Intravenous immunoglobulin (IVIG) is the first line treatment for Guillain-Barré syndrome and multifocal motor neuropathy, which are caused by anti-ganglioside antibody-mediated complement-dependent ...cytotoxicity. IVIG has many potential mechanisms of action, and sialylation of the IgG Fc portion reportedly has an anti-inflammatory effect in antibody-dependent cell-mediated cytotoxicity models. We investigated the effects of different IVIG glycoforms on the inhibition of antibody-mediated complement-dependent cytotoxicity. Deglycosylated, degalactosylated, galactosylated and sialylated IgG were prepared from IVIG following treatment with glycosidases and glycosyltransferases. Sera from patients with Guillain-Barré syndrome, Miller Fisher syndrome and multifocal motor neuropathy associated with anti-ganglioside antibodies were used. Inhibition of complement deposition subsequent to IgG or IgM autoantibody binding to ganglioside, GM1 or GQ1b was assessed on microtiter plates. Sialylated and galactosylated IVIGs more effectively inhibited C3 deposition than original IVIG or enzyme-treated IVIGs (agalactosylated and deglycosylated IVIGs). Therefore, sialylated and galactosylated IVIGs may be more effective than conventional IVIG in the treatment of complement-dependent autoimmune diseases.
Therapy by human immunoglobulin G (IgG) concentrates is a success story ongoing for decades with an ever increasing demand for this plasma product. The success of IgG concentrates on a clinical level ...is documented by the slowly increasing number of registered indication and the more rapid increase of the off-label uses, a topic dealt with in another contribution to this special issue of Frontiers in Immunology. A part of the success is the adverse event (AE) profile of IgG concentrates which is, even at life-long need for therapy, excellent. Transmission of pathogens in the last decade could be entirely controlled through the antecedent introduction by authorities of a regulatory network and installing quality standards by the plasma fractionation industry. The cornerstone of the regulatory network is current good manufacturing practice. Non-infectious AEs occur rarely and mainly are mild to moderate. However, in recent times, the increase in frequency of hemolytic and thrombotic AEs raised worrying questions on the possible background for these AEs. Below, we review elements of non-infectious AEs, and particularly focus on hemolysis and thrombosis. We discuss how the introduction of plasma fractionation by ion-exchange chromatography and polishing by immunoaffinity chromatographic steps might alter repertoire of specificities and influence AE profiles and efficacy of IgG concentrates.
Leishmania are obligatory intracellular parasitic protozoa that cause a wide range of diseases in humans, cycling between extracellular promastigotes in the mid-gut of sand flies and intracellular ...amastigotes in the phagolysosomes of mammalian macrophages. Although many of the molecular mechanisms of development inside macrophages remain a mystery, the development of a host-free system that simulates phagolysosome conditions (37 °C and pH 5.5) has provided new insights into these processes. The time course of promastigote-to-amastigote differentiation can be divided into four morphologically distinct phases: I, signal perception (0–5 h after exposure); II, movement cessation and aggregation (5–10 h); III, amastigote morphogenesis (10–24 h); and IV, maturation (24–120 h). Transcriptomic and proteomic analyses have indicated that differentiation is a coordinated process that results in adaptation to life inside phagolysosomes. Recent phosphoproteomic analysis revealed extensive differences in phosphorylation between promastigotes and amastigotes and identified stage-specific phosphorylation motifs. We hypothesized that the differentiation signal activates a phosphorylation pathway that initiates Leishmania transformation, and here we used isobaric tags for relative and absolute quantitation to interrogate the dynamics of changes in the phosphorylation profile during Leishmania donovani promastigote-to-amastigote differentiation. Analysis of 163 phosphopeptides (from 106 proteins) revealed six distinct kinetic profiles; with increases in phosphorylation predominated during phases I and III, whereas phases II and IV were characterized by greater dephosphorylation. Several proteins (including a protein kinase) were phosphorylated in phase I after exposure to the complete differentiation signal (i.e. signal-specific; 37 °C and pH 5.5), but not after either of the physical parameters separately. Several other protein kinases (including regulatory subunits) and phosphatases also showed changes in phosphorylation during differentiation. This work constitutes the first genome-scale interrogation of phosphorylation dynamics in a parasitic protozoa, revealing the outline of a signaling pathway during Leishmania differentiation.
The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium (identifier PXD000671). Data can be viewed using ProteinPilot™ software.
