Clinical applications of intravenous immunoglobulins (IVIg)--beyond immunodeficiencies and neurology

Vasculitides and the Complement System: a Comprehensive Review

Systemic vasculitides are a group of rare diseases characterized by inflammation of the arterial or venous vessel wall, causing stenosis or thrombosis. Clinical symptoms may be limited to skin or to other organs or may include multiple manifestations as systemic conditions. The pathogenesis is related to the presence of leukocytes in the vessels and to the IC deposition, which implies the activation of the complement system (CS) and then the swelling and damage of vessel mural structures. The complement system (CS) is involved in the pathogenesis of several autoimmune diseases, including systemic vasculitides. This enzymatic system is a part of the innate immune system, and its function is linked to the modulation of the adaptive immunity and in bridging innate and adaptive responses. Its activation is also critical for the development of natural antibodies and T cell response and for the regulation of autoreactive B cells. Complement triggering contributes to inflammation-driven tissue injury, which occurs during the ischemia/reperfusion processes, vasculitides, nephritis, arthritis, and many others diseases. In systemic vasculitides, a group of uncommon diseases characterized by blood vessel inflammation, the contribution of CS in the development of inflammatory damage has been demonstrated. Treatment is mainly based on clinical manifestations and severity of organ involvement. Evidences on the efficacy of traditional immunosuppressive therapies have been collected as well as data from clinical trials that involve the modulation of the CS. In particular in small-medium-vessel vasculitides, the CS represents an attractive target. Herein, we reviewed the pathogenetic role of CS in these systemic vasculitides as urticarial vasculitis, ANCA-associated vasculitides, anti-glomerular basement membrane disease, cryoglobulinaemic vasculitides, Henoch-Schönlein purpura/IgA nephropathy, and Kawasaki disease and therefore its potential therapeutic use in this context.

bIgG time for large eaters: monocytes and macrophages as effector and target cells of antibody-mediated immune activation and repression

The mononuclear phagocytic system consists of a great variety of cell subsets localized throughout the body in immunological and non-immunological tissues. While one of their prime tasks is to detect, phagocytose, and kill intruding microorganisms, they are also involved in maintaining tissue homeostasis and immune tolerance toward self through removal of dying cells. Furthermore, monocytes and macrophages have been recognized to play a critical role for mediating immunoglobulin G (IgG)-dependent effector functions, including target cell depletion, tissue inflammation, and immunomodulation. For this, monocyte and macrophage populations are equipped with a complex set of Fc-receptors, enabling them to directly interact with pro- or anti-inflammatory IgG preparations. In this review, we will summarize the most recent findings, supporting a central role of monocytes and macrophages for pro- and anti-inflammatory IgG activity.

How to Diagnose and Treat IBD Mimics in the Refractory IBD Patient Who Does Not Have IBD

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract and includes both Crohn's disease and ulcerative colitis. Patients with IBD often present with abdominal pain, diarrhea, and rectal bleeding but may also have a wide variety of other symptoms such as weight loss, fever, nausea, vomiting, and possibly obstruction. Given that the presentation of IBD is not specific, the differential diagnosis is broad and encompasses a wide spectrum of diseases, many of which can mimic and/or even coexist with IBD. It is important for physicians to differentiate symptoms due to refractory IBD from symptoms due to IBD mimics when a patient is not responding to standard IBD treatment. Many of the various IBD mimics include infectious etiologies (viral, bacterial, mycobacterial, fungal, protozoal, and helminthic infections), vascular causes, other immune causes including autoimmune etiologies, drug-induced processes, radiation-induced, and other etiologies such as small intestinal bacterial overgrowth, diverticulitis, and bile acid malabsorption. Thoughtful consideration and evaluation of these potential etiologies through patient history and physical examination, as well as appropriate tests, endoscopic evaluation, and cross-sectional imaging is required to evaluate any patient presenting with symptoms consistent with IBD.

Transmission of Hepatitis B Core Antibody and Galactomannan Enzyme Immunoassay Positivity via Immunoglobulin Products: A Comprehensive Analysis

BACKGROUND

Therapeutic immunoglobulins are used as replacement or immunomodulatory therapy, but can transmit clinically important molecules. We investigated hepatitis B virus (HBV) antibodies and galactomannan enzyme immunoassay (GM-EIA) positivity. Detection of HBV core antibody may prompt antiviral prophylaxis when commencing therapy such as rituximab; a positive GM-EIA result prompts investigation or treatment for invasive fungal disease.

METHODS

We performed a cross-sectional analysis of HBV serology in 80 patients established (>6 months) on immunoglobulin therapy; prospective analysis of HBV serology in 16 patients commencing intravenous immunoglobulin (IVIG); and pre- and post-infusion analysis of GM-EIA in 37 patients receiving IVIG.

