Mechanisms of action of intravenous immune globulin in immune-mediated diseases

Intravenous Immunoglobulin in Kawasaki Disease-Evolution and Pathogenic Mechanisms

Kawasaki disease (KD) is an acute vasculitis of childhood that affects the medium vessels with a special predilection to the involvement of coronary arteries. The major morbidity of this disease is due to coronary artery aneurysm, which occurs in about 25-30% of untreated cases. For decades now, intravenous immunoglobulin (IVIg) has consistently been shown to reduce the risk of CAAs to less than 5%. However, the mechanism of immunomodulation remains unclear. Several studies on the role of IVIg in the modulation of toll-like receptor pathways, autophagy, and apoptosis of the mononuclear phagocytic system, neutrophil extracellular trap, and dendritic cell modulation suggest a modulatory effect on the innate immune system. Similarly, certain studies have shown its effect on T-cell differentiation, cytokine release, and regulatory T-cell function. In this review, we discuss the potential mechanisms underlying the immunomodulatory actions of IVIg in patients with Kawasaki disease. Furthermore, we provide a summary of the evidence regarding various infusion protocols and dosages utilized in the treatment of KD patients.

The effect of intravenous immunoglobulins on the outcomes of patients with COVID-19: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

Severe or critical COVID-19 has been associated with exaggerated immune responses and anti-inflammatory agents including corticosteroid and interleukin-6 antagonist have been repurposed as the treatment modality against severe SARS-CoV-2 infections. However, the clinical efficacy and safety of intravenous immunoglobulin (IVIG) in the treatment of patients with COVID-19 was controversial.

METHODS

This meta-analysis of randomized controlled trials (RCTs) investigated the effectiveness of IVIG in patients with COVID-19. Electronic databases were searched for RCTs that compared the clinical efficacy of IVIG with standard of care or placebo in the hospitalized patients with COVID-19 were included.

RESULTS

Six RCTs involving 472 patients were included. Patients who received IVIG had a similar mortality rate to the controls (25.3% vs 27.0%, odds ratio [OR], 0.60; 95% confidence interval [CI], 0.27-1.31). Compared with the control group, the study group demonstrated a similar incidence of receiving mechanical ventilation (OR, 0.70; 95% CI, 0.45-1.11), intensive care unit (ICU) admission (OR, 0.58; 95% CI, 0.22-1.53), length of hospital stay (mean difference [MD], -1.81 days; 95% CI, -8.42 to 4.81) and ICU stay (MD, -0.61 days; 95% CI, -2.80 to 1.58).

CONCLUSIONS

The administration of IVIG in hospitalized patients with COVID-19 does not improve clinical outcomes.

Higher levels of IgA and IgG at sepsis onset are associated with higher mortality: results from the Albumin Italian Outcome Sepsis (ALBIOS) trial

Background

The role of intravenous immunoglobulins (IVIG) during sepsis is controversial, as different trials on IVIG have observed inconsistent survival benefits. We aimed to elucidate the possible association and clinical significance between circulating levels of immunoglobulins.

Methods

In a subset of 956 patients with severe sepsis and septic shock of the multicentre, open-label RCT ALBIOS, venous blood samples were serially collected 1, 2, and 7 days after enrolment (or at ICU discharge, whichever came first). IgA, IgG and IgM concentrations were assayed in all patients on day 1 and in a subgroup of 150 patients on days 2 and 7. Ig concentrations were measured employing a turbidimetric assay, OSR61171 system.

Results

IgA on day 1 had a significant predictive value for both 28-day and 90-day mortality (28-day mortality, HR: 1.50 (95% CI 1.18–1.92); 90-day mortality, HR: 1.54 (95% CI 1.25–1.91)). IgG, but not IgM, on day 1 showed similar results for 28-day (HR 1.83 (95% CI 1.33–2.51) and 90-day mortality HR: 1.66 (95% CI 1.23–2.25)). In addition, lower levels of IgG but not of IgA and IgM, at day 1 were associated with significantly higher risk of secondary infections (533 [406–772] vs 600 [452–842] mg/dL, median [Q1–Q3], p = 0.007).

Conclusions

In the largest cohort study of patients with severe sepsis or septic shock, we found that high levels of IgA and IgG on the first day of diagnosis were associated with a decreased 90-day survival. No association was found between IgM levels and survival. As such, the assessment of endogenous immunoglobulins could be a useful tool to identify septic patients at high risk of mortality.

Trial registration #NCT00707122, Clinicaltrial.gov, registered 30 June 2008

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00952-z.

Post-surgical staphylococcal toxic shock syndrome in pediatrics: A case report

Introduction

Toxic shock syndrome (TSS) is a rare but serious, life-threatening medical condition and potentially lethal if not detected and treated early. It is mainly caused by a toxin called toxin-1 produced by Staphylococcus aureus, and characterized by fever, hypotension, rash, skin desquamation and multisystem involvement.

Case presentation

Herein, we describe a nine-month-old male patient who presented to the hospital complaining of fever, vomiting and hypoactivity on day one post-orchidopexy. During hospitalization, his condition began to deteriorate with signs and symptoms of multisystemic failure. Laboratory tests and radiological images were done, leading to the decision to reopen and drain the surgical wound. Wound and nasal swabs were cultured and showed S. aureus infection, and the diagnosis of toxic shock syndrome was confirmed.

Discussion

TSS is a systemic illness resulting from overwhelming host response to bacterial exotoxins, that cause T cells activation and the release of pro-inflammatory cytokines (IL-1 and TNF-α causing fever, hypotension, and tissue injury). Also, it can present with CNS signs that may be misdiagnosed with meningitis in pediatrics.

