Evolution of ADAMTS13 antibodies in a fatal case of thrombotic thrombocytopenic purpura.

In a patient with fatal thrombotic thrombocytopenic purpura, the inhibitory activity of antibodies against ADAMTS13 rapidly escalated to extremely high levels despite daily plasma exchange and corticosteroid therapy. This increase was found to be because of a combination of higher antibody concentration and potency. Furthermore, during her course of the disease, the percentage of IgG(1) antibody progressively decreased whereas that of IgG(2) antibody increased, suggesting Th1-type cytokine response. These changes suggest that the course of TTP may be exacerbated by complex immune reactions. Further characterization of the factors contributing to this exacerbation may have important pathogenetic and therapeutic implications.

Transfusion-related acute lung injury resulting from designated blood transfusion between mother and child: a report of two cases.

Transfusion-related acute lung injury (TRALI) is an underdiagnosed serious complication of blood transfusion characterized by the rapid onset of respiratory distress, hypoxia, and noncardiogenic pulmonary edema during or soon after blood transfusion. The presence of anti-HLA and/or antigranulocyte antibodies in the plasma of donors is implicated in the pathogenesis of TRALI. We report 2 cases of TRALI that were caused by designated blood transfusion between mothers and their daughters; one in a 4-month-old girl who received designated packed RBCs donated by her mother and the second in a 78-year-old mother who received blood from her daughter. In both cases, examination of mother's serum revealed panel-reactive cytotoxic HLA antibodies. It is most likely that the mothers were sensitized from earlier pregnancy and produced HLA antibodies against the daughters' paternally derived HLA antigens. Designated blood transfusion between multiparous mothers and children might add an additional transfusion-related risk owing to the higher likelihood of the HLA antibody-antigen specificity between mother and child.

Clinical significance of RBC alloantibodies and autoantibodies in sickle cell patients who received transfusions.

BACKGROUND: The clinical significance of alloimmunization to RBC antigens in sickle cell patients was analyzed by a retrospective review of the records of pediatric and adult sickle cell patients who received transfusions and who were followed over a 10-year period. STUDY DESIGN AND METHODS: Charts of pediatric and adult sickle cell patients followed at Schneider Children's Hospital (SCH) and Long Island Jewish Medical Center between 1989 and 1999 were retrieved. Patients followed at SCH were classified as pediatric, regardless of age. Data on transfusion history, alloimmunization, and transfusion reactions from 1990 were retrieved from computerized blood bank records. Transfusion history, development of alloantibodies and autoantibodies, and transfusion reactions were correlated with clinical evidence of hemolysis or other adverse reactions from the charts. All patients received ABO- and Rh-compatible blood transfusions for which a partial or extended antigen match was not performed. RESULTS: Among pediatric patients, 29 percent developed clinically significant alloantibodies, and 8 percent developed autoantibodies. Seven patients developed delayed hemolytic and/or serologic transfusion reactions, two with hyperhemolysis, two with clinical evidence of hemolysis, and three with serologic evidence only. The two patients with hyperhemolysis had received extended antigen-matched RBC transfusions to provide blood compatible with their existing antibodies. Among adult patients, 47.0 percent developed significant alloantibodies, and 9.7 percent developed autoantibodies. Five incidences of delayed hemolytic and/or serologic transfusion reactions occurred, one with hyperhemolysis and four with serologic evidence only. CONCLUSION: The alloimmunization rate is 29 percent in pediatric and 47 percent in adult sickle cell patients when partial or extended RBC antigen match is not performed. However, the delayed serologic and/or hemolytic transfusion reactions did not result in severe clinical outcome in most instances. The most important adverse event was hyperhemolysis, which may be triggered by a transfusion, but was not prevented by matching for RBC antigens. In most instances, the cause of hyperhemolysis was multifactorial.