Low frequency of anti‐D alloimmunization following D+ platelet transfusion: the Anti‐D Alloimmunization after D‐incompatible Platelet Transfusions (ADAPT) study

Abstract

Summary The reported frequency of D alloimmunization in D- recipients after transfusion of D+ platelets varies. This study was designed to determine the frequency of D alloimmunization, previously reported to be an average of 5%±2%. A primary anti-D immune response was defined as the detection of anti-D ≥28 days following the first D+ platelet transfusion. Data were collected on 485 D- recipients of D+ platelets in 11 centres between 2010-2012. Their median age was 60 (range 2-100) years. Diagnoses included: haematological (203/485, 42%), oncological (64/485, 13%) and other diseases (218/485, 45%). Only 7/485 (1.44%; 95%CI 0.58-2.97%) recipients had a primary anti-D response after a median serological follow-up of 77 days (range: 28-2111). There were no statistically significant differences between the primary anti-D formers and the other patients, in terms of gender, age, receipt of immunosuppressive therapy, proportion of patients with haematological/oncological diseases, transfusion of whole blood-derived or apheresis platelets or both, and total number of transfused platelet products. This is the largest study with the longest follow-up of D alloimmunization following D+ platelet transfusion. The low frequency of D alloimmunization should be considered when deciding whether to administer Rh Immune Globulin to D- males and D- females without childbearing potential after transfusion of D+ platelets.

Platelet Transfusion Induces Alloimmunization to D and Non-D Rhesus Antigens

“…Data analyzed of the patients identified to have obviously been alloimmunized through PC transfusions included: age, gender, ABO blood group and Rh phenotype, main diagnoses, immunosuppressive drugs, transfusion history (Inselspital only), and date of alloantibody detection [7]. Transfusion history included every RBC and PC unit transfusion.…”

“…Since the introduction of mandatory universal pathogen inactivation of all PC in 2011 [2], AP-PC and BC-PC are considered clinically equivalent. However, some differences exist between both types of PC, such as the extent of residual contaminating red blood cells (RBC), which has been shown to be considerably lower for AP-PC (0.00017-0.009 ml) compared to BC-PC (0.036-0.59 ml) [3,4,5,6,7,8]. …”

“…So far, there is limited data on PC-induced alloimmunization against other Rh antigens than D [7,19] and incompatibilities of non-D Rh antigens have generally been disregarded in BC-PC or AP-PC transfusion [8]. …”

Anti-D Alloimmunization after RhD-Positive Platelet Transfusion in RhD-Negative Women under 55 Years Diagnosed with Acute Leukemia: Results of a Retrospective Study

“…We have focused our study on this subset of patients (only young women) because of the potential serious consequences of anti-D alloimmunization in future pregnancies (HDN). Previous studies reported an anti-D alloimmunization rate ranging from 0 to 19% in patients suffering from oncologic diseases and therefore immunosuppressed [5,9,12,13,14,15,16,17,18,19,20]. Lack of anti-D immunization is the most founded result in studies with small numbers of immunosuppressed patients [9,13,17,18,19,20].…”

“…Anti-D alloimmunization can therefore occur when platelets from RhD-positive donors are transfused to RhD-negative patients. Various studies of RhD-negative recipients receiving RhD-positive platelet transfusions reported an incidence of 0-19% RhD alloimmunization in cancer patients [5,6,7,8]. Prevention of anti-D alloimmunization by administering Rh immunoglobulin is a well-established practice for RhD-negative pregnant women to prevent hemolytic disease of the newborn (HDN).…”