Immunomodulation of autoimmune and inflammatory diseases with intravenous immunoglobulin

Protecting children and adults with primary antibody deficiencies against common and emergent pathogens and non-infectious complications

Prevention and treatment of infections are primary goals of treatment of children and adults with primary immune deficiencies due to decreased antibody production. Approaches to these goals include immunoglobulin replacement therapy, vaccination, and prophylactic treatment with antimicrobials. In this review, the infectious and non-infectious complications of antibody deficiencies will be discussed along with the limited number of studies that support the effective use of the available therapies and to drive the development of new therapies. Some illustrative case studies will be presented and the outlook for additional controlled clinical trials and potential for therapies driven by the underlying disease genetics will be considered.

Intravenous immunoglobulins improve skin fibrosis in experimental models of systemic sclerosis

Systemic sclerosis (SSc) is the most severe systemic autoimmune disease with currently no cure. Intravenous immunoglobulins (IVIg) are an attractive candidate in this disease to counteract inflammation and fibrosis but data are scarce and conflicting. This study, assessed the effects of IVIg in a murine HOCl-induced model of SSc. We showed that IVIg prevented skin inflammation and fibrosis, by mitigating the immune cell infiltration (p = 0.04), proinflammatory cytokines gene overexpression (IL1β, p = 0.04; TNFα, p = 0.04; IL6, p = 0.05), skin and dermal thickening (p = 0.003 at d21 and p = 0.0003 at d42), the expression markers of fibrosis, such as αSMA (p = 0.031 for mRNA and p = 0.05 for protein), collagen (p = 0.05 for mRNA and p = 0.04 for protein, p = 0.05 for the hydroxyproline content) and fibronectin (p = 0.033 for mRNA). Moreover, IVIg prevented HOCl-induced alterations in splenic cell homeostasis. When administered in curative mode, despite their ability to reduce skin and dermal thickness (p < 0.0001 and p = 0.0002), IVIg showed partial or more mixed effects on skin inflammation and established fibrosis. These data favor further clinical trials in SSc patients on the potential efficiency of early and/or repeated IVIg administration.

The Effect of a Combined Ganciclovir, Methylprednisolone, and Immunoglobulin Regimen on Survival and Functional Outcomes in Patients With Japanese Encephalitis

Objective: There is currently no effective treatment for Japanese encephalitis, which has a high rate of morbidity and mortality. This study assessed the effectiveness of a ganciclovir, methylprednisolone, and immunoglobulin combination (TAGMIC) therapy in decreasing cognitive impairment and mortality among patients with Japanese encephalitis.

Methods: We retrospectively assessed the clinical data of 31 patients diagnosed with Japanese encephalitis, who were admitted to an intensive care unit. Patients were divided into the TAGMIC and non-TAGMIC group according to their treatment regime. We compared the 60-day, 6-month, and overall mortality and survival curves between groups. We also compared Barthel Index scores, Montreal Cognitive Assessment (MoCA) scores, and diffusion tensor imaging (DTI) results.

Results: There was no significant difference in the 30-day mortality rate or Kaplan–Meier survival curve between groups. The 60-day, 6-month, and overall mortality rates in the TAGMIC group were significantly reduced (P = 0.043, P = 0.018, and P = 0.018, respectively) compared with the non-TAGMIC group (0, 0, 0 vs. 31.25, 37.5, 37.5%, respectively). The 60-day, 6-month, and overall Kaplan–Meier survival curves were significantly different between groups (P = 0.020, P = 0.009, P = 0.009, respectively). There was no significant difference in the Barthel Index scores of surviving patients. Among the five patients who underwent MoCA and DTI, four had a score of 0/5 for delayed recall (no cue), while the remaining patient had a score of 2/5. All five patients were able to achieve a score of 5/5 with classification and multiple-choice prompts, and had sparse or broken corpus callosum (or other) fibre bundles.

Conclusion: TAGMIC treatment can reduce mortality due to severe Japanese encephalitis. The memory loss of surviving patients is mainly due to a disorder of the memory retrieval process, which may be related to the breakage of related fibre bundles.

ABO incompatibility in renal transplantation

ABO blood group incompatibility (ABO-I) was historically considered an absolute contraindication to kidney transplantation due to the significant risk of acute antibody-mediated rejection and early graft loss. Nevertheless, the urge to minimize the gap between the candidates’ number on the waitlist for kidney transplants and the available kidney donors encourage investigation into finding ways to use organs from ABO-I kidney donors, especially in the era of using more potent immunosuppression therapies. This review aims to discuss a general overview of ABO-I kidney transplantation and the different protocols adopted by some transplant centers to meaningfully overcome this barrier.

Open MHC Class I Conformers: A Look through the Looking Glass

Studies carried out during the last few decades have consistently shown that cell surface MHC class I (MHC-I) molecules are endowed with functions unrelated with antigen presentation. These include cis–trans-interactions with inhibitory and activating KIR and LILR, and cis-interactions with receptors for hormones, growth factors, cytokines, and neurotransmitters. The mounting body of evidence indicates that these non-immunological MHC-I functions impact clinical and biomedical settings, including autoimmune responses, tumor escape, transplantation, and neuronal development. Notably, most of these functions appear to rely on the presence in hematopoietic and non-hematopoietic cells of heavy chains not associated with β2m and the peptide at the plasma membrane; these are known as open MHC-I conformers. Nowadays, open conformers are viewed as functional cis-trans structures capable of establishing physical associations with themselves, with other surface receptors, and being shed into the extracellular milieu. We review past and recent developments, strengthening the view that open conformers are multifunctional structures capable of fine-tuning cell signaling, growth, differentiation, and cell communication.

