[Delayed hemolytic transfusion reaction in sicle cell disease patients: a new challenge for the Hemovigilance network].

Delayed hemolytic reaction transfusion in patients with sickle cell disease (SCD) is a serious and still under diagnosed event. Clinical and biological presentation mimics an acute SCD complication. It is a life-threatening event, especially in hyperhemolysis syndrome (HS) characterized by a massive destruction of both the donor's and patient's red blood cells. The main cause is related to the presence of alloantibodies directed against red blood cell antigens, more rarely autoantibodies. In approximately a third of the cases, no new antibody is highlighted. Pathophysiological hypotheses are still under debate but most of the authors agree on the role played by the SCD inflammatory state. Several therapeutic approaches are used but the data are still insufficient to estimate their efficiency. It is admitted that a new transfusion may exacerbate the phenomenon and the benefit-risk of any transfusion must be carefully evaluated. Measures limiting alloimmunization and rigorous follow-up of SCD patients and their immunohematologic status can prevent some of these accidents. The Hemovigilance network has a role to play in the recognition and the description of this risk. A first analysis realized on the French national Hemovigilance database of the French National Agency for Medicines and Health Products Safety (ANSM) over the period 2000-2013, shows us interesting information but some inadequacies, described here, must be taken into account to strengthen these data and insure in the future a better reporting quality.