Intravenous Immunoglobulin Products Research Articles

Submicron immunoglobulin particles exhibit FcγRII-dependent toxicity linked to autophagy in TNFα-stimulated endothelial cells

In intravenous immunoglobulins (IVIG), and some other immunoglobulin products, protein particles have been implicated in adverse events. Role and mechanisms of immunoglobulin particles in vascular adverse effects of blood components and manufactured biologics have not been elucidated. We have developed a model of spherical silica microparticles (SiMPs) of distinct sizes 200–2000 nm coated with different IVIG- or albumin (HSA)-coronas and investigated their effects on cultured human umbilical vein endothelial cells (HUVEC). IVIG products (1–20 mg/mL), bare SiMPs or SiMPs with IVIG-corona, did not display significant toxicity to unstimulated HUVEC. In contrast, in TNFα-stimulated HUVEC, IVIG-SiMPs induced decrease of HUVEC viability compared to HSA-SiMPs, while no toxicity of soluble IVIG was observed. 200 nm IVIG-SiMPs after 24 h treatment further increased ICAM1 (intercellular adhesion molecule 1) and tissue factor surface expression, apoptosis, mammalian target of rapamacin (mTOR)-dependent activation of autophagy, and release of extracellular vesicles, positive for mitophagy markers. Toxic effects of IVIG-SiMPs were most prominent for 200 nm SiMPs and decreased with larger SiMP size. Using blocking antibodies, toxicity of IVIG-SiMPs was found dependent on FcγRII receptor expression on HUVEC, which increased after TNFα-stimulation. Similar results were observed with different IVIG products and research grade IgG preparations. In conclusion, submicron particles with immunoglobulin corona induced size-dependent toxicity in TNFα-stimulated HUVEC via FcγRII receptors, associated with apoptosis and mTOR-dependent activation of autophagy. Testing of IVIG toxicity in endothelial cells prestimulated with proinflammatory cytokines is relevant to clinical conditions. Our results warrant further studies on endothelial toxicity of sub-visible immunoglobulin particles.

Antibodies against glutamic acid decarboxylase in intravenous immunoglobulin preparations can affect the diagnosis of type 1 diabetes mellitus.

Intravenous immunoglobulins (IVIgs) contain various autoantibodies, including those against glutamic acid decarboxylase (GADAb), a valuable biomarker of type 1 diabetes mellitus. Passive transfer of GADAb from IVIgs to patients poses a risk of misdiagnosis, and information on the specific titres of GADAb and their impact on diagnostic accuracy remains limited. This study aimed to provide further insights into the origin of GADAb detected in patient serum following IVIg infusion. GADAb titres in IVIg products from Japan and the United States were measured using enzyme-linked immunosorbent assay-based assays. For reliable quantification, GADAb titres in pooled plasma were quantified and compared with those in the IVIg products. The determined titres were used to estimate the likelihood of passively detecting acquired GADAb in individuals receiving IVIgs. GADAbs were prevalent in IVIg products; however, the titres varied significantly among different lots and products. Importantly, IVIg-derived GADAb was estimated to remain detectable in patient serum for up to 100 days following a dosage of 2000 mg/kg. Clinicians should consider that IVIg preparations may contain GADAb, which can lead to false-positive results in serological assays. Careful interpretation of the assay results is key to the definitive diagnosis of type 1 diabetes mellitus.

Successful Treatment of Severe Pemphigus Vulgaris with Reduced Side Effects Using a Novel IVIg Preparation.

Pemphigus vulgaris (PV) is a rare autoimmune bullous dermatosis (AIBD) characterized by painful blistering of the skin and mucosa caused by autoantibodies that lead to loss of adhesion in the epidermis. Standard therapy for PV is corticosteroids, either alone or in combination with steroid-sparing immunosuppressants or infusions with rituximab. According to the published European guideline, high-dose intravenous immunoglobulin (IVIg) therapy with a dosage of 2g per kg body weight distributed over 2-5days every 4weeks is a promising treatment option, especially for severe or refractory disease. This report describes a 73-year-old female patient with severe and recurrent disease who achieved stabilization with IVIg treatment. However, the patient experienced side effects such as headaches, nausea, and vomiting, which affected daily life. Hence, she was transitioned to a new IVIg preparation with a new manufacturing process, resulting in fewer side effects and an improved quality of life. Further follow-up is necessary to fully evaluate the effectiveness and tolerability of this new IVIg product.