The consumption of immunoglobulins (Ig) is increasing due to better recognition of antibody deficiencies, an aging population, and new indications. This review aims to examine the various dosing ...regimens and research developments in the established and in some of the relevant off-label indications in Europe. The background to the current regulatory settings in Europe is provided as a backdrop for the latest developments in primary and secondary immunodeficiencies and in immunomodulatory indications. In these heterogeneous areas, clinical trials encompassing different routes of administration, varying intervals, and infusion rates are paving the way toward more individualized therapy regimens. In primary antibody deficiencies, adjustments in dosing and intervals will depend on the clinical presentation, effective IgG trough levels and IgG metabolism. Ideally, individual pharmacokinetic profiles in conjunction with the clinical phenotype could lead to highly tailored treatment. In practice, incremental dosage increases are necessary to titrate the optimal dose for more severely ill patients. Higher intravenous doses in these patients also have beneficial immunomodulatory effects beyond mere IgG replacement. Better understanding of the pharmacokinetics of Ig therapy is leading to a move away from simplistic "per kg" dosing. Defective antibody production is common in many secondary immunodeficiencies irrespective of whether the causative factor was lymphoid malignancies (established indications), certain autoimmune disorders, immunosuppressive agents, or biologics. This antibody failure, as shown by test immunization, may be amenable to treatment with replacement Ig therapy. In certain immunomodulatory settings e.g., idiopathic thrombocytopenic purpura (ITP), selection of patients for Ig therapy may be enhanced by relevant biomarkers in order to exclude non-responders and thus obtain higher response rates. In this review, the developments in dosing of therapeutic immunoglobulins have been limited to high and some medium priority indications such as ITP, Kawasaki' disease, Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy, myasthenia gravis, multifocal motor neuropathy, fetal alloimmune thrombocytopenia, fetal hemolytic anemia, and dermatological diseases.
Intravenous and subcutaneous immunoglobulin preparations, consisting of IgG class antibodies, are increasingly used to treat a broad range of pathological conditions, including humoral immune ...deficiencies, as well as acute and chronic inflammatory or autoimmune disorders. A plethora of Fab- or Fc-mediated immune regulatory mechanisms has been described that might act separately or in concert, depending on pathogenesis or stage of clinical condition. Attempts have been undertaken to improve the efficacy of polyclonal IgG preparations, including the identification of relevant subfractions, mild chemical modification of molecules, or modification of carbohydrate side chains. Furthermore, plasma-derived IgA or IgM preparations may exhibit characteristics that might be exploited therapeutically. The need for improved treatment strategies without increase in plasma demand is a goal and might be achieved by more optimal use of plasma-derived proteins, including the IgA and the IgM fractions. This article provides an overview on the current knowledge and future strategies to improve the efficacy of regular IgG preparations and discusses the potential of human plasma-derived IgA, IgM, and preparations composed of mixtures of IgG, IgA, and IgM.
How genome instability is harnessed for fitness gain despite its potential deleterious effects is largely elusive. An ideal system to address this important open question is provided by the protozoan ...pathogen
, which exploits frequent variations in chromosome and gene copy number to regulate expression levels. Using ecological genomics and experimental evolution approaches, we provide evidence that
adaptation relies on epistatic interactions between functionally associated gene copy number variations in pathways driving fitness gain in a given environment. We further uncover posttranscriptional regulation as a key mechanism that compensates for deleterious gene dosage effects and provides phenotypic robustness to genetically heterogenous parasite populations. Finally, we correlate dynamic variations in small nucleolar RNA (snoRNA) gene dosage with changes in ribosomal RNA 2'-
-methylation and pseudouridylation, suggesting translational control as an additional layer of parasite adaptation.
genome instability is thus harnessed for fitness gain by genome-dependent variations in gene expression and genome-independent compensatory mechanisms. This allows for polyclonal adaptation and maintenance of genetic heterogeneity despite strong selective pressure. The epistatic adaptation described here needs to be considered in
epidemiology and biomarker discovery and may be relevant to other fast-evolving eukaryotic cells that exploit genome instability for adaptation, such as fungal pathogens or cancer.
Intravenous immunoglobulin (IVIG), consisting of IgG, is the first-line treatment for Guillain–Barré syndrome and multifocal motor neuropathy. IgG, but neither IgM nor IgA, has been demonstrated in ...vitro to inhibit complement deposition mediated by anti-ganglioside autoantibodies in sera from patients with both conditions. The objective of this study is to investigate the in vitro effectiveness of IgM and IgA in inhibiting complement deposition to ganglioside/anti-ganglioside antibody complexes. Serum samples were obtained from patients with multifocal motor neuropathy associated with anti-GM1 IgM antibodies, Guillain–Barré syndrome associated with anti-GM1 IgG antibodies and Miller Fisher syndrome associated with anti-GQ1b IgG antibodies. Inhibition of complement deposition using different immunoglobulin preparations was measured by enzyme-linked immunosorbent assay. IgM/A-enriched IVIG and immunoglobulin isotypes (polyclonal IgM and IgA) showed higher potential in inhibiting complement deposition than standard IVIG. Although the safety concerns about the use of IgM and IgA for an immunotherapy still remain, IgM and IgA may serve as an alternative immunotherapy in those anti-ganglioside antibody-mediated neuropathies.
