Intravenous immunoglobulin therapy affects T regulatory cells by increasing their suppressive function

Restoring immune balance with Tregitopes: A new approach to treating immunological disorders

The induction of immunological tolerance is a promising strategy for managing autoimmune diseases, allergies, and transplant rejection. Tregitopes, a class of peptides, have emerged as potential agents for this purpose. They activate regulatory T cells, which are pivotal in reducing inflammation and promoting tolerance, by binding to MHC II molecules and facilitating their processing and presentation to Treg cells, thereby encouraging their proliferation. Moreover, Tregitopes influence the phenotype of antigen-presenting cells by attenuating the expression of CD80, CD86, and MHC class II while enhancing ILT3, resulting in the inhibition of NF-kappa B signaling pathways. Various techniques, including in vitro and in silico methods, are applied to identify Tregitope candidates. Currently, Tregitopes play a vital role in balancing immune activation and tolerance in clinical applications such as Pompe disease, diabetes-related antigens, and the prevention of spontaneous abortions in autoimmune diseases. Similarly, Tregitopes can induce antigen-specific regulatory T cells. Their anti-inflammatory effects are significant in conditions such as autoimmune encephalomyelitis, inflammatory bowel disease, and Guillain-Barré syndrome. Additionally, Tregitopes have been leveraged to enhance vaccine design and efficacy. Recent advancements in understanding the potential benefits and drawbacks of IVIG and the discovery of the function and mechanism of Tregitopes have introduced Tregitopes as a popular option for immune system modulation. It is expected that they will bring about a significant revolution in the management and treatment of autoimmune and immunological diseases. This article is a comprehensive review of Tregitopes, concluding with the potential of these epitopes as a therapeutic avenue for immunological disorders.

Mechanism underlying polyvalent IgG-induced regulatory T cell activation and its clinical application: Anti-idiotypic regulatory T cell theory for immune tolerance

The regulatory T (Treg) cells constitute a functionally defined subpopulation of T cells that modulate the immune system and maintain immune tolerance through suppression of the development of autoimmune responses to self-antigens and allergic reactions to external antigens. Reduction in the number or function of Treg cells has been suggested as a key immune abnormality underlying the development of autoimmune and allergic diseases. In vitro studies have demonstrated that purified polyvalent immunoglobulin G (IgG) from multiple healthy blood donors can exert immunomodulatory effects on Treg cells. Incubation of polyvalent human IgG with purified CD4+CD25high T cells increased the intracellular expression of interleukin (IL)-10. Intravenous administration of polyvalent human IgG induced significant expansions of CD4+ Foxp3+ Treg cells and clinical improvements in patients with autoimmune diseases. In human clinical trials, intramuscular administration of autologous total IgG significantly increased the percentage of IL-10-producing CD4+ Treg cells in the peripheral blood of healthy subjects and provided significant clinical improvements in patients with atopic dermatitis. These results suggest a clinical usefulness of polyvalent IgG-induced activation of Treg cells in human subjects. This review proposes a new hypothesis for immune tolerance mechanism by integrating the pre-existing "idiotypic network theory" and "Treg cell theory" into an "anti-idiotypic Treg cell theory." Based on this hypothesis, an "active anti-idiotypic therapy" for allergic and autoimmune diseases using autologous polyvalent IgG (as immunizing antigens) is suggested as follows: (1) Intramuscular or subcutaneous administration of autologous polyvalent IgG produces numerous immunogenic peptides derived from idiotypes of autologous IgG through processing of dendritic cells, and these peptides activate anti-idiotypic Treg cells in the same subject. (2) Activated anti-idiotypic Treg cells secrete IL-10 and suppress Th2 cell response to allergens and autoimmune T cell response to self-antigens. (3) These events can induce a long-term clinical improvements in patients with allergic and autoimmune diseases. Further studies are needed to evaluate the detailed molecular mechanism underlying polyvalent IgG-induced Treg cell activation and the clinical usefulness of this immunomodulatory therapy for autoimmune and allergic diseases.

Low-dose intravenous immunoglobulin (IVIg) in different immune-mediated conditions

IVIg has been used for a long time as a replacement therapy for primary and secondary immunodeficiencies. Beside this supplementary role, when used at higher doses (i.e., 2 g/kg/monthly) it exerts an immunomodulatory role able to control multiple autoimmune and systemic inflammatory diseases. Several mechanisms of action have been described and hypothesized, nonetheless a synergistic action on the different component of the immune response seems to be crucial. The other side of the coin are the costs which showed an increase during the years due to the production of highly purified preparations which limit side reactions. This renders the product not easily accessible especially for low-income countries. Moreover, it is based on plasma donations that experienced a significant shrinkage after the COVID-19 pandemic and the consequences are still impactful. Due to the above-mentioned problems different authors tried to find out if a lower dosage of IVIg (< 2 g/kg/monthly) might exert an immunoregulatory role. In this review we aimed to summarize the current literature about a possible beneficial effect of a lower dosage of IVIg in multiple conditions that would help to treat a vast majority of patients. Even though in some cases (e.g., Kawasaki disease and immune thrombocytopenia) results are promising, for other conditions more research is needed.

Regulatory T Cell-Targeted Immunomodulatory Therapy for Long-Term Clinical Improvement of Atopic Dermatitis: Hypotheses and Perspectives

Atopic dermatitis (AD) is a chronically relapsing inflammatory skin disorder characterized by itching and eczematous lesions. It is often associated with a personal or familial history of allergic diseases. Allergic inflammation induced by immunoglobulin E and T-helper type 2 (Th2) cell responses to common environmental agents has been suggested to play an essential role in AD pathogenesis. The standard therapies for AD, including topical or systemic agents, focus on controlling skin inflammation. Recently developed monoclonal antibody to interleukin-4 receptor alpha or Janus kinase inhibitors can provide significant clinical improvements in patients with AD by inhibiting Th2 cell-mediated skin inflammation. However, the clinical efficacy of the Th2 cell-targeted therapy is transient and incomplete in patients with AD. Patients with AD are seeking a permanent cure. Therefore, the development of novel immunomodulatory strategies that can improve a long-term clinical outcome and provide a long-term treatment-free clinical remission of AD (disease-modifying therapy) is needed. Regulatory T (Treg) cells play a critical role in the maintenance of immune tolerance and suppress the development of autoimmune and allergic diseases. This review provides three working hypotheses and perspectives for the treatment of AD by Treg cell activation. (1) A decreased number or function of Treg cells is a critical event that causes the activation of Th2 cells, leading to the development and maintenance of AD. (2) Activation of Treg cells is an effective therapeutic approach for AD. (3) Many different immunomodulatory strategies activating Treg cells can provide a long-term clinical improvement of AD by induction of immune tolerance. The Treg cell-targeted immunomodulatory therapies for AD include allergen immunotherapy, microbiota, vitamin D, polyvalent human immunoglobulin G, monoclonal antibodies to the surface antigens of T cell or antigen-presenting cell, and adoptive transfer of autologous Treg cells or genetically engineered Treg cells expanded in vitro.

Intravenous immunoglobulin use in patients with unexplained recurrent pregnancy loss

PROBLEM

Recurrent pregnancy loss (RPL) affects up to 4% of couples attempting to conceive. RPL is unexplained in over 50% of cases and no effective treatments exist. Due to the immune system's pivotal role during implantation and pregnancy, immune-mediated RPL may be suspected and immunomodulatory treatments like intravenous immunoglobulin (IVIg) have been administered but remain controversial. The goal of our study was to evaluate our center's 6 year-outcomes and to develop a framework for IVIg use in RPL.

METHOD OF THE STUDY

Retrospective, single-center cohort study. All patients having received IVIg for unexplained RPL at the McGill Reproductive Immunology Clinic (MRIC) from January 2014 to December 2020 were included if maternal age was <42 years, body mass index (BMI) < 35 kg/m² , non-smoker and having had ≥3 consecutive RPL despite previous treatment with aspirin and progesterone. IVIg 0.6-0.8 g/kg was given prior to conception and monthly during pregnancy until 16-20 weeks' gestation. We compared IVIg treated patient's outcomes to a separate "natural history cohort". This cohort was composed of patients consulting at the McGill recurrent pregnancy loss clinic and the MRIC over a 2-year period (January 2020 to December 2021) with similar inclusion criteria as the treatment cohort but did not receive IVIg or other immunomodulatory treatments. The association of IVIg with outcomes (compared to no IVIg) was evaluated among the groups of patients with primary RPL and secondary RPL. The primary outcome was live birth rate (LBR), secondary outcomes included IVIg safety, obstetrical, and neonatal complications.