Analysis of mild and severe neonatal enterovirus infections in a Chinese neonatal tertiary center: a retrospective case-control study.

To compare the clinical characteristics, virus serotype, and outcome in cases of mild and severe enteroviral infection at a tertiary neonatal intensive care unit in China. A retrospective analysis of cases hospitalized between June and August 2019. Samples (stool or throat swabs) were examined using reverse transcription polymerase chain reaction. Positive cases were divided into two groups: mild infection and severe infection. A total of 149 cases were assigned to one of two groups: mild infection (n = 104) and severe infection (n = 45). There were no significant differences between the groups in terms of sex, gestational age, birth weight, mode of delivery, and onset within 7 days. Clinical symptoms in both groups mostly resembled sepsis (fever, rash, poor feeding, and lethargy); however, there were significant variations in concomitant symptoms such as hepatitis, thrombocytopenia, encephalitis, coagulopathy, and myocarditis. Severe cases were more likely to have abnormal complete blood counts, biochemical parameters, and cerebrospinal fluid markers. The predominant serotypes implicated in neonatal enterovirus infections were echoviruses and Coxsackievirus B. Invasive ventilation, intravenous immunoglobulin, vasoactive medications, and blood product transfusions were often required, with high mortality rates among severe cases. We found significant differences between mild and severe cases of neonatal enterovirus infection with respect to complications, laboratory findings, and enterovirus serotypes. It is crucial to exercise caution when newborns exhibit symptoms of sepsis, during an enterovirus outbreak. Anemia, thrombocytopenia, abnormal liver function, and coagulation dysfunction should be monitored closely as they could indicate the presence of a severe enteroviral infection.

Autoantibody profiles in intravenous immunoglobulin preparations: A possible cause of mistaken autoimmunity diagnosis.

Intravenous immunoglobulins (IVIgs) derived from the pooled plasma of thousands of donors contain numerous types of IgG molecules, including autoantibodies commonly used to diagnose autoimmunity. While these autoantibodies can cause misinterpretation of serological tests for IVIg recipients, their profiles in IVIg preparations are not fully understood. Using binding-capability based immune assays, we measured 18 varieties of clinically relevant autoantibodies in domestic blood donor-derived IVIg products. In addition, we analyzed an IVIg product from a US brand to evaluate the influence of regional and racial differences. Based on the determined autoantibody titers, pharmacokinetics of passively acquired autoantibodies and their possible detection period in serum were estimated. Anti-thyroglobulin (Tg), anti-thyroidperoxidase (TPO), and anti-Sjögren's-syndrome-related antigen A (SS-A) antibodies were present in considerable amounts in IVIg products. Notably, these three autoantibodies can be detected in IVIg recipients' sera for up to 3 months after infusion. To the best of our knowledge, this is the first study that analyzed multiple autoantibody profiles in both pooled plasma and IVIg products and that further evaluated their potential influences on diagnosis of autoimmunity. Clinicians should keep in mind that IVIgs contain several autoantibodies and that their infusion can produce false-positive serology results. To establish an accurate diagnosis, serological tests must be carefully interpreted and clinical symptoms should be more purposefully considered if patients are receiving IVIg therapy.

Protective antibody concentrations in primary immunodeficiency following infusion with 5% or 10% intravenous immunoglobulin.