RESULTS

Pre-IVIG, 9 of 80 patients tested positive for HBV surface antibody and 1 of 80 tested equivocal for HBV core antibody. On IVIG, 79 of 79 tested positive for surface antibody, 37 of 80 tested positive for core antibody, and 10 of 80 tested equivocal for core antibody. There were significant differences by product, but among patients receiving products that appear to transmit core antibody, negative results correlated with lower surface antibody titers and longer time since infusion, suggesting a simple concentration effect. There was a progressive increase with each infusion in the percentage of patients testing positive for HBV core antibody among patients newly commencing IVIG. Some patients "seroreverted" to negative during therapy. Certain IVIG products tested positive for GM-EIA and there were rises in index values in corresponding patient samples from pre- to post-infusion. Overall, 5 of 37 patient samples pre-infusion and 15 of 37 samples post-infusion tested positive for GM-EIA.

CONCLUSIONS

HBV antibodies and GM-EIA positivity are common in patients receiving IVIG and confound diagnostic results.

Immunotherapies in Alzheimer's disease: Too much, too little, too late or off-target?

Years of research have highlighted the importance of the immune system in Alzheimer's disease (AD), a system that, if manipulated during strategic time windows, could potentially be tackled to treat this disorder. However, to minimize adverse effects, it is essential to first grasp which exact aspect of it may be targeted. Several clues have been collected over the years regarding specific immune players strongly modulated during different stages of AD progression. However, the inherent complexity of the immune system as well as conflicting data make it quite challenging to pinpoint a specific immune target in AD. In this review, we discuss immune-related abnormalities observed in the periphery as well as in the brain of AD patients, in relation to known risk factors of AD such as genetics, type-2 diabetes or obesity, aging, physical inactivity and hypertension. Although not investigated yet in clinical trials, C5 complement system component, CD40/CD40L interactions and the CXCR2 pathway are altered in AD patients and may represent potential therapeutic targets. Immunotherapies tested in a clinical context, those aiming to attenuate the innate immune response and those used to facilitate the removal of pathological proteins, are further discussed to try and understand the causes of the limited success reached. The prevailing eagerness to move basic research data to clinic should not overshadow the fact that a careful preclinical characterization of a drug is still required to ultimately improve the chance of clinical success. Finally, specific elements to consider prior to initiate large-scale trials are highlighted and include the replication of preclinical data, the use of small-scale human studies, the sub-typing of AD patients and the determination of pharmacokinetic and pharmacodynamics parameters such as brain bioavailability and target engagement.

Immunological evidence and regulatory potential for cell-penetrating antibodies in intravenous immunoglobulin

Anti-DNA cell-penetrating autoantibodies have been extensively studied in autoimmune but not in normal sera. We investigated herein the presence and properties of cell-penetrating antibodies (CPAbs) in intravenous immunoglobulin (IVIg), a blood product of pooled normal human IgG. IVIg cell penetration was observed into various cell lines, as well as cells from several organs of mice injected intravenously with IVIg therapeutic dose. In all cell types examined in vitro and in vivo, intracellular IgG localized in the cytoplasm, in contrast to the nuclear accumulation of disease-related CPAbs. IVIg was found to rapidly enter cells via an energy-independent mode. The CPAb-fraction was isolated and found to be polyreactive to nuclear and cytoplasmic components; although it corresponded to ~2% of IVIg, it accounted for its inhibitory effect on splenocyte activation. Investigation of IVIg cell penetration capacity provides insight into its mechanisms of action and may account for some of its beneficial effects in numerous diseases.

Acute pulmonary embolism caused by highly aggregated intravenous immunoglobulin

BACKGROUND AND OBJECTIVES

Six patients died and one patient survived following infusion of a specific lot of intravenous immunoglobulin (IVIG) within half an hour in May 2008. This study elucidated the underlying pathogenesis.

MATERIALS AND METHODS

A variety of protein fractionation and identification approaches were employed to determine the abnormal components in IVIG products obtained from the hospital where the patients were treated. Animal studies using mice and monkeys were conducted to elucidate the pathophysiological mechanisms. In animal experiments, the effect and distribution of immunoglobulin was investigated using HE staining and immunohistochemistry (IHC) separately, while platelets and fibrinogen depletion were utilized to determine a possible link between thromboembolism formation in animals and the lethal effect of the IVIG. The size and distribution of the protein aggregates were determined with Coulter Counter Multisizer-3 after the dilution of the IVIG with plasma, and the lethal effect of the protein aggregates was simulated with artificial microparticles.

RESULTS

The IVIG retrieved from the hospital was found to have striking similarities to the heat-treated IVIG in terms of protein aggregation profiles and lethal effects. Post-mortem examination indicated that immunoglobulin aggregates were mainly found in the lung of the animals, while depletion of platelets and fibrinogen from the IVIG preparations failed to prevent the death of the animals. Similar amount of artificial microparticles caused animal death in similar fashion.

CONCLUSIONS

Our findings indicate that the retrieved IVIG exerted its lethal effects by blocking the pulmonary circulation without markedly altering the coagulation cascade or immunological events.

