Anti-cytokine nature of natural human immunoglobulin: one possible mechanism of the clinical effect of intravenous immunoglobulin therapy

Anti-cytokine autoantibodies: mechanistic insights and disease associations

Anti-cytokine autoantibodies (ACAAs) are increasingly recognized as modulating disease severity in infection, inflammation and autoimmunity. By reducing or augmenting cytokine signalling pathways or by altering the half-life of cytokines in the circulation, ACAAs can be either pathogenic or disease ameliorating. The origins of ACAAs remain unclear. Here, we focus on the most common ACAAs in the context of disease groups with similar characteristics. We review the emerging genetic and environmental factors that are thought to drive their production. We also describe how the profiling of ACAAs should be considered for the early diagnosis, active monitoring, treatment or sub-phenotyping of diseases. Finally, we discuss how understanding the biology of naturally occurring ACAAs can guide therapeutic strategies.

B-cell receptor profiling before and after IVIG monotherapy in newly diagnosed idiopathic inflammatory myopathies

OBJECTIVE

To unravel B-cell receptor (BcR) characteristics in muscle tissues and peripheral blood and gain more insight into BcR repertoire changes in peripheral blood in idiopathic inflammatory myopathies (IIMs), and study how this correlates to the clinical response to IVIG.

METHODS

Nineteen treatment-naive patients with newly diagnosed IIM were prospectively treated with IVIG monotherapy. RNA-based BcR repertoire sequencing was performed in muscle biopsies collected before, and in peripheral blood (PB) collected before and nine weeks after IVIG treatment. Results were correlated to patients' clinical improvement based on the total improvement score (TIS).

RESULTS

Prior to IVIG treatment, BcR clones found in muscle tissue could be retrieved in peripheral blood. Nine weeks after IVIG treatment, new patient-specific dominant BcR clones appeared in peripheral blood while pre-treatment dominant BcR clones disappeared. The cumulative frequency of all dominant BcR clones before treatment was significantly higher in individuals who responded to IVIG compared with those who did not respond to IVIG, and correlated with a higher CK. During follow-up, a decrease in the cumulative frequency of all dominant clones correlated with a higher TIS.

CONCLUSION

In treatment-naive patients with newly diagnosed IIM, muscle tissue and peripheral blood share expanded BcR clones. In our study a higher cumulative frequency of dominant BcR clones in blood before treatment was associated with a higher CK and better treatment response, suggesting that response to IVIG may depend on the composition of the pre-treatment BcR repertoire.

Case Report: Susceptibility to viral infections and secondary hemophagocytic lymphohistiocytosis responsive to intravenous immunoglobulin as primary manifestations of adenosine deaminase 2 deficiency

Deficiency of adenosine deaminase 2 (DADA2) is an autosomal recessive disease associated with a highly variable clinical presentation, including systemic vasculitis, immunodeficiency, and cytopenia. We report a case of a 16-year-old girl affected by recurrent viral infections [including cytomegalovirus (CMV)-related hepatitis and measles vaccine virus-associated manifestations] and persistent inflammation, which occurred after Parvovirus infection and complicated by secondary hemophagocytic lymphohistiocytosis (HLH). HLH’s first episode presented at 6 years of age and was preceded by persistent fever and arthralgia with evidence of Parvovirus B19 infection. The episode responded to intravenous steroids but relapsed during steroids tapering. High-dose intravenous immunoglobulin (IVIG) helped manage her clinical symptoms and systemic inflammation. The frequency of IVIG administration and the dosage were progressively reduced. At the age of 9, she experienced varicella zoster virus (VZV) reactivation followed by the recurrence of the inflammatory phenotype complicated by HLH with neurological involvement. Again, high-dose steroids and monthly IVIG resulted in a quick response. Targeted next-generation sequencing (NGS) for autoinflammatory diseases and immunodeficiencies revealed the homozygous Leu183Pro ADA2 mutation, which was confirmed by Sanger analysis. ADA2 enzymatic test showed a complete loss of ADA2 activity. For about 3 years, IVIG alone was completely effective in preventing flares of inflammation and neurological manifestations. Anti-TNF treatment was started at the age of 13 for the appearance of recurrent genital ulcers, with a complete response. This case further expands the clinical spectrum of DADA2 and emphasizes the importance of extensive genetic testing in clinical phenotypes characterized by persistent unspecific inflammatory syndromes. The use of high doses of IVIG might represent a possible effective immune modulator, especially in combination with anti-TNF treatment.

Convalescent plasma in COVID-19: renewed focus on the timing and effectiveness of an old therapy

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the coronavirus disease 2019 (COVID-19) pandemic that has strained health care systems worldwide and resulted in high mortality. The current COVID-19 treatment is based on supportive and symptomatic care. Therefore, convalescent plasma (CP), which provides passive immunization against many infectious diseases, has been studied for COVID-19 management. To date, a large number of randomized and non-randomized clinical trials as well as many systematic reviews have revealed conflicting results. This article summarizes the basic principles of passive immunization, particularly addressing CP in COVID-19. It also evaluates the effectiveness of CP as a therapy in patients with COVID-19, clinical trial reports and systematic reviews, regulatory considerations and different protocols that are authorized in different countries to use it safely and effectively. An advanced search was carried out in major databases (PubMed, Cochrane Library, and MEDLINE) and Google Scholar using the following key words: SARS-CoV-2, COVID-19, convalescent plasma, and the applied query was “convalescent plasma” AND “COVID-19 OR SARS-CoV-2”. The results were filtered and duplicate data were removed. Collective evidence indicates that two cardinal players determine the effectiveness of CP use, time of infusion, and quality of CP. Early administration of CP with high neutralizing anti-spike IgG titer is hypothesized to be effective in improving clinical outcome, prevent progression, decrease the length of hospital stay, and reduce mortality. However, more reliable, high quality, well-controlled, double-blinded, randomized, international and multicenter collaborative trials are still needed.

