The Functional Role of IgA in the IgM/IgA-Enriched Immunoglobulin Preparation Trimodulin

In comparison to human immunoglobulin (Ig) G, antibodies of IgA class are not well investigated. In line with this, the functional role of the IgA component in IgM/IgA-enriched immunoglobulin preparations is also largely unknown. In recent years, powerful anti-pathogenic and immunomodulatory properties of human serum IgA especially on neutrophil function were unraveled. Therefore, the aim of our work is to investigate functional aspects of the trimodulin IgA component, a new plasma-derived polyvalent immunoglobulin preparation containing ~56% IgG, ~23% IgM and ~21% IgA. The functional role of IgA was investigated by analyzing the interaction of IgA with FcαRI, comparing trimodulin with standard intravenous IgG (IVIG) preparation and investigating Fc receptor (FcR)-dependent functions by excluding IgM-mediated effects. Trimodulin demonstrated potent immunomodulatory, as well as anti-pathogenic effects in our neutrophil model (neutrophil-like HL-60 cells). The IgA component of trimodulin was shown to induce a strong FcαRI-dependent inhibitory immunoreceptor tyrosine-based activation motif (ITAMi) signaling, counteract lipopolysaccharide-induced inflammation and mediate phagocytosis of Staphylococcus aureus. The fine-tuned balance between immunomodulatory and anti-pathogenic effects of trimodulin were shown to be dose-dependent. Summarized, our data demonstrate the functional role of IgA in trimodulin, highlighting the importance of this immunoglobulin class in immunoglobulin therapy.

Effectiveness and Safety of an Intravenous Immune Globulin (IVIG) Preparation in Post-exposure Prophylaxis (PEP) Against Measles in Infants

Background: Administration of measles virus (MV)-specific IgG as post-exposure prophylaxis (PEP) is known to effectively prevent measles. Since the introduction of active immunization against measles, the levels of MV-specific IgG antibodies in the population have dropped. Therefore, the concentration of MV-specific antibodies in immunoglobulin products derived from human plasma donors has declined as the proportion of vaccinated donors has increased. Literature on the effectiveness of PEP with current available immunoglobulins is limited. Here we examine the effectiveness of 400 mg/kg intravenous immunoglobulin (IVIG) (IgVena®, Kendrion) as PEP in infants during a measles outbreak in Austria, 2019.Methods: After exposure to a highly contagious measles patient, identified infants were evaluated for eligibility for IVIG PEP. Infants were tested for measles maternal antibodies, if the result was expected to be available within 72 h after exposure. IVIG was administered to eligible infants with negative maternal IgG antibody levels (n = 11), infants with protective levels but result beyond 72 h (n = 2) and infants not tested for maternal IgG antibodies (n = 52). Telephone enquiries were made asking for measles infection. Effectiveness was calculated using exact logistic regression. Samples of four out of seven used IVIG batches were tested for MV-neutralizing antibody capacity.Results: In 63 (96.9%) of 65 infants PEP with IVIG was administered. The parents of two infants declined IVIG PEP. None of the infants with IVIG PEP got measles or symptoms suggestive for measles, but both infants who did not receive PEP were infected. Effectiveness of IVIG PEP was calculated to be 99.3% (CI 95%: 88.7–100%). No serious adverse event of IVIG treatment was observed. The investigation on MV-neutralizing antibody capacity showed a geometric mean titer ranging from 10.0 to 12.7 IU/ml, resulting in a 1.57–2.26-fold higher concentration than postulated as minimum level for immunity.Conclusions: Our findings suggest that the used IVIG preparation provided an at least non-inferior protection rate compared to IVIG preparations derived from donors before the global introduction of standard active immunization against measles.

