggers included 255 hematological patients in contrast to over 20.000 patients involved in transfusion trigger studies in other patient categories such as major surgery and patients with critical illness.

Learning Objectives of the manuscript
After viewing this presentation the participant will be able to:
- Surveillance of possible pathological implications of extracellular vesicles in transfusion products needs adjustment of transfusion quality control parameters and hemovigilance reporting.
- The development of targeted immune therapy of malignancy can be associated with cross reactivity against non-malignant cells and tissues
- Haematology patients use circa one-third of all available blood products, but in contrast to other medical disciplines do not use evidence based transfusion triggers.

Learning Objectives of the presentation
After viewing this presentation the participant will be able to:
- Extracellular vesicles (EVs) are present in abundance in collected blood since they are released in the circulation by platelets, red and white cells as well as from the endothelium upon activation or as a result of apoptosis.
- The amount of EVs is also largely dependent on the component preparation and storage methods and that the impact of pathogen inactivation methods should be studied with respect to EV content and types.
- EVs play a controversial role in transfusion and often exhibit potent pro-thrombotic and inflammatory potentials.
- Pre-clinical and clinical studies should objectively delineate EV role and possible pathological implications.