Inadequate production of immunoglobulin G (IgG) antibodies renders patients with primary immunodeficiencysusceptible to infection by numerous pathogens, some of which can lead to severe asthma exacerbation and possible death. These patients who are immunocompromised are often reliant on intravenous immunoglobulin (IVIG) therapies, which provide passive antibodies against various respiratory pathogens, including measles virus and encapsulated bacteria. We conducted a subanalysis of data from a multicenter, multinational, phase III, open-label bioequivalencestudy to compare protective concentrations of IgG antibodies provided by a 5% and a 10% IVIG product in patients with primaryimmunodeficiency. Patients on stable 21- or 28-day regimens of previous IVIG products were assigned to receive study treatment (adults: 5% IVIG and 10% IVIG; children: 10% IVIG) at doses of 300-800 mg/kg per infusion. Trough concentrations of total IgG, IgG subclasses, measles-neutralizing antibodies, and IgG against Haemophilus influenzae type b and Streptococcus pneumoniae serotypes were evaluated. A total of 48 patients (33 adults ages 16-55 years; 15 children ages 2-15 years) were enrolled and received treatment.No statistically significant differences in trough concentrations of total IgG, IgG subclasses, measles neutralizing antibodies, or IgG directed at encapsulated bacteria were observed between the 5% and 10% formulations in analyses by age (adult or pediatric) or infusion schedule (every 21 or 28 days). All evaluated patients had trough IgG concentrations above accepted thresholds for protection against disease. These findings support the conclusion that, at dose levels and infusion schedules prescribed in clinical practice,this 5% and 10% IVIG product provided consistent, predictable, and bioequivalent IgG concentrations for adult and pediatricpatients with primary immunodeficiency disease. Both formulations delivered trough antibody concentrations of total IgG, measles- neutralizing antibodies, and antibodies against encapsulated bacteria that are above thresholds accepted as protective.

Evolution of neutralizing antibodies through vaccination and breakthrough infections in the era of COVID-19 endemicity.

Despite a high vaccination rate, the COVID-19pandemic continues with immune-evading Omicron variants. The success of additional antigenic stimulation through breakthrough infection (BI)and updated vaccination in overcoming antigenic imprinting needs to be determined. Participants in a long-term follow-up cohort of healthcare worker (HCW)vaccinee were categorized according to their infection/vaccination status. Anti-SARS-CoV-2spike/nucleocapsid protein antibodies were measured, and plaque reduction neutralization tests (PRNTs)against wild-type (WT),BA.5,BN.1,and XBB.1.5were conducted. The neutralization activity of intravenous immunoglobulin (IVIG)products was evaluated to assess the immune status of the general population. Ninety-fiveHCWs were evaluated and categorized into seven groups. The WT PRNT ND50 value was highest regardless of infection/vaccination status, and groups with recent antigenic stimulation showed high PRNT titers overall. Groups with double Omicron stimulation, either by BI plus BA.4/5bivalent vaccination or repeated BI, exhibited significantly higher BA.5and BN.1 PRNT to WT PRNT ratios than those with single Omicron stimulation. Overall group immunity was estimated to be boosted in January 2023, reflecting the effect of the BA.4/5bivalent booster and additional BIs, but slightly declined in June 2023. A substantial increase in the antibody concentrations of IVIG products was noticed in 2022, and recently produced IVIG products exhibited a substantial level of cross-reactive neutralizing activity against emerging variants. Neutralizing activity against emerging variants could be enhanced by repeated antigenic stimulation via BI and/or updated vaccination. Overall group immunity was elevated accordingly, and IVIG products showed substantial activity against circulating strains.

Appropriateness of Immunosuppression and Blood Product Utilization in Acquired Hemophilia A: A Multicentre Provincial Practice Audit

