Thrombocytopenia alloimmune

PlPlAl-negative platelets are used to treat neonatal alloimmune thrombocytopenic purpura, a rare, transient, but severe thrombocytopenia in the newborn due to platelet destruction by maternal antibody (1). The mother is usually a PlPlAl-negative person who has produced anti-PIPIAI as a result of previous blood transfusions or pregnancy. The antibody crosses the placenta and destroys the PIPIAI-positive platelets of the neonate. 

Platelet concentrates contain a considerable number of leukocytes and it is not clear whether allo-antibody formation is caused by the platelets themselves or by these contaminating leukocytes (112). There is in fact evidence that leukocyte-free platelets could prevent refractoriness to platelet transfusion (113), and also that induction of anti-HLA antibodies is reduced (114). It has also been found that that the use of HLA-matched platelets almost entirely avoids alloimmunization (114). There was severe but transient thrombocytopenia after the infusion of whole blood from a donor who was subsequently found to have a high-titer platelet-specific antibody (anti-PlAl) (115) this, however, is very rare. 

---