Safety of intravenous immunoglobulin and plasma exchange in critically ill patients

OBJECTIVE

To assess the safety profile of intravenous immunoglobulin (IVIG) and plasma exchange (PLEX) when used to treat critically ill patients.

METHODS

We performed a retrospective analysis of consecutive patients who received IVIG or PLEX while admitted to our medical intensive care unit (ICU), neuroscience ICU or haematologic/oncologic ICU between 2007 and 2011.Patients who were transferred into an ICU while receiving therapy or who continued therapy after discharge from the ICU were included in the analysis.

RESULTS

A total of 118 consecutive patients were included in the study. Fifty-nine patients received IVIG. Twenty of these patients (34%) developed renal failure during the hospitalisation, including 15 (25.4%) in whom renal function worsened during or shortly after IVIG administration and 4 (6.8%) in whom IVIG was considered a possible cause. Transfusion reactions occurred in five patients (8%). Seven patients (12%) did not receive the full intended course of IVIG. Thirty-four patients (58%) who received IVIG died during their hospitalisation. Fifty-nine patients received PLEX. Hypotension requiring an intervention was noted with 39 sessions (8.5%) and led to discontinuation of the session in 11 (2.4%). Other adverse events included line-related infections (n = 4), pneumothorax (n = 4) and electrolyte abnormalities and transfusion reactions (n = 10). Six patients (10%) did not receive full intended treatment course of PLEX. Nineteen patients (32%) treated with PLEX died during their hospitalisation.

DISCUSSION

Intravenous immunoglobulin and PLEX are generally well tolerated by critically ill patients. Intravenous immunoglobulin was associated with worsening renal function in one-quarter of patients.

Controlled tetra-Fc sialylation of IVIg results in a drug candidate with consistent enhanced anti-inflammatory activity

Despite the beneficial therapeutic effects of intravenous immunoglobulin (IVIg) in inflammatory diseases, consistent therapeutic efficacy and potency remain major limitations for patients and physicians using IVIg. These limitations have stimulated a desire to generate therapeutic alternatives that could leverage the broad mechanisms of action of IVIg while improving therapeutic consistency and potency. The identification of the important anti-inflammatory role of fragment crystallizable domain (Fc) sialylation has presented an opportunity to develop more potent Ig therapies. However, translating this concept to potent anti-inflammatory therapeutics has been hampered by the difficulty of generating suitable sialylated products for clinical use. Therefore, we set out to develop the first, to our knowledge, robust and scalable process for generating a well-qualified sialylated IVIg drug candidate with maximum Fc sialylation devoid of unwanted alterations to the IVIg mixture. Here, we describe a controlled enzymatic, scalable process to produce a tetra-Fc-sialylated (s4-IVIg) IVIg drug candidate and its qualification across a wide panel of analytic assays, including physicochemical, pharmacokinetic, biodistribution, and in vivo animal models of inflammation. Our in vivo characterization of this drug candidate revealed consistent, enhanced anti-inflammatory activity up to 10-fold higher than IVIg across different animal models. To our knowledge, this candidate represents the first s4-IVIg suitable for clinical use; it is also a valuable therapeutic alternative with more consistent and potent anti-inflammatory activity.

Persistent Immune Activation in CVID and the Role of IVIg in Its Suppression

Common variable immunodeficiency (CVID) is one of the most common and clinically important primary immune deficiencies. CVID patients have poor humoral immunity, resulting in recurrent infections of the gastrointestinal and upper respiratory tracts, as well as increased incidence of some forms of cancers and autoimmune diseases. The treatment for CVID is IgG replacement, often given as intravenous immunoglobulins (IVIg). IVIg consists of monomeric IgG purified from pooled plasma from healthy donors and is used to treat an increasing number of conditions including autoimmune diseases. In the case of CVID, IVIg has mainly been seen as reconstitution therapy, providing patients with pathogen-specific antibodies. Recent evidence shows that IVIg has diverse effects on the immune system of CVID patients, and one important component is that IVIg alleviates the state of chronic immune activation. In this review, we will discuss causes and consequences of persistent immune activation in CVID, possible underlying mechanisms for how IVIg treatment reduces immune activation, and implications for our understanding of primary as well as acquired immune deficiencies.

European consensus proposal for immunoglobulin therapies

The use of immunoglobulin (Ig) preparations (intravenous, IVIg, subcutaneous, SCIg) for replacement and immunomodulation therapy worldwide has tripled in the past 20 years and represents an ever-increasing cost factor for healthcare organizations. The limited access to the starting material of this essential medicinal product is currently the driving force for human plasma collection. Increasing awareness and improved diagnosis of human primary immunodeficiencies and a broadening of immunomodulatory indications are responsible for this development, and on a longer run might lead to plasma supply shortages. Consensus recommendations for the optimal use of Ig in clinical practice, including priority rankings for the most urgent indications, are therefore urgently needed. During a recent meeting in Kreuth, Germany, expert nominees from 36 Council of Europe states, together with colleagues from observer countries and regulatory agencies came up with this consensus statement.