It requires early identification and treatment despite its rarity with mortality rate of 81% even with treatment.

The patient's presentation, examination and laboratories tests with the blood and wound cultures were highly suggestive for this condition.

Conclusion

Physicians must maintain a high index of suspicion for TSS, as early diagnosis and treatment make a difference. This condition shouldn't be excluded even in young age patients or after simple procedure as in our case in which TSS occurred after orchidopexy.

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Toxic shock syndrome is a life-threatening condition that can be highly mortal even with treatment.

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Post-surgical TSS is very rare and according to the literature this is the first reported case post-orchidopexy.

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Broad spectrum antibiotics with debridement of the necrotic tissue as management are the best option to treat this condition.

Refractoriness to drugs in migraine may be the result of developing anti-drug antibodies

INTRODUCTION

Migraine is a common neurological disease and is listed second among the most disabling health conditions worldwide. Refractory migraine (RM) is a term used to emphasize the unresponsiveness of migraine to various treatment options, encompassing both episodic refractory and chronic refractory migraine. In this paper we discuss various known and possible mechanisms of pharmacological refractoriness in RM, such as possible involvement of the gut microbiome, the blood-brain barrier, migraine genetics and various mechanisms of pharmacokinetic and pharmacodynamic tolerance. Development of medication-overuse headache as a secondary disorder following migraine is also considered. We argue that the available literature is insufficient to fully explain the mechanisms of refractoriness and we present our hypothesis.

HYPOTHESIS

Refractoriness to drugs in migraine may be the result of developing anti-drug antibodies. Most migraine drugs are small molecules, which cannot elicit an immune response on their own due to their size. However, such molecules can bind to peptide carriers in their vicinity, greatly increasing their immunogenicity. A small molecule possessing this binding ability is called a hapten. Haptens form hapten-carrier complexes (HCCs), which can evoke powerful immune responses. Immune reactions to HCCs are known to be predominantly 'drug allergies' or type 1 drug hypersensitivity reactions', usually resulting from IgE or non-IgE mediated mast cell degranulation. We argue that the immune reaction to HCCs can take shape in developing neutralizing anti-drug antibodies (ADA) in the form of IgG and IgA class antibodies. Since biological therapeutics, such as various monoclonal antibodies, face the issue of ADA-induced drug tolerance, HCCs, being similar in the sense that they carry peptide antigens, are of sufficient size and may be considerably immunogenic, can be responded to in a similar way by producing neutralizing ADA. Furthermore, we argue that such responses are expected to happen more frequently than is thought, due to IgG and IgA being prevalent antibodies, which utilize their neutralizing capabilities on regular basis. Finally, it is important to consider that neutralization reactions in normal immune responses are typically asymptomatic, with the only clinical expression being progressive drug tolerance. These cases may be overshadowed by the life-threatening cases of drug allergy induced anaphylaxis, possibly leading to neutralization reactions being underrecognized.

DISCUSSION

This hypothesis aims to stimulate more research regarding drug resistance, and if it receives support from empirical evidence, it may help further elucidate the mechanisms underlying refractory diseases and contribute to the development of more effective treatment of many disorders.

IgM autoantibodies recognizing ACE2 are associated with severe COVID-19

SARS-CoV-2 infection induces severe disease in a subpopulation of patients, but the underlying mechanisms remain unclear. We demonstrate robust IgM autoantibodies that recognize angiotensin converting enzyme-2 (ACE2) in 18/66 (27%) patients with severe COVID-19, which are rare (2/52; 3.8%) in hospitalized patients who are not ventilated. The antibodies do not undergo class-switching to IgG, suggesting a T-independent antibody response. Purified IgM from anti-ACE2 patients activates complement. Pathological analysis of lung obtained at autopsy shows endothelial cell staining for IgM in blood vessels in some patients. We propose that vascular endothelial ACE2 expression focuses the pathogenic effects of these autoantibodies on blood vessels, and contributes to the angiocentric pathology observed in some severe COVID-19 patients. These findings may have predictive and therapeutic implications.

Intravenous immunoglobulin for adjunctive treatment of severe infections in ICUs

PURPOSE OF REVIEW

This review focuses on the emerging literature regarding the use of intravenous immunoglobulins (IVIg) in critically ill patients with severe infections. The aim is to provide an accessible summary of the most recent evidence of IVIg use in sepsis and septic shock and to help clinicians to understand why there is still equipoise regarding the potential benefit of this adjunctive therapy in this setting.

RECENT FINDINGS

Observational studies with propensity score matching analyses and investigating the effect of IVIg in severe infections including necrotizing soft tissue infection have been recently published. These studies suffer important flaws precluding robust conclusion to be drawn. Some recent randomized controlled trials raised interesting findings supportive of personalized medicine but are likely to be underpowered or confounded.

SUMMARY

Insufficient evidence is available to support IVIg use in sepsis and septic shock, apart from the specific case of streptococcal toxic shock syndrome. Current literature suggests that IVIg efficacy in sepsis or septic shock could depend on the IVIg preparation (IgM-enriched or minimal IgM), time of administration (<24 h), dose, and the inflammatory/immunomodulation profile of the patients. Investigator-initiated research, incorporating these parameters, is warranted to determine whether IVIg benefits critically ill patients with severe infection.

