Controversy: HLA Antibodies Responsible for Fetal/Neonatal Alloimmune Thrombocytopenia – an Update

This review focuses on reports and data dealing with an association between an alloimmunization against HLA class I antigens and fetal/neonatal alloimmune thrombocytopenia (FNAITP) that have been published since 2000. Current serological requirements for a presumed diagnosis of FNAITP in newborns are presented to understand the hesitation towards a diagnosis of HLA antibody- associated FNAITP. Three already published case reports are extensively discussed, and data from 3 series of presumed FNAITP are presented. Furthermore, the data on light chain restriction of such HLA antibodies are discussed in view of a possible clonality of these antibodies in presumed FNAITP.