Could Intravenous Immunoglobulin Collected from Recovered Coronavirus Patients Protect against COVID-19 and Strengthen the Immune System of New Patients?

The emergence of the novel coronavirus in Wuhan, China, which causes severe respiratory tract infections in humans (COVID-19), has become a global health concern. Most coronaviruses infect animals but can evolve into strains that cross the species barrier and infect humans. At the present, there is no single specific vaccine or efficient antiviral therapy against COVID-19. Recently, we showed that intravenous immunoglobulin (IVIg) treatment reduces inflammation of intestinal epithelial cells and eliminates overgrowth of the opportunistic human fungal pathogen Candida albicans in the murine gut. Immunotherapy with IVIg could be employed to neutralize COVID-19. However, the efficacy of IVIg would be better if the immune IgG antibodies were collected from patients who have recovered from COVID-19 in the same city, or the surrounding area, in order to increase the chance of neutralizing the virus. These immune IgG antibodies will be specific against COVID-19 by boosting the immune response in newly infected patients. Different procedures may be used to remove or inactivate any possible pathogens from the plasma of recovered coronavirus patient derived immune IgG, including solvent/detergent, 60 °C heat-treatment, and nanofiltration. Overall, immunotherapy with immune IgG antibodies combined with antiviral drugs may be an alternative treatment against COVID-19 until stronger options such as vaccines are available.

Rationale for including intravenous immunoglobulin in the multidrug protocol of curative treatment of pemphigus vulgaris and development of an assay predicting disease relapse

Analysis of reported outcomes of treatment of pemphigus vulgaris (PV) patients demonstrated that the multidrug approach offers a lower relapse rate compared to the FDA-approved prednisone/rituximab regimen. The multidrug protocol protects keratinocytes from autoantibody attack by systemic corticosteroids and mitochondrion-protecting drugs, selectively eliminates pathogenic autoantibodies by intravenous immunoglobulin (IVIg) and inhibits autoantibody production by cytotoxic immunosuppressors. Therefore, IVIg should be always added to the prednisone/rituximab regimen that does not eliminate circulating autoantibodies. To decrease risk for relapse to a minimum, PV should be maintained in full clinical remission until the critical mass of autoreactive plasma cells dies off. The two major factors that determine patient's risk for a relapse are the composition of the pool of pathogenic autoantibodies and the innate abilities of keratinocytes to sustain an autoantibody attack. As it is currently impossible to evaluate the risk for a relapse, development of a biomarker assay that could do so would be helpful in a long-term management of PV patients. We compared the magnitude of cytochrome c (CytC) release in keratinocytes by serum from PV patients in acute disease stage vs. remission and identified very strong positive correlation with disease severity. PV patients whose serum contained autoantibodies requiring higher amounts of normal IgG to neutralize their ability to release CytC were found to be at a higher risk for disease relapse. However, lack of very strong statistical correlation suggested that CytC is not an ideal biomarker to predict disease relapse, which should prompt a search for alternative candidates.

Minimal B Cell Extrinsic IgG Glycan Modifications of Pro- and Anti-Inflammatory IgG Preparations in vivo

Select residues in the biantennary sugar moiety attached to the fragment crystallizable of immunoglobulin G (IgG) antibodies can modulate IgG effector functions. Thus, afucosylated IgG glycovariants have enhanced cytotoxic activity, whereas IgG glycovariants rich in terminal sialic acid residues can trigger anti-inflammatory effects. More recent evidence suggests that terminal α2,6 linked sialic acids can be attached to antibodies post IgG secretion. These findings raise concerns for the use of therapeutic antibodies as they may change their glycosylation status in the patient and hence affect their activity. To investigate to what extent B cell extrinsic sialylation processes modify therapeutic IgG preparations in vivo, we analyzed changes in human intravenous IgG (IVIg) sialylation upon injection in mice deficient in B cells or in mice lacking the sialyltransferase 1, which catalyzes the addition of α2,6 linked sialic acid residues. By performing a time course of IgG glycan analysis with HILIC-UPLC-FLR (plus MS) and xCGE-LIF our study suggests that therapeutic IgG glycosylation is stable upon injection in vivo. Only a very small fraction of IgG molecules acquired sialic acid structures predominantly in the Fab- but not the Fc-portion upon injection in vivo, suggesting that therapeutic antibody glycosylation will remain stable upon injection in vivo.