Convalescent Plasma Reduces Mortality and Decreases Hospitalization Stay in Patients with Moderate COVID-19 Pneumonia

Humans infected with SARS-CoV-2 may develop COVID-19, which manifests across a wide spectrum of clinical severity ranging from mild upper respiratory tract illnesses to diffuse viral pneumonia, causing acute respiratory failure. Many therapies have been tested for their efficacy in treating COVID-19. Controversy surrounds convalescent plasma transfusions as an effective treatment for COVID-19. This study discusses the efficacy of this treatment on COVID-19 patients. Electronic medical record data were collected from patients diagnosed with COVID-19, from November 2020 to August 2021, in the Galilee Medical Center's COVID-19 departments. Epidemiological, clinical, laboratory and imaging variables were analyzed. Multivariate stepwise regression and discriminant analyses were used to identify and validate the correlation between convalescent treatment and either death or time to negative PCR and hospitalization length. The study population included 270 patients, 100 of them treated with convalescent plasma. The results show that convalescent plasma therapy significantly prevented mortality in moderate patients, reduced hospitalization length and time to negative PCR. Additionally, high BMI, elderly age, high CRP and 4C-scores correlated with the severity and mortality of COVID-19 patients. Convalescent plasma also significantly reduced inflammatory markers, especially in moderate COVID-19 patients. In non-critical hospitalized patients, convalescent plasma therapy reduces morbidity and mortality in moderate COVID-19 patients and hospitalization length. Identifying patients who could benefit from this treatment could reduce the risk of death and shorten their hospitalization stay.

Successful Treatment of Steroid-Refractory Checkpoint Inhibitor Myocarditis with Globulin Derived-Therapy: A case report and literature review

Immune checkpoint inhibitor (ICI) monoclonal antibody drugs are an important interface of immunology and cancer biology with the intended goal to create cancer specific treatments with less systemic toxicity. Recognition of immune-related adverse events is critical and these include significant cardiovascular toxicity and myocarditis. Compared with other immune-related events, ICI associated myocarditis is rare but is associated with high mortality. The majority of cases present early in the course of therapy and patients can rapidly progress to fulminant myocarditis. Initially, the mainstay of treatment in patients with ICI-associated myocarditis is immunosuppressive therapy with glucocorticoids. For those who do not respond to steroids, the optimal treatment is unclear. This review summarizes the potential adjunctive treatment options for patients with steroid-refractory myocarditis by illustrating a case of myocarditis that was treated with Thymoglobulin and immunoglobulin.

Potential mechanisms of action of convalescent plasma in COVID-19

The COVID-19 pandemic will be remembered as one of the worst catastrophic events in human history. Unfortunately, no universally recognized effective therapeutic agents are currently available for the treatment of severe SARS-CoV-2 infection. In this context, the use of convalescent plasma from recovered COVID-19 patients has gained increasing interest thanks to the initially positive clinical reports. A number of mechanisms of action have been proposed for convalescent plasma, including direct neutralization and suppression of viremia, anti-inflammatory and immunomodulation effects and mitigation of the COVID-19-associated hypercoagulable state. These immune and non-immune mechanisms will be critically discussed in this narrative review.

COVID-19: Imbalanced Immune Responses and Potential Immunotherapies

The ongoing pandemic coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is rapidly spreading and has resulted in grievous morbidity and mortality worldwide. Despite the high infectiousness of SARS-CoV-2, the majority of infected individuals are asymptomatic or have mild symptoms and could eventually recover as a result of their balanced immune function. On the contrary, immuno-compromised patients are prone to progress into severe or critical types underpinned by the entanglement of an overexuberant proinflammatory response and injured immune function. Therefore, well-coordinated innate and adaptive immune systems are pivotal to viral eradication and tissue repair. An in-depth understanding of the immunological processes underlying COVID-19 could facilitate rapidly identifying and choosing optimal immunotherapy for patients with severe SARS-CoV-2 infection. In this review, based on current immunological evidence, we describe potential immune mechanisms and discuss promising immunotherapies for COVID-19, including IL-6R blockades, convalescent plasma, intravenous gamma globulin, thymosin alpha1, corticosteroids, and type-I interferon, and recent advances in the development of COVID-19 vaccines.

A review of COVID-19 convalescent plasma use in COVID-19 with focus on proof of efficacy

Convalescent plasma (CP) therapy is rapidly becoming an established consideration in the treatment of COVID-19 patients though there is a need to critically review this area for proof of efficacy. Neutralizing antibodies (NAb) present in CP generated in response to SARS-CoV-2 infection directed against the receptor-binding domain (RBD) of the spike protein are considered to play main role in viral clearance. CP infusion may also help in the modulation of immune response by its immunomodulatory effect. The FDA allows for administration of CP to COVID-19 patients. The present published literature in COVID-19 is limited to case series and randomised controlled trial where plasma therapy was used in moderate, severe and critically ill patients. Though multiple uncertainties exist regarding to its efficacy, appropriate donor selection and NAb titres, the efficacy data of CP use inCOVID-19 is limited having shown hope with early and severe to critically ill COVID-19 patients.