RESULTS

Among 169 patients with unexplained RPL that were included in the study, 111 had primary RPL (38 exposed to IVIg and 83 controls) and 58 had secondary RPL (nine exposed to IVIG and 49 controls). Among patients with primary RPL (n = 111), the LBR was 64.3% (18/28) among patient exposed to IVIg compared to 43.4% (36/83) in controls (p = 0.079); regression analysis adjusting for BMI and number of previous miscarriages showed benefit favoring the use of IVIg (OR = 3.27, CI 95% (1.15-10.2), p = 0.03) when evaluating for live birth. In the subgroup of patients with ≥5 previous RPL and primary RPL (n = 31), IVIg was associated with higher LBR compared to control (10/15 (66.7%) vs. 3/16 (18.8%); p = 0.0113) but not the in the sub-group of patients with <5 miscarriages and primary RPL (8/13 (61.5%) vs. 33/67 (49.3%); p = 0.548). IVIG treatment did not improve LBR in patients with secondary RPL in our study (3/9 (33.3%) vs. 23/49 (47%); p = 0.495). There were no serious adverse events in the IVIg treatment group, obstetrical/neonatal complications were similar between groups.

CONCLUSION

IVIg may be an effective treatment for patients with RPL if appropriately used in specific groups of patients. IVIg is a blood product and subject to shortages especially with unrestricted off-label use. We propose considering IVIg in well-selected patients with high order RPL who have failed standard medical therapy. Further mechanistic studies are needed to understand immune-mediated RPL and IVIg's mode of action. This will enable further refinement of treatment criteria and the development of standardized protocol for its use in RPL.

Intravenous Immunoglobulin: Mechanism of Action in Autoimmune and Inflammatory Conditions

Intravenous immunoglobulin (IVIG) is the mainstay of therapy for humoral immune deficiencies and numerous inflammatory disorders. Although the use of IVIG may be supplanted by several targeted therapies to cytokines, the ability of polyclonal normal IgG to act as an effector molecule as well as a regulatory molecule is a clear example of the polyfunctionality of IVIG. This article will address the mechanism of action of IVIG in a number of important conditions that are otherwise resistant to treatment. In this commentary, we will highlight mechanistic studies that shed light on the action of IVIG. This will be approached by identifying effects that are both common and disease-specific, targeting actions that have been demonstrated on cells and processes that represent both innate and adaptive immune responses.

Type 1 diabetes and inborn errors of immunity: Complete strangers or 2 sides of the same coin?

Type 1 diabetes (T1D) is a polygenic disease and does not follow a mendelian pattern. Inborn errors of immunity (IEIs), on the other hand, are caused by damaging germline variants, suggesting that T1D and IEIs have nothing in common. Some IEIs, resulting from mutations in genes regulating regulatory T-cell homeostasis, are associated with elevated incidence of T1D. The genetic spectrum of IEIs is gradually being unraveled; consequently, molecular pathways underlying human monogenic autoimmunity are being identified. There is an appreciable overlap between some of these pathways and the genetic variants that determine T1D susceptibility, suggesting that after all, IEI and T1D are 2 sides of the same coin. The study of monogenic IEIs with a variable incidence of T1D has the potential to provide crucial insights into the mechanisms leading to T1D. These insights contribute to the definition of T1D endotypes and explain disease heterogeneity. In this review, we discuss the interconnected pathogenic pathways of autoimmunity, β-cell function, and primary immunodeficiency. We also examine the role of environmental factors in disease penetrance as well as the circumstantial evidence of IEI drugs in preventing and curing T1D in individuals with IEIs, suggesting the repositioning of these drugs also for T1D therapy.

Regulatory factors involved in Th17/Treg cell balance of immune thrombocytopenia

Immune thrombocytopenia is a common heterogeneous autoimmune disease that is characterized by decreasing peripheral blood platelet counts and increasing risk of bleeding. Studies have shown that an imbalance between T helper 17 (Th17) and Regulatory T (Treg) cells differentiated from CD4+T-cells is a key factor influencing the development and pathogenesis of immune thrombocytopenia. Th17 cells promote the development of chronic inflammatory disorders and induce autoimmune diseases, whereas Treg cells regulate immune homeostasis and prevent autoimmune diseases. Several regulators affecting the production and maintenance of these cells are also essential for proper regulation of Th17/Treg balance; these regulatory factors include cell surface proteins, miRNAs, and cytokine signaling. In this review, we focus on the function and role of balance between Th17 and Treg cells in immune thrombocytopenia, the regulatory factors, and therapeutic goals of this balance in immune thrombocytopenia.

Intravenous Immunoglobulins as Immunomodulators in Autoimmune Diseases and Reproductive Medicine

Intravenous administration of immunoglobulins has been routinely used for more than 60 years in clinical practice, developed initially as replacement therapy in immunodeficiency disorders. Today, the use of intravenous immunoglobulins (IVIGs) is embedded in the modern algorithms for the management of a few diseases, while in most cases, their application is off-label and thus different from their registered therapeutic indications according to the summary of product characteristics. In this review, we present the state-of-the-art use of IVIGs in various autoimmune conditions and immune-mediated disorders associated with reproductive failure, as approved therapy, based on indications or off-label. IVIGs are often an alternative to other treatments, and the administration of IVIGs continues to expand as data accumulate. Additionally, new insights into the pathophysiology of immune-mediated disorders have been gained. Therefore, the need for immunomodulation has increased, where IVIG therapy represents an option for stimulating, inhibiting and regulating various immune processes.

Efficacy and safety of blood derivatives therapy in Alzheimer's disease: a systematic review and meta-analysis

BACKGROUND

Blood derivatives therapy is a conventional clinical treatment, while the treatment for Alzheimer's disease (AD) is relatively novel. To provide clinical references for treating AD, this meta-analysis was performed to evaluate the efficacy and safety of blood derivatives therapy on the patients with AD.

METHODS

A systematic articles search was performed for eligible studies published up to December 6, 2021 through the PubMed, Embase, Cochrane library, ClinicalTrials.gov , Chinese National Knowledge Infrastructure database, and Wanfang databases. The included articles were screened by using rigorous inclusion and exclusion criteria. Study selection and data-extraction were performed by two authors independently. Random effects model or fixed effects model was used. Quality of studies and risk of bias were evaluated according to the Cochrane risk of bias tool. All analyses were conducted using Review Manager 5.4. The study was designed and conducted according to the Preferring Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline.

RESULTS

A total of three plasma administrations (two plasma exchange and one young plasma infusion) and five intravenous immunoglobulin (IVIG) randomized controlled trials with a sample size of 1148 subjects diagnosed with AD were included. There was no significant difference in cognitive improvement and all-cause discontinuation between intervention and placebo groups (RR 1.10, 95% CI 0.79-1.54). And Intervention groups showed not a statistically significant improvement in cognition of included subjects measured by the ADAS-Cog (MD 0.36, 95% CI 0.87-1.59), ADCS-ADL (MD -1.34, 95% CI - 5.01-2.32) and NPI (MD 2.20, 95% CI 0.07-4.32) score compared to the control groups. IVIG is well tolerated for AD patients even under the maximum dose (0.4 g/kg), but it is inferior to placebo in Neuropsychiatric Inventory scale in AD patients (MD 2.19, 95% CI 0.02-4.37).

CONCLUSIONS

The benefits of blood derivatives therapy for AD are limited. It is necessary to perform well-designed randomized controlled trials with large sample sizes focusing on the appropriate blood derivatives for the specific AD sub-populations in the future.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021233886.