Hyperviscosity-related splenic infarction, gastrointestinal ischaemia-reperfusion injury and transient dysarthria in a patient with distributive shock due to idiopathic systemic capillary leak syndrome (Clarkson's syndrome)

Clarkson's syndrome, also known as idiopathic systemic capillary leak syndrome, is characterised by vascular hyperpermeability resulting in intravascular hypovolaemia and shock. A clinician should consider the diagnosis if other causes of shock, for example, sepsis and anaphylaxis, are ruled out and concomitant hyperviscosity is not caused by a myeloproliferative disease. Here, we describe a patient presenting with severe plasma leakage and assumable blood hyperviscosity leading to splenic infarction, gastrointestinal ischaemia-reperfusion syndrome and transient dysarthria. Our patient was first suspected of polycythaemia vera and phlebotomies were performed. Awareness of this syndrome and subsequent correct treatment is essential to prevent complications and to reduce mortality. As in our patient, most patients with Clarkson's syndrome have a monoclonal gammopathy, light-chain-type kappa. Prophylactic treatment with intravenous immunoglobulin (IVIg) is advised to prevent recurrence of capillary leak. Our patient did not suffer from another symptomatic episode after starting IVIg.

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.

Immunoglobulins Treatment in Multiple Sclerosis and Experimental Autoimmune Encephalomyelitis

Intravenously administered immunoglobulins (IgG) treatment has several modes of action that can regulate the immune response during different steps of the inflammatory process in experimental autoimmune encephalomyelitis (EAE) and Multiple Sclerosis (MS). The immunomodulatory effects IgG are largely dependent on their ability to interact with membrane molecules of lymphocytes and monocytes. Better understanding of these mechanisms of action in relation to the pathogenesis of MS, is important in order to decide the time of initiation and the duration of treatment in MS patients. In order to have the best beneficial effect on disease course, future research should focus on the initial events that activate the disease and on the early treatment modalities of IgG in MS.

Streptococcal toxic shock syndrome in the intensive care unit

The streptococcal toxic shock syndrome is a severe complication associated with invasive infections by group A streptococci. In spite of medical progresses in the care of patients with septic shock during the last decades, this condition has remained associated with a high mortality. Early recognition and multidisciplinary management are key to the care of patients with streptococcal toxic shock syndrome, with intensive and appropriate intensive support of failing organs, rapid diagnosis of infectious source(s), and surgical management. The epidemiology and risk factors for streptococcal toxic shock syndrome remain to be better studied, including the possible causal role of exposure to nonsteroidal anti-inflammatory drugs. In this review article, the authors review the current knowledge of streptococcal toxic shock syndrome and discuss the pathophysiology as well as its supportive and specific treatment.

Potentiation of cytokine-induced proliferation of human Natural Killer cells by intravenous immunoglobulin G

Intravenous IgG (IVIG) therapy can be used for immunomodulation. IL-2 is an immunoregulatory cytokine. We evaluated IVIG modulation of human blood lymphocyte response to IL-2 and other cytokines. Neither IVIG nor low concentrations of IL-2 (3-30U/ml) induced lymphocyte proliferation, but in combination they synergistically enhanced proliferation of NK cells. The CD56(bright) cells expanded more than CD56(dim) NK cells, with 90% of NK cells dividing up to 8 generations by day 6, while <8% of T cells divided. IVIG also potentiated NK cell proliferation with IL-12, IL-15 and IL-18. The IVIG+cytokine-expanded NK cells were less cytotoxic for K562 cells, than NK cells with cytokine alone. IVIG also enhanced interferon-γ production with IL-2, IL-12 and IL-18. In conclusion, IVIG selectively potentiates NK cell proliferation and interferon-γ secretion with IL-2, IL-12, IL-15 and IL-18 in vitro. These findings warrant evaluation in vivo in relation to NK cells and the immunoregulatory actions of IVIG.

A comprehensive review and update on the biologic treatment of adult noninfectious uveitis: part II

INTRODUCTION

Treatment of adult, noninfectious uveitis remains a major challenge for ophthalmologists around the world, especially in regard to recalcitrant cases. It is reported to comprise approximately 10% of preventable blindness in the USA. The cause of uveitis can be idiopathic or associated with infectious and systemic disorders. The era of biologic medical therapies provides new options for patients with otherwise treatment-resistant inflammatory eye disease.

AREAS COVERED

This two-part review gives a comprehensive overview of the existing medical treatment options for patients with adult, noninfectious uveitis, as well as important advances for the treatment ocular inflammation. Part I covers classic immunomodulation and latest information on corticosteroid therapy. In part II, emerging therapies are discussed, including biologic response modifiers, experimental treatments and ongoing clinical studies for uveitis.

EXPERT OPINION

The hazard of chronic corticosteroid use in the treatment of adult, noninfectious uveitis is well documented. Corticosteroid-sparing therapies, which offer a very favorable risk-benefit profile when administered properly, should be substituted. Although nothing is currently approved for on-label use in this indication, many therapies, through either translation or novel basic science research, have the potential to fill the currently exposed gaps.

Clinical efficacy of polyspecific intravenous immunoglobulin therapy in patients with streptococcal toxic shock syndrome: a comparative observational study

BACKGROUND

Streptococcal toxic shock syndrome (STSS) and necrotizing fasciitis are the 2 most severe invasive manifestations caused by group A Streptococcus (GAS). Intravenous immunoglobulin (IVIG) therapy has been suggested as adjunctive treatment with a beneficial effect on mortality. However the clinical evidence is limited. Here we aim to further document the clinical efficacy of administered IVIG therapy in a comparative observational study of well-defined patients with STSS.

METHODS

The effect of IVIG was evaluated in patients with STSS prospectively identified in a nationwide Swedish surveillance study conducted between April 2002 and December 2004. Detailed data on symptoms, severity of disease, treatment, and outcome were obtained from 67 patients. Crude and adjusted analyses with logistic regression were performed.