Convalescent COVID-19 plasma

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a new human disease. December 31, 2019 marked the day the World Health Organization (WHO) first became aware of an infectious outbreak in the Hubei province in China. Until January 2021, more than two million people died from COVID-19. The use of convalescent plasma (CP) has been widely used in different outbreaks as the first therapeutic option given the lack of effective medications or vaccines, and often as a last chance or experimental treatment. CP is a strategy of passive immunisation. Possible mechanisms of CP-COVID-19 action are antiviral and immunomodulatory. The established protocol for CP-COVID-19 collection defines activities and criteria related to recruiting and informing potential CP donors, clinical and laboratory examination, plasma collection, labelling and storage. Plasma is collected by apheresis/plasmapheresis. Administration of plasma is performed at the request of clinicians, according to the strict indications based on the severity of clinical picture, expressed by precisely determined "scoring" of symptoms. The risks transfusion recipients are likely to be exposed to do not differ from those of standard plasma recipients. At the Blood Transfusion Institute of Serbia, the first plasmapheresis from the recovered patient-donor was performed on 11 April 2020 and so far, collection and distribution of CP-COVID-19 have been performed continuously. During the observation period, preliminary results of the effect of CP transfusion, along with other applied therapy, indicate its favourable effect, both worldwide and in Serbia. CP-COVID-19 should be used as early as possible in the course of infection in order to achieve the best outcomes.

Pathogenesis-directed therapy of 2019 novel coronavirus disease

The 2019 novel coronavirus disease (COVID-19) now is considered a global public health emergency. One of the unprecedented challenges is defining the optimal therapy for those patients with severe pneumonia and systemic manifestations of COVID-19. The optimal therapy should be largely based on the pathogenesis of infections caused by this novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since the onset of COVID-19, there have been many prepublications and publications reviewing the therapy of COVID-19 as well as many prepublications and publications reviewing the pathogenesis of SARS-CoV-2. However, there have been no comprehensive reviews that link COVID-19 therapies to the pathogenic mechanisms of SARS-CoV-2. To link COVID-19 therapies to pathogenic mechanisms of SARS-CoV-2, we performed a comprehensive search through MEDLINE, PubMed, medRxiv, EMBASE, Scopus, Google Scholar, and Web of Science using the following keywords: COVID-19, SARS-CoV-2, novel 2019 coronavirus, pathology, pathologic, pathogenesis, pathophysiology, coronavirus pneumonia, coronavirus infection, coronavirus pulmonary infection, coronavirus cardiovascular infection, coronavirus gastroenteritis, coronavirus autopsy findings, viral sepsis, endotheliitis, thrombosis, coagulation abnormalities, immunology, humeral immunity, cellular immunity, inflammation, cytokine storm, superantigen, therapy, treatment, therapeutics, immune-based therapeutics, antiviral agents, respiratory therapy, oxygen therapy, anticoagulation therapy, adjuvant therapy, and preventative therapy. Opinions expressed in this review also are based on personal experience as clinicians, authors, peer reviewers, and editors. This narrative review linking COVID-19 therapies with pathogenic mechanisms of SARS-CoV-2 has resulted in six major therapeutic goals for COVID-19 therapy based on the pathogenic mechanisms of SARS-CoV-2. These goals are listed below: 1. The first goal is identifying COVID-19 patients that require both testing and therapy. This is best accomplished with a COVID-19 molecular test from symptomatic patients as well as determining the oxygen saturation in such patients with a pulse oximeter. Whether a symptomatic respiratory illness is COVID-19, influenza, or another respiratory pathogen, an oxygen saturation less than 90% means that the patient requires medical assistance. 2. The second goal is to correct the hypoxia. This goal generally requires hospitalization for oxygen therapy; other respiratory-directed therapies such as prone positioning or mechanical ventilation are often used in the attempt to correct hypoxemia due to COVID-19. 3. The third goal is to reduce the viral load of SARS-CoV-2. Ideally, there would be an oral antiviral agent available such as seen with the use of oseltamivir phosphate for influenza. This oral antiviral agent should be taken early in the course of SARS-CoV-2 infection. Such an oral agent is not available yet. Currently, two options are available for reducing the viral load of SARS-CoV-2. These are post-Covid-19 plasma with a high neutralizing antibody titer against SARS-CoV-2 or intravenous remdesivir; both options require hospitalization. 4. The fourth goal is to identify and address the hyperinflammation phase often seen in hospitalized COVID-19 patients. Currently, fever with an elevated C-reactive protein is useful for diagnosing this hyperinflammation syndrome. Low-dose dexamethasone therapy currently is the best therapeutic approach. 5. The fifth goal is to identify and address the hypercoagulability phase seen in many hospitalized COVID-19 patients. Patients who would benefit from anticoagulation therapy can be identified by a marked increase in d-dimer and prothrombin time with a decrease in fibrinogen. To correct this disseminated intravascular coagulation-like phase, anticoagulation therapy with low molecular weight heparin is preferred. Anticoagulation therapy with unfractionated heparin is preferred in COVID-19 patients with acute kidney injuries. 6. The last goal is prophylaxis for persons who are not yet infected. Potential supplements include vitamin D and zinc. Although the data for such supplements is not extremely strong, it can be argued that almost 50% of the population worldwide has a vitamin D deficiency. Correcting this deficiency would be beneficial regardless of any impact of COVID-19. Similarly, zinc is an important supplement that is important in one's diet regardless of any effect on SARS-CoV-2. As emerging therapies are found to be more effective against the SARS-CoV-2 pathogenic mechanisms identified, they can be substituted for those therapies presented in this review.

