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Neonatal alloimmune thrombocytopenia (NAIT) results from maternal immunization against fetal platelet antigens and can occur during the first pregnancy. The most common complications of NAIT are neonatal thrombocytopenia, intracerebral hemorrhage, and fetal death. Most cases of NAIT in Caucasians are caused by anti-HPA-1a (PlA1). Anti-HPA-5b (Bra) accounts for only 4.3 percent of all NAIT cases. NAIT due to anti-HPA-5b is thought to be milder and have fewer complications than NAIT caused by anti-HPA-1a because of the lower number of HPA-5b antigenic sites per platelet. This report describes a severe case of NAIT due to anti-HPA-5b that was treated by intrauterine platelet transfusion.

Autoimmune hemolytic anemia (AIHA) presents a difficult challenge to clinicians and blood bankers alike. Autoantibodies in the serum significantly complicate serologic evaluation, and necessitate performing procedures such as adsorptions to eliminate the possibility of underlying alloantibodies. In many instances the blood that is issued may be phenotypically similar but remains crossmatch incompatible, generating a considerable degree of anxiety among the clinical staff who are responsible for transfusing the patient. We report a case of warm autoimmune hemolytic anemia (WAIHA) in which the transfusion of red cells was complicated by a febrile transfusion reaction. Evaluation of the reaction resulted in a significant delay in transfusion therapy. Subsequent administration of leukocyte-poor red cells resulted in uneventful transfusions with a good therapeutic response. Retrospective analysis of the pretransfusion sample demonstrated significant levels of anti-neutrophil antibodies. This case resulted in the establishment of our policy to administer all red cell transfusions to patients with autoantibodies (warm or cold) as leukocyte- poor red cells.

Plasma converted to serum by the addition of bovine thrombin prior to compatibility testing agglutinated all donor red cells. This finding prompted an investigation of bovine thrombin- associated incompatibility that showed that (1) thrombin derived from bovine plasma contains IgG antibodies directed against all human red cells, and (2) excess (50 units/mL) bovine thrombin used for conversion of plasma to serum may cause hemagglutination and erroneous serologic test results because of the presence of heteroagglutinins.

Immune hemolytic anemia due to minor ABO incompatibility between recipient and donor is a well-recognized occurrence in kidney and liver transplantation. In some cases, the responsible antibodies have been shown to be derived from the donor passenger lymphocytes using Gm allotyping. We report a case of acute, transient hemolysis following heart-lung transplantation in which serologic and Gm allotype studies confirmed the etiology of hemolysis.