IVIG ameliorate inflammation in collagen-induced arthritis: projection for IVIG therapy in rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic inflammatory autoimmune disease that leads to joint destruction and disability. Despite a significant progress in administration of biological agents for RA patients, there is still a need for improved therapy. Intravenous immunoglobulins (IVIG), a pooled polyspecific immunoglobulin (Ig)G extracted from 5000 to 20 000 healthy subjects, showed beneficial therapeutic effect in patients with immune deficiency, sepsis and autoimmune diseases. The current study aimed to investigate the beneficial effect of treatment with IVIG in established collagen-induced arthritis in DBA/1j mice. Murine arthritis was induced in DBA/1j mice. Treatment with IVIG began when the disease was established. The clinical score was followed twice a week until day 48. The mice were bled for plasma and the paws were hematoxylin and eosin (H&E)-stained. Cytokine profile in the plasma was analyzed by Luminex technology and titers of circulating anti-collagen antibodies in the plasma was tested by enzyme-linked immunosorbent assay. Our results show that treatment with IVIG in murine significantly reduced the clinical arthritis score (P < 0·001). Moreover, mode of action showed that IVIG significantly reduced circulating levels of inflammatory cytokines [interferon (IFN)-γ, interleukin (IL)-1β, IL-17, IL-6, tumor necrosis factor (TNF)-α, P < 0·001], inhibiting anti-collagen antibodies (P < 0·001) in the plasma of collagen-induced arthritis mice. Importantly, histopathological examination revealed that IVIG treatment prevented the migration of inflammatory immune cells into the cartilage and synovium, reduced the extent of joint damage and preserved joint architecture. Our results proved for the first time the valuable anti-inflammatory treatment of IVIG in experimental RA. We propose IVIG therapy for a subgroup of patients with rheumatologically related diseases.

Nanomaterials-Mediated Immunomodulation for Cancer Therapeutics

Immunotherapy holds great promise in overcoming the limitations of conventional regimens for cancer therapeutics. There is growing interest among researchers and clinicians to develop novel immune-strategies for cancer diagnosis and treatment with better specificity and lesser adversity. Immunomodulation-based cancer therapies are rapidly emerging as an alternative approach that employs the host's own defense mechanisms to recognize and selectively eliminate cancerous cells. Recent advances in nanotechnology have pioneered a revolution in the field of cancer therapy. Several nanomaterials (NMs) have been utilized to surmount the challenges of conventional anti-cancer treatments like cytotoxic chemotherapy, radiation, and surgery. NMs offer a plethora of exceptional features such as a large surface area to volume ratio, effective loading, and controlled release of active drugs, tunable dimensions, and high stability. Moreover, they also possess the inherent property of interacting with living cells and altering the immune responses. However, the interaction between NMs and the immune system can give rise to unanticipated adverse reactions such as inflammation, necrosis, and hypersensitivity. Therefore, to ensure a successful and safe clinical application of immunomodulatory nanomaterials, it is imperative to acquire in-depth knowledge and a clear understanding of the complex nature of the interactions between NMs and the immune system. This review is aimed at providing an overview of the recent developments, achievements, and challenges in the application of immunomodulatory nanomaterials (iNMs) for cancer therapeutics with a focus on elucidating the mechanisms involved in the interplay between NMs and the host's immune system.

Intravenous Immunoglobulins at the Crossroad of Autoimmunity and Viral Infections

Intravenous immunoglobulins (IVIG) are blood preparations pooled from the plasma of donors that have been first employed as replacement therapy in immunodeficiency. IVIG interact at multiple levels with the different components of the immune system and exert their activity against infections. Passive immunotherapy includes convalescent plasma from subjects who have recovered from infection, hyperimmune globulin formulations with a high titer of neutralizing antibodies, and monoclonal antibodies (mAbs). IVIG are used for the prevention and treatment of several infections, especially in immunocompromised patients, or in case of a poorly responsive immune system. The evolution of IVIG from a source of passive immunity to a powerful immunomodulatory/anti-inflammatory agent results in extensive applications in autoimmune diseases. IVIG composition depends on the antibodies of the donor population and the alterations of protein structure due to the processing of plasma. The anti-viral and anti-inflammatory activity of IVIG has led us to think that they may represent a useful therapeutic tool even in COVID-19. The human origin of IVIG carries specific criticalities including risks of blood products, supply, and elevated costs. IVIG can be useful in critically ill patients, as well as early empirical treatment. To date, the need for further well-designed studies stating protocols and the efficacy/tolerability profile of IVIG and convalescent plasma in selected situations are awaited.

ABO-incompatible living kidney transplantation

ABO-incompatible living kidney transplantation is nowadays a routine procedure to expand living donor pool. The past decades have seen the evolution of desensitization protocol and immunosuppression regimen. Despite increased bleeding events, infectious complications, and rejection episodes reported in some studies, favorable graft and patient survival rate are now achieved, regardless of various protocols among transplant centers. Several issues such as the usage of rituximab and standardization of blood group antibody titration remain to be settled. The deposition of C4d is no longer the histopathologic hallmark of antibody-mediated rejection, which have inspired innovative strategies of peripheral molecular screening and the improvement of histological diagnosis of AMR (antibody-mediated rejection). The better understanding of the underlying mechanism might facilitate the distinction and therapeutic schemes of AMR.