Introduction: Acquired hemophilia A (AHA) is a life-threatening bleeding disorder associated with significant morbidity and mortality. Despite publication of international consensus guidelines, quality of care and guideline adherence have not been examined. While some jurisdictions have reference centres for AHA management, in Canadian provinces outside of Quebec, AHA is managed in both hemophilia treatment centres (HTCs) and community hospitals. We performed a multicentre practice audit in a Canadian province to assess use of immunosuppressive therapy (IST), blood product utilization, and evaluate treatment burden and outcomes. Methods: We included adults diagnosed with AHA (January 2000-December 2021) in Alberta, Canada, and examined the following quality of care indicators: delayed IST initiation from diagnosis, corticosteroid use alone in high-risk AHA (FVIII <0.01 IU/ml or FVIII inhibitor >20 BU/ml), cyclophosphamide use in low-risk patients (FVIII ≥0.01 IU/ml and inhibitor ≤20 BU/ml), prolonged cyclophosphamide use (>6 weeks), and inappropriate use of plasma, intravenous immunoglobulin (IVIG) and hemostatic products. Outcome measures included response, length of stay (LOS) and 30-day readmission. We evaluated treatment burden including frailty syndromes, increased level of care and hospitalization for treatment-related adverse events. Results: Of the 38 patients diagnosed with AHA, 25 (66%) were female, the median age was 74 years (IQR 61-81), and median Charlson comorbidity index was 5 (IQR 3-7). Cardiovascular comorbidities were common, including venous thromboembolism (5; 13%), atrial fibrillation (5; 13%), and myocardial infarction (4; 11%). Fifteen (39%) had ≥1 frailty syndromes, including functional dependence (6; 16%), dementia (6; 16%), falls/fractures (5; 13%), and depression/anxiety (3; 8%). Five (13%) patients required higher levels of care (long term care placement) following discharge. Twenty-one (55%) patients had high-risk disease and 17 (45%) had low-risk. In those with low-risk disease, 11 (29%) had inhibitor titres 5-20 BU/ml and 6 (16%) had inhibitors <5 BU/ml. Despite diagnostic delays ≥7 days from bleeding in 15 (39%), most received prompt initiation of IST (median 0 days [IQR 0-3] from diagnosis). First-line IST included: prednisone (38; 100%), cyclophosphamide (23; 61%), and rituximab (13; 34%). IVIG was prescribed in 5 (13%), out of keeping with guideline recommendations. We observed very high rates of first-line cyclophosphamide use in low risk AHA (11/17; 65%), including 4/6 with inhibitor titres <5 BU/ml (Table 1). First-line cyclophosphamide was also used in 3 reproductive-aged women. Prolonged courses of cyclophosphamide >6 weeks and >6 months were used in 21/23 (91%) and 7/23 (30%) patients, respectively. Two high-risk patients did not receive cyclophosphamide or rituximab-containing therapy. Of the 58 episodes of bleeding events, 41 (71%) were ISTH major bleeds. Fifteen (26%) bleeding events did not receive hemostatic therapy, whereas 27 (47%), 19 (33%), and 3 (5%) were treated with recombinant factor VIIa, activated prothrombin complex concentrates, and porcine FVIII, respectively. Dosing of bypassing agents was in keeping with guidelines. DDAVP and human FVIII were inappropriately used in 3/58 (5%) and 1 (2%) bleeding episodes, respectively. Most patients (24; 63%) received red cell transfusions with a median of 2 (IQR 0-7) units each. Five (13%) patients received a total of 18 units of plasma. Clinical responses included: complete remission (CR) in 30 (79%), partial remission in 3 (8%), and unevaluable due to early deaths in 5 (13%). All 5 patients who relapsed (13%) achieved second CR. The median LOS was 38 days (IQR 19-57) across 95 hospitalizations. The 30-day readmission rate was 24%. Reasons for admission included bleeding (50/95; 53%), infections (14/95; 15%), and other treatment side-effects (13/95; 14%). Conclusion: In this provincial cohort of AHA patients with high comorbidity and frailty, we identified gaps in quality of care including overuse of cyclophosphamide in patients with low-titre inhibitors, prolonged duration of cyclophosphamide, and inappropriate use of IVIG and plasma. Aggressive cytotoxic therapy predisposes patients to unnecessary risks of infections and malignancies. Our findings highlight the need for centralization of care in specialized centres and education initiatives.

Comparative effectiveness of two intravenous immunoglobulin products in children with Kawasaki disease, a nationwide cohort study

Kawasaki Disease (KD) is the most common acquired pediatric heart disease in the developed world. Rapid infusion of high-dose intravenous immunoglobulin is the standard therapy. Different manufacturing processes of IVIG may influence their efficacy. This study aims to conduct a head to head comparison of two IVIGs, TBSF and Privigen, from a nationwide perspective. The main data source was the National Health Insurance Research Database (NHIRD) of Taiwan. A total of 3368 KD cases involving children under 2 years of age were enrolled from January 2015 to November 2020. The primary endpoint was IVIG resistance, which we defined as the total amount exceeding 26 g in one admission. The secondary endpoints encompassed two distinct criteria: coronary involvement, which was defined as the prolonged use of aspirin or anti-coagulation agents between 180 and 360 days after the index date, and recurrence, which was defined as readmission for IVIG therapy occurring more than 30 days after previous KD index day and continuing until the end of the follow-up period. Privigen demonstrated a lower IVIG resistance rate at 9.4% in comparison to TBSF, which exhibited a rate of 9.7% (odds ratio 0.72, 95% CI 0.52–0.99). Privigen had a lower odds of coronary involvement (odds ratio 0.38, 95% CI 0.18–0.82). There is no difference in recurrence rate (odds ratio 0.60, 95% CI 0.22–1.68). Privigen might have a lower rate of IVIG resistance and reduced coronary artery involvement. The discrepancy may be due to the concentration, the stabilizers, or the source of plasma. Further investigation is needed to compare the effectiveness of different IVIGs in the large randomized controlled clinical trial.

