INTRODUCTION: IVIG use is increasing in transplant recipients for desensitization, treatment & prevention of ABMR and infections. The complications of IVIG are often related to the excipient content, however, the development of newer, isosmolar products with higher antibody content has eliminated many of those concerns. Despite these advances, some patients receiving high dose IVIG (HD-IVIG) developed clinically significant hemolysis (all blood group A, B or AB). Here we investigate the anti-A/B titers in currently available IVIG products and assess risk for hemolysis. METHODS: IgM titers of anti-A/B were determined at room temperature immediate spin. IgG titers of anti-A/B were determined at the antihuman globulin phase at 37ºC. Titers are reported as the reciprocal of the highest dilution with macroscopic agglutination. RESULTS: We assessed anti-A/B titers in 5 different IVIG products. All IVIG products contained anti-A activity (range 1:4-1:64) while anti-B activity was less (0-1:16). For Octagam® 5% 2 different lots were examined. The anti-A/B activity varied (anti-A maximum 1:2-1:8) (anti-B 0-1:2). For Octagam® 10%, (not currently FDA-approved) 5 different lots were examined. The anti-A/B activity varied (anti-A maximum 1:8-1:32) (anti-B 1:4-1:16) although most samples exhibited (anti-A maximum 1:8-1:16) & (anti-B 1:4-1:8). Currently available 10% IVIG products exhibited strong anti-A & anti-B titers: Gamunex®10% (anti-A 1:32, anti-B 1:4) & Privigen® 10% (anti-A 1:64, anti-B 1:8). Also, significant hemolytic episodes with these products were seen. The product with the least anti-A/B activity was Carimune® 9% (anti-A 1:4, anti-B 1:0). In our clinical practice (2003-present) we use Carimune® 9% for blood group A, B & AB without hemolysis. However, the sucrose content of Carimune® limits use post-transplant d/t risk of osmotic nephropathy. Although, 5% IVIG preparations contained less anti-A/B activity, their use is limited d/t volume considerations. CONCLUSIONS: 1). Anti-A/B titers vary by lots in IVIG preparations. 2). Risk for hemolysis after HD-IVIG is Coombs+ and induced by high-titer anti-A/B antibodies in isosmolar products. 3) Currently, we use Carimune® 9% pre-transplant for desensitization given on dialysis for blood groups A,B & AB. Post-transplant we recommend using isosmolar liquid products with the lowest anti-A/B titer and split doses (1gm/kg, given over 2 days).

Jordan, S.: Grant/Research Support, Octapharma, Inc.

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