Fc function of a new intravenous immunoglobulin product: IGIV 10% triple virally inactivated solution

Effect of Methylene Blue Pathogen Inactivation on the Integrity of Immunoglobulin M and G

Introduction

In the light of the ongoing SARS-CoV-2 pandemic, convalescent plasma is a treatment option for CO-VID-19. In contrast to usual therapeutic plasma, the therapeutic agents of convalescent plasma do not represent clotting factor activities, but immunoglobulins. Quarantine storage of convalescent plasma as a measure to reduce the risk of pathogen transmission is not feasible. Therefore, pathogen inactivation (e.g., Theraflex®-MB, Macopharma, Mouvaux, France) is an attractive option. Data on the impact of pathogen inactivation by methylene blue (MB) treatment on antibody integrity are sparse.

Methods

Antigen-specific binding capacity was tested before and after MB treatment of plasma (n = 10). IgG and IgM isoagglutinin titers were tested by agglutination in increasing dilutions. Furthermore, the binding of anti-EBV and anti-tetanus toxin IgG to their specific antigens was assessed by ELISA, and IgG binding to Fc receptors was assessed by flow cytometry using THP-1 cells expressing FcRI and FcRII.

Results

There was no significant difference in the isoagglutinin titers, the antigen binding capacity of anti-EBV and anti-tetanus toxin IgG, as well as the Fc receptor binding capacity before and after MB treatment of plasma.

Conclusion

MB treatment of plasma does not inhibit the binding capacity of IgM and IgG to their epitopes, or the Fc receptor interaction of IgG. Based on these results, MB treatment of convalescent plasma is appropriate to reduce the risk of pathogen transmission if quarantine storage is omitted.

In vitro evaluation of the biological activities of IgG in seven Chinese intravenous immunoglobulin preparations

The IgG activities of antigen recognition, Fc-mediated complement activation and cellular Fcγ-receptors (FcγRs) binding are critical for intravenous immunoglobulin (IVIg) immunotherapy in a variety of immune deficiency diseases. Further, these activities could be influenced by different plasma sources and the IVIg manufacturing processes of different manufacturers. This study evaluated and compared the biological activities of IgG in 7 IVIg preparations produced by different Chinese manufacturers. By using ELISA and two-dimensional immunoblotting, the binding capacity and antibody repertoire of IVIg against typical pathogenic antigens were investigated. Further, Fc-mediated complement activation and receptor binding activities were measured by the haemolysis method and flow-cytometric assay respectively. The results showed that all of the preparations tested have a broad spectrum of antibodies against the E. coli O157:H7 proteome, and each IVIg has its own distinct antibody repertoire. Compared to the European Pharmacopoeia IgG standard, the mean indices of the pathogenic antigen binding capacity, complement activation activity and FcγRs binding activity in Chinese preparations were 152%, 143% and 87%. The biological activities varied widely among the 7 IVIg preparations, and no significant differences were observed between the different batches of most IVIgs from the same manufacturer. This study will contribute to the improvement of the IVIg product quality evaluation system and an increased understanding of the variety of IgG biological activities in Chinese IVIg preparations.

Intravenous immunoglobulin G: trends in production methods, quality control and quality assurance

Intravenous immunoglobulin G (IVIG) is now the leading product obtained by fractionation of human plasma. It is the standard replacement therapy in primary and acquired humoral deficiency, and is also used for immunomodulatory therapy in various autoimmune disorders and transplantation. Over the last 30 years, the production processes of IVIG have evolved dramatically, gradually resulting in the development of intact IgG preparations safe to administer intravenously, with normal half-life and effector functions, prepared at increased yield, and exhibiting higher pathogen safety. This article reviews the developments that have led to modern IVIG preparations, the current methods used for plasma collection and fractionation, the safety measures implemented to minimize the risks of pathogen transmission and the major quality control tests that are available for product development and as part of mandatory batch release procedures.

A 10% ready-to-use intravenous human immunoglobulin offers potential economic advantages over a lyophilized product in the treatment of primary immunodeficiency

Intravenous immunoglobulin (IVIg) replacement therapy is the standard of care for patients with primary humoral immunodeficiencies. This study evaluated differences in infusion time between a 10% IVIg ready-to-use solution and a 6% IVIg lyophilized product and addressed potential cost implications. After receiving in-hospital treatment with 6% IVIg lyophilized solution for at least 6 months, 14 patients with humoral immunodeficiency without anti-IgA antibodies received five successive infusions with 10% IVIg ready-to-use solution. Data on infusion times were collected during the last two infusions of each IVIg product when maximum infusion rates had been reached. The median infusion time was reduced from 104.4 min with the 6% IVIg lyophilized solution to 51.0 min with the 10% IVIg ready-to-use solution (51% reduction), with corresponding median maximum infusion rates of 4.1 ml/kg/h and 5.9 ml/kg/h, respectively. Median gammaglobulin (IgG) trough levels were 7.1 g/l for the 6% IVIg lyophilized solution and 7.9 g/l for the 10% IVIg ready-to-use solution. Fewer adverse events were observed after infusing with 10% IVIg ready-to-use solution compared with 6% IVIg lyophilized preparation. We conclude that the 10% IVIg ready-to-use solution was well tolerated by most patients and reduced the median infusion time by 51% compared with a 6% lyophilized preparation of IVIg. The reduced bed occupancy and nursing time associated with a reduced infusion time, together with the elimination of a reconstitution step, were estimated to provide a cost-saving of 59.42 euros per patient per infusion. Thus, this product has the potential to reduce overall costs of IVIg treatment. Reduced infusion time is also likely to improve patients' quality of life.