Intravenous immunoglobulin therapy in COVID-19-related encephalopathy

Objective

To report on efficacy and safety of intravenous immunoglobulin (IVIg) therapy in a case series of patients with COVID-19-related encephalopathy.

Methods

We retrospectively collected data on all patients with COVID-19 hospitalized at two Italian hospitals who developed encephalopathy during disease course and were treated with IVIg.

Results

Five patients (two females, mean age 66.8 years) developed encephalopathy after a mean of 12.6 days, since the onset of respiratory/constitutional symptoms related to COVID-19. Four patients suffered severe respiratory distress, three of which required invasive mechanical ventilation. Neurological manifestations included impaired consciousness, agitation, delirium, pyramidal and extrapyramidal signs. EEG demonstrated diffuse slowing in all patients. Brain MRI showed non-specific findings. CSF analysis revealed normal cell count and protein levels. In all subjects, RT-PCR for SARS-CoV-2 in CSF tested negative. IVIg at 0.4 g/kg/die was commenced 29.8 days (mean, range: 19–55 days) after encephalopathy onset, leading to complete electroclinical recovery in all patients, with an initial improvement of neuropsychiatric symptoms observed in 3.4 days (mean, range: 1–10 days). No adverse events related to IVIg were observed.

Conclusions

Our preliminary findings suggest that IVIg may represent a safe and effective treatment for COVID-19-associated encephalopathy. Clinical efficacy may be driven by the anti-inflammatory action of IVIg, associated with its anti-cytokine qualities.

Electronic supplementary material

The online version of this article (10.1007/s00415-020-10248-0) contains supplementary material, which is available to authorized users.

Convalescent plasma in Covid-19: Possible mechanisms of action

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible of the coronavirus disease 2019 (COVID-19) pandemic. Therapeutic options including antimalarials, antivirals, and vaccines are under study. Meanwhile the current pandemic has called attention over old therapeutic tools to treat infectious diseases. Convalescent plasma (CP) constitutes the first option in the current situation, since it has been successfully used in other coronaviruses outbreaks. Herein, we discuss the possible mechanisms of action of CP and their repercussion in COVID-19 pathogenesis, including direct neutralization of the virus, control of an overactive immune system (i.e., cytokine storm, Th1/Th17 ratio, complement activation) and immunomodulation of a hypercoagulable state. All these benefits of CP are expected to be better achieved if used in non-critically hospitalized patients, in the hope of reducing morbidity and mortality.

Convalescent plasma in Covid-19: Possible mechanisms of action

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible of the coronavirus disease 2019 (COVID-19) pandemic. Therapeutic options including antimalarials, antivirals, and vaccines are under study. Meanwhile the current pandemic has called attention over old therapeutic tools to treat infectious diseases. Convalescent plasma (CP) constitutes the first option in the current situation, since it has been successfully used in other coronaviruses outbreaks. Herein, we discuss the possible mechanisms of action of CP and their repercussion in COVID-19 pathogenesis, including direct neutralization of the virus, control of an overactive immune system (i.e., cytokine storm, Th1/Th17 ratio, complement activation) and immunomodulation of a hypercoagulable state. All these benefits of CP are expected to be better achieved if used in non-critically hospitalized patients, in the hope of reducing morbidity and mortality.

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Coronavirus disease 19 (COVID-19) is an emerging viral threat with major repercussions for public health.

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There is not specific treatment for COVID-19.

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Convalescent plasma (CP) emerges as the first option of management for hospitalized patients with COVID-19.

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Transference of neutralizing antibodies helps to control COVID-19 infection and modulates inflammatory response.

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Other plasma components may enhance the antiviral and anti-inflammatory properties of CP.

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.

Immunoglobulin Therapy in a Patient With Severe Chikungunya Fever and Vesiculobullous Lesions

Chikungunya virus (CHIKV) is an emerging arbovirus whose transmission has already been reported in several countries. Although the majority of individuals acutely infected with CHIKV appear to become asymptomatic, reports showing the occurrence of atypical and severe forms of the disease are increasing. Among them, the neurological and skin manifestations require medical attention. Treatment of CHIKV infection is almost symptomatic. In this sense, we report the case of a 56-years-old man who presented fever, headaches, paresthesia and pain in the right arm with visible red spots on the skin starting 30 days before Hospital admission. Tests determined Chikungunya infection and excluded other co-morbidities. Disease evolved with edema in hands and feet and extensive hemorrhagic bullous lesions on the skin of upper and lower limbs. Variations in hematological counts associated with liver dysfunction determined this patient's admission to the Intensive Care Unit. Then, he received intravenous antibiotic and immunoglobulin therapy (400 mg/Kg/day for the period of 5 days) with total recovery from the lesions after 10 days of follow-up. A general improvement in blood cell count and successful wound healing was observed. After discharge, no other clinical sign of the disease was reported until nowadays. This case reports for the first time the successful administration of intravenous immunoglobulin therapy to a patient with severe atypical dermatological form of Chikungunya Fever without any associated comorbidity.

