A Systematic Review of Alloimmunisation in RhD Negative Patients Following the Transfusion of RhD Positive Platelet Components

Abstract

Background: Donated platelets are transfused as therapeutic products to treat patients with low platelet count. Transfusing incompatible platelet components to RhD negative patients can cause immunization against the D antigen. Platelets do not express the antigen on their cell surface membrane, but residual red blood cells in RhD positive platelets can cause alloimmunization in RhD negative recipients. Such immunized individuals can form D antibodies that would destroy donor’s cells upon re exposure. This would lead to hemolytic disease of the foetus and new born during pregnancy, and hemolytic transfusion reaction following incompatible transfusion. Inconsistency has been observed in the literature regarding the reported frequencies of alloimmunization against the D antigen after incompatible platelet transfusion. Methods: 4,750 publication records were systematically screened, and 32 deemed eligible for inclusion in the study. A cut-off of 28 days was used to identify primary responders as those who form D antibodies after 28 days following transfusion. Patients were excluded if they received anti-D prophylaxis, and/or received RhD positive components other than platelets. A grading system was utilized to assess for risk of bias to outweigh studies quality in terms of design, conduct, and reporting. Results: The range of frequencies of alloimmunization in immunosuppressed patients who exclusively received only whole blood or whole blood and apheresis is 0-8.3%. Additionally, the rate recorded for immunocompetent patients who exclusively received only whole blood or whole blood and apheresis is 0-13.5%. Those who exclusively received apheresis platelets had a minimal risk of 0-2.1% regardless of the immune status of the participant. An evidence of a good quality showed that D pos platelet components impose risk regardless of the source. Conclusion: the risk of alloimmunization in RhD negative patients following the transfusion of RhD positive apheresis platelets is low due to the low residual RBC content. However, a considerable risk is associated with whole blood platelets. The evidence that was accumulated in this systematic review suggest limitation of Anti-D prophylaxis prescription to recipients of incompatible whole blood platelets, especially children and pre-menopausal females.