Latest insights on ABO-incompatible living-donor renal transplantation

This review summarizes the latest insights on ABO‐incompatible living‐donor renal transplantation. Desensitization protocols and clinical outcomes were investigated, and a comparison was made with kidney‐paired donation, which is not permitted in Japan for ethical reasons. Although renal transplantation is greatly beneficial for most patients with end‐stage kidney disease, many of these patients must remain on dialysis therapy for extended periods due to the scarcity of organs from deceased donors. ABO blood type incompatibility was once believed to be a contraindication to renal transplantation due to the increased risk for antibody‐mediated rejection and early graft loss attributable to isoagglutinins. Recently, pretransplant desensitization strategies, such as removal of isoagglutinins and antibody‐producing cells, have achieved successful outcomes, although it remains unclear whether graft survival and patient morbidity are equivalent to those for ABO‐compatible renal transplantation. The present review suggested that ABO‐incompatible living‐donor renal transplantation might be a favorable radical renal replacement therapy for patients with end‐stage kidney disease.

Predictors of Intravenous Immunoglobulin Nonresponse and Racial Disparities in Kawasaki Disease

BACKGROUND

Kawasaki disease (KD) is the most common cause of acquired heart disease in American children. Intravenous immunoglobulin (IVIG) nonresponse is a known risk factor for cardiac sequelae. Previously reported risk factors for nonresponse include age, male sex and laboratory abnormalities. We set out to identify additional risk factors for IVIG nonresponse in a racially diverse KD population.

METHODS

We conducted a retrospective chart review at a referral center in the Southeastern United States of children meeting ICD-9 (International Statistical Classification of Disease and Related Health Problems) criteria for KD and being treated with IVIG.

RESULTS

Four-hundred and fifty-nine children met inclusion criteria, 67 were excluded for subsequent rheumatologic diagnosis, unknown race, or failure to meet the American Heart Association guideline criteria. Our final cohort consisted of 392 subjects, with median age of 2.7 years, 65.1% male, 66.1% White, 24.2% Black, 4.9% Asian and 82.9% responded to a single dose of IVIG. Coronary ectasia or aneurysm developed in 27%; 7.4% developed aneurysms and 2.3% giant coronary aneurysms. Nonresponders were more likely to be Black, have higher white blood cell, erythrocyte sedimentation rate and C-reactive protein, lower hemoglobin, develop ectasia or aneurysm and require critical care and hospital readmission. Responders achieved echocardiographic normalization more often compared with nonresponders (81.3% vs. 60.9%, P = 0.002) and coronary artery pseudonormalization (87.2% vs. 69.7%, P = 0.03) at 1 year. Black nonresponders had the slowest normalization at 1 year (52.9%, P = 0.02).

CONCLUSIONS

Nonresponders have higher rates and greater severity of coronary involvement than responders. Our study uniquely demonstrates Black race as a risk factor for nonresponse and for delayed normalization of cardiac involvement at 1-year follow-up.

Long-Term Follow-Up after Intravenous Immunoglobulin Therapy in Patients with Severe Ocular Mucous Membrane Pemphigoid Unresponsive to Conventional Therapy

Mucous membrane pemphigoid (MMP) is a heterogeneous group of rare, systemic, autoimmune subepidermal inflammatory disease that affects mucous membranes and the eye. In its most severe forms, this disease needs systemic therapy, usually based on steroids and immunosuppressant agents. In unresponsive cases or in the presence of contraindications or severe side effects due to conventional systemic corticosteroid and/or immunosuppressant therapy, a therapy shift to high-dose intravenous immunoglobulins (IVIg) has been recommended in other reports. This new therapy has proven to be effective in stopping ocular pemphigoid, but the data regarding the long-term effect on the disease activity or reactivation are extremely scarce, so the novel scientific aim of this study was to evaluate the clinical outcomes after a 9-year follow-up in 12 eyes (6 patients) affected by MMP with ocular involvement, successfully treated with IVIg therapy, as previously described in our report published in 2008. The evaluation of ocular and extraocular disease progression was performed at the end of IVIg therapy and at the end of the follow-up period. After 9 years, all the eyes enrolled showed a long-lasting remission of ocular and oral symptoms with a significant steroid-sparing effect. In conclusion, the IVIg has to be considered as a safe and successful alternative therapy in patients with severe ocular mucous membrane pemphigoid; furthermore, this kind of therapy seems to be effective in maintaining the clinical remission by the time.

The risk of hospitalization for respiratory tract infection (RTI) in children who are treated with high-dose IVIG in Kawasaki Disease: a nationwide population-based matched cohort study

Background

Kawasaki disease (KD) is an immune-mediated systemic vasculitis, and infection plays an important role in the pathophysiology of KD. The susceptibility to infectious disease in patients with KD remains largely unclear. This study aimed to investigate the risk of respiratory tract infection (RTI)-related hospitalizations in children with KD.

Methods

Data from the Taiwanese National Health Insurance Research Database was analyzed. We excluded patients with history of congenital abnormality, allergic diseases, or hospitalization history. Children with KD were selected as KD group and age- and sex-matched non-KD patients were selected as control group with 1:4 ratio. Both cohorts were tracked for one year to investigate the incidences of RTI-related hospitalizations. Cox regression hazard model was used to adjust for confounding factors and calculate the adjusted hazard ratio (aHR).

Results

Between January 1996 and December 2012, 4,973 patients with KD were identified as the KD group and 19,683 patients were enrolled as the control group. An obviously reduced risk of RTI-related hospitalizations was observed in KD patients (aHR: 0.75, 95% CI [0.66-0.85]). The decreased risk persisted through the first six-months follow-up period with a peak protection in 3-6 months (aHR: 0.49, 95% CI [0.37-0.64]).

Conclusions

KD patients had approximately half reduction of risk for RTI-related hospitalizations. The protective effects persisted for at least six months. Further studies are warranted to elucidate the entire mechanism and investigate the influences of intravenous immunoglobulin.

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.

Immune Gamma Globulin Therapeutic Indications in Immune Deficiency and Autoimmunity

Immune gamma globulin (IgG) has a long history in the treatment of both primary immune deficiency and autoimmune disorders. Disease indications continue to expand and new-generation products increase the versatility of delivery. This review encompasses a historical perspective as well as current and future implications of human immune globulin for the treatment of immune-mediated illness.