RESULTS

Twenty-three patients received IVIG therapy compared with 44 who did not. No significant difference in comorbidities, severity of disease, organ failures, or sex was seen, but the IVIG group was slightly younger and had a higher degree of necrotizing fasciitis (56% vs 14%). The primary endpoint was 28-day survival. Adjusted analysis revealed that factors influencing survival in STSS were Simplified Acute Physiology Score II (odds ratio [OR], 1.1; P = .007), clindamycin (OR, 8.6; P = .007), and IVIG (OR, 5.6; P = .030).

CONCLUSIONS

This comparative observational study of prospectively identified STSS patients demonstrates that both IVIG and clindamycin therapy contribute to a significantly improved survival in STSS.

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

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

Intravenous immunoglobulins are a therapeutic option in the treatment of multiple sclerosis relapse

OBJECTIVE

The objective of the study is to evaluate the efficacy and tolerability of intravenous immunoglobulin (IVIG) monotherapy in the treatment of multiple sclerosis (MS) relapse.

BACKGROUND

High-dose intravenous methylprednisolone (IVMP) and plasmapheresis have been shown to shorten the recovery period of an MS relapse. Options for those who have contraindications for or are unresponsive to these treatments are very limited. Intravenous immunoglobulin has been used experimentally in these situations, even though there are no previous studies on its efficacy as monotherapy in MS relapse.

SUBJECTS AND METHODS

Twelve consecutive MS patients with acute MS relapse were treated with IVIG 0.4 g/kg per day for 5 days, and the next 5 patients received IVMP 1000 mg/d for 3 days. Volumetric brain magnetic resonance imaging (MRI) and clinical evaluation using expanded disability status scale (EDSS) were performed at baseline and at 3 weeks after treatment. EDSS score after 1 year of the treatment was collected from the patient records. MRI evaluation was performed blindly but not the clinical examination and EDSS scoring.

RESULTS

A significant reduction in the volumes of T2-, fluid-attenuated inversion recovery-, and gadolinium-enhanced lesions was detected in the IVIG-treated group, but not in the IVMP-treated patients. The difference between the groups did not reach statistical significance. The EDSS score improved equally in both groups.

CONCLUSIONS

Intravenous immunoglobulin did not show inferiority compared with IVMP in the treatment of an acute MS relapse evaluated clinically and radiologically. Therefore, we suggest that IVIG may be tried as a therapy in acute MS relapse, especially in case of contraindications to IVMP and plasmapheresis.

In vivo modulation of the expressions of Fas and CD25 by intravenous immunoglobulin in common variable immunodeficiency

Although the presence of physiologic anti-CD95 (Fas, APO-1) autoantibodies in intravenous immunoglobulin (IVIG) preparations is known, the effects of these antibodies in patients with common variable immunodeficiency are unclear (CVID). The aim of the study was to assess the effects of IVIG in Fas expression, activation markers and the subsets of T cells in patients with CVID. We studied 15 cases with CVID and 10 healthy controls with no signs of immunodeficiency. The Fas expression of T cells, activation markers (CD25, CD69 and HLA-DR) and T-cell subsets were analyzed by four-color flow cytometry. We found that the Fas expression of CD3+ T cells in patients was significantly higher than in controls. In addition, there was a significant increase in the Fas expression of CD3+ T cells and CD4+ T cells, and the CD25 expression of CD3+ and CD4+ T cells after IVIG supplementation (P < 0.05). The CD69 and HLA-DR expressions of T cells and CD8+ T cells were not affected by IVIG infusion. Our observation showed that IVIG replacement causes an increase in the Fas and CD25 expressions in patients with CVID. These data suggest that the Fas protein may have an important role in the effects of IVIG for the control of autoimmunity in patients with CVID, as well as in the generation of autoimmune disease.

Sugar-free, glycine-stabilized intravenous immunoglobulin prevents skin but not renal disease in the MRL/lpr mouse model of systemic lupus

Intravenous immunoglobulin (IVIG) has a therapeutic potential in many autoimmune diseases. Based on its immune modulating and complement inhibiting effects, IVIG has been tested in systemic lupus erythematosus (SLE), but due to osmotic tubular injury caused by immunoglobulin-stabilizing sugar components, lupus nephritis had been accelerated in some patients, thus IVIG use in SLE has been abandoned. The availability of non-sugar-stabilized IVIG raised the possible re-evaluation of IVIG for SLE. We investigated high-dose, long-term non-sugar-stabilized IVIG treatment on skin and renal SLE manifestations in the MRL/lpr mouse model. Animals were treated once a week with glycine-stabilized IVIG or saline (0.2 ml/ 10 g BW) from 6 weeks until they were humanely killed at 5 months of age. IVIG diminished macroscopic cutaneous lupus compared with saline treated mice. Histology and complement-3 immunostaining also demonstrated a significant reduction of skin disease after IVIG treatment. However, renal histology and function were similar in both groups. Compared with typical osmotic tubular damage induced by 5% sucrose and 10% maltose (used for IVIG stabilization), we did not observe any osmotic tubular injury in the glycine-stabilized IVIG treated mice. Our data demonstrate a beneficial effect of IVIG on skin lupus without renal side-effects. Deeper understanding of the organ-specific pathomechanism may aid an individualized SLE therapy.