Antibody-Mediated Clearance of Brain Amyloid-β: Mechanisms of Action, Effects of Natural and Monoclonal Anti-Aβ Antibodies, and Downstream Effects.

Immunotherapeutic efforts to slow the clinical progression of Alzheimer's disease (AD) by lowering brain amyloid-β (Aβ) have included Aβ vaccination, intravenous immunoglobulin (IVIG) products, and anti-Aβ monoclonal antibodies. Neither Aβ vaccination nor IVIG slowed disease progression. Despite conflicting phase III results, the monoclonal antibody Aducanumab received Food and Drug Administration (FDA) approval for treatment of AD in June 2021. The only treatments unequivocally demonstrated to slow AD progression to date are the monoclonal antibodies Lecanemab and Donanemab. Lecanemab received FDA approval in January 2023 based on phase II results showing lowering of PET-detectable Aβ; phase III results released at that time indicated slowing of disease progression. Topline results released in May 2023 for Donanemab's phase III trial revealed that primary and secondary end points had been met. Antibody binding to Aβ facilitates its clearance from the brain via multiple mechanisms including promoting its microglial phagocytosis, activating complement, dissolving fibrillar Aβ, and binding of antibody-Aβ complexes to blood-brain barrier receptors. Antibody binding to Aβ in peripheral blood may also promote cerebral efflux of Aβ by a peripheral sink mechanism. According to the amyloid hypothesis, for Aβ targeting to slow AD progression, it must decrease downstream neuropathological processes including tau aggregation and phosphorylation and (possibly) inflammation and oxidative stress. This review discusses antibody-mediated mechanisms of Aβ clearance, findings in AD trials involving Aβ vaccination, IVIG, and anti-Aβ monoclonal antibodies, downstream effects reported in those trials, and approaches which might improve the Aβ-clearing ability of monoclonal antibodies.

Assessment of antibody levels to SARS-CoV-2 in patients with idiopathic inflammatory myopathies receiving treatment with intravenous immunoglobulin

Antibodies to Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2) have been reported in pooled healthy donor plasma and intravenous immunoglobulin products (IVIG). It is not known whether administration of IVIG increases circulating anti-SARS-CoV-2 antibodies (COVID ab) in IVIG recipients. COVID ab against the receptor binding domain of the spike protein were analyzed using a chemiluminescent microparticle immunoassay in patients with idiopathic inflammatory myopathies (IIM) both receiving and not receiving IVIG (IVIG and non-IVIG group, respectively). No significant differences in COVID ab levels were noted between IVIG and non-IVIG groups (417 [67–1342] AU/mL in IVIG vs 5086 [43–40,442] AU/mL in non-IVIG, p = 0.11). In linear regression models including all post-vaccination patient samples, higher number of vaccine doses was strongly associated with higher COVID ab levels (2.85 [1.21, 4.48] log AU/mL, regression coefficient beta [95% CI], p = 0.001), while use of RTX was associated with lower ab levels (2.73 [− 4.53, − 0.93] log AU/mL, beta[95%CI], p = 0.004). In the IVIG group, higher total monthly doses of IVIG were associated with slightly higher COVID ab levels (0.02 [0.002–0.05] log AU/mL, p = 0.04). While patients on IVIG did not have higher COVID ab levels compared to the non-IVIG group, higher monthly doses of IVIG were associated with higher circulating levels of COVID ab in patients receiving IVIG, particularly in patients concomitantly receiving RTX. Our findings suggest that IIM patients, especially those at increased risk of COVID infection and worse COVID outcomes due to RTX therapy may have protective benefits when on concurrent IVIG treatment.