The use of IVIg in fetal and neonatal alloimmune thrombocytopenia- Principles and mechanisms

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a rare neonatal disorder that is caused by alloimmunization against platelet antigens during pregnancy. Although rare, affecting only 1 in 1000 live births, it can cause intracranial hemorrhage and other bleeding complications that can lead to miscarriage, stillbirth and life-long neurological complications. One of the gold-standard therapies for at risk pregnancies is the administration of IVIg. Although IVIg has been used in a variety of different disorders for over 40 years, its exact mechanism of action is still unknown. In FNAIT, the majority of its therapeutic effect is thought the be mediated through the neonatal Fc receptor, however other mechanisms cannot be excluded. Due to safety, supply and other concerns that are associated with IVIg use, alternative therapies that could replace IVIg are additionally being investigated. This includes the possibility of a prophylaxis regimen for FNAIT, similarly to what has been successfully used in hemolytic disease of the fetus and newborn for over 50 years.

Using the K/BxN mouse model of endogenous, chronic, rheumatoid arthritis for the evaluation of potential immunoglobulin-based therapeutic agents, including IVIg and Fc-μTP-L309C, a recombinant IgG1 Fc hexamer

BACKGROUND

High-dose intravenous immunoglobulin (IVIg), and more recently, subcutaneously-delivered Ig (SCIg), are used to treat a variety of autoimmune diseases; however, there are challenges associated with product production, availability, access and efficacy. These challenges have provided incentives to develop a human recombinant Fc as a more potent alternative to IVIg and SCIg for the treatment of autoimmune diseases. Recently, a recombinant human IgG1 Fc hexamer (Fc-μTP-L309C) was shown to be more efficacious than IVIg in a variety of autoimmune mouse models. We have now examined its efficacy compared to IVIg and SCIg in the K/BxN mouse model of endogenous, chronic rheumatoid arthritis (RA).

RESULT

Using the serum-transfer K/BxN model and the endogenous autoimmune model, amelioration of the arthritis was achieved. Effective treatment required high and frequent doses of IVIg, SCIg and Fc-μTP-L309C. However, Fc-μTP-L309C was efficacious at 10-fold lower doses that IVIg/SCIg. Also, arthritis could be prevented when Fc-μTP-L309C was given prior to onset of the arthritis in both the endogenous model and in the serum transfer model.

CONCLUSIONS

Our results show that Fc-μTP-L309C is a powerful treatment for the prevention and amelioration of severe, chronic arthritis in a true autoimmune mouse model of RA. Thus, the K/BxN endogenous arthritis model should be useful for testing potential therapeutics for RA. Our findings provide rationale for further examination of the treatment efficacy of immunoglobulin-based therapeutics in rheumatoid arthritis.

Enhanced serum immunoglobulin G clearance in myotonic dystrophy-associated hypogammaglobulinemia: a case series and review of the literature

BACKGROUND

Myotonic dystrophy type 1 is an autosomal dominant disorder characterized by muscle weakness, myotonia, cataracts, and cardiac conduction defects; it is associated with expansions of cytosine-thymine-guanine repeats in the myotonic dystrophy protein kinase. Hypogammaglobulinemia is a lesser known association of myotonic dystrophy type 1 and the underlying pathogenesis of immunoglobulin G depletion remains unclear.

CASE PRESENTATION

Here we report a kindred of two members (a 62-year-old white woman and a 30-year-old white man; mother and son) with myotonic dystrophy type 1-associated hypogammaglobulinemia associated with altered intravenous immunoglobulin elimination kinetics and reduced half-life. There was no history of systemic immunosuppression or renal or gastrointestinal protein loss in either patient, and no underlying case for a secondary immunodeficiency could be found. One patient required fortnightly intravenous immunoglobulin to maintain adequate trough immunoglobulin G levels.

CONCLUSIONS

Ongoing study of myotonic dystrophy type 1-associated hypogammaglobulinemia using contemporary tools of genomic medicine may help to further delineate the pathogenesis of this entity.

Effects of IVIg treatment on autoantibody testing in neurological patients: marked reduction in sensitivity but reliable specificity

BACKGROUND

Therapy of autoimmune diseases of the central and peripheral nervous system with intravenous IgG immunoglobulin (IVIg) is well established. Since IVIg is produced from pooled human plasma, autoantibodies can be found in IVIg products and, accordingly, in patient sera after transfusion. The de novo evidence or disappearance of anti-neural autoantibodies after IVIg treatment has so far not been systematically examined.