Identification of target antigens of self-reactive IgG in intravenous immunoglobulin preparations

Intravenous immunoglobulin (IVIg) contains a wide range of self-reactive immunoglobulins (Ig) G. Acidic pH is known to increase the reactivity of purified IgG with self-antigens. We describe here the target antigens of IgG autoantibodies in IVIg and analyze the influence of acidic pH on IgG reactivities. We used 2-DE and immunoblotting with protein extracts of human umbilical vein endothelial cells (HUVEC) and HEp-2 cells. Two IVIg preparations obtained by ethanol fractionation [one with an acidic pH step (acidic-IVIg) and one with beta-propiolactone (propiolactone-IVIg)] and a pool of sera from 12 healthy individuals were tested. Serum IgG of 3 healthy individuals and IgG purified from the same sera with elution at pH 2.8 were also tested individually. Finally, propiolactone-IVIg was acidified at pH 2.8. IgG obtained with a step at low pH recognized many more target spots than IgG obtained without acidic pH. Our findings demonstrate that an acidic pH step artificially enlarges the repertoire of self-reactive IgG. Thus, protein spots recognized by IgG in propiolactone-IVIg represent the core set of self-antigens targeted by IVIg. Overall, 96 proteins were identified by MS. Fourteen were recognized in both extracts including glycolysis proteins such as alpha-enolase, RNA processing and cytoskeletal proteins such as lamin-A/C.

Epidermolysis bullosa acquisita in a great Dane

Autoimmune subepidermal blistering diseases in dogs were all classified as bullous pemphigoid until 1998. Since then, refinements in reagents and immunological techniques have allowed diseases which are histologically similar but which have a different molecular pathogenesis to be described. This report describes the first case of one such disease, epidermolysis bullosa acquisita, to be documented in the UK. The dog presented with a severe blistering and ulcerative disease affecting the oral cavity, pinnae and distal limbs. The diagnosis was confirmed by histopathology and direct and indirect immunofluorescent demonstration of immunoglobulin G reactivity to basement membrane antigens. Treatment with glucocorticoids, azathioprine, colchicine and an intravenous infusion of immunoglobulins resulted in complete resolution. The drugs were discontinued 12 months after the start of treatment and the dog remained in remission.

Bacterial translocation is downregulated by anti-TNF-alpha monoclonal antibody administration in rats with cirrhosis and ascites

BACKGROUND/AIMS

TNF-alpha is involved in the development of bacterial translocation in rats with cirrhosis. The aim of the current study was to evaluate the effect of anti-TNF-alpha mAb treatment on the incidence of bacterial translocation and systemic infections in rats with cirrhosis and ascites.

METHODS

Thirty rats with cirrhosis and ascites were randomly assigned to receive two intraperitoneal doses of anti-TNF-alpha mAb, distilled water or immunoglobulin on days 0 and 4. On day 10, a laparotomy was performed.

RESULTS

One out of 11 animals receiving anti-TNF-alpha mAb treatment, 7 out of 10 of the placebo group (p<0.01), and 5 out of 9 of the IgG group developed bacterial translocation (p<0.05). A significantly reduced number of systemic infections were observed in animals receiving anti TNF-alpha mAb treatment vs animals receiving placebo (p<0.01). TNF-alpha in serum at laparotomy in animals receiving anti-TNF-alpha mAb was higher than that in the rest of groups and was also higher in the overall series of animals showing bacterial translocation.

CONCLUSIONS

In the experimental model of CCl(4)-induced rat with cirrhosis and ascitic fluid, anti-TNF-alpha mAb administration decreases the incidence of bacterial translocation, in a TNF-alpha/sTNF-alpha receptor-independent manner, without increasing the risk of systemic infections.

Efficacy of intravenous immunoglobulin treatment in refractory uveitis

PURPOSE

To assess the efficacy of intravenous immunoglobulin (IVIg) therapy in patients with severe uveitis otherwise unresponsive to conventional immunomodulatory agents.

METHODS

Data on five consecutive patients treated with IVIg and followed to the present time by one of the authors (CSF) were reviewed. All patients had severe and recalcitrant uveitis of diverse etiologies. Main outcome measures were control of intraocular inflammation, steroid-sparing effect, visual acuity, and side effects.

RESULTS

The duration of IVIg therapy was 3 to 36 months (mean, 16.8 months). Treatment was effective in controlling the intraocular inflammation in 3 of 5 patients. One of those patients required maintenance of systemic steroids at a dose of 10 mg per day. Visual acuity has stabilized or improved in these three patients. No immediate or long-term side effect was observed in any of the patients.

CONCLUSIONS

Intravenous immunoglobulin therapy was an effective therapeutic modality in the treatment of three of five patients with severe uveitis that was unresponsive to conventional immunomodulatory agent(s). No adverse events were observed.

Maintenance of antigen-specific immunological memory through variable regions of heavy and light chains of anti-idiotypic antibody

Immunological memory is characterized by a quick and enhanced immune response after re-exposure to the same antigen. To explain the mechanism involved in generation and maintenance of immunological memory, we had earlier proposed a hypothesis involving the relay of memory by idiotypic and anti-idiotypic B cells. The peptidomimic present in the hypervariable region of anti-idiotypic antibody was hypothesized to carry forward immunological memory. In the present work, we provide evidence supporting a role for the anti-idiotypic antibody in eliciting antigen-specific B-cell and T-cell responses. Employing the idiotypic monoclonal antibody (Ab(1)) specific for haemagglutinin (H) protein of rinderpest virus, Ab(2beta) was generated, which possesses an internal image of the H protein in the region between amino acids 527 and 556. We demonstrate that antigen-specific memory is perpetuated by immunization with Ab(2), as shown by maintenance of antigen-specific T-cell responses upon restimulation in vitro of Ab(2) immune splenocytes by antigen-presenting cells expressing H protein or pulsed with H-protein-derived peptides. We have also shown that boosting with antigen-specific anti-idiotypic B cells generates a memory response in antigen-primed mice. Evidence has been provided for the existence of an antigen-specific B-cell idiotypic network in the body that supports the perpetuation of immunological memory as proposed in the relay hypothesis.

