Blood transfusion in autoimmune rheumatic diseases

Autoimmune rheumatic disorders (ARD) represent a wide spectrum of disorders that affect in priority the joints, bones, muscles, and connective tissues. Examples of ARD include rheumatoid arthritis, systemic lupus erythematosus, Sjögren syndrome, polymyositis, systemic sclerosis, antiphospholipid syndrome and mixed connective tissue disease. Patients with ARD often require transfusion of red cell concentrates (RCC) or other blood-derived components. The presence of an autoimmune background, often complicated by the use of immunosuppressive medications, renders these patients quite vulnerable. Exposing them to RCC, when indicated, can trigger transfusion-related immunomodulation that can be aggravated by the role played by the donor microbiome, and the complement activation and the immune dysregulation induced by iron, leading to an amplification of the immune problems. Furthermore, patients are challenged by the transfused extracellular vesicles which could have a potentially negative role, particularly in patients with antiphospholipid syndrome. Despite the very vigorous screening, transfusion transmissible infections can still represent a risk to these patients, particularly in cytomegalovirus seronegative patients or when dormant pathogens are activated in the immunosuppressed transfusion recipient. The ARD population is also more at risk for transfusion-related reactions. One, therefore, has to consider a restrictive transfusion strategy if possible and, if needed, resort to the numerous blood bank procedures to reduce the immunogenicity of blood products or use safer, more targeted, industrial plasma-derived products subjected to purification and pathogen reduction technologies.