METHODS

We screened 50 neurological patients before and after IVIg treatment for classical onconeural and the most common neurological surface autoantibodies as well as for ganglioside autoantibodies and 23 different antinuclear autoantibodies using immunoblot or cell-based indirect immunofluorescence assays. Furthermore, we screened 31 neurological patients with previously known seropositivity for disappearance of the corresponding antibody after treatment.

RESULTS

After IVIg treatment, 90% of all sera were de novo positive for antinuclear antibodies, especially for Ro-52. In contrast, 94% of all sera did not show any de novo-positive anti-neural antibodies. In the remaining three cases, titers were very low. Importantly, 12.9% of all tested sera of patients with known antibody positivity turned false negative after IVIg treatment and titers were falsely low in 37% of the remaining sera.

CONCLUSIONS

Here, we present for the first time results of a broad screening for clinically relevant autoantibodies before and after IVIg treatment in neurological patients. We identified a high specificity but reduced sensitivity for anti-neural antibody testing after IVIg transfusion. In contrast, antinuclear antibody testing is not reliable after IVIg treatment. These results are of high practical importance for diagnostic of neuroimmunological diseases.

Transient derangements in Hepatitis B serology in patients post-intravenous immunoglobulin therapy-a case-based review

Intravenous immunoglobulin (IVIg) is a commonly utilized therapy in multiple medical subspecialities, indicated for the management of various primary and secondary immunodeficiency states and autoimmune and inflammatory conditions. A lack of awareness exists among clinicians regarding the serological downstream effects of its use. An observed phenomenon post-IVIg is the passive transfer of antibodies from the product which can lead to transiently positive hepatitis B serology in recipients. When confounding viral serology is encountered, there is a risk to patients of treatment delays and mismanagement. Three patients encountered in the hematology department of a tertiary referral hospital developed spurious hepatitis B serology after administration of IVIg, whose cases are briefly outlined here. These cases highlight the need for routine pre-treatment viral screening and emphasize the importance of clinicians recognizing such potentially confounding results. This is of particular relevance to the sizeable subset of hematology patients who are planned for future immunomodulatory treatment (such as rituximab), where previous hepatitis B infection can often be a barrier to timely treatment.

Treatment of pemphigus vulgaris: part 2 - emerging therapies

Introduction: Corticosteroids and immunosuppressive agents have been the mainstay for the treatment of pemphigus vulgaris (PV). While they have benefited patients, they have been associated with the risks of prolonged immune suppression and a high incidence of significant and catastrophic side effects. Relapses are common. Novel agents promising targeted therapies, that may provide better outcomes, are being studied. Areas covered: Recently rituximab with corticosteroids has been recommended as the first-line treatment for PV. A number of known and new therapeutic agents currently investigated are BAFF, P13K, BTK inhibitors along with the use of IVIg and CAR-T therapy. The possible role of these therapeutic targets in the pathophysiology appears to be the rationale for the treatment of this potentially fatal disease. Expert opinion: While there is significant enthusiasm for these therapies, certain concerns and consequences are being under-discussed. None of the current clinical trials in progress are specific for PV, except possibly CAR-T therapy. The major issue(s) that are unclear is whether these therapies would be successful in providing long-term clinical remissions. Will these therapies require additional agents to be effective? Will the benefits be limited in duration? The answers to many questions will determine their final place in the algorithm for the treatment of PV.

Intravenous immunoglobulin therapy: a snapshot for the internist

Intravenous immunoglobulins are the cornerstone for the treatment of primary humoral immunodeficiencies and may be used for a great number of other autoimmune, neurological and hematological conditions as well. Given their wide application, the possibility of running across a patient who needs this kind of therapy is becoming increasingly common. Generally, intravenous immunoglobulins are well tolerated. However, numerous adverse reactions ranging from mild to severe have been reported and linked to patient- and product-related factors. For all these reasons, we present herein a comprehensive review of the on- and off-label applications of intravenous immunoglobulins and provide a guide for the internist how to minimize the risk of adverse reactions and manage them.