Biologics in dermatology: an integrated review

The advent of biologics in dermatologic treatment armentarium has added refreshing dimensions, for it is a major breakthrough. Several agents are now available for use. It is therefore imperative to succinctly comprehend their pharmacokinetics for their apt use. A concerted endeavor has been made to delve on this subject. The major groups of biologics have been covered and include: Drugs acting against TNF-α, Alefacept, Ustekinumab, Rituximab, IVIG and Omalizumab. The relevant pharmacokinetic characteristics have been detailed. Their respective label (approved) and off-label (unapproved) indications have been defined, highlighting their dosage protocol, availability and mode of administration. The evidence level of each indication has also been discussed to apprise the clinician of their current and prospective uses. Individual anti-TNF drugs are not identical in their actions and often one is superior to the other in a particular disease. Hence, the section on anti-TNF agents mentions the literature on each drug separately, and not as a group. The limitations for their use have also been clearly brought out.

LC-MS analysis of polyclonal IgGs using IdeS enzymatic proteolysis for oxidation monitoring

Susceptibility of IgGs to oxidation is a significant issue for intravenous immunoglobulin preparations (IVIG) in liquid solution and raises both safety and efficacy concerns. Here we present an optimized chromatography method coupled to mass spectrometry (MS) to determine the oxidation of Fc/2 fragments derived from polyclonal IgGs after IdeS treatment. Separation of the four IgG subclasses was achieved using a diphenyl column and UV/MS detections were used for quantification and characterization. Several oxidized Fc/2 fragments generated by stress conditions were resolved and oxidized methionines were identified. This procedure can be used to monitor the oxidative status of IVIG preparations during formulation or stability studies.

Guidelines for the use of human immunoglobulin therapy in patients with primary immunodeficiencies in Latin America

Antibodies are an essential component of the adaptative immune response and hold long-term memory of the immunological experiences throughout life. Antibody defects represent approximately half of the well-known primary immunodeficiencies requiring immunoglobulin replacement therapy. In this article, the authors review the current indications and therapeutic protocols in the Latin American environment. Immunoglobulin replacement therapy has been a safe procedure that induces dramatic positive changes in the clinical outcome of patients who carry antibody defects.

Treatment of spinal cord injury with intravenous immunoglobulin G: preliminary evidence and future perspectives

Neuroinflammation plays an important role in the secondary pathophysiological mechanisms of spinal cord injury (SCI) and can exacerbate the primary trauma and thus worsen recovery. Although some aspects of the immune response are beneficial, it is thought that leukocyte recruitment and activation in the acute phase of injury results in the production of cytotoxic substances that are harmful to the nervous tissue. Therefore, suppression of excessive inflammation in the spinal cord could serve as a therapeutic strategy to attenuate tissue damage. The immunosuppressant methylprednisolone has been used in the setting of SCI, but there are complications which have attenuated the initial enthusiasm. Hence, there is interest in other immunomodulatory approaches, such as intravenous Immunoglobulin G (IVIg). Importantly, IVIg is used clinically for the treatment of several auto-immune neuropathies, such as Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy (CIPD) and Kawasaki disease, with a good safety profile. Thus, it is a promising treatment candidate for SCI. Indeed, IVIg has been shown by our team to attenuate the immune response and result in improved neurobehavioral recovery following cervical SCI in rats through a mechanism that involves the attenuation of neutrophil recruitment and reduction in the levels of cytokines and cytotoxic enzymes Nguyen et al. (J Neuroinflammation 9:224, 2012). Here we review published data in the context of relevant mechanisms of action that have been proposed for IVIg in other conditions. We hope that this discussion will trigger future research to provide supporting evidence for the efficiency and detailed mechanisms of action of this promising drug in the treatment of SCI, and to facilitate its clinical translation.

14th International Congress on Antiphospholipid Antibodies Task Force Report on Catastrophic Antiphospholipid Syndrome

The 'Task Force on Catastrophic Antiphospholipid Syndrome (CAPS)' was developed on the occasion of the 14th International Congress on Antiphospholipid Antibodies. The objectives of this Task Force were to assess the current knowledge on pathogenesis, clinical and laboratory features, diagnosis and classification, precipitating factors and treatment of this condition in order to address recommendations for future research. This article summarizes the studies analyzed by the Task Force, its recommendations and the future research agenda.

New insights into the prevention of staphylococcal infections and toxic shock syndrome

Staphylococcus aureus is a major human pathogen capable of causing various diseases, from skin infections to life-threatening pneumonia and toxic shock syndrome. S. aureus exoproteins, including superantigens, contribute significantly to the pathogenesis of this organism. Antibiotics inhibit growth, but often provide no protection from S. aureus exoproteins. With the emergence of antibiotic-resistant S. aureus, new therapeutic options to treat or prevent S. aureus-associated diseases are critical. Most S. aureus infections begin on the skin or mucosal surfaces from direct inflammatory or cytotoxic effects of exotoxins. Therefore, antitoxin therapies that prevent toxin production and prevent their effects on host cells are being researched. Current treatments for staphylococcal diseases and recent developments in antitoxin therapeutic agents and vaccines are reviewed.