Induction of immune tolerance by oral IVIG

In the last years evidence has been provided for the importance of B cells in the pathogenesis of rheumatoid arthritis (RA). Several studies have supported the concept that humoral immunity, manifested by the production of autoantibodies, such as rheumatoid factors (RFs), plays a significant role in the course of the disease. Specific targeting of autoantibody-producing B cells, such as RF-producing B cells, should therefore be a promising new approach in the treatment of RA. We used a mouse model to induce human RF responses and asked the question whether oral treatment with the antigen (human IgG) recognized by RFs could induce immune tolerance to RF responses. Balb/c mice were orally treated with polyvalent human IgG before and after immunization with insoluble immune complexes (ICs) that triggered the induction of RFs. Serum titers of RFs were significantly reduced after both primary and booster immunization when human IgG was given as a single oral dose or continuously in drinking water. Continuous treatment with human IgG even prevented booster effects on RFs when treatment started after primary immunization. Treatment with IgG fragments provided evidence that the observed effect of human IgG was mediated by the Fc part and not the Fab part of IgG. Furthermore, transfer of spleen cells obtained from mice after oral treatment with human IgG suppressed RF responses in recipient mice. These data give promising indications that oral human IgG might represent an alternative approach for immunosuppressive B-cell targeted therapies in RA.

Intravenous polyclonal IgM-enriched immunoglobulin therapy in sepsis: a review of clinical efficacy in relation to microbiological aetiology and severity of sepsis

The efficacy of intravenous polyclonal immunoglobulin (IVIG) as adjunct therapy in sepsis has long been debated. Clinical trials have yielded contradicting results, in part due to the varying study design and varying microbiological aetiologies. In most trials, the study drug has been IVIG containing polyclonal IgG. However, in recent reports, the efficacy of IgM-enriched IVIG as adjunct therapy in sepsis has been highlighted. Here we review studies on IgM-enriched IVIG therapy in sepsis and we discuss the clinical efficacy in relation to microbiological aetiology and severity of sepsis. The results suggest that patients most likely to benefit from IgM-enriched IVIG therapy are those with Gram-negative septic shock.

IgM-enriched human intravenous immunoglobulin suppresses T lymphocyte functions in vitro and delays the activation of T lymphocytes in hu-SCID mice

Previous studies of an experimental human immunoglobulin preparation for intravenous use, containing normal pooled IgM (IVIgM), have shown its beneficial therapeutic effect in experimental autoimmune diseases. The mechanisms of its immunomodulatory activity remain however, poorly understood. In the experiments reported here, IVIgM inhibited the proliferation of various autonomously growing human lymphoid cell lines in vitro, as well as of MLR- and of PHA-stimulated human T-lymphocytes. These effects of IVIgM were observed at non-apoptotic concentrations and were stronger on a molar basis than those of normal pooled IgG for intravenous use (IVIg). Both preparations, when administered to SCID mice, repopulated with human peripheral blood mononuclear cells, delayed the expression of the early activation marker CD69 on both human CD4+ and CD8+ T-lymphocytes, activated by the mouse antigenic environment. The data obtained show that normal pooled human IgM exerts a powerful antiproliferative effect on T-cells that is qualitatively similar but quantitatively superior to that of therapeutic IVIg. Our results suggest that infusions with IVIgM might have a significant beneficial immunomodulating activity in patients with selected autoimmune diseases.

Modulation of lymphocyte phenotype and function by immunoglobulins

BACKGROUND

Immunoglobulins have immune-modulating capacities and are used for the treatment of different dermatological diseases. They have also been reported for the treatment of severe atopic dermatitis (AD).

OBJECTIVES

To determine the effects of immunoglobulins on the phenotype and function of peripheral T and B lymphocytes from patients with AD in comparison with healthy donors (HD) as controls.

METHODS

We studied lymphocyte activation and T-cell cytokine production from 12 patients with AD and 10 HD by multicolour flow cytometric analysis in the presence of immunoglobulins.

RESULTS

Immunoglobulins significantly inhibited T-cell activation (CD69), by 71% (AD) and by 62% (HD). Production of interferon-gamma and interleukin-4 was also significantly inhibited, by 44%/24% (AD) and 38%/10% (HD), respectively. In addition, CD86 expression on B lymphocytes was downregulated by 30% in AD and by 29% in HD, whereas CD23 expression was decreased without reaching statistical significance.

CONCLUSIONS

Our data demonstrate that, in vitro, immunoglobulins modulate the activation and cytokine production of peripheral blood lymphocytes from both HD and patients with AD.

Emerging drugs for chronic urticaria

Chronic urticaria (CU), with or without angioedema, is a frequent disorder defined as the occurrence of pruritic wheals for > 6 weeks. Studies carried out in the last two decades showed that the origin of the disease is autoimmune in up to 50% of cases. Currently available treatments include antihistamines, corticosteroids and ciclosporin; recently, leukotriene receptor antagonists proved effective in a subset of patients as well. For patients with an unremitting and extremely severe disease unresponsive to standard treatments, plasmapheresis and immunosuppressive drugs have been successfully attempted. Recent findings that the autologous plasma skin test scores positive in nearly all patients and that plasmas from patients with both autoimmune and 'idiopathic' chronic urticaria are frequently characterised by signs of thrombin activation (plasma levels of prothrombin fragment F(1.2) are significantly increased) suggest that clotting cascade might be somehow involved in the pathogenesis of CU. These findings put under a new light some rather sparse studies of the effect of drugs active on the coagulation system (heparin and oral anticoagulants) in patients with CU.

The patient: Emerging clinical applications of intravenous immunoglobulin

Intravenous immunoglobulin (IGIV) originally was used as prophylactic treatment of infections in patients with primary immunodeficiency disease. Today, administration of IGIV, due in large part to its immunomodulatory activity, has expanded to include a number of other disorders. Available data suggest that the accepted indications for IGIV will continue to expand. As the number of clinical applications for this therapy grows, so will market opportunities; current preparations will be modified and improved and new products introduced. Intravenous immunoglobulin therapy has improved the lives of many patients with immune-related disorders. Future applications will ideally advance this paradigm further.

