Anti-A and anti-B hemagglutinin depletion during Cohn purification process of 5% immunoglobulin

An optimized microplate-based method to evaluate complement-dependent hemolysis mediated by intravenous immunoglobulins (IVIG)

Hemolytic reactions can cause serious complications after administration of Intravenous Immunoglobulin (IVIG), due to passive transfer of anti-A and anti-B IgG antibodies (isoagglutinins). A maximum allowable amount of isoagglutinins is established in the US and EU for licensed IVIG, as measured by a specified direct hemagglutination test (DHAT). Despite this limit, reports of hemolysis have increased over time, raising the question of how well the DHAT predicts clinically significant hemolysis. This study was undertaken to develop a microplate-based complement-dependent hemolysis assay (CDHA) that reproducibly measures functional hemolytic activity of IVIG, for assessment of IVIG products. An IVIG working reference reagent (NIBSC 14/160) was qualified as an assay control and for quantitation purposes. Hemolytic activities of 36 IVIG product lots encompassing seven brands and including 6 clinically hemolytic lots were measured. Hemolytic activity varied among IVIG product brands, and to a lesser extent, from lot-to-lot for individual brands. Correlation between the CDHA and DHAT was not robust which may reflect imprecision of the DHAT method or additional variables that influence complement-dependent hemolysis after opsonization. In conclusion, the CDHA provides a simple, specific, and sensitive tool for IVIG product characterization and investigation of hemolytic events by manufacturers, researchers, and regulatory authorities.

Treatment-associated hemolysis in Kawasaki disease: association with blood-group antibody titers in IVIG products

Hemolytic anemia resulting from IV Immunoglobulin (IVIG) treatment can be a serious complication, especially for those with underlying conditions with a high level of inflammation and after administration of high IVIG dosages, such as Kawasaki disease (KD), a multisystem vasculitis affecting young children. This hemolysis is caused by antibodies against blood groups A and B, but the precise mechanism for hemolysis is not known. We performed a single center, partly retrospective, partly prospective study of a cohort of 581 patients who received IVIG for treatment of KD from 2006 to 2013. Factors associated with hemolysis were identified through univariable and multivariable logistic regression. Six IVIG preparations were assayed for their hemolytic effect with serological and cellular assays to clarify the mechanism of red cell destruction. During the study period, a sudden increase in the incidence of hemolysis was observed, which coincided with the introduction of new IVIG preparations in North America that contained relatively high titers of anti-A and anti-B. These blood-group-specific antibodies were of the immunoglobulin G2 (IgG2) subclass and resulted in phagocytosis by monocyte-derived macrophages in an FcγRIIa-dependent manner. Phagocytosis was increased in the presence of proinflammatory mediators that mimicked the inflammatory state of KD. An increased frequency of severe hemolysis following IVIG administration was caused by ABO blood-group-specific IgG2 antibodies leading to FcγRIIa-dependent clearance of erythrocytes. This increase in adverse events necessitates a reconsideration of the criteria for maximum titer (1:64) of anti-A and anti-B in IVIG preparations.

A prospective observational study of the incidence, natural history, and risk factors for intravenous immunoglobulin-mediated hemolysis

BACKGROUND

Intravenous Immune Globulin (IVIG) is used to treat numerous immune-mediated and inflammatory conditions. There is growing awareness of hemolysis, occasionally severe, as a side-effect of this therapy. While most cases are associated with anti-A and/or anti-B isoagglutinins, the frequency and mechanism of hemolysis remain poorly characterized.

STUDY DESIGN AND METHODS

A prospective observational study was conducted to determine incidence, natural history and risk factors for IVIG-mediated hemolysis. A total of 99 infusions of high-dose IVIG (2 g/kg or higher) administered to 78 non-group O patients were monitored and graded according to Canadian IVIG Hemolysis Pharmacovigilance Group. Serum ferritin and C3/C4 levels were monitored as indicators of macrophage activation and complement consumption, respectively. Supplementary investigations included assessment for ABO zygosity, Secretor status, FcR polymorphisms, eluate IgG subclass, monocyte monolayer assay, and a panel of cytokines.

RESULTS

Hemolysis was observed in 32 of 99 (32%) of infusions, with 19 of 99 (19%) grade 2 or higher. Hemolysis was only apparent 5-10 days after a completed IVIG infusion in 84% of cases and was associated with increases in serum ferritin without complement-consumption. In univariate analysis, increased risk was observed in group AB patients, first-time IVIG recipients, those not taking immuosuppressive medications, or patients treated with a specific IVIG brand; however, in multivariate analysis, product association was no longer observed. No other patient- or practice-related risk factors were identified.

CONCLUSION

IVIG-mediated hemolysis is common and frequently severe. Monitoring for 5-10 days following an infusion should be considered in non-O patients receiving high-dose IVIG with known risk factors.