Intravenous immunoglobulin replacement treatment reduces in vivo elastase secretion in patients with common variable immune disorders

BACKGROUND

Intravenous immunoglobulin (IVIg) treatment partially replaces antibody defects and modulates innate and adaptive immune cells in patients with primary antibody deficiencies.

MATERIALS AND METHODS

This study was focused on the evaluation of the effects of in vivo IVIg administration on neutrophils from patients with common variable immune disorders (CVID). We examined polymorphonuclear neutrophil (PMN) phagocytosis, PMN oxidative burst, release of neutrophil elastase, serum level of interleukin-8 and PMN expression of CXCR1, CD11c and CD66b.

RESULTS

CVID patients on chronic IVIg treatment had reduced elastase release, but normal expression of CXCR1, CD66b and CD11c receptors on PMN, normal phagocytic ability and normal secretion of interleukin-8. We found that IVIg infusions rapidly reduced the serum level of interleukin-8, the expression of its receptor, CXCR1, and the release of neutrophil elastase, suggesting that IVIg exert a dampening effect on neutrophil activity. In contrast, IVIg infusions did not alter neutrophil phagocytosis or the expression of the other receptors analysed.

DISCUSSION

These findings add further information regarding the anti-inflammatory role of immunoglobulins and suggest additional benefits in keeping with recent attempts to use new therapies targeting neutrophil inflammation.

rIgG1 Fc Hexamer Inhibits Antibody-Mediated Autoimmune Disease via Effects on Complement and FcγRs

Activation of Fc receptors and complement by immune complexes is a common important pathogenic trigger in many autoimmune diseases and so blockade of these innate immune pathways may be an attractive target for treatment of immune complex-mediated pathomechanisms. High-dose IVIG is used to treat autoimmune and inflammatory diseases, and several studies demonstrate that the therapeutic effects of IVIG can be recapitulated with the Fc portion. Further, recent data indicate that recombinant multimerized Fc molecules exhibit potent anti-inflammatory properties. In this study, we investigated the biochemical and biological properties of an rFc hexamer (termed Fc-μTP-L309C) generated by fusion of the IgM μ-tailpiece to the C terminus of human IgG1 Fc. Fc-μTP-L309C bound FcγRs with high avidity and inhibited FcγR-mediated effector functions (Ab-dependent cell-mediated cytotoxicity, phagocytosis, respiratory burst) in vitro. In addition, Fc-μTP-L309C prevented full activation of the classical complement pathway by blocking C2 cleavage, avoiding generation of inflammatory downstream products (C5a or sC5b-9). In vivo, Fc-μTP-L309C suppressed inflammatory arthritis in mice when given therapeutically at approximately a 10-fold lower dose than IVIG, which was associated with reduced inflammatory cytokine production and complement activation. Likewise, administration of Fc-μTP-L309C restored platelet counts in a mouse model of immune thrombocytopenia. Our data demonstrate a potent anti-inflammatory effect of Fc-μTP-L309C in vitro and in vivo, likely mediated by blockade of FcγRs and its unique inhibition of complement activation.

Review: Bacterial endotoxin and the human monoclonal antibody HA-IA: specificity, potential mechanisms of action, and limits to its effectiveness

Bacterial endotoxins are lipopolysaccharides present in the outer membrane of all Gram-negative bacteria (GNB). Endotoxins consist of a lipid moiety, lipid A, that is covalently linked to highly variable, serotype O-specific polysaccharide lateral chains. In contrast, the endotoxin core, which includes lipid A, is better conserved and can be recognized by antibodies showing cross-reactivity among various GNB. Such polyclonal and monoclonal antibodies have been developed in an attempt to neutralize the biological and dele. terious effects of endotoxin, thus preventing lipid A from binding to macrophages. In fact, almost all the biological activities of endotoxin are elicited by lipid A, and there is substantial evidence to the effect that the monocyte-macrophage is the principal mediator of endotoxicity. Antiserum against LPS isolated from rough mutants of GNB (expressing virtually only the central core-lipid A), has been shown to counteract the lethal effects of endotoxin in animals and humans. However, such serum or plasma contains antibodies of different specificities and isotypes which represent different effector functions, insofar as LPS is a very complex and highly heterogenous macromolecule. Because of the difficulties encountered in investigating the nature and specificity of the protection afforded by these antisera, and their limited capacity of production for therapeutic use, specific anti-lipid A monoclonal antibodies have been produced in their stead. A variety of mouse and human monoclonal antibodies against LPS have been generated and selected for their ability to cross-react with many GNB species. The most recent clinical trials involving the treatment of septic patients with human HA-IA (Centoxin) or with murine (E5) anti-lipid A monoclonal antibody showed no difference in survival rates, as compared to treatment with a placebo. However, statistical significance was demonstrated in subsets of patients suffering from documented Gram-negative septicemia or Gram-negative sepsis without refractory shock. The usefulness of anti-lipid A antibodies will undoubtedly remain controversial, since they appear to benefit only a minority of all patients treated, and also because no consensus exists regarding their specificity and modes of action. The aim of this review is to describe results which demonstrate the requirements for, difficulties in and limits to, elucidating the ability of certain antibodies to recognize structural elements present in the lipid A domain of LPS. A clear demonstration of antibody cross-reactivity was obtained only when rough LPS bacteria were used, and was markedly enhanced when smooth bacteria had been pretreated with cell wall active antibiotics. Further, new data have recently demonstrated the specific involvement of HA-IA in the immunocytoadherence assay in the presence of human complement and human red blood cells. Such phenomena may form part of the potential role for natural or monoclonal human IgM anti-lipid A antibodies, which will be to remove IgM-lipid A immune complexes through transhepatic clearance via C3b binding to the CR1 present on circulating human erythrocytes. Insofar as immunocytoadherence is a multiparameter phenomenon, various limiting factors probably interfere with its mechanism of clearance. These factors may be absent in various subsets of septic patients under treatment, thus explaining therapeutic failures with HA-IA in humans or preclinical animal studies. Several clinical settings involving defects to CR1 expression, C3b production, LPS recognition and hepatic clearance dysfunction are described. Long term, however, it will impossible to specify the patient subsets suitable for monoclonal therapy without first defining their characteristics. HA-IA may be able to inhibit one of the earliest stages in activation of the cytokine cascade by sequestrating and eliminating biologically active lipid A. The major problem today in terms of using anti-lipid A antibodies is an efficiently early detection of specific pathway defects which detract from or nullify the HA-IA therapeutic effect.