Intravenous Immunoglobulin Initiation in Patients with Chronic Inflammatory Demyelinating Polyradiculoneuropathy: A US Claims-based Cohort Study.

Intravenous immunoglobulin (IVIG) is recommended as first-line therapy for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), an immune-mediated neuropathy. The clinical profile of patients with CIDP newly initiating IVIG is poorly characterized. This claims-based cohort study describes characteristics of US patients with CIDP initiating IVIG treatment. Adult immunoglobulin (IG)-naïve patients with CIDP diagnosed between 2008 and 2018 and a subgroup of patients subsequently initiating IVIG were identified in the Merative MarketScan Research Databases. Demographics, clinical characteristics, and diagnostic procedures were described for patients initiating IVIG. Of 32,090 patients with CIDP identified, 3975 (mean age 57years) subsequently initiated IVIG. In the 6months prior to IVIG initiation, diagnoses of comorbidities including neuropathy (75%), hypertension (62%), and diabetes (33%) were frequent, as were CIDP features/symptoms/markers of functional status including chronic pain (80%), difficulty walking (30%), and weakness (30%). CIDP-related laboratory/diagnostic procedures were performed in approximately 20- > 40% of patients in the 3months prior to IVIG initiation (63.7% underwent electrodiagnostic/nerve conduction testing in the 6months prior to IVIG initiation). Patient characteristics by initial IVIG product differed only in IVIG initiation year, US geographic region, and insurance type. Comorbidities, CIDP severity or functional status markers, and other clinical variables were generally well balanced across initial IVIG product groups. A heavy burden of symptoms, comorbidities, and diagnostic testing exists in patients with CIDP initiating IVIG. Characteristics of patients with CIDP initiating different IVIG products are well balanced, suggesting an absence of clinical or demographic determinants underlying IVIG selection.

Analysis of trough levels of total IgG, IgG subclasses, measles neutralizing antibodies and IgG antibodies to encapsulated pathogens after infusion of a 5% or 10% intravenous immunoglobulin

IntroductionPatients with primary immunodeficiency (PI) are at risk of infection due to low IgG levels. We report trough levels of total IgG, IgG subclasses, measles neutralizing antibody (MVab) titers, Haemophilus influenzae type B and seven Streptococcus pneumoniae serotypes in PI patients receiving a 5% and 10% intravenous immunoglobulin (IVIG) formulation. MethodsGMX07 was a bioequivalence trial comparing Gammaplex 10% IVIG with Gammaplex 5% IVIG in patients with PI. Adult patients received the 5% for ≥ five infusions, then the 10% for ≥ five infusions, or vice versa. Pediatric patients received the 10% for 5 infusions. Doses were 300–800 mg/kg/infusion. Trough IgG levels were measured before each infusion. Trough levels for MVab, H. influenzae and S. pneumoniae titers were measured after the last infusion. Results33 adults received the 5%, 32 received the 10%. 15 pediatric patients received the 10%. In adults, median IgG trough levels = 952.5 mg/dL for the 10% and 937.0 mg/dL for the 5%. In pediatric patients, median trough level = 879.5 mg/dL. Trough levels of IgG subclasses were comparable across formulations and age groups. Adult patients had a mean MVab titer of 2908 mIU/mL with the 5% vs 3213 mIU/mL for the 10%. In pediatric patients, mean MVab titer was 2122 mIU/mL. In adults, median trough levels of IgG antibodies to H. influenzae were 2.80 µg/mL for the 5% and 2.76 µg/mL for the 10%. Trough levels of IgG antibodies to all S. pneumoniae serotypes were consistent across formulations and age groups. No clinically meaningful differences were noted between formulations, 21-day vs 28-day regimens, or age groups. DiscussionMaintaining IgG trough levels and mean MVab trough titers above protective thresholds is critical for patients with PI. No trough levels or titers fell below the protective thresholds. While thresholds for protective levels for H. influenzae or S. pneumoniae are not clearly defined, delivery of these antibodies to PI patients was demonstrated. ConclusionOur results indicate protective trough levels of IgG and antibody titers are delivered with the 5% and 10% formulations of this IVIG product, with similar results for adult and pediatric PI patients.