Intravenous immunoglobulin-mediated immunosuppression and the development of an IVIG substitute

Immunoglobulins are glycoproteins produced by the cells of the immune system. Their primary function is to protect the body from pathogenic infection. Moreover, a concentrated polyclonal mixture of immunoglobulin G (IgG), the so-called intravenous IgG (IVIG), has been used to treat various chronic and systemic disorders of the immune system. Studies on the effects of IVIG in autoimmune disease models have revealed that IgG Fc fragments confer protection against various autoimmune diseases. The identification of this IgG Fc immunomodulatory component is important for the development of IVIG substitutes. The focus of this review is to introduce one of the Fc regulatory entities and to provide a summary of the current knowledge of the putative general mechanisms underlying IVIG activity in vivo on the basis of these Fc fragments. We also address the recent insights into several approaches for the development of IVIG substitutes.

Intracranial injection of Gammagard, a human IVIg, modulates the inflammatory response of the brain and lowers Aβ in APP/PS1 mice along a different time course than anti-Aβ antibodies

Gammagard IVIg is a therapeutic approach to treat Alzheimer's disease currently in phase 3 clinical trials. Despite the reported efficacy of the approach the mechanism of action is poorly understood. We have previously shown that intracranial injection of anti-Aβ antibodies into the frontal cortex and hippocampus reveals important information regarding the time course of events once the agent is in the brain. In the current study we compared IVIg, mouse-pooled IgG, and the anti-Aβ antibody 6E10 injected intracranially into the frontal cortex and hippocampus of 7-month-old APP/PS1 mice. We established a time course of events ranging from 1 to 21 d postinjection. IVIg and pooled mouse IgG both significantly reduced Aβ deposition to the same degree as the 6E10 anti-Aβ antibody; however, the clearance was much slower to occur, happening between the 3 and 7 d time points. In contrast, as we have previously shown, Aβ reductions were apparent with the 6E10 anti-Aβ group at the 1 d time point. Also, neuroinflammatory profiles were significantly altered by the antibody treatments. APP/PS1 transgenic mice at 7 months of age typically exhibit an M2a inflammatory phenotype. All antibody treatments stimulated an M2b response, yet anti-Aβ antibody was a more rapid change. Because the neuroinflammatory switch occurs before the detectable reductions in amyloid deposition, we hypothesize that the IVIg and pooled mouse IgG act as immune modulators and this immune modulation is responsible for the reductions in amyloid pathology.

Use of intravenous immunoglobulin in an Asian paediatric population over a 10-year period

AIMS

There is a paucity of data on the pattern of intravenous immunoglobulin (IVIG) usage in the paediatric population. This study aimed to assess the prevalence, trends, indications and burden of cost of IVIG usage in the Singaporean paediatric population.

METHODS

Pharmacy data of all IVIG prescriptions between 2000 and 2009 in the two major paediatric public hospitals in Singapore were retrospectively reviewed. Each prescription was cross-referenced with the patient's hospital records to confirm the administration of IVIG and indication of use.

RESULTS

Over the 10-year period, a total 78,155 g of IVIG valued at an estimated $5.2 million was prescribed. There was an increasing trend of 445.6 g/year (P = 0.02) over this period. Analysis of patients showed that the most common indication for IVIG use was Kawasaki disease, both in terms of the proportion of patients (60%) and amount of IVIG used (34%). Kawasaki disease was also the only indication where there were significant increasing trends in both patient numbers (7.4 patients/year) and amount of IVIG used (247.5 g/year). The indications with the highest amount of IVIG used per patient were for conditions related to primary immunodeficiency diseases and stem cell transplantation, where repeat transfusions were required. More than 75% of indications were Food and Drug Administration approved.

CONCLUSION

Albeit substantial and increasing, the use of IVIG in Singaporean children is mostly evidence based.

Catastrophic antiphospholipid syndrome (CAPS)

Catastrophic antiphospholipid syndrome (CAPS) is a very severe variant of the classic APS, characterised by clinical evidence of multiple organ involvement developing over a very short period of time, histopathological evidence of multiple small vessel occlusions and laboratory confirmation of the presence of antiphospholipid antibodies (aPL), usually in high titre. Although patients with catastrophic APS represent less than 1% of all patients with APS, this is usually a life-threatening condition. In this article, we aimed to review the state-of-the art about current knowledge in pathogenesis, clinical manifestations, diagnosis and treatment strategies in CAPS.

Intravenous immunoglobulin therapy: how does IgG modulate the immune system?