Immunomodulation of inflammatory leukocyte markers during intravenous immunoglobulin treatment associated with clinical efficacy in chronic inflammatory demyelinating polyradiculoneuropathy

OBJECTIVE

The objective of the study was to profile leukocyte markers modulated during intravenous immunoglobulin (IVIg) treatment, and to identify markers and immune pathways associated with clinical efficacy of IVIg for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with potential for monitoring treatment efficacy.

METHODS

Response to IVIg treatment in newly diagnosed IVIg-naïve and established IVIg-experienced patients was assessed by changes in expression of inflammatory leukocyte markers by flow cytometry. The adjusted INCAT disability and Medical Research Council sum scores defined clinical response.

RESULTS

Intravenous immunoglobulin modulated immunopathogenic pathways associated with inflammatory disease in CIDP. Leukocyte markers of clinical efficacy included reduced CD185⁺ follicular helper T cells, increased regulatory markers (CD23 and CD72) on B cells, and reduction in the circulating inflammatory CD16⁺ myeloid dendritic cell (mDC) population and concomitant increase in CD62L and CD195 defining a less inflammatory lymphoid homing mDC phenotype. A decline in inflammatory CD16⁺ dendritic cells was associated with clinical improvement or stability, and correlated with magnitude of improvement in neurological assessment scores, but did not predict relapse. IVIg also induced a nonspecific improvement in regulatory and reduced inflammatory markers not associated with clinical response.

CONCLUSIONS

Clinically effective IVIg modulated inflammatory and regulatory pathways associated with ongoing control or resolution of CIDP disease. Some of these markers have potential for monitoring outcome.

IVIg attenuates complement and improves spinal cord injury outcomes in mice

Objective

Traumatic spinal cord injury (SCI) elicits immediate neural cell death, axonal damage, and disruption of the blood–spinal cord barrier, allowing circulating immune cells and blood proteins into the spinal parenchyma. The inflammatory response to SCI involves robust complement system activation, which contributes to secondary injury and impairs neurological recovery. This study aimed to determine whether intravenous immunoglobulin (IVIg), an FDA‐approved treatment for inflammatory conditions, can scavenge complement activation products and improve recovery from contusive SCI.

Methods

We used functional testing, noninvasive imaging, and detailed postmortem analysis to assess whether IVIg therapy is effective in a mouse model of severe contusive SCI.

Results

IVIg therapy at doses of 0.5–2 g/kg improved the functional and histopathological outcomes from SCI, conferring protection against lesion enlargement, demyelination, central canal dilation, and axonal degeneration. The benefits of IVIg were detectable through noninvasive diffusion tensor imaging (DTI), with IVIg treatment counteracting the progressive SCI‐induced increase in radial diffusivity (RD) in white matter. Diffusion indices significantly correlated with the functional performance of individual mice and accurately predicted the degree of myelin preservation. Further experiments revealed that IVIg therapy reduced the presence of complement activation products and phagocytically active macrophages at the lesion site, providing insight as to its mechanisms of action.

Interpretation

Our findings highlight the potential of using IVIg as an immunomodulatory treatment for SCI, and the value of DTI to assess tissue damage and screen for the efficacy of candidate intervention strategies in preclinical models of SCI, both quantitatively and noninvasively.

Intravenous immunoglobulins (IVIG) in systemic sclerosis: a challenging yet promising future

The etiology and pathogenesis of systemic sclerosis are still largely unknown, but a variety of humoral and cellular autoimmune phenomena have been documented. In addition, the rarity of the disease, the broad spectrum of clinical manifestations, and the relevant risk of severe complications as well as the highly variable disease course render its management a major challenge. Some immunomodulatory agents have been used, but no single agent has given a convincing proof of effectiveness, and treatment has remained largely symptomatic through recent years. Novel therapies are currently being tested and may have the potential of modifying the disease process and overall clinical outcome. Efficacy of intravenous immunoglobulins (IVIG) in different regimens (1-2 g/kg of body weight, administered over 2-5 consecutive days) has been described in a limited number of trials and small case series, showing benefits in skin, articular, and lung interstitial disease symptoms. However, studies on IVIG in systemic sclerosis still remain few, and further randomized controlled trials should be undertaken to assess their clinical effectiveness or define the optimal dosage and times of administration.

Anti-citrullinated-protein-antibody-specific intravenous immunoglobulin attenuates collagen-induced arthritis in mice

Administration of intravenous immunoglobulin (IVIg) is a recognized safe and efficient immunomodulation therapy for many autoimmune diseases. Anti-idiotypic antibody binding to pathogenic autoantibodies was proposed as one of the mechanisms attributed to the protective activity of IVIg in autoimmunity. The aim of this study was to fractionate the anti-anti-citrullinated protein anti-idiotypic-antibodies (anti-ACPA) from an IVIg preparation and to test it as a treatment for collagen-induced arthritis in mice. IVIg was loaded onto an ACPA column. The eluted fraction was defined as ACPA-specific-IVIg (ACPA-sIVIg). Collagen-induced-arthritis (CIA) was induced in mice. Mice were treated weekly with ACPA-sIVIg, low-dose-IVIg, high-dose-IVIg and phosphate-buffered saline (PBS). Sera-ACPA titres, anti-collagen anitbodies and cytokine levels were analysed by enzyme-linked immunosorbent assay (ELISA); antibody-forming-cell activity by enzyme-linked imunospot (ELISPOT) assay; and expansion of regulatory T cell (Treg ) population by fluorescence activated cell sorter (FACS). ACPA-sIVIg inhibited ACPA binding to citrullinated-peptides (CCP) in vitro 100 times more efficiently than the IVIg compound. ACPA-sIVIg was significantly more effective than the IVIg-preparation in attenuating the development of collagen-induced arthritis. Splenocytes from CIA mice treated with ACPA-sIVIg reduced the ACPA and anti-collagen-antibody titres, including the number of anti-collagen and ACPA antibody-forming cells. In parallel, splenocytes from ACPA-sIVIg treated mice secreted higher levels of anti-inflammatory cytokines and lower proinflammatory cytokines. The ACPA-sIVIg inhibitory potential was accompanied with expansion of the Treg population. Low-dose IVIg did not affect the humoral and cellular response in the CIA mice in comparison to the PBS-treated mice. Based on our results, IVIg may be considered as a safe compound for treating patients with rheumatoid arthritis by neutralizing pathogenic autoantibodies, reducing proinflammatory cytokines and expanding the Treg population.