Evaluation of a Personalized Subcutaneous Immunoglobulin Treatment Program for Neurological Patients

BACKGROUND

Subcutaneous immunoglobulin (SCIg) treatment has been shown to control symptoms and improve overall satisfaction in patients with neurological disorders. However, a large injection volume can be overwhelming and a barrier to successful SCIg treatment. We established a nurse-led individualized approach program to facilitate a smooth and successful treatment transition from intravenous immunoglobulin (IVIg) to SCIg. The program involved a lead nurse to provide two or more individual educational sessions on SCIg administration, establish a written transition plan, and liaise care with physicians.

OBJECTIVES

We aimed to evaluate the impact of our program to a successful transition defined as SCIg retention or adherence without a need to restart IVIg by six or twelve months.

METHODS

We reviewed medical charts of all patients with immune-mediated neuromuscular disorders who were in our program during January 2010 to Dec 2016.

RESULTS

Nineteen patients were identified. Mean IVIg treatment duration was 31.5 months (range 4-98) before the transition. Mean steady state SCIg dosage was 26.2 g/week (SD 10.3). All patients were initially able to switch to SCIg, with a retention rate of 17/19 (89.5%) at six months and 15/19 (78.9%) at twelve months. Two patients reverted back to IVIg treatment due to worsening of their symptoms at two and three months, while two required supplemental IVIg infusions. There were no major adverse events reported during the twelve-month period, but one minor cutaneous adverse event (redness around the injection site).

CONCLUSIONS

Successful treatment transition may be achieved with the nurse led individualized approach program.

Intravenous Immunoglobulin Controls Th17 Cell-Mediated Osteoclastogenesis

The purpose of this study was to determine the regulatory role of intravenous Ig (IVIg) in Th17 cytokine–induced RANK ligand (RANKL) expression and osteoclast (OC) differentiation from OC precursors (pre-OC). Human CD14⁺ monocytes were isolated and stimulated by Th17 cytokines (IL-17, IL-21, and IL-22) and RANKL expression was investigated using a real-time PCR. CD14⁺ monocytes were incubated with RANKL, Th17 cytokines, and M-CSF, with/without IVIg, and OC differentiation was determined by counting tartrate-resistant acid phosphatase-positive multinucleated cells. OC differentiation was investigated after monocytes were cocultured with Th17 cells in the presence of IVIg. Th17 cell differentiation was determined using enzyme-linked immunosorbent assay and flow cytometry after CD4⁺ T cells were cultured with IVIg under Th17 condition. Th17 cytokines stimulated monocytes to express RANKL and IVIg suppressed the Th17 cytokine-induced RANKL expression. OCs were differentiated when pre-OC were cocultured with RANKL or Th17 cytokines and IVIg reduced the osteoclastogenesis. IVIg also decreased osteoclastogenesis when pre-OC were cocultured with Th17 cells. IVIg decreased both Th17 and Th1 cell differentiation while it did not affect Treg cell differentiation. In summary, IVIg inhibited Th17 cytokine-induced RANKL expression and OC differentiation. IVIg reduced osteoclastogenesis when monocytes were cocultured with Th17 cells. IVIg also reduced Th17 polarization. IVIg could be a new therapeutic option for Th17 cell–mediated osteoclastogenesis.

GM-CSF and IL-4 are not involved in IVIG-mediated amelioration of ITP in mice: a role for IL-11 cannot be ruled out

Previously, we have reported that interleukin (IL)-4, granulocyte-macrophage colony-stimulating factor (GM-CSF), and IL-11, but not IL-33, are up-regulated in two strains of mice with immune thrombocytopenia (ITP) that are responsive to intravenous immunoglobulin (IVIg) treatment. Previously, IL-4 was ruled out in the mechanism of IVIg; however, other publications have suggested this cytokine as a major player in the mechanism of IVIg action. Thus, we sought to further investigate a role for IL-4 and, in addition, GM-CSF and IL-11 in the mechanism of action of IVIg using a murine model of ITP. A passive platelet antibody model was used to generate ITP in IL-4 receptor knock-out (IL-4R^-/- ), IL-11 receptor knock-out (IL-11Rα^-/- ) and GM-CSF knock-out (Csf2^-/- ) mice. We also used a neutralizing antibody to IL-11 and recombinant human IL-11 (rhIL-11) in addition to depleting basophils in vivo to study the effect of IVIg to ameliorate ITP. Our results showed that basophils, IL-4 and GM-CSF were unimportant in both ITP induction and its amelioration by IVIg. The role of IL-11 in these processes was less clear. Even though IL-11Rα^-/- mice with ITP responded to IVIg similarly to wild-type (WT) mice, treatment of ITP WT mice with rhIL-11 instead of IVIg showed an increase in platelet numbers and WT mice administered anti-IL-11 showed a significant reduction in the ability of IVIg to ameliorate the ITP. Our findings indicate that neither IL-4, basophils or GM-CSF have roles in IVIg amelioration of ITP; however, a role for IL-11 requires further study.

