Blood transfusion remains an integral part of patient management in current medical practice and plays a critical role across diverse clinical settings, including surgery, obstetrics, neonatal care, intensive care units and hematological and oncology conditions. Despite its life saving benefits, blood transfusion is associated with inherent risks, including infectious and immunological consequences [1]. According to the World Health Organization, over 118 million blood donations are collected globally each year [2]. Although immunological complications occur more frequently, the public concern is largely limited to the transfusion-transmitted infections [1].

According to the World Heath Organization, over 118 million units of blood are collected globally each year [2]. Although immunological complications occure more refequently, the public concern is largely limited to the transfusion-transmitted infections [1]. However, the current focus of the scientific community is to understand the underlying mechanisms and devise mitigation strategies for immunological complications of blood transfusion, which often present greater challenges in terms of prediction and prevention.

Immunoloigcal complications of blood transfusion include: acute and delayedhemolytic transfusion reactions, febrile nonhemolytic transfusion reactions, allergic or anaphylactic transfusion reactions, transfusion related acute lung injury, platelet refractoriness, transfusion-associated graft-versus-host disease and post-transfusion purpura. Recent evidence from in vitro studies and animal models sugges that stored blood components contain apoptotic and necrotic cells Stored blood products contain apoptotic and necrotic cells, which can impair the antigen-presenting functions of recipient macrophages and dendritic cells, thereby suppressing immune responses against against donor alloantigens and resulting in transfusion related immunomodulation [3].

Immunological reactions result in a range of signs and symptoms, including fever (with or without chills and rigors), skin redness (erythema), hives (urticaria), bronchospasm, and low blood pressure (hypotension). However, similar clinical symptoms can arise from different underlying causes, and many immunological reactions may occur without any noticeable symptoms (Figure 1). Rapid progress has been made in recent years to mitigate the immunological complications of blood transfusion [4]. This review article discusses the various immunological complications of blood transfusion and the recent mitigation strategies.