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

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

Immunomodulation by IVIg and the Role of Fc-Gamma Receptors: Classic Mechanisms of Action after all?

Intravenous IgG (IVIg) contains polyclonal immunoglobulin G (IgG) from thousands of donors. It is administered at a low dose at regular intervals as antibody replacement therapy and at a higher dose as immunomodulatory treatment in various auto-immune or auto-inflammatory diseases. The working mechanism of immunomodulation is not well understood. Many different explanations have been given. During the last decade, we have focused on classical antibody binding via the Fc-domain of the IgG molecules to the common IgG receptors, i.e. the Fcγ receptors (FcγRs). Variation in the genes encoding human FcγRs determines function as well as expression among immune cells. As described here, NK cells and myeloid cells, including macrophages, can express different FcγR variants, depending on the individual's genotype, copy number variation (CNV), and promoter polymorphisms. B-cells seem to only express the single inhibitory receptor. Although these inhibitory FcγRIIb receptors are also expressed by monocytes, macrophages, and only rarely by NK cells or neutrophils, their presence is unlikely to explain the immunomodulatory capacity of IVIg, nor does the sialylation of IgG. Direct IVIg effects at the level of the activating FcγRs, including the more recently described FcγRIIc, deserve renewed attention to describe IVIg-related immunomodulation.

Biologics in dermatology: an integrated review

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

Therapeutic effect of IVIG on inflammatory arthritis in mice is dependent on the Fc portion and independent of sialylation or basophils

High-dose i.v. Ig (IVIG) is used to treat various autoimmune and inflammatory diseases; however, the mechanism of action remains unclear. Based on the K/BxN serum transfer arthritis model in mice, IVIG suppression of inflammation has been attributed to a mechanism involving basophils and the binding of highly sialylated IgG Fc to DC-SIGN-expressing myeloid cells. The requirement for sialylation was examined in the collagen Ab-induced arthritis (CAbIA) and K/BxN serum transfer arthritis models in mice. High-dose IVIG (1-2 g/kg body weight) suppressed inflammatory arthritis when given prophylactically. The same doses were also effective in the CAbIA model when given subsequent to disease induction. In this therapeutic CAbIA model, the anti-inflammatory effect of IVIG was dependent on IgG Fc but not F(ab')2 fragments. Removal of sialic acid residues by neuraminidase had no impact on the anti-inflammatory activity of IVIG or Fc fragments. Treatment of mice with basophil-depleting mAbs did not abrogate the suppression of either CAbIA or K/BxN arthritis by IVIG. Our data confirm the therapeutic benefit of IVIG and IgG Fc in Ab-induced arthritis but fail to support the significance of sialylation and basophil involvement in the mechanism of action of IVIG therapy.

Mechanistic effects of IVIg in neuroinflammatory diseases: conclusions based on clinicopathologic correlations

The mechanisms of action of IVIg on immunoregulatory and neuroinflammatory network have been predominantly based on in vitro experiments and animal studies, rather than direct effects on human tissues. Based on clinicopathologic correlations and tissues obtained before and after IVIg therapy, the better documented and clinically-relevant in-vivo actions of IVIg include effects on: a) Antibodies. An extracted antigen-specific anti-immunoglobulin (idiotypic) fraction appears partially responsible for its effect in myasthenia gravis and GBS; b) Complement. Sera from Dermatomyositis (DM) patients responding to IVIg, inhibit complement consumption and intercept MAC formation leading to disappearance of MAC deposits in the repeated muscle biopsies and normalization of muscle tissue; c) Genes. In repeated muscle biopsies from DM patients who improved after IVIg, but not from Inclusion-Body-Myositis (IBM) who did not improve, there is a 2-fold alteration of 2206 tissue genes associated with inflammation, fibrosis, tissue remodeling and regeneration; and d) degenerative-proinflammatory molecules and β-amyloid, implicated in neurodegenerative CNS diseases and IBM. In repeated muscle biopsies of IBM patients who did not respond to IVIg, the mRNA or protein expression for chemokines, IFN-γ, TGF-ß, IL-10, Ubiquitin and aB-crystallin is reduced, but not for the key molecules ICOS, ICOSL, IL-6, IL1-β, perforin, APP, nitric oxide synthase and nitrotyrosine, in spite of good IVIg penetration in muscles. Collectively, the selective effectiveness of IVIg in human diseases seems to correlate in vivo with inhibition of causative inflammatory mediators. Study of accessible tissues before and after therapy and clinicopathologic correlations, may help explain the differential effect of IVIg in autoimmune or neuroinflammatory diseases.