Method for screening influenza neutralizing antibodies in crude human plasma and its derivatives using SPR

We applied Surface Plasmon Resonance (SPR) technology to develop a method for potency screening and quantification of anti-influenza antibodies in minimally processed human plasma samples and intravenous immunoglobulin (IGIV) products. We found that specific antibodies in human plasma or IGIV capable of inhibiting binding of influenza hemagglutinin to receptor-analogous glycans do so in concentration-dependent manner. We ranked the inhibitory activity of plasma samples from multiple donors and found a good correlation (r = 0.87) of SPR assay measurements and conventional hemagglutination inhibition (HAI) assay results. This method was also applied to screen for specific anti-influenza antibodies in IGIV lots manufactured pre- and post-2009 H1N1 pandemic. The SPR method was also applied to study binding inhibition of the intact A/California/04/2009 H1N1 and B/Victoria/504/2000 influenza viruses to α2,6 or α2,3-linked synthetic glycans. In contrast to recombinant H1 hemagglutinin, which was found to interact primarily with α2,6-linked terminal sialic acids, intact H1N1 or influenza B virus recognized both types of receptor analogs with different observed dissociation rates and the inhibitory activity of plasma antibodies was dependent on the type of sialic acid link. The SPR method can provide a high-throughput, time-saving and semi-automated alternative to conventional assays such as HAI or microneutralization in situations where screening of large numbers of plasma donations to identify high titer units is needed to product highly potent immunoglobulins.

SARS-CoV-2 spike antibody concentration in gamma globulin products from high-prevalence COVID-19 countries are transmitted to X-linked agammaglobulinemia patients.

Patients with X-linked agammaglobulinemia (XLA) are characterized by humoral impairment and are routinely treated with intravenous immunoglobulin (IVIG). In this study, we aimed to investigate the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in IVIG preparations harvested globally and evaluate the transfer of SARS-CoV-2 antibodies to the XLA patient. A single-center, prospective cohort study was conducted in the period of November 2020 to November 2022. Clinical and laboratory data, specifically, SARS-CoV-2 spike IgG levels from the serum of 115 IVIG preparations given to 5 XLA patient were collected. Concurrently, SARS-CoV-2 spike IgG levels from the serum of the 5 XLA was collected monthly. Five XLA patients were evaluated within the study period. All were treated monthly with commercial IVIG preparations. A total of 115 IVIG treatments were given over the study period. The origin country and the date of IVIG harvesting was obtained for 111 (96%) of the treatments. Fifty-four IVIG preparations (49%) were harvested during the COVID-19 pandemic of which 76% were positive (>50AU/mL) for SARS-CoV-2 spike antibodies which were subsequently transmitted to the XLA patients in an approximate 10-fold reduction. SARS-CoV2 spike IgG was first detected in IVIG batches that completed their harvest date by September 2021. Positive products were harvested from origin countries with a documented prevalence over 2,000 per 100,000 population. As the prevalence of COVID-19 infections rises, detection of SARS-CoV-2 spike IgG in commercial IVIG products increases and is then transmitted to the patient. Future studies are needed to investigate the neutralizing capabilities of SARS-CoV-2 IgG and whether titer levels in IVIG remain consistent as the incidence of infection and vaccination rates in the population changes.

Reduction of Infusion Time Using a 10% Intravenous Immunoglobulin Formulation With a 15-Minute Rate Escalation Protocol During Staffing Shortages Due to COVID-19.

The COVID-19 pandemic changed home infusion nursing dramatically by increasing demand for home infusion nurses while decreasing their availability. Home infusion of intravenous immunoglobulin (IVIg) is an option for treatment of numerous conditions and requires considerable infusion time. Use of a higher-concentration IVIg product and shorter escalation increments may decrease required infusion time. The authors conducted a retrospective database analysis that identified 23 patients receiving IVIg before transitioning to a 10% IVIg product with a 15-minute rate escalation protocol (Gammaplex 10% IVIg) and evaluated the total infusion time before and after the transition. Among the 23 who received IVIg, the mean ± SD IVIg dose per dosing cycle before transitioning was 1.2 ± 0.7 g/kg given in 1 to 5 infusions per cycle. The mean ± SD time per infusion was 2.8 ± 0.8 hours before the transition and 2.6 ± 0.7 hours per infusion after the transition. The infusion time decreased after transition in 13 patients (56.5%), did not change in 5 patients (21.7%), and increased in 5 patients (21.7%). Nurse education on IVIg rate escalation may facilitate faster achievement of the maximum safe infusion rate and reduce infusion times. A trial transition to this 10% IVIg product with a 15-minute rate escalation protocol may also reduce infusion times.

