Acquired red blood cell alloantibodies in transfused patients of 80 years or over: a 2008-2013 national haemovigilance survey.

BACKGROUND: As transfusion in the elderly patients has increased over the last decades, and with the aim of improving blood policy, post-transfusion red blood cell alloimmunisation, a delayed serological transfusion reaction, was investigated in patients 80 years old or over. MATERIALS AND METHODS: For every adverse reaction to a transfusion, a report is sent to the French haemovigilance database. All cases of red blood cell alloimmunisation reported in the haemovigilance database were collected, and an analysis was performed on those cases in transfused patients 80 years old or over. RESULTS: There were 11,625 reports of red blood cell alloimmunisation from 1 January, 2008 to 31 December, 2013, of which 3,617 (31.1%) occurred in patients 80 years old or over. Among this subgroup, red blood cell concentrates were the most frequently involved blood component (3,482 reports, 96.3%). Red blood cell alloimmunisation after transfusion of platelet concentrates was also notified (132 reports, 3.7%). Anti-KEL1 was the most frequent antibody (874 reports, 24.2%). The imputability of the blood component was certain in 2,340 cases (64.7%) and probable in 1,078 (29.8%). In 2013, the incidence of red blood cell alloimmunisation was 4.14 per 1,000 transfused patients aged 80 years old or over. DISCUSSION: In a 6-year national survey in which 40,570 reports were made, there were 3,617 cases of red blood cell alloimmunisation in transfused recipients of 80 years old or over. This delayed serological transfusion reaction is not rare. Red blood cell concentrates were predominantly involved, but cases caused by platelet concentrates were also described. In order to prevent alloimmunisation in the elderly, several factors must be evaluated before transfusing matched red blood cell concentrates: the patient's age, pathology and its outcome, the type of transfusion support (chronic or not), life expectancy, and blood product availability.