An update on ABO-incompatible kidney transplantation

ABO-incompatible kidney transplantation is nowadays a well-established procedure to expand living donor transplantation to blood group incompatible donor/recipient constellations. In the last two decades, transplantation protocols evolved to more specific isohaemagglutinin elimination techniques and established competent antirejection protection protocols without the need of splenectomy. ABOi kidney transplantation associated accommodation despite isohaemagglutinin reappearance, C4d positivity of peritubular capillaries as well as the increased incidence of bleeding complications is currently under intense investigation. However, most recent data show excellent graft survival rates equivalent to ABO-compatible kidney transplantation outcome.

Novel NLRP12 mutations associated with intestinal amyloidosis in a patient diagnosed with common variable immunodeficiency

Heterozygous mutations in the NLRP12 gene have been found in patients with systemic auto-inflammatory diseases. However, the NLRP12-associated periodic fever syndromes show a wide clinical spectrum, including patients without classical diagnostic symptoms. Here, we report on a 20-year-old female patient diagnosed with common variable immunodeficiency (CVID), who developed intestinal amyloidosis and carried novel compound heterozygous mutations in NLRP12, identified by whole exome and transcriptome sequencing. CVID is a primary immunodeficiency characterized by low serum immunoglobulins, recurrent bacterial infections and development of malignancy, but it also presents with a magnitude of autoimmune features. Because of the unspecific heterogeneous clinical features of the disease, a delay in diagnosis is common. Secondary, inflammatory (AA type) amyloidosis has infrequently been observed in CVID patients. Based on our case observation and a critical review of the literature, we suggest that NLRP12 mutations might account for a small fraction of CVID patients with severe auto-inflammatory complications.

Development, manufacturing and characterization of a highly purified, liquid immunoglobulin g preparation from human plasma

BACKGROUND

The use of plasma-derived immunoglobulin G (IgG) is increasing, and the number of diseases, including immunodeficiencies, neurological diseases and autoimmune conditions, treated with intravenous IgG (IVIG) is expanding. Consequently, there is a great need for high-yield production processes for plasma-derived IgG. The aim of this work was to develop a high-yield process leading to a highly purified, liquid, ready-to-use IgG for intravenous use.

METHODS

Plasma from healthy, voluntary, non-remunerated donors was fractionated by ethanol precipitation. IgG was extracted from fraction II + III using a phosphate/acetate buffer, pH 4, and purified by chromatography.

RESULTS

Precipitation with 6% polyethylene glycol at pH 7 removed high molecular-weight contaminating proteins, aggregates and contaminating viruses. Ion exchange chromatography at pH 5.7 on serially connected anion and cation exchange columns allowed for elution of IgG from the cation exchange column in good yield and high purity. Further safety was achieved by solvent/detergent treatment and repeated ion exchange chromatography. The product consisted of essentially only IgG monomers and dimers, and had a high purity with very low levels of IgM and IgA.

CONCLUSION

A process providing highly purified IVIG in good yield was developed.

Beneficial effect of a multimerized immunoglobulin Fc in an animal model of inflammatory neuropathy (experimental autoimmune neuritis)

Intravenous immunoglobulin (IVIg) is one of the first-line therapies for inflammatory neuropathies. Clinical use of IVIg for these disorders is limited by expense and availability. Here, we investigated a synthetic product alternative to IVIg. The aim of this study was to test the therapeutic efficacy of a novel recombinant polyvalent murine IgG2a Fc compound (stradomer™) in experimental autoimmune neuritis (EAN). Seventy-four Lewis rats were immunized with myelin, randomized into three groups, and were treated with albumin, IVIg, or stradomer at 1% of IVIg dose. Rats were assessed clinically, electrophysiologically, and histologically. The clinical disease severity was evaluated by clinical grading and weight changes. The electrophysiological studies recorded motor conduction velocity (MCV), amplitudes, and latencies of the evoked compound muscle action potential (CMAP) and spinal somatosensory evoked potential. The treatment efficacy of the IVIg and stradomer groups was compared to the albumin (control) group. We demonstrate that stradomer has a similar therapeutic efficacy to human IVIg in EAN. Rats receiving stradomer or IVIg showed significantly lower clinical scores and less prominent weight loss compared with controls. A statistically significant improvement in both MCV and the amplitudes of distal and proximal evoked CMAP was observed in the stradomer and IVIg groups. Finally, treatment with both IVIg and stradomer resulted in statistically less inflammation and demyelinating changes in the sciatic nerve as evidenced by lower histological grade. These results reveal the potential of using fully recombinant multimerized immunoglobulin Fc instead of IVIg for treating inflammatory neuropathies.

Dose-related regulatory effect of intravenous immunoglobulin on dendritic cells-mediated immune response

CONTEXT

Intravenous immunoglobulin (IVIG) has been successfully applied in immune-related diseases of adults and neonates, such as human immunodeficiency virus (HIV) infection and systemic lupus erythematosus (SLE).