The yin/yang balance of the MHC-self-immunopeptidome

The MHC-self immunopeptidome of professional antigen presenting cells is a cognate ligand for the TCRs expressed on both conventional and thymic-derived natural regulatory T cells. In regulatory T cells, the TCR signaling associated with MHC-peptide recognition induces antigen specific as well as bystander immunosuppression. On the other hand, TCR activation of conventional T cells is associated with protective immunity. As such the peripheral T cell repertoire is populated by a number of T cells with different phenotypes and different TCRs, which can recognize the same MHC-self-peptide complex, resulting in opposite immunological outcomes. This article summarizes what is known about regulatory and conventional T cell recognition of the MHC-self-immunopeptidome at steady state and in inflammatory conditions associated with increased T and B cell self-reactivity, discussing how changes in the MHC-ligandome including epitope copy number and post-translational modifications can tilt the balance toward the expansion of pro-inflammatory or regulatory T cells.

Systems biology and artificial intelligence analysis highlights the pleiotropic effect of IVIg therapy in autoimmune diseases with a predominant role on B cells and complement system

Intravenous immunoglobulin (IVIg) is used as treatment for several autoimmune and inflammatory conditions, but its specific mechanisms are not fully understood. Herein, we aimed to evaluate, using systems biology and artificial intelligence techniques, the differences in the pathophysiological pathways of autoimmune and inflammatory conditions that show diverse responses to IVIg treatment. We also intended to determine the targets of IVIg involved in the best treatment response of the evaluated diseases. Our selection and classification of diseases was based on a previously published systematic review, and we performed the disease characterization through manual curation of the literature. Furthermore, we undertook the mechanistic evaluation with artificial neural networks and pathway enrichment analyses. A set of 26 diseases was selected, classified, and compared. Our results indicated that diseases clearly benefiting from IVIg treatment were mainly characterized by deregulated processes in B cells and the complement system. Indeed, our results show that proteins related to B-cell and complement system pathways, which are targeted by IVIg, are involved in the clinical response. In addition, targets related to other immune processes may also play an important role in the IVIg response, supporting its wide range of actions through several mechanisms. Although B-cell responses and complement system have a key role in diseases benefiting from IVIg, protein targets involved in such processes are not necessarily the same in those diseases. Therefore, IVIg appeared to have a pleiotropic effect that may involve the collaborative participation of several proteins. This broad spectrum of targets and 'non-specificity' of IVIg could be key to its efficacy in very different diseases.

The short-term predictive value of CD4+ cells for combination therapy with high-dose dexamethasone and immunoglobulin in newly diagnosed primary immune thrombocytopenia patients

INTRODUCTION

Dexamethasone (DXM) or immunoglobulin (IVIg) are first-line therapies for primary immune thrombocytopenia (ITP), with an effective rate of 80 %. Some patients with both severe bleeding symptoms and platelet counts of <30 × 10⁹/L received a combination of DXM and IVIg. Autoimmune disorders, especially involving CD4⁺ T-cells, play a key role in the pathogenesis of ITP. We assumed that variations in the immune status of CD4⁺ T-cells will lead to different treatment responses. Until now, there have been few relevant clinical studies on CD4⁺ T-cells and the outcome of first-line therapies.

METHODS

A prospective study enrolling 42 newly diagnosed ITP patients and 30 normal control volunteers was performed. The profiles of major CD4⁺ T-cells, including T helper (Th)1, Th2, Th17, and regulatory T (Treg) cells, and the related levels of interleukin (IL)-2, IL-17, and IL-23 were examined. The platelet number was recorded at the time point of day 0, day 14, and day 30.

RESULTS

Greater concentrations of Th1 and Th17 cells and lower relative numbers of Treg cells were found in the ITP group. As for the treatment outcome on day 14, the profiles of Th2 and IL-2 were significantly greater in the NR group, while the expression of IL-17 was elevated in the CR group. As for the treatment outcome on day 30, higher levels of Th2 cells were observed in those patients who needed 2× pulses of HD DXM compared to those who needed only 1× pulse of HD DXM and IVIg, and receiver operating characteristic curve analysis showed that lower Treg cell may predict favorable values. Meanwhile, the higher IL-23 value may predict a poor early response.

CONCLUSIONS

Our results indicate that Th1, Th17, and Treg cells and IL-2 and IL-23 participate in the onset of ITP. Higher profiles of Th2, IL-2 and IL-23 may predict poor treatment outcomes. Higher levels of IL-17 and lower profile of Treg may predict sensitivity to HD DXM and IVIg combination therapy.

Intramuscular administration of autologous total immunoglobulin G induces immunomodulatory effects on T cells in healthy human subjects: An open-labeled prospective single-arm trial

BACKGROUND

We hypothesized that intramuscular administration of autologous total immunoglobulin G (IgG) could induce an immunomodulatory effect in human subjects. In our previous studies, we showed that intramuscular administration of autologous total IgG could induce significant clinical improvements and increases of the serum levels of interleukin-10 (IL-10) and interferon-gamma (IFN-γ) in patients with atopic dermatitis.

OBJECTIVE

To investigate the mechanism of immunomodulation induced by intramuscular administration of autologous total IgG, we evaluated changes in T cells before and after intramuscular administrations of autologous total IgG in this study.

METHODS

Thirteen healthy adults received 8 intramuscular injections of 50 mg autologous total IgG for 4 weeks (from week 0 to week 4). The percentages of IL-10- or IFN-γ-producing peripheral blood T cells, as well as serum levels of IL-10, IFN-γ, and immunoglobulins, were measured at baseline (week 0) and at weeks 4, 8, and 12.

RESULTS

The percentage of IL-10-producing CD4+ T cells was significantly increased at weeks 8 and 12 compared to baseline (P < .05), while the percentage of IFN-γ-producing CD3+ T cells was significantly increased at week 12 compared to baseline (P < .05). There were no significant differences in the serum levels of IL-10, IFN-γ, and immunoglobulins before and after intramuscular administration of autologous total IgG (P > .05). No serious adverse events were observed.

CONCLUSION

Intramuscular administration of autologous total IgG induced immunomodulatory effects on T cells in healthy human subjects. This simple intervention could be a safe, effective, and economical T cell immunomodulation method for human subjects (NCT03695757).

eQTL Highlights the Potential Role of Negative Control of Innate Immunity in Kawasaki Disease

Purpose

Kawasaki disease (KD) is an acute systemic vasculitis mainly found in the medium-sized arteries, especially the coronary arteries. Immune system is involved in the pathogenesis of acute KD in children, but the functional differences in the immune system between healthy children and KD patients remain unclear.

Patients and Methods

A total of 190 KD patients and 119 healthy controls were recruited for the next-generation sequencing of 512 targeted genes from 4 immune-related pathways. Subsequently, the peripheral blood mononuclear cells (PBMCs) were isolated. RNA sequencing of the LPS treated PBMCs from additional 20 KD patients and 20 healthy controls was used to examine the differentially expressed genes (DEGs). Then, an expression quantitative trait locus (eQTL) analysis combined with previously analyzed RNA data were used to examine the DEGs. Finally, the serum levels of 13 cytokines were detected before and after LPS treatment in 40 samples to confirm the findings from eQTL analysis.

Results

A total of 319 significant eQTL were found, and both eQTL analysis and RNA sequencing showed some DEGs were involved in the connective tissue disorders and inflammatory diseases. DEGs that function to negatively regulate immunity were closely related to the pathogenesis of KD. In addition, the serum levels of IL-10 (an inflammatory and immunosuppressive factor) and SCD25 (an important immunosuppressant) reduced significantly in the KD patients.

Conclusion

Our study shows the expression of factors responsible for the negative control of innate immunity is altered, which plays an important role in the etiology of KD.