Evaluation of anti-Yersinia psueudotuberculosis-derived mitogen antibody in intravenous immunoglobulin products

Antibody titers against the superantigen, Yersinia pseudotuberculosis-derived mitogen, suggestive of mediating Kawasaki disease-like manifestation in Y. pseudotuberculosis infections, in immunoglobulin products were evaluated. Trace, but detectable titer was demonstrated in the products. Thus, attention is required when evaluating anti-Y. pseudotuberculosis-derived mitogen IgG titers in patient sera post intravenous immunoglobulin therapy.

Incidence and risk factors for intravenous immunoglobulin-related hemolysis: A systematic review of clinical trial and real-world populations.

BackgroundSevere hemolysis rarely occurs in patients receiving intravenous immunoglobulin (IVIG) therapy. A systematic review was performed to assess the incidence of IVIG‐related hemolysis and the impact of patient and product risk factors.Study Design and MethodsA systematic literature search for terms related to “IVIG products”, “hemolysis,” and “adverse events” was conducted in Embase for articles published between January 1, 2015, and May 31, 2021. Studies with no clinical datasets, no IVIG treatment, or where IVIG was used to treat hemolytic conditions were excluded. Of the 430 articles retrieved, 383 were excluded based on titles/abstracts and 14 were excluded after in‐depth review.ResultsIn total, 33 articles were analyzed and separated into observational studies (n = 16), clinical trials (n = 8), and case reports (n = 9). The incidence proportion for IVIG‐related hemolysis ranged from 0% to 19% in observational studies and 0%–21% in clinical trials. A higher incidence of IVIG‐related hemolysis was consistently reported in patients with blood groups A and AB. Hemolysis occurred more frequently in patients treated with IVIG for some conditions such as Kawasaki disease; however, this may be confounded by the high dose of IVIG therapy. IVIG‐related hemolysis incidence was lower in studies using IVIG products citing manufacturing processes to reduce isoagglutinin levels than products that did not.ConclusionThis analysis identified patient and product risk factors including blood group, IVIG dose, and IVIG manufacturing processes associated with elevated IVIG‐related hemolysis incidence.

A homogeneous bioluminescent immunoassay for parallel characterization of binding between a panel of antibodies and a family of Fcγ receptors

Fc engineering efforts are increasingly being employed to modulate interaction of antibodies with variety of Fc receptors in an effort to improve the efficacy and safety of the therapeutic antibodies. Among the various Fc receptors, Fc gamma receptors (FcγRs) present on variety of immune cells are especially relevant since they can activate multiple effector functions including antibody dependent cellular cytotoxicity (ADCC) and antibody dependent cellular phagocytosis (ADCP). Depending on the desired mechanism of action (MOA) of the antibody, interactions between Fc domain of the antibody and FcγR (denoted as Fc/FcγR) may need to be enhanced or abolished. Therefore, during the antibody discovery process, biochemical methods are routinely used to measure the affinities of Fc/FcγR interactions. To enable such screening, we developed a plate based, simple to use, homogeneous immunoassays for six FcγRs by leveraging a luminescent protein complementation technology (NanoBiT). An added advantage of the NanoBiT immunoassays is their solution-based format, which minimizes well known surface related artifacts associated with traditional biosensor platforms (e.g., surface plasmon resonance and biolayer interferometry). With NanoBiT FcγRs assays, we demonstrate that assays are specific, report IgG subclass specific affinities and detect modulation in Fc/FcγR interactions in response to the changes in the Fc domain. We subsequently screen a panel of therapeutic antibodies including seven monoclonal antibodies (mAbs) and four polyclonal intravenous immunoglobulin (IVIg) products and highlight the advantages of parallel screening method for developing new antibody therapies.

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.