Neonatal alloimmune thrombocytopenia. Case reports, diagnostic and therapeutic considerations

Two families are presented, where the mothers have given birth to children with neonatal alloimmune thrombocytopenia (NAITP) due to immunization towards the platelet specific antigen PIA1, which is responsible for most of the cases with NAITP. Anti-PIA1 has previously been difficult to demonstrate, but current techniques, such as the platelet suspension immunofluorescence test (PSIFT) used here, have made routine laboratory diagnosis possible. Both mothers in these families were HLA-B8 positive. This antigen shows strong association with PIA1 immunization.