Inhibitory effect of pooled human immunoglobulin on cytokine production in peripheral blood mononuclear cells

Human intravenous immunoglobulins (IVIG) are widely used as immunomodulators because of their ability to modify the course of various immune-mediated diseases. We investigated the mechanisms responsible for the regulatory effects of IVIG on in vitro human peripheral blood mononuclear cell (PBMC) cytokine production. Pre-incubation of PBMCs with IVIG inhibited lipopolysaccharide (LPS) and phorbol 12-myristate 13-acetate (PMA)/ionomycin stimulated cytokine secretion. Pre-incubation of PBMCs with IVIG induced a significant inhibition of LPS-stimulated (IL-6) secretion (p = 0.045); the effect on tumor necrosis factor-alpha (TNF-alpha) secretion was not significant (p = 0.234). Pre-incubation of PBMCs with IVIG inhibited IL-6 secretion (p = 0.033) stimulated with anti-CD14 antibody cross-linking but had no significant effect on TNF-alpha secretion (p = 0.125). PBMC pre-incubation with anti-CD14-blocking antibody induced a significant reduction (p = 0.042) in LPS-stimulated TNF-alpha secretion in comparison with a non-significant reduction (p =0.256) noted with IVIG pre-treatment. In contrast, pre-incubation of PBMCs with anti-CD14 antibody did not induce a significant reduction in LPS-stimulated IL-6 secretion (p = 0.166) in comparison with a significant reduction (p = 0.001) induced with IVIG pre-treatment. Our data suggest that the immunoregulatory properties of IVIG may rely on several mechanisms, some of which may be independent of CD14. Our data also showed that cross-linking cell membrane-bound IVIG with anti-human kappa- and lambda-chain antibodies resulted in cytokine secretion levels similar to those elicited by LPS. In addition, intracellular DNA staining results did not support the involvement of apoptosis in the regulatory mechanisms of IVIG. This data may further our understanding of the immunoregulatory effects exerted by IVIG on the production of inflammatory-response mediators.

Engineering the Fc region of immunoglobulin G to modulate in vivo antibody levels

We have engineered the Fc region of a human immunoglobulin G (IgG) to generate a mutated antibody that modulates the concentrations of endogenous IgGs in vivo. This has been achieved by targeting the activity of the Fc receptor, FcRn, which serves through its IgG salvage function to maintain and regulate IgG concentrations in the body. We show that an IgG whose Fc region was engineered to bind with higher affinity and reduced pH dependence to FcRn potently inhibits FcRn-IgG interactions and induces a rapid decrease of IgG levels in mice. Such FcRn blockers (or 'Abdegs,' for antibodies that enhance IgG degradation) may have uses in reducing IgG levels in antibody-mediated diseases and in inducing the rapid clearance of IgG-toxin or IgG-drug complexes.

Life-threatening purpura and vasculitis

Palpable purpura, the inflammation of blood vessels is the hallmark of vasculitis. It can be observed in a variety of settings, where vessels can be affected primarily or as a secondary event. Every patient with vasculitis should be considered to have a systemic disease unless proven otherwise. One or more systemic symptoms occur in at least 50% of patients and there is no way to predict systemic involvement. Patients may demonstrate mild systemic involvement like arthralgia and arthritis, fever and malaise or more severe symptoms such as massive proteinuria and raised creatinine leading to chronic renal failure, severe intestinal bleeding or perforation with a fatal outcome. In this article we will review the life-threatening aspects of purpura and vasculitis.

Human pooled immunoglobulin in the treatment of chronic pain syndromes

OBJECTIVE

To examine the use of intravenous immunoglobulin (i.v.i.g.) in chronic pain.

DESIGN

A prospective multiple-dose, open-label cohort study in 130 consecutive patients who suffered from 12 chronic pain syndromes. The largest symptom groups were (number of patients): Fibromyalgia (48); Spinal pain (20); Complex regional pain syndrome (CRPS, 11); Peripheral neuropathic pain (12); and Atypical odontalgia or atypical facial pain (11). All patients had insufficient pain relief with established treatments. Pain relief was recorded using average pain intensity values as documented in standardized diaries. A specific treatment protocol was developed, and patients were enrolled over a 36-month period.

RESULTS

Overall, 20% of patients had>70% pain relief and 27.7% of patients reported relief between 25% and 70%. Six patients (4.6%) had moderately increased pain levels for a duration of up to 9 weeks. Good relief, of more than 70%, was found in all major symptom groups. Patients with pain of short duration (<2 years) reported high relief rates (33.8% of patients in this group reported relief of >70%). No serious adverse events were reported. conclusions: i.v.i.g. may be effective in patients suffering from chronic pain. Controlled studies are needed to evaluate the efficacy of i.v.i.g. in these patients. Patients with a good response to i.v.i.g. may be models for the study of neuroimmune interactions in chronic pain.

Pulsed intravenous immunoglobulin therapy in livedoid vasculitis: An open trial evaluating 9 consecutive patients

BACKGROUND

Livedoid vasculitis (LV) usually presents with painful, slowly healing ulcerations of the lower limbs. The precise pathophysiology of this relatively rare disease remains obscure. Therapeutic strategies usually include rheologic, anti-inflammatory, or immunosuppressive agents. However, no continuing benefit has been reported in any of these modalities. Recently, encouraging case reports about the successful use of intravenous immunoglobulin (IVIg) in LV have been published.