•We studied the in vitro efficacy of IgM/IgA in inhibiting complement deposition.•IgM and IgA were more effective at inhibiting complement deposition than IVIG.•IgM/A-rich IVIG was more effective at inhibiting complement deposition than IVIG.•IgM and IgA serve as an alternative immunotherapy in GBS and MMN.
Background
The treatment of chronic pain is still unsatisfactory. Despite the availability of different drugs, most patients with chronic pain do not receive satisfactory pain relief or report side ...effects. Converging evidence implicates involvement of the immune system in the pathogenesis of different types of nociceptive and neuropathic chronic pain.
Design
At a workshop in Liverpool, UK (October 2012), experts presented evidence suggesting immunological involvement in chronic pain and recent data supporting the concept that the established immune‐modulating drug, polyvalent immunoglobulin G (IgG), either given intravenously (IVIg) or subcutaneously (SCIg), may reduce pain in some peripheral neuropathies and a range of other pain disorders. Workshop's attendees discussed the practicalities of using IVIg and SCIg in these disorders, including indications, cost‐effectiveness, and side effects.
Results
IgG may reduce pain in a range of nociceptive and neuropathic chronic pain conditions, including diabetes mellitus, Sjögren's syndrome, fibromyalgia, complex regional pain syndrome, post‐polio syndrome, and pain secondary to pathological autoantibodies.
Conclusions
IgG is a promising treatment in several chronic pain conditions. IgG is a relatively safe therapeutic strategy, with uncommon and mild side effects but high costs. Randomized, controlled trials and predictive tests are needed to better support the use of IgG for refractory chronic pain.
Hereditary angioedema (HAE), a rare but life-threatening condition, manifests as acute attacks of facial, laryngeal, genital, or peripheral swelling or abdominal pain secondary to intra-abdominal ...edema. Resulting from mutations affecting C1 esterase inhibitor (C1-INH), inhibitor of the first complement system component, attacks are not histamine-mediated and do not respond to antihistamines or corticosteroids. Low awareness and resemblance to other disorders often delay diagnosis; despite availability of C1-INH replacement in some countries, no approved, safe acute attack therapy exists in the United States. The biennial C1 Esterase Inhibitor Deficiency Workshops resulted from a European initiative for better knowledge and treatment of HAE and related diseases. This supplement contains work presented at the third workshop and expanded content toward a definitive picture of angioedema in the absence of allergy. Most notably, it includes cumulative genetic investigations; multinational laboratory diagnosis recommendations; current pathogenesis hypotheses; suggested prophylaxis and acute attack treatment, including home treatment; future treatment options; and analysis of patient subpopulations, including pediatric patients and patients whose angioedema worsened during pregnancy or hormone administration. Causes and management of acquired angioedema and a new type of angioedema with normal C1-INH are also discussed. Collaborative patient and physician efforts, crucial in rare diseases, are emphasized. This supplement seeks to raise awareness and aid diagnosis of HAE, optimize treatment for all patients, and provide a platform for further research in this rare, partially understood disorder.
Intravenously applied normal human immunoglobulin G (IgG) has anti-inflammatory effects in the treatment of autoimmune diseases. Systemic inflammation can originate from an overreacting amplification ...loop of the complement system. In blood, C3b2-containing complexes maintain complement amplification much better than the extremely short-lived C3b. Therefore, in patients with the complement-dependent autoimmune disease, dermatomyositis, we studied whether intravenously applied normal human IgG (IVIG) stimulated in vivo inactivation of these complexes. In the course of IVIG treatment, clinically effective in 6 of 8 patients, the concentration of C3b2-containing complexes dropped to 37% ± 14% (n = 6) of the pretreatment level when having infused 0.5 g IgG/kg body weight, increased marginally and in parallel to factor Bb thereafter until full-dose IgG was infused. By day 14 following infusion of 2 g IgG/kg body weight the concentration of C3b2-containing complexes was 66% ± 19%. The plasma concentration of C3 remained constant in myopathic or increased by 15% to 20% in amyopathic patients. In contrast to this, IVIG infusion was associated with consumption of up to 40% of plasma C4 at day 1 to 2 after completion of IVIG infusion. Thus, IVIG had an immediate and long-lasting attenuating effect on complement amplification in vivo, despite the fact that it induced classical complement pathway activation.
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