High-Dose Intravenous Immunoglobulin in Skin Autoimmune Disease

The immunomodulatory potential and low incidence of severe side effects of high-dose intravenous immunoglobulin (IVIg) treatment led to its successful application in a variety of dermatological autoimmune diseases over the last two decades. IVIg is usually administered at a dose of 2 g per kg body weight distributed over 2–5 days every 4 weeks. They are most commonly used as a second- or third-line treatment in dermatological autoimmune disease (pemphigus vulgaris, pemphigus foliaceus, bullous pemphigoid, mucous membrane pemphigoid, epidermolysis bullosa acquisita, dermatomyositis, systemic vasculitis, and systemic lupus erythematosus). However, first-line treatment may be warranted in special circumstances like concomitant malignancy, a foudroyant clinical course, and contraindications against alternative treatments. Furthermore, IVIg can be considered first line in scleromyxedema. Production of IVIg for medical use is strictly regulated to ensure a low risk of pathogen transmission and comparable quality of individual batches. More common side effects include nausea, headache, fatigue, and febrile infusion reactions. Serious side effects are rare and include thrombosis and embolism, pulmonary edema, renal failure, aseptic meningitis, and severe anaphylactic reactions. Regarding the mechanism of action, one can discriminate between functions of the Fcγ region and the F(ab)2 region and their effects on a cellular level. These functions are not mutually exclusive, and more than one pathway may contribute to the beneficial effects. Here, we present a historical background, details on manufacturing, hypotheses on the mechanisms of action, information on the clinical application in the abovementioned conditions, and a brief outlook on future directions of IVIg treatment in dermatology.

Intravenous immunoglobulin (IVIg) or IVIg-treated macrophages reduce DSS-induced colitis by inducing macrophage IL-10 production

Intravenous immunoglobulin (IVIg) is used to treat immune-mediated diseases but its mechanism of action is poorly understood. We have reported that co-treatment with IVIg and lipopolysaccharide activates macrophages to produce large amounts of anti-inflammatory IL-10 in vitro. Thus, we asked whether IVIg-treated macrophages or IVIg could reduce intestinal inflammation in mice during dextran sulfate sodium (DSS)-induced colitis by inducing macrophage IL-10 production in vivo. Adoptive transfer of IVIg-treated macrophages reduces intestinal inflammation in mice and collagen accumulation post-DSS. IVIg treatment also reduces DSS-induced intestinal inflammation and its activity is dependent on the Fc portion of the antibody. Ex vivo, IVIg induces IL-10 production and reduces IL-12/23p40 and IL-1β production in colon explant cultures. Co-staining tissues for mRNA, we demonstrate that macrophages are the source of IL-10 in IVIg-treated mice; and using IL-10-GFP reporter mice, we demonstrate that IVIg induces IL-10 production by intestinal macrophages. Finally, IVIg-mediated protection is lost in mice deficient in macrophage IL-10 production (LysMcre^+/- IL-10^fl/fl mice). Together, our data demonstrate a novel, in vivo mechanism of action for IVIg. IVIg-treated macrophages or IVIg could be used to treat people with intestinal inflammation and may be particularly useful for people with inflammatory bowel disease, who are refractory to therapy.

Complications of Immunoglobulin Therapy and Implications for Treatment of Inflammatory Neuropathy: A Review

BACKGROUND

Intravenous Immunoglobulin (IVIg) forms a cornerstone of effective treatment for acute and chronic inflammatory neuropathies, with a class I evidence base in Guillain-Barré Syndrome (GBS), Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) and multifocal motor neuropathy (MMN). It is generally considered to be a safe therapy however there are several recognised complications which are reviewed in this article.