Intravenous immunoglobulin (IVIG) preparations comprise pooled IgG antibodies from the serum of thousands of donors and were initially used as an IgG replacement therapy in immunocompromised patients. Since the discovery, more than 30 years ago, that IVIG therapy can ameliorate immune thrombocytopenia, the use of IVIG preparations has been extended to a wide range of autoimmune and inflammatory diseases. Despite the broad efficacy of IVIG therapy, its modes of action remain unclear. In this Review, we cover the recent insights into the molecular and cellular pathways that are involved in IVIG-mediated immunosuppression, with a particular focus on IVIG as a therapy for IgG-dependent autoimmune diseases.

IVIg prevents the in vitro activation of T cells by neutralizing the T cell activators

Clinical observations in patients treated with IVIg revealed significant modulations in T cell populations and functions. However, it is unclear whether IVIg acts directly on activated T cells to suppress their functions. To clarify the exact mechanism of IVIg action, we studied its effect on T cells activated using anti-CD3/CD28 microbeads to mimic stimulatory signals provided by accessory cells. We report here that IVIg reduces T cell proliferation and cytokine secretion by interfering with the ability of anti-CD3/CD28 microbeads to deliver activating signals to T cells. We further show that the interference occurs between IVIg and anti-CD3/CD28 microbeads and does not involve T cells. In conclusion, our work suggests that T cells are not a direct target of IVIg and that the modulation of T cell populations and functions observed in treated patients is the indirect consequence of a direct effect of IVIg on accessory cells.

The safety profile of home infusion of intravenous immunoglobulin in patients with neuroimmunologic disorders

OBJECTIVES

To assess the overall safety of high-dose intravenous immunoglobulin (IG) products used to treat patients with neuroimmunological disorders in a supervised home-based setting.

METHODS

The incidence of adverse reactions was assessed in a retrospective chart review of 420 patients who consecutively received 4076, home-based, individual, intravenous immunoglobulin (IVIG) infusions between January 2009 and December 2009.

RESULTS

A total of 90 patients (21.4%) developed adverse reactions related to IVIG administration (2.6% per individual infusion). A total of 95.5% of adverse reactions were mild, and no serious side effects were observed. The incidence of adverse reactions was significantly lower in the subgroup of patients with neuroimmunological disorders who received premedication (18.2% compared with 29.3%, P = 0.02). There was no significant statistical difference in the incidence of side effects among the different brands of IVIG used in this study.

CONCLUSIONS

The combination of premedication and well-defined clinical, IVIG infusion policies may reduce the incidence of high-dose IVIG adverse reactions administered in a home-based setting in patients with neuroimmunological disorders.

Novel approaches in the treatment of myositis and myopathies

The inflammatory myopathies are a heterogeneous group of disorders characterized by muscle weakness and inflammation. Although no standard therapeutic guidelines exist, traditional treatment has included corticosteroids and a variety of second-line immunosuppressants. As treatment of refractory disease has been difficult, newer agents and approaches have been used with varying response. The advent of standardized treatment response criteria by the International Myositis Assessment and Clinical Studies (IMACS) group has helped investigators to evaluate and compare clinical trial outcomes in a more rigorous fashion. The use of intravenous immunoglobulin (IVIG), rituximab, biologic agents including tumor necrosis factor (TNF) inhibitors, stem-cell transplantation, gene therapy, and vascular occlusion resistance training are reviewed here. As our understanding of disease pathogenesis at the immunologic, genetic, and molecular level expands, the discovery of novel therapeutic targets hold promise for the successful treatment of these conditions.

Immunoglobulins in adult sepsis and septic shock

For more than 30 years, intravenously administered immunoglobulins (ivIG) have been used to treat primary and secondary syndromes of immune deficiency. Increasing insight into pathomechanisms of severe sepsis and septic shock have led to the implementation of ivIG therapy in the strategies for adjunctive therapy in sepsis in both adults and children. Direct antitoxic effects, as well as indirect immunomodulatory mechanisms of ivIG have been described in the literature and were the basis for the rationale to use these substances in life-threatening infections and hyperinflammatory states. Several clinical trials have been performed, most of them as minor, investigator-initiated protocols. This review summarizes the results of clinical investigations and systematic meta-analyses that have implications for the development of therapeutic strategies, and international guidelines for the management of severe sepsis and septic shock in adult patients.

In vitro and in vivo properties differ among liquid intravenous immunoglobulin preparations

Objective To compare in vitro and in vivo biological and biochemical properties of five liquid intravenous immunoglobulin (IVIg) preparations licensed for therapeutic use in Europe.

Methods ClairYg® was compared in a blinded manner to four other liquid IVIg preparations licensed in Europe (Octagam®, Kiovig®, Gamunex®, Privigen®). Three batches of each preparation were tested, except for the IgG repertoires and the animal model.