Study on risk factors for severe hand, foot and mouth disease in China

Background

Epidemics of HFMD are elevated every year globally, especially in mainland China. The disease now presents as an increasing threat to public health worldwide.

Methods

Five hundred and seventy-one EV71-infected HFMD patients in Beijing You'an Hospital were grouped by disease severity: Mild (no severe complication) (n = 221), and Severe group (complicated with brainstem encephalitis (BE), and/or pulmonary edema (PE) (n = 350)). Clinical and laboratory findings and levels of 7 serum cytokines were analyzed.

Results

Univariate analysis showed that (RR)>26/min (p<0.001), age<4 yo (p = 0.001), GLU>8.3 mmol/L (p = 0.008), CL<98 mmol/L (p = 0.026), and WBC>1.2×10⁹/L (p = 0.040) were associated with severe cases. Results of multivariate analysis indicated five independent risk factors (RR>26/min (p<0.001), Age<4 yo (p<0.001), GLU>8.3 mmol/L (p = 0.011), LYM>40% (p = 0.010), and ALT>40 U/L (p = 0.045)). In addition to single-factor analysis, we further analyzed the use of different combinations of risk factors. “GLU>8.3 and CL<98 and RR>26” (confidence ration (CR) = 100%) is the top indicator, followed by “ALT>40 and LYM>40% and RR>26 and Age<4 yo” (CR = 92.9%).

Serum levels of IL-2, IL-4, IL-10, IFNγ, GM-CSF, and TNFα were higher in severe cases than in mild cases. A new evaluation scoring system by scoring each risk factor 1 and independent risk factor 2 was developed for early identification of severe HFMD cases.

Conclusions

Five independent risk factors, along with indicative combinations of risk factors, for severe cases were identified, and a scoring system was created to facilitate the use of indicators for early medical intervention.

Intravenous immunoglobulin and Alzheimer's disease: what now?

Intravenous immunoglobulin (IVIG) products are prepared from purified plasma immunoglobulins from large numbers of healthy donors. Pilot studies with the IVIG preparations Octagam and Gammagard in individuals with mild-to-moderate Alzheimer’s disease (AD) suggested stabilization of cognitive functioning in these patients, and a phase II trial with Gammagard reported similar findings. However, subsequent reports from Octagam’s phase II trial and Gammagard’s phase III trial found no evidence for slowing of AD progression. Although these recent disappointing results have reduced enthusiasm for IVIG as a possible treatment for AD, it is premature to draw final conclusions; a phase III AD trial with the IVIG product Flebogamma is still in progress. IVIG was the first attempt to use multiple antibodies to treat AD. This approach should be preferable to administration of single monoclonal antibodies in view of the multiple processes that are thought to contribute to AD neuropathology. Development of “AD-specific” preparations with higher concentrations of selected human antibodies and perhaps modified in other ways (such as increasing their anti-inflammatory effects and/or ability to cross the blood–brain barrier) should be considered. Such preparations, if generated with recombinant technology, could overcome the problems of high cost and limited supplies, which have been major concerns relating to the possible widespread use of IVIG in AD patients. This review summarizes the recent AD IVIG trials and discusses the major issues relating to possible use of IVIG for treating AD, as well as the critical questions which remain.

Intravenous immunoglobulin preparation attenuates LPS-induced production of pro-inflammatory cytokines in human monocytic cells by modulating TLR4-mediated signaling pathways

Intravenous immunoglobulin (IVIG) has been used for the treatment of inflammatory and autoimmune diseases. The ability to modulate cytokine production has been formerly described as one of the mechanisms of its action. This study aimed to investigate the effect of IVIG on the production of pro-inflammatory cytokines in lipopolysaccharide (LPS)-stimulated monocytic cells. Peripheral blood mononuclear cells (PBMCs) or THP-1 cells treated with phorbol myristate acetate (PMA) were stimulated with LPS. The protein levels of pro-inflammatory cytokines [tumor necrosis factor (TNF)-α, interleukin (IL)-6, and high-mobility group box 1 (HMGB1)] in the culture supernatants were determined using appropriate enzyme-linked immunosorbent assay kits. The mRNA of TNF-α was determined by reverse transcription-polymerase chain reaction. The phosphorylation of nuclear factor kappa B (NF-κB) and the mitogen-activated protein kinases was examined by Western blot analyses. IVIG suppressed the production of pro-inflammatory cytokines such as TNF-α and IL-6 in LPS-stimulated PBMCs. Furthermore, IVIG inhibited TNF-α, IL-6, and HMGB1 production from LPS-stimulated THP-1 cells treated with PMA. In addition, Fc fragment prepared from the IVIG inhibited production of these cytokines from the cells to the same degree as IVIG, whereas Fab and F(ab')(2) fragments inhibited this only partially. We showed that IVIG and Fc fragments suppressed LPS-induced signal transduction pathways involving phosphorylation of NF-κB, p38, and c-Jun N-terminal kinase (JNK). Taken together, our results suggest that IVIG attenuates LPS-induced cytokine production predominantly mediated by its Fc region. The activity might be regulated by inhibiting NF-κB, p38, and JNK pathways in human monocytic cells.