Intravenous immunoglobulin as an important adjunct in the prevention and therapy of coronavirus 2019 disease

The coronavirus disease-19 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) challenged globally with its morbidity and mortality. A small percentage of affected patients (20%) progress into the second stage of the disease clinically presenting with severe or fatal involvement of lung, heart and vascular system, all contributing to multiple-organ failure. The so-called 'cytokines storm' is considered the pathogenic basis of severe disease and it is a target for treatment with corticosteroids, immunotherapies and intravenous immunoglobulin (IVIg). We provide an overview of the role of IVIg in the therapy of adult patients with COVID-19 disease. After discussing the possible underlying mechanisms of IVIg immunomodulation in COVID-19 disease, we review the studies in which IVIg was employed. Considering the latest evidence that show a link between new coronavirus and autoimmunity, we also discuss the use of IVIg in COVID-19 and anti-SARS-CoV-2 vaccination related autoimmune diseases and the post-COVID-19 syndrome. The benefit of high-dose IVIg is evident in almost all studies with a rapid response, a reduction in mortality and improved pulmonary function in critically ill COVID-19 patients. It seems that an early administration of IVIg is crucial for a successful outcome. Studies' limitations are represented by the small number of patients, the lack of control groups in some and the heterogeneity of included patients. IVIg treatment can reduce the stay in ICU and the demand for mechanical ventilation, thus contributing to attenuate the burden of the disease.

Intravenous Immunoglobulin: Revisited - My Experience

Background:

Many a times while treating dermatoses conventional therapies are either contraindicated or not effective. Intravenous immunoglobulin (IVIG) is a good alternative available to tide over crises.

Method:

Over the last 15 years of my practice I have used IVIg in various severe or recalcitrant diseases (including TEN, autoimmune blistering disease,connective tissue disorders , chronic urticaria etc) which were either unresponsive to conventional modality of therapy or primary therapy could not be given because of co-morbidities.

Result:

IVIg a sterile, highly purified preparation containing more than 95% unmodified IgG,was first approved by FDA in 1981 for 6 diseases. As mentioned above in many circumstances we reached a situation when either conventional primary therapy was contraindicated or patients were not responding. IVIg came to our rescue in large number of conditions to tide over the crisis and also created the environment leading to conventional therapy becoming effective. Very few minor side effects like low grade fever and myalgia were observed in very few cases. No serious or severe side effects were seen, however , one has to be prepared for anaphylactic reaction which is a theoretical possibility.

Conclusion:

It can be said that IVIg though not a magic drug, is a very effective tool available in the armamentarium of Dermatologists to treat plethora of chronic and intractable dermatoses.

A systemic review of intravenous immunoglobulin G treatment in women with recurrent implantation failures and recurrent pregnancy losses

Over the last few decades, the advancement in reproductive technologies and protocols to improve embryo quality through culture techniques and genetic testing to eliminate chromosomally abnormal embryos resulted in better pregnancy rates and outcomes after fertility treatments. Unfortunately, some patients still struggle with recurrent implantation failures (RIFs) and recurrent pregnancy losses (RPLs). Immune etiologies have been attributed to play an important role in some of those patients. Maintaining a pre-conceptional anti-inflammatory environment for implantation and pregnancy continuation yields superior results. Intravenous immunoglobulin G (IVIG) treatment has been reported to enhance reproductive outcome in patients with RIF and RPL with immune dysregulations. In this systemic review, we analyzed outcomes of IVIG trials for RIF and RPL, its mechanism of action, dosing, administration, side-effects, and evidence for its use in women with RIF and RPL.

Treatment of Secondary Immune Thrombocytopenia with Non-Hodgkin Lymphoma: A Case Report and Literature Review

Secondary immune thrombocytopenic purpura (ITP) with non-Hodgkin lymphoma (NHL) is a rare disease. Although some treatment regimens are available for primary ITP, the treatment strategy for secondary ITP remains unconfirmed. We herein report a 79-year-old man who was diagnosed with secondary ITP with mantle cell lymphoma. Although intravenous immunoglobulin (IVIG) has been considered an effective option for secondary ITP, similar to the treatment of primary ITP, our patient did not benefit from IVIG. A literature review including the current report revealed that IVIG was ineffective in all treated patients. Secondary ITP with NHL should be treated differently from primary ITP.

Is there a Role of Intravenous Immunoglobulin in Immunologic Recurrent Pregnancy Loss?

Recurrent pregnancy loss (RPL) commonly refers to three or more miscarriages that occur before 20 weeks of pregnancy. The immunological cause of RPL could be either an auto- or alloimmune-related event or both. Because of the discovery of immunological abnormalities in RPL patients in clinical practice, several immunomodulatory therapies were introduced to maintain the immune balance at the maternal-fetal interface. Intravenous immunoglobulin (IVIg) is one of the immunomodulators. In recent years, several studies have analyzed the therapeutic effect of IVIg on RPL patients with antiphospholipid syndrome (APS) or unexplained RPL. However, their results are controversial. IVIg can be used in RPL patients with APS who have previously failed in other treatments. It is recommended that IVIg infusion could be considered used before conception in RPL patients who have cellular immune abnormalities such as increased natural killer (NK) cell counts, NK cell cytotoxicity, or increased T helper (Th)1/Th2 ratio, depending on the cut-off values of each hospital. The aim of this review was to summarize the mechanisms, efficacy, pharmacokinetics, and side effects associated with passive immunization using IVIg in immunologic RPL, according to the literature published in recent years. We hope that more obstetricians will be able to understand the timing and indication of IVIg properly in immunologic RPL patients and effectively enhance pregnancy outcomes for mothers and neonates.

Natural Antibodies: from First-Line Defense Against Pathogens to Perpetual Immune Homeostasis

Natural antibodies (nAbs) are most commonly defined as immunoglobulins present in the absence of pathological conditions or deliberate immunizations. Occurrence of nAbs in germ- and antigen-free mice suggest that their production is driven, at least in part, by self-antigens. Accordingly, nAbs are constituted of natural autoantibodies (nAAbs), and can belong to the IgM, IgG, or IgA subclasses. These nAbs provide immediate protection against infection while the adaptive arm of the immune system mounts a specific and long-term response. Beyond immediate protection from infection, nAbs have been shown to play various functional roles in the immune system, which include clearance of apoptotic debris, suppression of autoimmune and inflammatory responses, regulation of B cell responses, selection of the B cell repertoires, and regulation of B cell development. These various functions of nAbs are afforded by their reactivity, which is broad, cross-reactive, and shown to recognize evolutionarily fixed epitopes shared between foreign and self-antigens. Furthermore, nAbs have unique characteristics that also contribute to their functional roles and set them apart from antigen-specific antibodies. In further support for the role of nAbs in the protection against infections and in the maintenance of immune homeostasis, the therapeutic preparation of polyclonal immunoglobulins, intravenous immunoglobulin (IVIG), rich in nAbs is commonly used in the replacement therapy of primary and secondary immunodeficiencies and in the immunotherapy of a large number of autoimmune and inflammatory diseases. Here, we review several topics on nAbs features and functions, and therapeutic applications in human diseases.

Efficacy and safety of intravenous immunoglobulin with rituximab versus rituximab alone in childhood-onset steroid-dependent and frequently relapsing nephrotic syndrome: protocol for a multicentre randomised controlled trial

INTRODUCTION

Guidelines for the treatment of steroid-dependent nephrotic syndrome (SDNS) and frequently relapsing nephrotic syndrome (FRNS) are lacking. Given the substantial impact of SDNS/FRNS on quality of life, strategies aiming to provide long-term remission while minimising treatment side effects are needed. Several studies confirm that rituximab is effective in preventing early relapses in SDNS/FRNS; however, the long-term relapse rate remains high (~70% at 2 years). This trial will assess the association of intravenous immunoglobulins (IVIgs) to rituximab in patients with SDNS/FRNS and inform clinicians on whether IVIg's immunomodulatory properties can alter the course of the disease and reduce the use of immunosuppressive drugs and their side effects.

METHODS AND ANALYSIS

We conduct an open-label multicentre, randomised, parallel group in a 1:1 ratio, controlled, superiority trial to assess the safety and efficacy of a single infusion of rituximab followed by IVIg compared with rituximab alone in childhood-onset FRNS/SDNS. The primary outcome is the occurrence of first relapse within 24 months. Patients are allocated to receive either rituximab alone (375 mg/m²) or rituximab followed by IVIg, which includes an initial Ig dose of 2 g/kg, followed by 1.5 g/kg injections once a month for the following 5 months (maximum dose: 100 g).

ETHICS AND DISSEMINATION

The study has been approved by the ethics committee (Comité de Protection des Personnes) of Ouest I and authorised by the French drug regulatory agency (Agence Nationale de Sécurité du Médicament et des Produits de Santé). Results of the primary study and the secondary aims will be disseminated through peer-reviewed publications.