Results Levels of anti-A and anti-B antibodies were lower in ClairYg® (0·11/0·11) relative to a positive EDQM standard and Octagam® (0·11/0·08) than in other preparations (0·33–0·69/0·42–0·46). IgG in ClairYg® recognized 365 and 416 protein spots in HEp-2 cell and Escherichia coli protein extracts vs. 230–330 and 402–842 protein spots, respectively, for IgG in other preparations. IgA content (301 vs. 165–820 ng/mg of IgG), Factor XI and Factor XII antigen (0·46 vs. 0·85–2·40 mU/mg of IgG and 7·8 vs. 20·0–46·2 lU/mg of IgG) C1q binding (0·42 vs. 0·67–1·89 arbitrary units) and C5a uptake (0·41 vs. 0·45–0·66% of activation) were lower in ClairYg® than in other preparations. Finally, intravenous infusion of ClairYg®, Gamunex® and Privigen® had no major effect on arterial blood pressure in spontaneously hypertensive rats.

Conclusions Our results evidence some differences in the biological and biochemical properties among licensed liquid IVIg preparations.

Immunopathological events initiated and maintained by pathogenic IgG autoantibodies in an experimental autoimmune kidney disease

The experimental models of Heymann nephritis (HN) and slowly progressive Heymann nephritis (SPHN) give us rare opportunities to investigate the etiologies and pathogenesis of two immunopathological processes in rats leading to: (1) autoimmune disease, where the autoimmune disease HN and SPHN is initiated and maintained by cross-reactive pathogenic IgG autoantibodies (aabs) directed against the renal proximal convoluted tubules' brush border (BB) cells - where the nephritogenic antigen (ag) is produced and localized - damaging and releasing BB associated nephritogenic ag into the circulation which in turn contributes to continuation of the autoimmune disease; and (2) immune complex glomerulonephritis, where the glomerular injury is initiated, proceeding into a chronic progressive disease by depositing immune complexes (ICs) - made up of a glomerular epithelial cell produced endogenous nephritogenic ag and the developing pathogenic IgG aab directed against the nephritogenic ag, and complement components - on the epithelial side of the glomerular basement membrane. We also observed how the normally functioning immune system is able to avert autoimmune disease developments by circulating specific non-pathogenic IgM aabs clearing the system of intracytoplasmic ags released from cells at the end of their life spans or following damage by toxic agents. We also described how an autoimmune disease SPHN can be prevented and when present terminated by the implementation of a new vaccination technique we have developed and call modified vaccination technique. By increasing the specific IgM aab production against the native nephritogenic ag - by injecting ICs made up of: [nephritogenic ag X homologous anti-nephritogenic ag IgM ab] in slight ag excess into SPHN rats - pathogenic IgG aab producing native and modified nephritogenic ags were removed from the circulation and termination of the autoimmune disease causing immune events was achieved. Even though HN and SPHN are not well-known disease models, their studies are important because the etiologies and pathogenesis of two conditions - that can also occur in humans, namely autoimmune diseases and membranous glomerulonephritis - can be simultaneously investigated.

Polyvalent immunoglobulin significantly attenuated the formation of IL-1β in Escherichia coli-induced sepsis in pigs

Evidence suggests that adjunctive treatment with intravenous immunoglobulin preparations enriched with IgA and IgM reduce mortality in sepsis. The mode of action of polyvalent immunoglobulin is complex, including neutralization of toxins and modulation of complement activation and cytokine formation toward an anti-inflammatory profile. In this study we explored the effect of Pentaglobin, containing IgG, IgA and IgM, on the initial inflammatory reaction as well as on hemodynamics, using a well characterized and standardized porcine model of sepsis. Anesthetized and mechanically ventilated pigs, mean weight 14.9 kg, were allocated into two groups of 8 animals, receiving either Pentaglobin or saline, before sepsis was induced by intravenous Escherichia coli infusion. Five negative controls received saline only. All animals were observed for 4 h under extensive invasive monitoring. Pentaglobin significantly (p < 0.05) attenuated IL-1β formation by 38% at the end of the experiment, and markedly increased (p < 0.05) the formation of IL-10 at 60 min. TNF-α, IL-6, IL-8 and expression of the cell surface marker wCD11R3 were lower in the Pentaglobin group, but the differences were not significant. The serum concentration of LPS was three times higher in the Pentaglobin group (p < 0.005), indicating binding of LPS to Pentaglobin. Complementary in vitro experiments showed a higher binding affinity for IgM and IgA to LPS than for IgG. LPS-induced formation of IL-6 was significantly (p < 0.05) attenuated by Pentaglobin in an in vitro whole blood model. In conclusion, Pentaglobin decreased the key inflammasome IL-1β molecule in an E. coli-model of pigs sepsis.