METHODS

We initiated an open single center trial to investigate the efficacy and safety of IVIg in LV. Nine patients with LV, 7 of whom were refractory to other treatment modalities, were included. Therapy with IVIg at a dose of 0.5 g/kg body weight per day over 2 or 3 consecutive days was performed monthly. Skin involvement before and after therapy was assessed by means of a clinical score.

RESULTS

In all patients, significant regression of skin lesions was observed after therapy resulting in a decrease of the clinical score (including differential semiquantitative assessment of erythema, ulceration, and pain) from 6.5 +/- 1.7 at the beginning to 1.3 +/- 1.2 after therapy (P <.001). IVIg was well tolerated and therapy was finished in all patients.

CONCLUSION

In all patients clinical evaluation revealed a marked improvement of erythema, pain, and healing of areas of active ulceration. Although this was an open non-controlled study, we propose that IVIg is a promising therapeutic option in LV refractory to other treatment modalities.

Successful intravenous human immunoglobulin treatment of drug-induced Stevens-Johnson syndrome in a dog

A two-year-old, male English springer spaniel developed severe mucocutaneous ulceration following treatment with trimethoprim-potentiated sulphadiazine. The clinical signs were consistent with Stevens-Johnson syndrome (SJS): there were no target or arciform lesions typical of erythema multiforme minor and major; more than one mucosal surface was affected; epidermal detachment affected less than 10 per cent of the body surface area; and there was a clear history of drug exposure. Systemic signs included a severe hepatopathy, dyspnoea, pyrexia and cachexia. Glucocorticoid therapy was associated with secondary infection by Pseudomonas aeruginosa. The clinical signs rapidly resolved following a single intravenous infusion of 0.51 g/kg human immunoglobulin (ivHIG) as a 5 per cent solution. By blocking FAS/FAS ligand (CD95/CD95L) interactions, ivHIG is thought to prevent keratinocyte apoptosis. It also binds to immunoglobulin G Fc receptors, inhibiting cell activation and cytokine synthesis, neutralises autoantibodies and immune complexes, blocks complement activity, is antimicrobial and increases colloid osmotic pressure. To the authors' knowledge, this is the first report of successful treatment of canine SJS using ivHIG, although it has been used to treat erythema multiforme in a cat and toxic epidermal necrolysis in a dog.

The MHC class I-like Fc receptor promotes humorally mediated autoimmune disease

The MHC class I family-like Fc receptor, FcRn, is normally responsible for extending the life span of serum IgG Ab's, but whether this molecule contributes to autoimmune pathogenesis remains speculative. To determine directly whether this function contributes to humoral autoimmune disease, we examined whether a deficiency in the FcRn heavy chain influences autoimmune arthritis in the K/BxN mouse model. FcRn deficiency conferred either partial or complete protection in the arthritogenic serum transfer and the more aggressive genetically determined K/BxN autoimmune arthritis models. The protective effects of an FcRn deficiency could be overridden with excessive amounts of pathogenic IgG Ab's. The therapeutic saturation of FcRn by high-dose intravenous IgG (IVIg) also ameliorated arthritis, directly implicating FcRn blockade as a significant mechanism of IVIg's anti-inflammatory action. The results suggest that FcRn is a potential therapeutic target that links the initiation and effector phases of humoral autoimmune disease.

Recurrent high level parvovirus B19/genotype 2 viremia in a renal transplant recipient analyzed by real-time PCR for simultaneous detection of genotypes 1 to 3

Organ transplant recipients infected with parvovirus B19 frequently develop persistent viremia associated with chronic anemia and pure red cell aplasia. In this study, a male renal transplant recipient who had been infected with parvovirus B19/genotype 2 after renal transplantation at the age of 34 years is described. The patient was repeatedly treated with high dose intravenous immunoglobulin (IVIG) that resulted in the resolvement of symptoms but not in virus eradication. During an observation period of 33 months after transplantation three phases associated with high parvovirus B19 viremia were observed. Both the first and the second viremic phases were combined with severe anemia. Parvovirus B19 specific IgM-antibodies were initially detected at the beginning of the second phase in continually rising concentrations. Initially eradication of the virus by immunoglobulin therapy was reported after the first viremic phase [Liefeldt et al. (2002): Nephrol Dial Transplant 17:1840-1842]. Retrospectively this statement has to be corrected. It was based on the use of a qualitative PCR assay specific for parvovirus B19 genotype 1 associated with reduced sensitivity for detection of genotype 2. After sequence analysis of the viral DNA and adjustment of a real-time PCR assay (TaqMan) for quantitative detection of all three B19 virus genotypes analysis of consecutive serum samples allowed the demonstration of long lasting phases with reduced viral loads following IVIG-treatment. These results demonstrate that IVIG treatment of parvovirus B19-triggered anemia in transplant recipients offers an opportunity to resolve symptoms, but does not guarantee eradication of the virus. Since reactivation of parvovirus B19 infection can result in high virus load associated with the recurrence of symptoms repeated screening for viral DNA is recommended using the TaqMan system established for quantitative detection of all three genotypes of parvovirus B19.

Hypocomplementemic urticarial vasculitis with angioedema, a rare presentation of systemic lupus erythematosus: rapid response to rituximab

We report a case of hypocomplementemic urticarial vasculitis and recurrent angioedema in a patient with systemic lupus erythematosus unresponsive to mycophenolate mofetil, high-dose methylprednisolone, and intravenous immunoglobulin that responded rapidly to rituximab. Rituximab is a monoclonal antibody against CD20 transmembrane protein on the surface of mature and malignant B cells. No adverse effects occurred during or after therapy, and the patient was discharged from the hospital for outpatient rituximab infusion and follow-up care.