TRIAL REGISTRATION NUMBER

NCT03560011.

Emerging benefits of Fc fusion technology in the context of recombinant factor VIII replacement therapy

Although the primary reason for recombinant factor VIII Fc fusion protein (rFVIIIFc) development was to reduce treatment burden associated with routine prophylaxis, new evidence suggests additional benefits of Fc fusion technology in the treatment of people with haemophilia A. Preclinical research has been utilized to characterize the potential immunomodulatory properties of rFVIIIFc, including an ability to reduce inflammation and induce tolerance to factor VIII. This has since been expanded into clinical research in immune tolerance induction (ITI) with rFVIIIFc, results of which suggest the potential for rapid tolerization in first‐time ITI patients and therapeutic benefit in patients undergoing rescue ITI. The potential for improved joint health through the anti‐inflammatory properties of rFVIIIFc has also been suggested. In addition, a new avenue of research into the role of rFVIIIFc in promoting bone health in patients with haemophilia A, potentially through reduced osteoclast formation, has yielded encouraging results that support further study. This review summarizes the existing preclinical and clinical studies of immunomodulation and tolerization with rFVIIIFc, as well as studies in joint and bone health, to elucidate the potential benefits of rFVIIIFc in haemophilia A beyond the extension of factor VIII half‐life.

Tregitopes regulate the tolerogenic immune response and decrease the foetal death rate in abortion-prone mouse matings

The imbalance in immune tolerance may cause the variety of reproductive failures. An intravenous immunoglobulin infusion (IVIg) therapy is used to improve the live birth rate in women suffering from recurrent pregnancy loss, recurrent spontaneous abortions and recurrent implantation failures. However, the results of IVIg studies are still inconclusive as IVIg infusion in women suffering from pregnancy loss is sometimes ineffective. One of the mechanisms of action of this treatment is inhibition of B cells differentiation and expansion of Tregs and secretion of interleukin 10. It was proposed that immunomodulatory effects of IVIg may be attributed to tregitopes - self-IgG-derived epitopes present in the structure of immunoglobulins. Similarly to IVIg, tregitopes cause the expansion of Tregs and secretion of antigen-specific effector cytokine response. Here, we studied whether the administration of mouse tregitope 167 and/or 289 can prevent abortions in mouse abortion-prone mouse matings. We revealed that tregitopes reduce the foetal death rate. This may be driven by observed higher pool of peripheral Tregs, increased production of IL-10 by Tregs and Bregs and/or maintaining the tolerogenic phenotype of antigen-presenting cells. We believe that our findings may indicate a potential alternative to IVIg for therapeutic intervention in case of pregnancy failures.

Engineering of Fc Multimers as a Protein Therapy for Autoimmune Disease

The success of Intravenous Immunoglobulin in treating autoimmune and inflammatory processes such as immune thrombocytopenia purpura and Kawasaki disease has led to renewed interest in developing recombinant molecules capable of recapitulating these therapeutic effects. The anti-inflammatory properties of IVIG are, in part, due to the Fc region of the IgG molecule, which interacts with activating or inhibitory Fcγ receptors (FcγRs), the neonatal Fc Receptor, non-canonical FcRs expressed by immune cells and complement proteins. In most cases, Fc interactions with these cognate receptors are dependent upon avidity—avidity which naturally occurs when polyclonal antibodies recognize unique antigens on a given target. The functional consequences of these avid interactions include antibody dependent cell-mediated cytotoxicity, antibody dependent cell phagocytosis, degranulation, direct killing, and/or complement activation—all of which are associated with long-term immunomodulatory effects. Many of these immunologic effects can be recapitulated using recombinant or non-recombinant approaches to induce Fc multimerization, affording the potential to develop a new class of therapeutics. In this review, we discuss the history of tolerance induction by immune complexes that has led to the therapeutic development of artificial Fc bearing immune aggregates and recombinant Fc multimers. The contribution of structure, aggregation and N-glycosylation to human IgG: FcγR interactions and the functional effect(s) of these interactions are reviewed. Understanding the mechanisms by which Fc multimers induce tolerance and attempts to engineer Fc multimers to target specific FcγRs and/or specific effector functions in autoimmune disorders is explored in detail.

Therapeutic normal IgG intravenous immunoglobulin activates Wnt-β-catenin pathway in dendritic cells

Therapeutic normal IgG intravenous immunoglobulin (IVIG) is a well-established first-line immunotherapy for many autoimmune and inflammatory diseases. Though several mechanisms have been proposed for the anti-inflammatory actions of IVIG, associated signaling pathways are not well studied. As β-catenin, the central component of the canonical Wnt pathway, plays an important role in imparting tolerogenic properties to dendritic cells (DCs) and in reducing inflammation, we explored whether IVIG induces the β-catenin pathway to exert anti-inflammatory effects. We show that IVIG in an IgG-sialylation independent manner activates β-catenin in human DCs along with upregulation of Wnt5a secretion. Mechanistically, β-catenin activation by IVIG requires intact IgG and LRP5/6 co-receptors, but FcγRIIA and Syk are not implicated. Despite induction of β-catenin, this pathway is dispensable for anti-inflammatory actions of IVIG in vitro and for mediating the protection against experimental autoimmune encephalomyelitis in vivo in mice, and reciprocal regulation of effector Th17/Th1 and regulatory T cells.

Therapeutic administration of Tregitope-Human Albumin Fusion with Insulin Peptides to promote Antigen-Specific Adaptive Tolerance Induction

Type 1 Diabetes (T1D) is an autoimmune disease that is associated with effector T cell (Teff) destruction of insulin-producing pancreatic beta-islet cells. Among the therapies being evaluated for T1D is the restoration of regulatory T cell (Treg) activity, specifically directed toward down-modulation of beta-islet antigen-specific T effector cells. This is also known as antigen-specific adaptive tolerance induction for T1D (T1D ASATI). Tregitopes (T regulatory cell epitopes) are natural T cell epitopes derived from immunoglobulin G (IgG) that were identified in 2008 and have been evaluated in several autoimmune disease models. In the T1D ASATI studies presented here, Tregitope peptides were administered to non-obese diabetic (NOD) mice at the onset of diabetes within two clinically-relevant delivery systems (liposomes and in human serum albumin [HSA]-fusion products) in combination with preproinsulin (PPI) target antigen peptides. The combination of Tregitope-albumin fusions and PPI peptides reduced the incidence of severe diabetes and reversed mild diabetes, over 49 days of treatment and observation. Combining HSA-Tregitope fusions with PPI peptides is a promising ASATI approach for therapy of T1D.

Differential immunomodulation of T-cells by immunoglobulin replacement therapy in primary and secondary antibody deficiency

Patients with primary or secondary antibody deficiency (PAD or SAD) are at increased risk of recurrent infections that can be alleviated by immunoglobulin replacement therapy (IRT). In addition to replenishing antibody levels, IRT has been suggested to modulate immune response in patients with antibody deficiency. Although both commonly treated with IRT, the underlying causes of PAD and SAD vary greatly, suggesting differential modulation of T-cell function that may lead to different responses to IRT. To explore this, peripheral blood mononuclear cells (PBMCs) were sampled from 17 PAD and 14 SAD patients before and 2–10 months after initiation of IRT, and analyzed for changes in T-cell phenotype and function. Proportions of CD4, CD8, Treg, or memory T-cells did not significantly change post-IRT compared to pre-IRT. However, we report distinct modulation in T-cell function between PAD and SAD patients post-IRT. Upon α-CD3/CD28 stimulation, proportion of IFN-γ+ CD4 and CD8 T-cells increased in SAD (p = 0.005) but not PAD patients post-IRT compared to baseline. Interestingly, total T-cell proliferation was reduced post-IRT in both PAD and SAD patients, although the reduction in proliferation was primarily due to reduced CD4 T-cell proliferation in PAD (p = 0.025) in contrast to CD8 T-cells in SAD (p = 0.042). In summary, even though IRT provides patients with passive humoral immunity-mediated protection in PAD and SAD, our findings suggest that IRT immunomodulation of T-cells is different in T-cell subsets depending on underlying immunodeficiency.

