Impact of transfusion of blood components on the recipient immune system

Abstract

Transfusions of blood provide essential therapeutic measures in a number of pathological conditions. However, when carrying out blood component therapy, it is important to consider probability of post-transfusion complications. Most of them are immune-mediated side effects. The unfavorable consequences of blood transfusions can manifest at long-range time periods, and pathogenesis of these phenomena may be associated not only with the presence of alloantibodies. They may be caused by alloimmunization to HLA antigens, leukocyte factors, including cytokines, products of leukocyte degranulation, as well as storage-related erythrocyte damage («storage lesion»), immunomodulatory properties of extracellular vesicles or microparticles derived from blood components, and other factors. Despite significant number of publications on this issue, a lot of unresolved issues still remain, concerning transfusion-related effects of blood components on the immune system of recipients. The review article provides the results of current studies in this area. We present and discuss the results of current studies and the features of transfusion-mediated immunomodulation (TRIM) revealed over recent years, when transfusing different blood components. The role of plasma factors, microparticles, platelets and erythrocytes, HLA sensitization and microchimerism in the development of TRIM is highlighted, the data on occurrence and clinical features of TRIM in perioperative period are presented. A separate section of the review provides information about recent clinical studies, devoted to the issues of TRIM in different clinical cohorts, including newborns, patients with malignant neoplasms, immunocompromised patients after heart and vascular surgery. The data on TRIM incidence in the patients with exhausted immune system due to previous disease or treatment, severe comorbidity, extensive surgical thoracic/abdominal intervention and artificial circulation are also in scope. As based on the studies performed, the role of distinct measures, e.g., washing of erythrocyte concentrates, leukodepletion, and gamma irradiation are discussed in view of potential TRIM prevention. The results of published research do not allow us to draw definite conclusions about the effects of blood component transfusion on the immune system of recipients with respect to differences between the studied groups of patients, characteristics of the studied disorders and clinical situations, diversity of hemocomponents, as well as varying standards of transfusion therapy adopted in different countries. However, the systematic literature review may provide some guidance in transfusion-mediated immune modulation.