BACKGROUND: @entity1 receiving red-blood-cells may form antibodies against the alloantigens expressed by red-blood-cells, with the risk of serious morbidity and the need for extensive phenotype-matching in subsequent transfusions. The incidence of @entity5155 is considered variable for specific @entity1 groups and for first time antibody formation. We therefore studied the cumulative incidence of the first formed alloantibody as a function of red-blood-cells exposure. METHODS: We performed a new-user cohort among all previously non-transfused non-alloimmunized @entity1 that received non-extended matched ( @entity69956 ) red-blood-cells transfusions from January 2005 to December 2009 in our university medical centre. Alloimmunization incidences were estimated by Kaplan-Meier survival-analysis. RESULTS: A total of 3002 previously non-transfused @entity1 received 31103 red-blood-cell units. A first time alloantibody forming event was experienced by 54 (1  8%) @entity1 . The cumulative incidence of @entity5155 was 1  0% at 5 units, 2  4% at 10 units, 3  4% at 20 units and 6  5% at 40 units of red-blood-cells transfused. CONCLUSION: The risk to develop a first red-blood-cells alloantibody increases up to the 40th transfusion and is similar for @entity1 and @entity1 . More data are needed to examine the risk after 40th transfusion.

Red-blood-cell XXXX and number of red-blood-cell transfusions.

@entity1 :: ('9606', 'Species') :: ['women', 'Patients', 'patients', 'patient', 'men'] @entity5155 :: ('MESH:C536394', 'Disease') :: ['alloimmunization'] @entity69956 :: ('28;6007', 'Gene') :: ['ABO and RhD']
@entity5155 :: (MESH:C536394,Disease) :: ['alloimmunization']