The imbalance between regulatory memory B cells reveals possible pathogenesis involvement in pediatric immune thrombocytopenia

Introduction: CD19⁺CD24^hiCD38^hi regulatory B cells (B_regs) and CD19⁺CD27⁺ memory B cells (B_mems) are B cell subsets with specific immunoregulatory properties. In this study, the balance of these subsets was investigated in pediatric immune thrombocytopenia (ITP) patients, and the frequencies of B_regs and B_mems before and after first-line therapy were measured. Methods: Forty-nine pediatric ITP patients and 19 normal controls were enrolled in this study. The total CD19⁺ B cells, B_regs and B_mems in the peripheral blood (PB) of all cases were measured by flow cytometry. Results: We found higher frequencies of total CD19⁺ B cells and B_mems in newly diagnosed ITP patients than those in normal controls (p < 0.01), whereas the frequencies of CD19⁺CD24^hiCD38^hi B_regs was significantly lower in ITP patients (p < 0.001). After therapy with MP + IVIG, the level of CD19⁺CD24^hiCD38^hi B_regs and B_mems were almost normalized. Conclusion: Our results indicated that pediatric ITP patients were characterized by a decline in CD19⁺CD24^hiCD38^hi Bregs and increment of CD19⁺CD27⁺Bmems, and an increase of total CD19⁺ B cells in their peripheral blood.

The novel polyclonal Ab preparation trimodulin attenuates ex vivo endotoxin-induced immune reactions in early hyperinflammation

Sepsis is a syndrome associated with excessive inflammation. Since mortality from sepsis remains high, more laboratory research is needed to provide insight into more effective ways to use novel, potentially more beneficial agents in sepsis. We investigated the ex vivo immunomodulatory effect of a novel polyclonal Ab preparation, trimodulin, containing IgM (∼23%), IgA (∼21%) and IgG (∼56%). Using whole blood and purified PBMCs from healthy volunteers and patients with sepsis, various ex vivo investigations upon endotoxin challenge and pre- and post-trimodulin treatment were performed. Endotoxin-induced TNF-α secretion was noticeably lower with than without trimodulin, implying attenuation of the hyper-responsive state. Trimodulin also lowered TLR2, TLR4, CD11b and CD64 detection on LPS/lipoteichoic acid-stimulated monocytes. These responses were observed in cells from healthy volunteers only shortly after ex vivo endotoxin stimulation and in whole blood from patients with early-stage sepsis. Furthermore, trimodulin markedly reduced lymphocyte proliferation and release of pro- and anti-inflammatory cytokines, but did not affect phagocytosis or oxidative-burst activities of endoxin-stimulated cells. Thus, trimodulin mitigated monocyte and lymphocyte hyperinflammatory responses early after endotoxin exposure. Determining whether early in vivo administration of trimodulin will elicit similar positive immunomodulatory effects and offer a clinical benefit warrants investigation.

Passive Serum Therapy to Immunomodulation by IVIG: A Fascinating Journey of Antibodies

The immunoregulatory and anti-infective properties of normal circulating polyclonal Abs have been exploited for the therapeutic purposes in the form of IVIG as well as several hyperimmune globulins. Current knowledge on the therapeutic use of normal Igs is based on the discoveries made by several pioneers of the field. In this paper, we review the evolution of IVIG over the years. More importantly, the process started as an s.c. replacement in γ globulin-deficient patients, underwent metamorphosis into i.m. Ig, was followed by IVIG, and is now back to s.c. forms. Following successful use of IVIG in immune thrombocytopenic purpura, there has been an explosion in the therapeutic applications of IVIG in diverse autoimmune and inflammatory conditions. In addition to clinically approved pathological conditions, IVIG has been used as an off-label drug in more than 100 different indications. The current worldwide consumption of IVIG is over 100 tons per year.

IVIG-mediated effector functions in autoimmune and inflammatory diseases

Intravenous immunoglobulin (IVIG) is a pooled preparation of normal IgG obtained from several thousand healthy donors. It is widely used in the immunotherapy of a large number of autoimmune and inflammatory diseases. The mechanisms of action of IVIG are complex and, as discussed in this review, experimental and clinical data provide an indicator that the therapeutic benefit of IVIG therapy is due to several mutually non-exclusive mechanisms affecting soluble mediators as well as cellular components of the immune system. These mechanisms depend on Fc and/or F(ab')2 fragments. A better understanding of the effector functions of IVIG should help in identification of biomarkers of responses to IVIG in autoimmune patients.

Mechanisms of action and historical facts on the use of intravenous immunoglobulins in systemic lupus erythematosus

The current existing therapies for severe cases of systemic lupus erythematosus (SLE) patients are still limited. Intravenous immunoglobulin (IVIGs), which are purified from the plasma of thousands of healthy human donors, have been profiled as efficacious and life-saving options for SLE patients refractory to conventional therapy. The specific mechanism of action by which IVIGs generate immunomodulation in SLE is not currently understood. In this manuscript, we reviewed some of the hypothesis that have been postulated to explain the IVIG effects, including those on T and B cell intracellular signalling and activation, as well as the interferon signalling pathways involved in the detection of nucleic acids and the defective removal of immune complexes and debris.

Emerging immunotherapies for autoimmune kidney disease

Autoimmunity is a leading cause of chronic kidney disease and loss of native and transplanted kidneys. Conventional immunosuppressive therapies can be effective but are non-specific, noncurative, and risk serious side effects such as life-threatening infection and cancer. Novel therapies and targeted interventions are urgently needed. In this brief review we explore diverse strategies currently in development and under consideration to interrupt underlying disease mechanisms in immune-mediated renal injury. Because autoantibodies are prominent in diagnosis and pathogenesis in multiple human glomerulopathies, we highlight several promising therapies that interfere with functions of early mediators (IgG and complement) of the effector arm and with an epicenter (the germinal center) for induction of humoral immunity.

Immunoglobulin G Enhances Generation of Inducible T Regulatory Cells and Increases Their Regulatory Function

Intravenous immunoglobulin (IVIg) has been shown to be effective in the treatment of a variety of autoimmune diseases. To clarify the role of T regulatory cells (Tregs) in the immunoregulatory effect of IVIg, we focused on human inducible T regulatory cells (iTregs) and investigated the mechanism of action of IVIg. When immunoglobulin G (IgG) was added to a culture system that differentiates iTregs from anti-CD3 antibody activated CD4+CD25- T cells in the presence of syngeneic immature dendritic cells, interleukin (IL)-2 and transforming growth factor-β (TGF-β), the expression of forkhead box P3 (FoxP3), which is the master transcription factor for Tregs in CD4+CD25+ T cells, increased in an IgG concentration-dependent manner. The expression of FoxP3 in iTregs in the 20 mg/mL IgG group was twice as high as that in the saline group. iTregs that highly expressed FoxP3 not only partially suppressed the polyclonal proliferative response of T cells derived from the same individual but also produced significantly more inhibitory cytokines IL-10 and TGF-β. The ability of IgG to enhance iTregs differentiation was also observed in the Fc fragment, but not in the F(ab')₂ fragment. These results suggest the clinical regulation of immune responses by IVIg administration may contribute at least to enhancing the differentiation of iTregs and partial immunosuppressive functions.

Modulatory effect of intravenous immunoglobulin on Th17/Treg cell balance in women with unexplained recurrent spontaneous abortion

Recurrent spontaneous abortion (RSA) is a growing problem worldwide. In a majority of cases, the cause remains unknown but there is increasing evidence that immunologic factors play an important role. Intravenous immunoglobulin (IVIg) therapy has been proposed to have immune modulatory effects and therefore been applicable for the treatment of patients with RSA. Although its efficacy is still controversial, several recent studies suggest that IVIg treatment may improve pregnancy outcomes. CD4⁺ T cells and their related cytokines play an important role in maternal-fetal immune regulation, and an imbalance of Th17/Treg cell ratio has been proposed as a cause for RSA. We review the scientific evidence supporting a modulatory effect of IVIg on Th17/Treg cell balance and discuss the potential mechanisms how IVIg might enhance Treg cells function. We propose that correction of Th17/Treg cell dysregulation could be one of the mechanisms that can explain the positive therapeutic effects of IVIg therapy. Consequently, selecting patients with abnormal Th17/Treg cell ratios could increase the success of IVIg therapy.