OBJECTIVE

This study aims to investigate the distinct impacts of IVIG on cultured dendritic cells (DCs) from newborn and healthy adult.

MATERIALS AND METHODS

Blood samples were collected from eight full-term newborns and eight healthy adult volunteers. DCs from cord blood and peripheral blood were both cultured in the RPMI 1640 medium containing 10% fetal calf serum, 50 ng/ml granulocyte/macrophage colony-stimulating factor (GM-CSF) and 10 ng/ml recombinant human interleukin-4 (rhIL-4) for 5 d with therapeutic IVIG (20 mg/ml) or physiological IVIG (10 mg/ml). Lipopolysaccharides (LPSs, 1 μg/ml) were added on the fifth day to induce the maturation of immature DCs. The phagocytosis of monocytes, expression of MR (mannose receptor), CD14, CD1a, CD80, CD83, CD86 and MHC II were examined by flow cytometry. The expression of IL-4 mRNA was detected by RT-PCR, while IFN-γ, IL-12 and IL-10 were analyzed by enzyme-linked immunosorbent assay (ELISA) commercial kits.

RESULTS

IVIG of therapeutic dose inhibited the phagocytosis, differentiation and maturation of DCs, whereas physiological dose exhibited an accelerated role in vitro, especially on DCs from neonates, but aroused different effects on cytokine secretion.

DISCUSSION AND CONCLUSION

The different responses are generally due to immature immune system of neonate, which has a limit capacity to maintain immunity homeostasis. Modulation of DCs phagocytosis, differentiation, maturation and cytokine secretion by IVIG is of potential relevance to its dosage and immune status of patients.

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.

The advantage of specific intravenous immunoglobulin (sIVIG) on regular IVIG: experience of the last decade

During the last decade it has been shown that some components of intravenous immunoglobulin (IVIG) are responsible for their broadly therapeutic application. Currently, such specific subfractions are defined as specific IVIG (sIVIG) and are affinity-purified from commercial IVIGs that target specific antigens/antibodies related to a specific autoimmune disease. A remarkable example of the therapeutic potential of sIVIG is the proven enhanced anti-inflammatory potency of sialylated and recombinant sialylated IVIG obtained from total IVIG. In other experimental models, it has also been demonstrated that sIVIG work in many other contrivances, such as revealing anti-idiotypic networks blocking pathogenic antibodies ameliorating disease activity. sIVIG has also been shown to exert its action by modulating specific receptors expressed on immune cells in both inflammatory and autoimmune diseases. Indeed, sIVIG has emerged as a novel approach to treat different immune-mediated conditions in a more accurate antigen-specific manner. Herein we review experimental evidence supporting sIVIG-efficacy in treating autoimmune diseases and inflammation.

Immunoglobulin: production, mechanisms of action and formulations

Human immunoglobulin (Ig) began to be applied in the clinical practice with the treatment of primary immunodeficiencies. Quickly, applications of Ig increased, as its anti-inflammatory and immunomodulatory functions were elucidated. Currently, Ig is the most commonly used blood product. Ig is obtained by processing plasma; methods, in particular, techniques to reduce plasma viral loads have been evolving over the years and include: pasteurization, solvent/ detergent treatment, caprylic acid treatment and nanofiltration. These methods contribute to increased safety and quality of blood products. The mechanisms of action of Ig not only involve the blockade of Fc receptors of phagocytes, but also control complement pathways, idiotype-anti-idiotype dimer formation, blockage of superantigen binding to T cells, inhibition of dendritic cells and stimulation of regulatory T cells (Tregs). There are several formulations of Ig available, each one with its own peculiar characteristics. In Brazil, there is stringent legislation regulating the quality of Ig. Only Ig products that completely fulfill the quality control criteria are released for use. These standards involve different tests from visual inspection to determination of anti-complementary activity. This paper will further review the history and current status of Ig, including its production and mechanisms of action. The formulations available in Brazil and also the criteria of quality control currently applied will be presented.

Platelets in inflammation and immune modulations: functions beyond hemostasis

Platelets play central roles for maintaining the homeostasis of the blood coagulation. As they are also involved in immune responses and host defenses, increasing evidences have suggested that platelets exert other roles beyond their well-recognized function in preventing bleeding. This review is focused on inflammation, allergy and immune modulations of platelets. Platelets conduct immunoregulation through secretion of functional mediators, interaction with various immune cells, endothelial cells and beneficial for the leukocyte infiltration to inflamed/allergic tissues. In these regulations, the leukocytes are influenced by and receiving the signals from platelets. In contrast, rare attentions were focused on platelet regulations by immune system. An intriguingly example in the intravenous immunoglobulin (IVIg) treatment is discussed, in which dendritic cells exert anti-inflammatory effect through platelets. This further suggests that coagulant and immune systems are tightly associated rather than separate entities. The cross-talks between these two systems implicate that platelet therapy may have application beyond thrombosis, and immune interventions may have potentials to treat thrombosis diseases.

Soluble immune complexes shift the TLR-induced cytokine production of distinct polarized human macrophage subsets towards IL-10

BACKGROUND

Costimulation of murine macrophages with immune complexes (ICs) and TLR ligands leads to alternative activation. Studies on human myeloid cells, however, indicate that ICs induce an increased pro-inflammatory cytokine production. This study aimed to clarify the effect of ICs on the pro- versus anti-inflammatory profile of human polarized macrophages.