DISCUSSION AND CONCLUSION

Most adverse events are immediate and mild such as headache, fever and nausea although more serious immediate reactions such as anaphylaxis may rarely occur. Delayed complications are rare but may be serious, including thromboembolic events and acute kidney injury, and these and associated risk factors are also discussed. We emphasise the importance of safe IVIg administration and highlight practical measures to minimise complications of this therapy.

Small-Molecule Immunosuppressive Drugs and Therapeutic Immunoglobulins Differentially Inhibit NK Cell Effector Functions in vitro

Small-molecule immunosuppressive drugs (ISD) prevent graft rejection mainly by inhibiting T lymphocytes. Therapeutic immunoglobulins (IVIg) are used for substitution, antibody-mediated rejection (AbMR) and HLA-sensitized recipients by targeting distinct cell types. Since the effect of ISD and IVIg on natural killer (NK) cells remains somewhat controversial in the current literature, the aim of this comparative study was to investigate healthy donor's human NK cell functions after exposure to ISD and IVIg, and to comprehensively review the current literature. NK cells were incubated overnight with IL2/IL12 and different doses and combinations of ISD and IVIg. Proliferation was evaluated by ³[H]-thymidine incorporation; phenotype, degranulation and interferon gamma (IFNγ) production by flow cytometry and ELISA; direct NK cytotoxicity by standard ⁵¹[Cr]-release and non-radioactive DELFIA assays using K562 as stimulator and target cells; porcine endothelial cells coated with human anti-pig antibodies were used as targets in antibody-dependent cellular cytotoxicity (ADCC) assays. We found that CD69, CD25, CD54, and NKG2D were downregulated by ISD. Proliferation was inhibited by methylprednisolone (MePRD), mycophenolic acid (MPA), and everolimus (EVE). MePRD and MPA reduced degranulation, MPA only of CD56^bright NK cells. MePRD and IVIg inhibited direct cytotoxicity and ADCC. Combinations of ISD demonstrated cumulative inhibitory effects. IFNγ production was inhibited by MePRD and ISD combinations, but not by IVIg. In conclusion, IVIg, ISD and combinations thereof differentially inhibit NK cell functions. The most potent drug with an effect on all NK functions was MePRD. The fact that MePRD and IVIg significantly block NK cytotoxicity, especially ADCC, has major implications for AbMR as well as therapeutic strategies targeting cancer and immune cells with monoclonal antibodies.

Acute Seroconversion of Eastern Equine Encephalitis Coinfection With California Serogroup Encephalitis Virus

Eastern equine encephalitis (EEE) is a severe arboviral neuroinvasive disease with high mortality and neurological sequelae. Treatment for EEE is primarily supportive. Intravenous immunoglobulin (IVIg) and high-dose steroids have been used as empirical therapy for EEE with some case reports of benefit. We report a case of a patient who presented with encephalopathy with initial cerebrospinal spinal fluid (CSF) serology analysis showing California serogroup encephalitis virus IgG positivity. However, the rapid clinical deterioration of the patient into a comatose state prompted a second CSF serology analysis that showed seroconversion of high titer Eastern Equine Encephalitis virus IgM and positive titer of California serogroup encephalitis virus IgG. The patient completed a 5-day course of empiric IVIg without concurrent corticosteroid therapy but did not show significant clinical improvement.

Nonspecific immunoglobulin G is effective in preventing and treating cancer in mice

BACKGROUND

Previous accidental findings showed that administration of immunoglobulin G (IgG) in treating autoimmune diseases was able to inhibit cancers that happened to grow in these patients. However, such treatment has not been used to treat cancer patients clinically. The mechanism and optimal dosages of this treatment have not been established. Subsequent animal experiments confirmed this effect, but all previous studies in animal models used human IgG which was heterogeneous to the animal hosts and therefore could adversely interfere with the results.

MATERIALS AND METHODS

We tested different dosages of mouse IgG in treating and preventing three syngeneic cancer types (melanoma, colon cancer, and breast cancer) in three immune potent mouse models. The expression of Ki67, CD34, VEGF, MMPs, and cytokines in tumor tissues were examined with immunohistochemistry or quantitative real-time PCR to evaluate tumor proliferation, vascularization, metastasis, and proinflammatory response in the tumor microenvironment.

RESULTS

We found that low-dose IgG could effectively inhibit cancer progression, regulate tumor vessel normalization, and prolong survival. Administration of IgG before cancer cell inoculation could also prevent the development of cancer. In addition, IgG caused changes in a number of cytokines and skewed macrophage polarization toward M1-like phenotype, characterized by proinflammatory activity and inhibition of proliferation of cancer cells.