Analysis and functional consequences of increased Fab-sialylation of intravenous immunoglobulin (IVIG) after lectin fractionation

It has been proposed that the anti-inflammatory effects of intravenous immunoglobulin (IVIG) might be due to the small fraction of Fc-sialylated IgG. In this study we biochemically and functionally characterized sialic acid-enriched IgG obtained by Sambucus nigra agglutinin (SNA) lectin fractionation. Two main IgG fractions isolated by elution with lactose (E1) or acidified lactose (E2) were analyzed for total IgG, F(ab’)₂ and Fc-specific sialic acid content, their pattern of specific antibodies and anti-inflammatory potential in a human in vitro inflammation system based on LPS- or PHA-stimulated whole blood. HPLC and LC-MS testing revealed an increase of sialylated IgG in E1 and more substantially in the E2 fraction. Significantly, the increased amount of sialic acid residues was primarily found in the Fab region whereas only a minor increase was observed in the Fc region. This indicates preferential binding of the Fab sialic acid to SNA. ELISA analyses of a representative range of pathogen and auto-antigens indicated a skewed antibody pattern of the sialylated IVIG fractions. Finally, the E2 fraction exerted a more profound anti-inflammatory effect compared to E1 or IVIG, evidenced by reduced CD54 expression on monocytes and reduced secretion of MCP-1 (CCL2); again these effects were Fab- but not Fc-dependent. Our results show that SNA fractionation of IVIG yields a minor fraction (approx. 10%) of highly sialylated IgG, wherein the sialic acid is mainly found in the Fab region. The tested anti-inflammatory activity was associated with Fab not Fc sialylation.

Mouse background and IVIG dosage are critical in establishing the role of inhibitory Fcγ receptor for the amelioration of experimental ITP

A recognized paradigm for the therapeutic action of intravenous immunoglobulin (IVIG) in immune thrombocytopenia (ITP) involves up-regulation of the inhibitory Fcγ receptor (FcγRIIB) in splenic macrophages. However, published data have indicated that opposing results are obtained when using FcγRIIB-deficient mice on different strain backgrounds. Herein we show BALB/c FcγRIIB(-/-) and wild-type, with or without spleens, all recover ITP with similar dynamics after IVIG (1 g/kg) treatment; however, this was not the case for C57BL/6 (B6) FcγRIIB(-/-). In investigating this conundrum, we found that wild-type B6 mice are much less sensitive than BALB/c to IVIG-mediated amelioration of ITP, requiring approximately 2- to 2.5-fold more IVIG than BALB/c. When using 2.5 g/kg IVIG in FcγRIIB(-/-) B6 mice, amelioration of ITP was as in wild-type in all animals. Our findings led us to the conclusion that different strains of mice respond differently to IVIG and that FcγRIIB plays no role in the mechanism of effect of IVIG in experimental ITP.

Primary immune deficiency in the intensive care unit: It is never too late to diagnose and treat

Common variable immunodeficiency disorders (CVIDs), a heterogeneous group of primary immune deficiencies, can present at all age. Our patient with a hitherto undiagnosed CVID, symptomatic since middle ages, presented with severe pneumonia. Specific management of his CVID in addition to standard therapy was life-saving.

Low-dose rituximab combined with short-term glucocorticoids up-regulates Treg cell levels in patients with immune thrombocytopenia

This randomized trial was performed to investigate the efficacy of low-dose rituximab in combination with glucocorticoids for treatment of patients with immune thrombocytopenia (ITP). Sixty-two patients were randomly separated into the glucocorticoids (control) and the experimental (glucocorticoids + rituximab) groups. Patients in both groups received dexamethasone 40 mg/day on days 1-4, followed by decrements of prednisone 60, 30, 15, 10 mg/day on days 5-7, 8-14, 15-21, 22-28, respectively. Patients in the experimental group also received rituximab 100 mg on days 7, 14, 21, 28. The overall response (OR) was similar in both groups at day 28 (experimental group vs. glucocorticoids group: 80.6 vs. 74.2%, P = .938); however, sustained response (SR) was more pronounced in the experimental group as compared to that in the glucocorticoids group (77.4 vs. 38.7%, P < .001). Both groups showed similar incidence of adverse events (experimental group vs. glucocorticoids group: 9.7 vs. 6.5%, P = .325). As expected, B cell depletion was seen in the experimental group. In addition, both groups experienced a significant up-regulation in Treg cell levels, but the up-regulation in the experimental group was maintained at an even higher level and persisted a longer time than those in the glucocorticoids group. Thus, low-dose rituximab combined with short-term glucocorticoids provides an alternative treatment for ITP prior to splenectomy.

Immunotherapy of systemic sclerosis

Scleroderma is a multisystem autoimmune disease characterized by an abnormal immune activation associated with the development of underlying vascular and fibrotic disease manifestations. This article highlights the current use of drugs targeting the immune system in scleroderma. Nonselective immunosuppression, and in particular cyclophosphamide, remains the main treatment for progressing skin involvement and active interstitial lung disease. Mycophenolate mofetil is a promising alternative to cyclophosphamide. The use of cyclosporine has been limited by modest efficacy and serious renal toxicity. Newer T-cell (sirolimus and alefacept) and B-cell (rituximab)-targeted therapies have provided some encouraging results in small pilot studies. Hematopoietic stem cell transplantation can be effective for severe fibrotic skin disease, but toxicity remains a concern. Clinical efficacy and safety of antifibrotic treatments (e.g., imatinib) await confirmation. Newer biological agents targeting key molecular or cellular effectors in scleroderma pathogenesis are now available for clinical testing.