MATERIALS AND METHODS

Monocytes isolated from peripheral blood of healthy donors were polarized for four days with IFN-γ, IL-4, IL-10, GM-CSF, M-CSF, or LPS, in the presence or absence of heat aggregated gamma-globulins (HAGGs). Phenotypic polarization markers were measured by flow cytometry. Polarized macrophages were stimulated with HAGGs or immobilized IgG alone or in combination with TLR ligands. TNF, IL-6, IL-10, IL-12, and IL-23 were measured by Luminex and/or RT-qPCR.

RESULTS

HAGGs did not modulate the phenotypic polarization and the cytokine production of macrophages. However, HAGGs significantly altered the TLR-induced cytokine production of all polarized macrophage subsets, with the exception of MΦ(IL-4). In particular, HAGGs consistently enhanced the TLR-induced IL-10 production in both classically and alternatively polarized macrophages (M1 and M2). The effect of HAGGs on TNF and IL-6 production was less pronounced and depended on the polarization status, while IL-23p19 and IL-12p35 expression was not affected. In contrast with HAGGs, immobilized IgG induced a strong upregulation of not only IL-10, but also TNF and IL-6.

CONCLUSION

HAGGs alone do not alter the phenotype and cytokine production of in vitro polarized human macrophages. In combination with TLR-ligands, however, HAGGs but not immobilized IgG shift the cytokine production of distinct macrophage subsets toward IL-10.

Involvement of Fc receptors in disorders of the central nervous system

Immunoglobulins are proteins with a highly variable antigen-binding domain and a constant region (Fc domain) that binds to a cell surface receptor (FcR). Activation of FcRs in immune cells (lymphocytes, macrophages, and mast cells) triggers effector responses including cytokine production, phagocytosis, and degranulation. In addition to their roles in normal responses to infection or tissue injury, and in immune-related diseases, FcRs are increasingly recognized for their involvement in neurological disorders. One or more FcRs are expressed in microglia, astrocytes, oligodendrocytes, and neurons. Aberrant activation of FcRs in such neural cells may contribute to the pathogenesis of major neurodegenerative conditions including Alzheimer's disease, Parkinson's disease, ischemic stroke, and multiple sclerosis. On the other hand, FcRs may play beneficial roles in counteracting pathological processes; for e.g., FcRs may facilitate removal of amyloid peptides from the brain and so protect against Alzheimer's disease. Knowledge of the functions of FcRs in the nervous system in health and disease is leading to novel preventative and therapeutic strategies for stroke, Alzheimer's disease, and other neurological disorders.

Changes of circulating antibody levels induced by ABO antibody adsorption for ABO-incompatible kidney transplantation

ABO-incompatible kidney transplantation using immunoadsorption to remove anti-A/B antibodies has become a successful clinical practice. Since the data on the specificity of the ABO columns are controversial, the present study assessed the efficiency and specificity of the ABO immunoadsorption, the effect on total immunoglobulins and antibodies previously induced by vaccination. Anti-A/B antibodies were measured by agglutination and ABO flow cytometry, total IgG/IgM, carbohydrate- and protein-specific antibodies by nephelometry and ELISA. The first immunoadsorption not only efficiently reduced donor-specific anti-A/B IgM (81%) and IgG (56%) but also reduced compatible anti-A/B IgM (59%) and IgG (34%). The measurements of antidonor A/B antibodies by direct agglutination (IgM) or flow cytometry better represented the effective antibody levels than the indirect agglutination test (IgG). The median reduction of total IgM and total IgG levels after a single immunoadsorption was 34% and 18%, respectively. Antibodies against pneumococcus and haemophilus polysaccharide antigens were significantly reduced, whereas antitetanus and antidiphtheria protein antibodies were not affected. Intravenous immunoglobulin administration restored the protective anticarbohydrate antibody levels. In summary, immunoadsorption efficiently removed antidonor A/B antibodies, but was not specific for A/B antigens. Anti-A/B antibody levels as determined by ABO flow cytometry are useful to establish the minimal number of immunoadsorptions needed for successful ABO-incompatible transplantation.

Advances in the understanding of the mechanism of action of IVIg

The IgG molecule is the main component of IVIg. Commercial preparations of IVIg are derived from a pool of donors and subsequently, IVIg products contain smaller amounts of IgA and IgM antibodies as well as Th2 cytokines and cytokine antagonists that may also contribute to therapeutic effects. Numerous targets for IVIg include: T-cells, cytokines, immune cell trafficking, B-cells, complement and Fc-receptors. IVIg has been demonstrated to inactivate auto-reactive T-cells by competing for and interrupting their interaction with antigen presenting cells. The balance of cytokines also appears to be restored by IVIg, with studies showing that IVIg contains antibodies and antagonists to pro-inflammatory cytokines. In addition, IVIg is thought to interfere with and prevent the passage of auto-immune T-cells into the blood-nerve barrier. The effects of exogenous antibodies on B-cells have been well studied; IVIg is thought to down-regulate antibody production by B-cells, interfere with B-cell proliferation via a blockade of cell surface receptors and prevent the activation of certain subtypes of B-cell. In addition, IVIg can affect innate immunity by interrupting the steps in the complement activation cascade and blocking Fc-receptor mediated activity, which results in down-regulation of macrophage activity. In conclusion, IVIg has numerous modes of action, which culminate in the down-regulation of the immune response; many of which may be relevant to neuromuscular disorders and immune neuropathies.