CONCLUSION

Our findings suggest that nonspecific IgG at low dosages could be a promising candidate for cancer prevention and treatment.

Generation of two high affinity anti-mouse FcRn antibodies: Inhibition of IgG recycling in wild type mice and effect in a mouse model of immune thrombocytopenia

Primary immune thrombocytopenia (ITP) is an autoimmune disease characterized by pathogenic immunoglobulin G (IgG) autoantibodies that bind to platelets, causing their phagocytic removal and leading to reductions in platelet number. The neonatal Fc receptor (FcRn) selectively salvages and recycles IgG, including pathogenic IgG, thereby extending the half-life of IgG in plasma. Two anti-mouse FcRn monoclonal antibodies (mAb) (4470 and 4464) were generated to evaluate the effect of inhibiting IgG recycling. Statistically significant reductions in plasma IgG concentration were observed upon administration of 4470 (10, 30 and 100 mg/kg) in wild-type mice. In a passive mouse model of ITP, 4464 alleviated the reduction in platelet number and/or preserved newly produced platelets when dosed prophylactically as well as in a therapeutic dosing regimen once platelet numbers had already been reduced. These results support the investigation of anti-FcRn therapy as a potential treatment for ITP.

Current practice patterns in CIDP: A cross-sectional survey of neurologists in the United States

To evaluate how neurologists make decisions regarding chronic inflammatory demyelinating polyneuropathy (CIDP), we conducted a cross-sectional quantitative survey of 100 community neurologists in the United States. Only 13% cited using the European Federation of Neurological Societies/Peripheral Nerve Society guideline. In addition, variability in treatment approaches existed regarding the dose of IVIg used, the length of IVIg therapy before determining response, the outcome measures used to determine IVIg response, and the protocol for weaning off therapy. Forty-three percent reported giving doses that were lower than the recommended IVIg loading dose for CIDP. Many reported giving nonspecific patient education about the rationale of IVIg use and treatment duration. The finding that approximately half of community neurologists endorsed electrodiagnostic criteria that do not support CIDP diagnosis indicated difficulties relying heavily upon neurophysiologic studies in diagnostic guidelines. More education on CIDP diagnosis and treatment and a clear, actionable, clinically focused guideline would enhance best practices, particularly in the midst of high information flow and multiple guidelines.

IqYmune® is an effective maintenance treatment for multifocal motor neuropathy: A randomised, double-blind, multi-center cross-over non-inferiority study vs Kiovig®-The LIME Study

Intravenous immunoglobulin (IVIg) is the gold‐standard for maintenance treatment of multifocal motor neuropathy (MMN). This phase III, randomised, double‐blind, multi‐centre, active‐control, crossover study, aimed to evaluate the non‐inferiority of IqYmune® relative to Kiovig®, primarily based on efficacy criteria. Twenty‐two adult MMN patients, treated with any brand of IVIg (except Kiovig® or IqYmune®) at a stable maintenance dose within the range of 1 to 2 g/kg every 4 to 8 weeks, were randomised to receive either Kiovig® followed by IqYmune®, or IqYmune® followed by Kiovig®. Each product was administered for 24 weeks. The primary endpoint was the difference between IqYmune® and Kiovig® in mean assessments of modified Medical Research Council (MMRC) 10 sum score (strength of 5 upper‐limb and 5 lower‐limb muscle groups, on both sides, giving a score from 0 to 100) during the evaluation period (non‐inferiority margin of Δ = 2). A linear mixed model analysis demonstrated the non‐inferiority of IqYmune® relative to Kiovig®, independently of the covariates (value at baseline, treatment period, and treatment sequence). The estimated “IqYmune® − Kiovig®” difference was −0.01, with a 95% confidence interval (CI) −0.51 to 0.48. The number of adverse reactions (ARs) and the percentage of patients affected were similar for the two products: 39 ARs in 10 patients with IqYmune® vs 32 ARs in 11 patients with Kiovig®. No thromboembolic events nor haemolysis nor renal impairment were observed. In this first clinical trial comparing two IVIg brands for maintenance treatment of MMN, efficacy and tolerability of both brands were similar.