SARS-CoV-2 Neutralization in Commercial Lots of Plasma-derived Immunoglobulin

Introduction: Patients suffering from primary or secondary immunodeficiency face times of increased insecurity and discomfort in the light of the raging Covid-19 pandemic, not knowing if and to what extend their comorbidities impact a potential Covid-19 course of disease. Furthermore, recently available vaccination options might not be amenable or effective for all patients of this heterogeneous population. Therefore, these patients often rely on passive immunization with plasma-derived, intravenous or subcutaneous immunoglobulin (IVIG/SCIG). Whether the ongoing Covid-19 pandemic and/or the progress in vaccination programs lead to increased and potentially protective titers in plasma-derived immunoglobulins (Ig) indicated e.g. for humoral immunodeficiency remains a pressing question for this patient population. Purpose: Here we investigated SARS-CoV-2 reactivity of US plasma-derived IVIG/SCIG products from the end of 2020 until 06/2021 as well as in convalescent plasma (CP) from 05/2020 to 08/2020. Methods: Final containers of IVIG/SCIG and CP donations were analyzed by commercial ELISA for SARS-CoV-2 S1-RBD IgG as well as microneutralization assay using a patient-derived SARS-CoV-2 (D614G) isolate. Neutralization capacities of 313 plasma single donations and 119 plasma-derived IVIG/SCIG lots were determined. Results obtained from both analytical methods were normalized against the international WHO standard. Finally, based on dense pharmacokinetic profiles of an IVIG preparation from previously published investigations, possible steady-state plasma levels of SARS-CoV-2 neutralization capacities were approximated based on currently measured anti-SARS-CoV-2 potencies in IVIG/SCIG preparations. Results: CP donations presented with a high variability with regards to anti-SARS-reactivity in ELISA as well as in neutralization testing. While approximately 50% of convalescent donations were none/low neutralizing, approximately 10% were at or above 1000 IU/ml. IVIG/SCIG lots derived from pre-pandemic plasma donations did not show neutralizing capacities of SARS-CoV-2. Lots produced between 12/2020 and 06/2021, entailing plasma donations after emergence of SARS-CoV-2 showed a rapid and constant increase in anti-SARS-CoV-2 reactivity and neutralization capacity over time. Neutralization capacity increased from a mean of 20 IU/ml in 12/2020 to 505 IU/ml in 06/2021, while lot-to-lot variability was substantial. Pharmacokinetic (PK) extrapolations based on non-compartmental superposition principles using steady-state reference profiles from previously published PK investigations on IVIG in PID, yielded potential steady-state trough plasma levels of 16 IU/ml based on the average final container concentration from 05/2021 with 216 IU/ml. Maximum extrapolated trough levels could reach 64 IU/ml based on the latest maximal final container potency tested in 06/2021. Conclusions: SARS-CoV-2 reactivity and neutralization capacity in IVIG/SCIG produced from US plasma rapidly and in part exponentially increased in the first half of 2021. The observed increase of final container potencies is likely trailing the serological status of the US donor population in terms of Covid-19 convalescence and vaccination by at least 5 months due to production lead times and should in principle continue at least until fall 2021. In summary, the data support rapidly increasing levels of SARS-COV-2 antibodies in IVIG/SCIG products implicating that a certain level of protection could be possible against COVID-19 for regularly substituted PID/SID patients. Nevertheless, more research to confirm, which plasma levels are needed for protection against SARS-CoV-2 infection of immune-compromised patients is still needed.

Cross-neutralization activity against SARS-CoV-2 is present in currently available intravenous immunoglobulins

Background: Cross-reactivity against human coronaviruses with Flebogamma® DIF and Gamunex®-C, two available intravenous immunoglobulins (IVIG), has been reported. In this study, these IVIG were tested for neutralization activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), SARS-CoV and Middle East respiratory syndrome CoV (MERS-CoV). Materials & methods: Neutralization capacity of lots of IVIG manufactured prior to COVID-19 pandemic was assessed against these viruses in cell culture. Infectivity neutralization was quantified by percent reduction in plaque-forming units and/or cytopathic/cytotoxic methods. Results: All IVIG preparations showed neutralization of SARS-CoV-2 isolates. All IVIG lots produced neutralization of SARS-CoV. No IVIG preparation showed significant neutralizing activity against MERS-CoV. Conclusion: The tested IVIG contain antibodies with significant in vitro cross-neutralization capacity against SARS-CoV-2 and SARS-CoV, but not MERS-CoV. These preparations are currently under evaluation as potential therapies for COVID-19.

