Abstract
Abstract 4404
Hemolytic anemia and renal failure are among the very rare side effects related to immunoglobulin transfusions. Anti-A/B antibodies are implicated in hemolytic events upon transfusion of high doses, given in short time. Recently several cases of IVIG induced hemolytic anemia have been published as case reports (MJ Thomas et al. Blood 1993; AG Brox et al. Am J Med 1987; Z Daw et al. Transfusion 2008; JR Wilson et al. Muscle Nerve 1997; J Coghill et al. Biol Blood Marrow Transplant 2006; RL Comenzo et al. J Pediatr 1992; F Yin et al. J Hematol 2008). One recent report describes the development of acute kidney injury related to hemoglobinuria as a result of IVIG induced hemolytic anemia (CC Welles et al. Am J Kid Dis 2009). In most cases, high cumulative doses 2gr/kg were administered. Most of the patients showed a positive direct antiglobulin test, and most were of non-O blood type. Various concentrations of anti-A, anti-B, and anti-D hemagglutinin were detected in the different IVIG products that were infused in each case. A systematic comparison of anti A/B and free-light chain content was performed in 5 different, commercially available IVIG preparations. The quantitative estimation of IgG anti-A/B in IVIG preparations is depending on choosing the appropriate method. Thus, hemagglutination, ABO-ELISA, and FACS all detect some form of anti-A/B albeit with different sensitivity and specificity. The immune complex which forms in A1-patients will activate complement and induce the IVIG-associated hemolytic anemia. In such patients the Direct Antiglobulin Test (Coombs Test) will turn reactive. In most countries, health authorities set a limit of anti-A RBC agglutination titers <32 or <64 which is arbitrary of this semi quantitative procedure. Here we subject a hemagglutination system to various cell suspension buffer conditions and look at variations. To achieve high sensitivity in the hemagglutination striking-pattern assay, two type A1 red blood cells (RBC) were selected and the assay performed using 4 different suspension conditions as a function of pH and molarity. Quantitative estimation of light chains was done using nephelometry with polyclonal antibodies against the hidden light chain determinant on free kappa and lambda light chains devoid of cross-reaction with the kappa and lambda epitopes on intact IgG (The Binding Site, Oxford). A BN prospect system was used to evaluate the information. To determine the anti-A/B content a series of dilutions was made and the last agglutinating concentration (mg/(ml) was taken as the final content. The last agglutinating concentration of immunoglobulin preparations 1 to 5 varied from 1.95 to 25 in NaCl. In NaCl+Liss (low ionic strength solution, which enhances antigen-antibody binding) variation was from 6.25 to 25, in phosphate buffered saline (PBS) it varied from 4.4 to 25 and in PBS+Liss it varied from 3.125 to 25. Preparation 2 was the strongest agglutinator and preparation 4 the lowest in all milieus. The 5 IgG preparations assessed contained < 0.3% free kappa of total IgG and < 0.28% free lambda light chains. It is likely that the induction of side effects under usual administration conditions by anti-A is improbable with trigger limits acknowledged by the health authorities; however, transfusions of high doses of IVIG during short times could reach critical limits. High anti-A content IVIG transfusions, especially to A-type recipients, could reach critical limits to cause hemolysis. The FLC content appears at trace concentrations.
References on poster
Disclosures:
Schleis: octapharma USA Inc: Employment. Nydegger:octapharma AG: Consultancy.
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