Autoantibodies to calcium channels in type 1 diabetes mediate autonomic dysfunction by different mechanisms in colon and bladder and are neutralized by antiidiotypic antibodies

Autoantibodies (Abs) directed against L-type voltage-gated calcium channels (VGCCs) have been shown to contribute to autonomic dysfunction of the gastrointestinal tract and bladder in patients with Type 1 diabetes mellitus (T1D). We used a passive transfer model to determine whether the functional activity of the Ab requires crosslinking of channels in colon and bladder and can be neutralized by intravenous immunoglobulin (IVIg). Mice were injected with mono- and divalent F(ab) fragments of patient IgG with anti-VGCC activity and tested for gut and bladder function using a colonic migrating motor complex (MMC) assay and bladder-filling cystometry. The ability of IVIg to neutralize anti-VGCC IgG-mediated autonomic dysfunction was investigated by injection of mice with an equimolar concentration of IVIg prior to T1D IgG injection, or by injection with T1D IgG passed over a sepharose 4B column coupled with F(ab')(2) from IVIg. Passive transfer of T1D IgG and its F(ab')(2) or F(ab) fragments reduced the amplitude of spontaneous colonic motility. In contrast, intact IgG and F(ab')(2,) but not F(ab), produced the urodynamics features of an overactive bladder. T1D IgG-mediated colonic and bladder dysfunction was neutralized in vivo by prior injection of animals with equimolar IVIg. Moreover, anti-VGCC activity was depleted by preabsorption of patient IgG on a IVIg F(ab')(2) column. The activity of anti-VGCC IgG is mediated by the antigen-binding site consistent with a true functional Ab. The pathogenic effect on the bladder requires crosslinking of the channel, whereas monovalent binding of Ab is sufficient for disruption of colon motility. The anti-VGCC Abs are neutralized by antiidiotypic antibodies present in IVIg that may prevent the emergence of these Abs in healthy individuals.

Immune regulation by B cells and antibodies a view towards the clinic

B lymphocytes contribute to immunity in multiple ways, including production of antibodies, presentation of antigen to T cells, organogenesis of secondary lymphoid organs, and secretion of cytokines. Recent clinical trials have shown that depleting B cells can be highly beneficial for patients with autoimmune diseases, implicating B cells and antibodies as key drivers of pathology. However, it should be kept in mind that B cell responses and antibodies also have important regulatory roles in limiting autoimmune pathology. Here, we analyze clinical examples illustrating the potential of antibodies as treatment for immune-mediated disorders and discuss the underlying mechanisms. Furthermore, we examine the regulatory functions of activated B cells, their involvement in the termination of some experimental autoimmune diseases, and their use in cell-based therapy for such pathologies. These suppressive functions of B cells and antibodies do not only open new ways for harnessing autoimmune illnesses, but they also should be taken into account when designing new strategies for vaccination against microbes and tumors.

Antibody therapy (IVIG): evaluation of the use of genomics and proteomics for the study of immunomodulation therapeutics

BACKGROUND AND OBJECTIVES

Intravenous immunoglobulin (IVIG) is used for an increasingly diverse number of therapeutic applications as an immunomodulation drug. Although it has demonstrated therapeutic effectiveness, the mechanism of action of IVIG in these disorders is poorly understood; this lack of understanding complicates rational clinical application and reimbursement for 'off-label' use.

MATERIALS AND METHODS

Selected literature on the clinical use of IVIG as an immunomodulation drug is reviewed. We present a brief description of DNA microarray and protein microarray technology and the application of such technologies to the study of immune system cells. The several studies on the application of DNA microarray technology to study gene expression in response to IVIG are presented.

RESULTS

There is increasing data on the use of DNA microarray and protein microarray technology to study gene expression in immune system cells including T cells, B cells, macrophages, and leucocytes. There is less information on the effect of IVIG on gene expression in immune system cells. However, there is sufficient information available to suggest that this is a practical approach with the caveat that such work will require careful experimental design and clear definition of the normal population.

CONCLUSIONS

DNA and protein microarray assays can be used to (i) provide rational indications for the clinical use of IVIG, (ii) provide for specific analysis of raw material and end product IVIG in screening for content related to immunomodulation, and (iii) accelerate the development of next generation products which would be more focused and/or targeted therapeutics.

Proteomics of Blood-Based Therapeutics

Blood-based therapeutics are cellular or plasma components derived from human blood. Their production requires appropriate selection and treatment of the donor and processing of cells or plasma proteins. In contrast to clearly defined, chemically synthesized drugs, blood-derived therapeutics are highly complex mixtures of plasma proteins or even more complex cells. Pathogen transmission by the product as well as changes in the integrity of blood constituents resulting in loss of function or immune modulation are currently important issues in transfusion medicine. Protein modifications can occur during various steps of the production process, such as acquisition, enrichment of separate components (e.g. coagulation factors, cell populations), virus inactivation, conservation, and storage. Contemporary proteomic strategies allow a comprehensive assessment of protein modifications with high coverage, offer capabilities for qualitative and even quantitative analysis, and for high-throughput protein identification. Traditionally, proteomics approaches predominantly relied on two-dimensional gel electrophoresis (2-DE). Even if 2-DE is still state of the art, it has inherent limitations that are mainly based on the physicochemical properties of the proteins analyzed; for example, proteins with extremes in molecular mass and hydrophobicity (most membrane proteins) are difficult to assess by 2-DE. These limitations have fostered the development of mass spectrometry centered on non-gel-based separation approaches, which have proven to be highly successful and are thus complementing and even partially replacing 2-DE-based approaches. Although blood constituents have been extensively analyzed by proteomics, this technology has not been widely applied to assess or even improve blood-derived therapeutics, or to monitor the production processes. As proteomic technologies have the capacity to provide comprehensive information about changes occurring during processing and storage of blood products, proteomics can potentially guide improvement of pathogen inactivation procedures and engineering of stem cells, and may also allow a better understanding of factors influencing the immunogenicity of blood-derived therapeutics. An important development in proteomics is the reduction of inter-assay variability. This now allows the screening of samples taken from the same product over time or before and after processing. Optimized preparation procedures and storage conditions will reduce the risk of protein alterations, which in turn may contribute to better recovery, reduced exposure to allogeneic proteins, and increased transfusion safety.