Cross-neutralization activity against SARS-CoV-2 is present in currently available intravenous immunoglobulins

BackgroundThere is a crucial need for effective therapies that are immediately available to counteract COVID-19 disease. Recently, ELISA binding cross-reactivity against components of human epidemic coronaviruses with currently available intravenous immunoglobulins (IVIG) Gamunex-C and Flebogamma DIF (5% and 10%) have been reported. In this study, the same products were tested for neutralization activity against SARS-CoV-2, SARS-CoV and MERS-CoV and their potential as an antiviral therapy.MethodsThe neutralization capacity of six selected lots of IVIG was assessed against SARS-CoV-2 (two different isolates), SARS-CoV and MERS-CoV in cell cultures. Infectivity neutralization was measured by determining the percent reduction in plaque-forming units (PFU) and by cytopathic effects for two IVIG lots in one of the SARS-CoV-2 isolates. Neutralization was quantified using the plaque reduction neutralization test 50 (PRNT50) in the PFU assay and the half maximal inhibitory concentration (IC50) in the cytopathic/cytotoxic method (calculated as the minus log10 dilution which reduced the viral titer by 50%).ResultsAll IVIG preparations showed neutralization of both SARS-CoV-2 isolates, ranging from 79 to 89.5% with PRNT50 titers from 4.5 to >5 for the PFU method and ranging from 47.0%-64.7% with an IC50 ~1 for the cytopathic method. All IVIG lots produced neutralization of SARS-CoV ranging from 39.5 to 55.1 % and PRNT50 values ranging from 2.0 to 3.3. No IVIG preparation showed significant neutralizing activity against MERS-CoV.ConclusionIn cell culture neutralization assays, the tested IVIG products contain antibodies with significant cross-neutralization capacity against SARS-CoV-2 and SARS-CoV. However, no neutralization capacity was demonstrated against MERS-CoV. These preparations are currently available and may be immediately useful for COVID-19 management.

Efficacy, safety, and tolerability of Kedrion 10% IVIG in primary immunodeficiency

Background: Primary immunodeficiency involving defective antibody formation requires antibody replacement therapy with immunoglobulin products to prevent and reduce infections. Immunoglobulin for intravenous use (IVIG) is a processed blood product with limited availability, and the various marketed IVIG products may have different tolerability among patients. New IVIG products are therefore necessary to offer options to patients and to reduce the risk of a product shortage. Methods: Forty-five adult and pediatric patients with primary immunodeficiency, documented agammaglobulinemia or hypogammaglobulinemia, and antibody deficiency were enrolled in a prospective, multi-centre, open-label, single-arm historically controlled Phase III study to evaluate the safety, efficacy, and pharmacokinetics of a new 10% IVIG produced by Kedrion. Results: Forty-four patients completed the study while one withdrew consent. Over the 12-month study period, only 2 episodes of acute serious bacterial infections (both bacterial pneumonias) were recorded, for a mean annual event rate of 0.04 per subject, with an upper one-sided 99% confidence limit of 0.11. Values for all secondary efficacy endpoints were comparable with those in similar studies. The primary safety endpoint was met as the rate of infusions temporally associated (i.e., within 72 hours) with ≥1 adverse event was 16% (upper 95% confidence limit 20.4%). Pharmacokinetics were assessed in 31 patients and found to be comparable with those published for other IVIG products. Conclusion: Kedrion IVIG 10% is safe, efficacious, and well tolerated by patients with primary immunodeficiency. Statement of novelty: This report describes the safety, efficacy, and pharmacokinetics of a new IVIG preparation.

Efficacy, safety, and tolerability of IVIG-SN in patients with primary immunodeficiency

Background: IVIG-SN is a modern intravenous immunoglobulin with multiple pathogen elimination steps. This clinical trial in patients with primary immunodeficiency (PID) was designed to evaluate the safety, efficacy, and tolerability of this product in adults and children. Methods: Forty-four patients with PID were treated with IVIG-SN for 12 months. IgG trough levels and pharmacokinetics of IVIG-SN were evaluated as well as efficacy and safety according to standard FDA guidelines. Results: Overall, a total of 572 IVIG-SN infusions were administered according to either a 21- or a 28-day schedule. IgG trough levels during the treatment period ranged from 823.00 to 902.77 mg/dL, respectively, and half-life in serum of the administered IgG was 43.45 ± 30.25 days. There were no deaths and no adverse events leading to withdrawal from the study. Of all infusions administered, only 137 (24%) were temporally associated with an adverse event (AE). The upper bound for the 95% CI for the frequency of infusions temporally associated with an AE was 29.2%. Drug-related AEs were predominantly mild, and there were no acute serious bacterial infections during the study. Efficacy was also demonstrated by low rates of missed work, school, or daycare days (mean 2.6 days); unscheduled visits to physicians (mean 1.7); and therapeutic antibiotic use (mean 15 days). Conclusion: IVIG-SN is effective in preventing infections and is safe and well tolerated. Statement of novelty: This efficacy and toxicity trial was conducted using a new IVIG preparation.