Jaben, Elizabeth A.

Abstract Abstract 4332 Background: Hemolytic anemia caused by the passive transfer of isoagglutinins, typically anti-A or anti-B antibodies, is a rare and likely under-recognized complication of intravenous immunoglobulin (IVIG) therapy. The Immunohematology Reference Laboratory at Mayo Clinic Rochester has detected 12 cases of passively acquired isoagglutinins following IVIG administration during the first seven months of this calendar year (January-July 2011). This frequency of detection is much higher than that seen over the three prior calendar years, when only two cases were detected. Given this “cluster” of isoagglutinin detection, we analyzed these 12 cases to determine the clinical significance of this finding as well as characteristics of resulting cases of hemolytic anemia. Materials/Methods: Charts of patients identified as having passively acquired isoagglutinins following IVIG therapy were analyzed for evidence of a significant drop in hemoglobin (defined as >1 g/dL) as well as evidence of hemolysis (elevated lactate dehydrogenase, reticulocytosis, spherocytosis, decreased haptoglobin, indirect hyperbilirubinemia, hemoglobinemia and hemoglobinuria). Cases with a >1 g/dL drop in hemoglobin and two or more of the above findings consistent with hemolysis were considered “confirmed” cases. Those with passively acquired isoagglutinins but without evidence of hemolysis or with an alternative explanation for anemia were considered “asymptomatic”, and cases without a full hemolytic evaluation but still clinically suspicious were categorized as “suspected” cases. Results: Passively acquired isoagglutinins were detected in 11 patients following 12 separate treatments with IVIG (one patient had antibodies noted after two separate treatment episodes >3 weeks apart). Four of these 12 cases were categorized as “confirmed” cases, five as “suspected” and three as “asymptomatic”. The indication for IVIG use was a neurologic disorder in three of the four confirmed cases, with immune thrombocytopenic purpura (ITP) being the indication in the other case. In suspected cases, ITP was the indication in four of the five cases, with the fifth patient carrying a diagnosis of Kawasaki’s disease. During the 7 month period reviewed, 250 unique patients were treated with IVIG, meaning 1.6% of patients (4/250) had confirmed IVIG-associated hemolytic anemia and another 1.6% (4 patients; 5 events) had suspected hemolytic anemia during this period. The mean decrease in hemoglobin was 4.1 g/dL in confirmed cases (range 1.3–7.1 g/dL) and 2.7 g/dL in suspected cases (range 1.7–4.2 g/dL). Eight of nine patients reviewed had blood type A positive; the other was B positive. The median time from initiation of therapy to hemoglobin nadir was eight days in confirmed and three days in suspected cases. The mean dose of IVIG administered in confirmed cases was 300 g (range 180–400 g) and was 162 g (range 50–300 g) in suspected cases. Red cell transfusion was required in three of the four confirmed cases. Privigen™ was the IVIG product utilized in all four confirmed and the first three suspected cases. After removal of Privigen™ from the Mayo Clinic formulary given concerns regarding these cases, two suspected cases of IVIG-associated hemolytic anemia occurred with Gamunex-C™, including one in a patient who previously suffered confirmed hemolysis after receipt of Privigen™. Conclusions: Hemolytic anemia is a rare complication of therapy with IVIG. The rate of hemolytic anemia following IVIG administration over the evaluated period is consistent with previous reports, but it should be noted that these cases were detected without the aid of an active surveillance policy, indicating the actual rate of hemolytic anemia associated with IVIG use was likely greater than that detected by this review. Our series suggests that those with blood type A may be at increased risk for this complication; further work is ongoing to better define risk factors for development of this potentially significant complication of IVIG therapy. Disclosures: Off Label Use: IVIG use in various off-label indications.

Patients are increasingly being prescribed antiplatelet agents (APAs) for a growing number of medical and surgical conditions. These agents are associated with an increased risk of hemorrhage, including intracranial hemorrhage (ICH). In the setting of warfarin use and ICH, strategies to reverse the drug effects have improved outcomes. No such strategy exists for APAs, and these patients continue to have poor posthemorrhage outcomes. One strategy is the use of platelet transfusions to provide functional, circulating platelets. Studies have shown mixed results regarding the benefit of this practice. Other strategies include the use of desmopressin and recombinant factor VIIa. More studies are necessary to delineate the effectiveness of the various strategies.

BackgroundGroup O red blood cell (RBC) units are used for emergency transfusions and are often uncrossmatched when transfused. We sought to determine the risk of alloimmunization and identify acute adverse outcomes of this practice.Study Design and MethodsThe transfusion medicine database was searched for emergency‐release transfusion (ERT) episodes from January 2006 through December 2010. The data collected included age and sex of the recipient, blood bank history, survival after the ERT episode, antibody screen results, antibody identifications, and compatibility of released units.ResultsA total of 1444 ERT episodes took place involving 1407 patients. A total of 4144 RBC units were released. Of the 129 positive antibody screens, 34 had no antibody on further work‐up, 14 had autoantibodies, 48 had a single antibody specificity, and 25 had multiple antibody specificities. Seven patients developed an antibody that could be attributed to the ERT episode, and 15 patients developed an antibody after ERT and additional RBC transfusions. There were 32 reported suspected transfusion reactions. No acute hemolytic transfusion reactions were reported. Seven patients were given a total of 10 incompatible RBC units. Of these patients, one developed a delayed serologic transfusion reaction. The rate of alloimmunization attributable to ERT was 3%. Overall, the rate of incompatible transfusion was less than 0.3% and the rate of a delayed hemolytic transfusion reaction was approximately 0.02%.ConclusionThere is minimal risk associated with the release of emergency uncrossmatched blood in the setting of an acutely bleeding patient. [Correction statement added after online publication 15‐Oct‐2012: the number of patients with autoantibodies, single antibody specificity and multiple antibody specificity has been update.]