High-dose of intravenous immunoglobulin modulates immune tolerance in premature infants

BACKGROUND

Intravenous immunoglobulin (IVIG) is commonly used to improve the immunomodulatory effects, although its regulatory effect on premature Treg cells is unclear. The purpose of this study is to study the effect of high dose of IVIG (HD-IVIG) on Treg cells expression and cytokine profile in premature birth.

METHODS

Fifty-two premature infants were enrolled in this study and thirty-one premature infants who were suspected to have intrauterine infection received HD-IVIG (1-2 g/kg) at the first day of birth; the remaining 21 premature infants were assigned as the control group. The peripheral blood CD4 + T and foxp3+ Treg cells were checked by flow cytometry, and cytokine concentrations were detected by cytometric bead array.

RESULTS

With the gestational age growth, peripheral blood CD4 + T and foxp3+ Treg cells of prematurity gradually declined from 50% to 35% and from 8% to 6%, respectively. Meanwhile, HD-IVIG increased the percentage of CD4 + T and foxp3+ Treg cells compared with their baseline levels (p < 0.001). HD-IVIG demonstrated different regulating effects on cytokines secretion, increased IL-17 and TGF-β, and inhibited IL-6 secretion.

CONCLUSION

Our results demonstrated that HD-IVIG not only enhanced the premature immune tolerance, but also suppressed the excessive inflammation response mediated by IL-6.

TRIAL REGISTRATION

This study was under the clinical study registration (ChiCTR-ORC-16008872, date of registration, 2016-07-21).

Immune modulation of i.v. immunoglobulin in women with reproductive failure

Background

The mechanism of maternal immune tolerance of the semi‐allogenic fetus has been explored extensively. The immune reaction to defend from invasion by pathogenic microorganisms should be maintained during pregnancy. An imbalance between the immune tolerance to the fetus and immune activation to the pathogenic organisms is associated with poor pregnancy outcomes. This emphasizes that the immune mechanism of successful reproduction is not just immune suppression, but adequate immune modulation.

Methods

In this review, the action of i.v. immunoglobulin G (IVIg) on the immune system and its efficacy in reproductive failure (RF) was summarized. Also suggested is the indication of IVIg therapy for women with RF.

Main findings (Results)

Based on the mechanism of the immune regulation of IVIg and following confirmation of the immune modulation effects of it in various aberrant immune parameters in patients with RF, it is obvious that IVIg is effective in recurrent pregnancy losses and repeated implantation failures with immunologic disturbances.

Conclusion

The authors recommend IVIg therapy in patients with RF with aberrant cellular immunologic parameters, including a high natural killer cell proportion and its cytotoxicity or elevated T helper 1 to T helper 2 ratio, based on each clinic's cut‐off values. Further clinical studies about the safety of IVIg in the fetus and its efficacy in other immunologic abnormalities of RF are needed.

Endothelial Cell Amplification of Regulatory T Cells Is Differentially Modified by Immunosuppressors and Intravenous Immunoglobulin

Immunosuppressive treatment is a prerequisite for both organ transplantation and tolerance of the allograft. However, long-term immunosuppression has been associated with a higher incidence of malignancies and infections. Immunosuppressors mainly target circulating immune cells and little is known of their “off-target” effects, such as their impact on endothelial cells (ECs). In chronic antibody-mediated rejection (AMR), the allograft endothelium is a target of damage, histologically detected as transplant glomerulopathy, and which correlates with poor graft survival. Under inflammatory conditions, EC expression of HLA class II antigens can lead to CD4⁺-T lymphocyte alloactivation and selective expansion of pro-inflammatory Th17 and pro-tolerance Treg subsets. This response can be modified and preactivation of the EC by HLA-DR antibody binding promoted a proinflammatory Th17 response. However, whether or not immunosuppressors alter EC immunogenicity has not been examined. In alloimmunized patients with AMR, cyclosporine A (CsA) and mycophenolic acid (MPA) are often combined with intravenous immunoglobulins (IVIgs). This study reports changes in the microvascular EC phenotype and function after treatment with CsA, MPA, or IVIg. Both CsA and MPA decreased HLA-DR and increased CD54 expression, whereas IVIg increased HLA-DR expression. Interleukin 6 secretion was reduced by all three immunomodulators. Preincubation of ECs with CsA or MPA limited, while IVIg amplified, Treg expansion. Because CsA, MPA, and IVIg are known for their ability to act upon leukocytes, we confirmed that ECs maintained their immunoregulatory role when allogeneic leukocytes were pretreated with CsA, MPA, or IVIg. The results reveal that individual immunosuppressors, used in the induction and maintenance of renal allograft tolerance, had direct and distinct effects on ECs. Results of experiments associating IVIg with either CsA or MPA underlined the differences observed using individual immunosuppressors. Paradoxically, CsA or MPA may increase EC mediated inflammatory responses and long-term exposure may contribute to limitation of allograft tolerance. In contrast, IVIg interaction with the endothelium may mediate some of its immunosuppressive effects through promotion of Treg expansion, contributing to the maintenance of allograft tolerance.

Commercial Intravenous Immunoglobulin Preparations Contain Functional Neutralizing Antibodies against the Staphylococcus aureus Leukocidin LukAB (LukGH)

The pathogenesis of Staphylococcus aureus is mediated by an array of important virulence factors, including the two-component leukocidin family of toxins. LukAB (also known as LukGH), the most recently discovered leukocidin, is potently lethal to phagocytes, produced during invasive human disease, and present in all known clinical isolates of S. aureus Intravenous immunoglobulin (IVIg) is often used clinically in severe S. aureus infections. The primary aim of this study was to assess the binding and neutralization potential of IVIg against LukAB. A secondary aim was to examine the lot-to-lot variability of IVIg in the binding and neutralization of LukAB. We studied 24 distinct lots of IVIg and compared them to serum from children with invasive S. aureus infection (in the acute and convalescent phases) and from healthy, uninfected controls. We found that all lots of IVIg contained functional antibodies targeting LukAB. After adjusting for total antibody content per sample, we found that the amount of anti-LukAB antibody in IVIg was similar to that seen with healthy controls and less than that seen with patients with invasive S. aureus infection. IVIg samples had lower neutralization capacity than samples from healthy controls and children with invasive infection. IVIg had remarkably little lot-to-lot variation in LukAB binding but had significantly more variation in toxin neutralization. These results represent the first report of functional antibodies against the important S. aureus leukocidin LukAB in IVIg. Given the frequent clinical use of IVIg for severe S. aureus infections, improving our understanding of functional antibody properties exhibited by this therapeutic is essential.

Therapeutic Potential of Intravenous Immunoglobulin in Acute Brain Injury

Acute ischemic and traumatic injury of the central nervous system (CNS) is known to induce a cascade of inflammatory events that lead to secondary tissue damage. In particular, the sterile inflammatory response in stroke has been intensively investigated in the last decade, and numerous experimental studies demonstrated the neuroprotective potential of a targeted modulation of the immune system. Among the investigated immunomodulatory agents, intravenous immunoglobulin (IVIg) stand out due to their beneficial therapeutic potential in experimental stroke as well as several other experimental models of acute brain injuries, which are characterized by a rapidly evolving sterile inflammatory response, e.g., trauma, subarachnoid hemorrhage. IVIg are therapeutic preparations of polyclonal immunoglobulin G, extracted from the plasma of thousands of donors. In clinical practice, IVIg are the treatment of choice for diverse autoimmune diseases and various mechanisms of action have been proposed. Only recently, several experimental studies implicated a therapeutic potential of IVIg even in models of acute CNS injury, and suggested that the immune system as well as neuronal cells can directly be targeted by IVIg. This review gives further insight into the role of secondary inflammation in acute brain injury with an emphasis on stroke and investigates the therapeutic potential of IVIg.