IVIg and LPS Co-stimulation Induces IL-10 Production by Human Monocytes, Which Is Compromised by an FcγRIIA Disease-Associated Gene Variant

Intravenous Immunoglobulin (IVIg) is used to treat autoimmune or inflammatory diseases, but its mechanism of action is not completely understood. We asked whether IVIg can induce interleukin-10 (IL-10) and reduce pro-inflammatory cytokine production in human monocytes, and whether this response is reduced in monocytes from people with an Fcγ receptor IIA (FcγRIIA) gene variant, which is associated with increased risk of inflammatory diseases and poor response to antibody-based biological therapy. IVIg increased IL-10 production and reduced pro-inflammatory cytokine production in response to bacterial lipopolysaccharide (LPS), which required FcγRI and FcγRIIB and activation of MAPKs, extracellular signal-regulated kinase 1/2 (ERK1/2), and p38. IL-10 production was lower and pro-inflammatory cytokine production was higher in monocytes from people with the FcγRIIA risk variant and the risk variant prevented IL-10 production in response to (IVIg+LPS). Finally, we show that IVIg did not induce MAPK activation in monocytes from people with the risk variant. Our results demonstrate that IVIg can skew human monocytes to an anti-inflammatory, IL-10-producing activation state, which is compromised in monocytes from people with the FcγRIIA risk variant. This research has profound implications for the use of IVIg because 25% of the population is homozygous for the FcγRIIA risk variant and its efficacy may be reduced in those individuals. In addition, this research may be useful to develop new therapeutic strategies to replace IVIg by cross-linking FcγRIs and FcγRIIBs to promote anti-inflammatory macrophage activation, independent of the FcγRIIA genotype.

IgG Glyco-Engineering to Improve IVIg Potency

Intravenous immunoglobulins (IVIg) are used in the treatment of different autoimmune and inflammatory diseases, such as immune thrombocytopenia and hemolytic anemia. One of the modes of action of IVIg is preventing phagocytosis of autoantibody-opsonized blood cells by saturation of the Fc-gamma receptors of macrophages in spleen and liver. IgG contains a fixed glycan, which is in most cases biantennary, at the asparagine residue at position 297 in the Fc tail. This glycan consists of a core structure of N-acetyl glucosamine (GlcNAc) and mannose groups, variably extended with core fucose, bisecting GlcNAc as well as terminal galactose and sialic acid. This structural glycan influences the binding affinity of IgG to Fc-gamma receptors. By glyco-engineering, we generated monoclonal IgG antibodies with different Fc-tail glycans and tested both their opsonizing and blocking capacity in a phagocytosis assay of IgG-opsonized erythrocytes with human monocyte-derived macrophages. In contrast to a lack of effect in opsono-phagocytosis, these IgG glycovariants differentially inhibited the uptake of opsonized erythrocytes. The level of bisecting GlcNAc and galactosylation had unexpectedly larger impact than core fucosylation, and suggest that targeted modifications different from the core fucose may well improve the immunomodulating efficacy of IVIg treatment.

Second IVIg course in Guillain-Barré syndrome patients with poor prognosis (SID-GBS trial): Protocol for a double-blind randomized, placebo-controlled clinical trial

One course of intravenous immunoglobulins (IVIg) of 2 g/kg is standard treatment in Guillain-Barré syndrome (GBS) patients unable to walk independently. Despite treatment some patients recover poorly, in part related to rapid consumption of IVIg, indicating that they may benefit from a second course of IVIg. The aim of the study is to determine whether a second course of IVIg, administered 1 week after start of the first course in patients with GBS and predicted poor outcome improves functional outcome on the GBS disability scale after 4 weeks. Secondary outcome measures include adverse events (AEs), Medical Research Council sumscore and GBS disability score after 8, 12, and 26 weeks, length of hospital and ICU admission, mortality, and changes in serum IgG levels. GBS patients of 12 years and older with a poor prognosis, based on the modified Erasmus GBS outcome score (mEGOS) at 1 week after start of the first IVIg course are eligible for randomization in this double-blind, placebo-controlled (IVIg or albumin) clinical trial. This study will determine if a second course of IVIg administered in the acute phase of the disease is safe, feasible, and effective in patients with GBS and a poor prognosis. This Dutch trial is registered prospectively as NTR 2224 in the Netherlands National Trial Register (NTR) which is the Primary Registry in the WHO Registry Network for the Netherlands.