Primary or anamnestic antibody response to the D antigen (RhD)after bone grafting: Case report and implications

Abstract

In August 2020, a group A D antigen (RhD)-negative woman aged 85 years was found unexpectedly to have a clear-cut anti-D (with a negative auto control) following a hip fracture.She had had four children between 1962 and 1969-the first two, RhD-positive, the third, RhD-negative, with the group of the fourth, unknown. Antibody screening results from around these pregnancies are unavailable, and prophylactic anti-D is unlikely to have been given as it became available in New Zealand only in 1968.In 1999, she reportedly had red blood cell (RBC) transfusions.Records are unavailable, but it is likely these were RhD-negative. In 2017, whilst undergoing total knee joint replacement, she received three RhD-negative RBC units. In 2018, during repair of a previous hip joint replacement, she had allogeneic bone grafting which was from an RhD-positive donor. Pre-operative antibody screening around the 2017 and 2018 operations were negative as also were eight antibody screens between 2013 and 2017 (done following visits to the Emergency Department for various orthopaedic problems). Other than as noted, she received no other blood components, nor any prophylactic anti-D or intravenous immunoglobulin.Given her history, two explanations are possible for her unexpected anti-D. Either primary alloimmunisation by the RhD-positive bone graft, or primary alloimmunisation during the pregnancies followed by an anamnestic response through the bone graft.