CD8+ T Cells Contribute to the Development of Coronary Arteritis in the Lactobacillus casei Cell Wall Extract-Induced Murine Model of Kawasaki Disease

OBJECTIVE

Kawasaki disease (KD) is the leading cause of acquired heart disease among children in developed countries. Coronary lesions in KD in humans are characterized by an increased presence of infiltrating CD3+ T cells; however, the specific contributions of the different T cell subpopulations in coronary arteritis development remain unknown. Therefore, we sought to investigate the function of CD4+ and CD8+ T cells, Treg cells, and natural killer (NK) T cells in the pathogenesis of KD.

METHODS

We addressed the function of T cell subsets in KD development by using a well-established murine model of Lactobacillus casei cell wall extract (LCWE)-induced KD vasculitis. We determined which T cell subsets were required for development of KD vasculitis by using several knockout murine strains and depleting monoclonal antibodies.

RESULTS

LCWE-injected mice developed coronary lesions characterized by the presence of inflammatory cell infiltrates. Frequently, this chronic inflammation resulted in complete occlusion of the coronary arteries due to luminal myofibroblast proliferation (LMP) as well as the development of coronary arteritis and aortitis. We found that CD8+ T cells, but not CD4+ T cells, NK T cells, or Treg cells, were required for development of KD vasculitis.

CONCLUSION

The LCWE-induced murine model of KD vasculitis mimics many histologic features of the disease in humans, such as the presence of CD8+ T cells and LMP in coronary artery lesions as well as epicardial coronary arteritis. Moreover, CD8+ T cells functionally contribute to the development of KD vasculitis in this murine model. Therapeutic strategies targeting infiltrating CD8+ T cells might be useful in the management of KD in humans.

Self-administered hyaluronidase-facilitated subcutaneous immunoglobulin therapy in complicated primary antibody deficiencies

Hyaluronidase-facilitated subcutaneous immunoglobulin (fSCIg) is a new immunoglobulin product for replacement therapy in patients with primary antibody deficiencies (PAD). The pre-administration of recombinant human hyaluronidase associated with 10% immunoglobulin allowed the infusion of larger (up to 600 ml) amounts of immunoglobulin at a single infusion site, enabling patients to receive the necessary treatment in a single monthly dose. Here, we report the effectiveness and the tolerability of fSCIg in patients with severe PAD-related comorbidities: refractory autoimmune thrombocytopenia; systemic granulomatous disease; severe enteropathy, and Type I diabetes. We conclude that fSCIg could be a feasible option to improve the adherence to replacement therapy also by patients with severe PAD.

Transforming growth factor β1 (TGFβ1)-induced CD44V6-NOX4 signaling in pathogenesis of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive clinical syndrome of fatal outcome. The lack of information about the signaling pathways that sustain fibrosis and the myofibroblast phenotype has prevented the development of targeted therapies for IPF. Our previous study showed that isolated fibrogenic lung fibroblasts have high endogenous levels of the hyaluronan receptor, CD44V6 (CD44 variant containing exon 6), which enhances the TGFβ1 autocrine signaling and induces fibroblasts to transdifferentiate into myofibroblasts. NADPH oxidase 4 (NOX4) enzyme, which catalyzes the reduction of O₂ to hydrogen peroxide (H₂O₂), has been implicated in the cardiac and lung myofibroblast phenotype. However, whether CD44V6 regulates NOX4 to mediate tissue repair and fibrogenesis is not well-defined. The present study assessed the mechanism of how TGF-β-1-induced CD44V6 regulates the NOX4/reactive oxygen species (ROS) signaling that mediates the myofibroblast differentiation. Specifically, we found that NOX4/ROS regulates hyaluronan synthesis and the transcription of CD44V6 via an effect upon AP-1 activity. Further, CD44V6 is part of a positive-feedback loop with TGFβ1/TGFβRI signaling that acts to increase NOX4/ROS production, which is required for myofibroblast differentiation, myofibroblast differentiation, myofibroblast extracellular matrix production, myofibroblast invasion, and myofibroblast contractility. Both NOX4 and CD44v6 are up-regulated in the lungs of mice subjected to experimental lung injury and in cases of human IPF. Genetic (CD44v6 shRNA) or a small molecule inhibitor (CD44v6 peptide) targeting of CD44v6 abrogates fibrogenesis in murine models of lung injury. These studies support a function for CD44V6 in lung fibrosis and offer proof of concept for therapeutic targeting of CD44V6 in lung fibrosis disorders.

Regulatory T cell frequency, but not plasma IL-33 levels, represents potential immunological biomarker to predict clinical response to intravenous immunoglobulin therapy

Background

Intravenous immunoglobulin (IVIG) is a polyspecific pooled immunoglobulin G preparation and one of the commonly used therapeutics for autoimmune diseases including those of neurological origin. A recent report in murine model proposed that IVIG expands regulatory T (T_reg) cells via induction of interleukin 33 (IL-33). However, translational insight on these observations is lacking.

Methods

Ten newly diagnosed Guillain-Barré syndrome (GBS) patients were treated with IVIG at the rate of 0.4 g/kg for three to five consecutive days. Clinical evaluation for muscular weakness was performed by Medical Research Council (MRC) and modified Rankin scoring (MRS) system. Heparinized blood samples were collected before and 1, 2, and 4–5 weeks post-IVIG therapy. Peripheral blood mononuclear cells were stained for surface CD4 and intracellular Foxp3, IFN-γ, and tumor necrosis factor alpha (TNF-α) and were analyzed by flow cytometry. IL-33 and prostaglandin E2 in the plasma were measured by ELISA.

Results

The fold changes in plasma IL-33 at week 1 showed no correlation with the MRC and MRS scores at weeks 1, 2, and ≥4 post-IVIG therapy. Clinical recovery following IVIG therapy appears to be associated with T_reg cell response. Contrary to murine study, there was no association between the fold changes in IL-33 at week 1 and T_reg cell frequency at weeks 1, 2, and ≥4 post-IVIG therapy. T_reg cell-mediated clinical response to IVIG therapy in GBS patients was associated with reciprocal regulation of effector T cells-expressing TNF-α.

Conclusion

T_reg cell expansion by IVIG in patients with autoimmune diseases lack correlation with IL-33. T_reg cell frequency, but not plasma IL-33 levels, represents potential immunological biomarker to predict clinical response to IVIG therapy.

Predisposing factors, pathogenesis and therapeutic intervention of Kawasaki disease

Kawasaki disease (KD) is an acute febrile childhood inflammatory disease, associated with coronary artery abnormalities. The disease is believed to result from an aberrant inflammatory response to an infectious trigger in a genetically predisposed individual. KD is associated with an endothelial cell injury as a consequence of T cell activation and cytotoxic effects of various proinflammatory cytokines. Intravenous immunoglobulin (IVIG) infusion and aspirin are the standard treatment of acute KD. However, 10-20% of patients show resistance to IVIG therapy and present higher risk of coronary vasculitis. The relative roles of second IVIG infusion, corticosteroids, calcineurin inhibitors, interleukin-1 antagonists and anti-tumor necrosis factor agents remain uncertain. In this review, we highlight the predisposing factors, pathogenesis and therapeutic intervention of KD, particularly new therapeutics for IVIG-resistant patients.

Aβ-Immunotherapeutic strategies: a wide range of approaches for Alzheimer's disease treatment

Current therapies to treat Alzheimer's disease (AD) are focused on ameliorating symptoms instead of treating the underlying causes of AD. The accumulation of amyloid β (Aβ) oligomers, whether by an increase in production or by a decrease in clearance, has been described as the seed that initiates the pathological cascade in AD. Developing therapies to target these species is a vital step in improving AD treatment. Aβ-immunotherapy, especially passive immunotherapy, is a promising approach to reduce the Aβ burden. Up to now, several monoclonal antibodies (mAbs) have been tested in clinical trials on humans, but none of them have passed Phase III. In all likelihood, these trials failed mainly because patients with mild-to-moderate AD were recruited, and thus treatment may have been too late to be effective. Therefore, many ongoing clinical trials are being conducted in patients at the prodromal stage. New structures based on antibody fragments have been engineered intending to improve efficacy and safety. This review presents the properties of this variety of developing treatments and provides a perspective on state-of-the-art of passive Aβ-immunotherapy in AD.