Intravenous immunoglobulin-based immunotherapy: an arsenal of possibilities for patients and science

The use of intravenous immunoglobulin (IVIG) concentrated from pooled healthy donors' plasma has gained increasing popularity. IVIG therapy has become important as a replacement therapy in primary and acquired humoral immunodeficiencies, and it has been extended to autoimmune, neurodegenerative and inflammatory conditions and transplantation therapy. Recurrent pregnancy failure and cancer are rather new platforms, where IVIG has shown its beneficial effects. This manuscript is focused on these two off-labelled usages. The immunomodulatory mechanisms of IVIG therapy appear as a coordinated orchestration of different functions, resulting in a synergistic effect. Treatment monitoring and detailed molecular analyses reveal how such treatments may interfere with disease pathogenesis. These finding may foster the development of novel therapeutic and/or preventive strategies. Studying this field with bidirectional bench-to-bedside and bedside-to-bench approaches fit well into 'the two-way road' paradigm of translational medicine.

Sustained high levels of interleukin-6 contribute to the pathogenesis of enterovirus 71 in a neonate mouse model

Enterovirus 71 (EV71) is the major causative agent of hand, foot, and mouth disease (HFMD) in young children and has been consistently associated with the most severe complications of the disease, including central nervous system inflammation and pulmonary edema. Increasing frequency and amplitude of EV71 outbreaks have raised awareness and concerns worldwide. Previous reports proposed that overwhelming virus replication combined with the induction of massive proinflammatory cytokines is responsible for the pathogenicity of EV71. Specifically, elevated interleukin-6 (IL-6) levels were observed consistently in patients and strongly correlated with disease severity. In this study, we show in the neonate mouse model that sustained high levels of IL-6 produced upon EV71 infection lead to severe tissue damage and eventually death of the animals. Administration of anti-IL-6 neutralizing antibodies after the onset of the clinical symptoms successfully improved the survival rates and clinical scores of the infected hosts. Compared to untreated infected controls, anti-IL-6-treated mice displayed reduced tissue damage, absence of splenic atrophy, and increased immune cell activation. In addition, markedly elevated systemic levels of IL-10 were measured in the protected animals. Furthermore, there was no significant difference in virus titers between anti-IL-6-treated mice and untreated mice, indicating that the anti-IL-6 antibody-mediated protection is independent of the virus load. Our findings thus demonstrate that IL-6 plays a major role in EV71-induced immunopathogenesis. As there is still neither vaccine nor treatment available against EV71, anti-IL-6 antibody treatment represents a potential therapeutic approach to providing protection from the most severe complications of the disease.

Beneficial effect of triple treatment plus immunoglobulin in experimental nephrotic syndrome

Combinations of antiproteinurics, including angiotensin I-converting enzyme inhibitors + angiotensin II receptor antagonist + statins, are promising choices in the treatment of steroid-resistant nephrotic syndrome. We aimed to investigate the effects of high doses of immunoglobulin in addition to these combinations in rats with adriamycin-induced nephrosis. The study included 40 rats allocated into five groups: control, nephrotic syndrome without treatment, dual therapy (DT) with enalapril + losartan, triple therapy (TT) with enalapril + losartan + simvastatin, and quadruple therapy (QT) with enalapril + losartan + simvastatin + a high dose of immunoglobulin. The proteinuria levels were not statistically different between DT, TT and QT groups at weeks 5, 8, 12 and 16. At week 16, serum creatinine levels in the QT group were significantly lower than those in the control, DT and TT groups. The glomerulosclerosis index in the DT group was significantly lower than in the TT and QT groups. The scores for interstitial fibrosis and TGF-beta staining were similar among treatment groups. In conclusion, we showed that quadruple therapy including immunoglobulin had a beneficial effect on renal function in the late phase, but it had no additional effects in reducing proteinuria or in glomerulosclerosis score in experimental nephrotic syndrome. Further studies with angiotensin I-converting enzyme inhibitors (ACEIs), angiotensin II receptor antagonists (AIIRAs) and immunoglobulin combinations would offer some benefits in the treatment of nephrotic syndrome.

History of immunoglobulin replacement

The provision of antibodies to prevent and treat infection began with the application of "curative serum" in the first years of the last century. After the process of large-scale plasma fractionation was developed in the 1940s, the general use of immunoglobulin expanded. Intravenous immunoglobulin products became available in the 1970s, and their only use for the provision of antibodies governed the opinion of experts over the next decade. Modulation of inflammation and immunosuppression were introduced in treatment of inflammatory and autoimmune diseases and became accepted indications. The history of adverse events of treatment and their management are outlined in this article. Consensus indications and evidence-based off-label uses are discussed.

The use of i.v. IG therapy in dermatology

The intravenous administration of exogenous pooled human immunoglobulin (i.v. IG) was originally licensed as antibody replacement therapy in patients with primary immunodeficiencies and there are currently six FDA-approved uses for this agent. Despite a current lack of FDA approval, off-label treatment of a multitude of dermatologic disorders with i.v. IG has shown exciting potential for this unique treatment modality. The diseases successfully treated with i.v. IG include autoimmune bullous diseases, connective tissue diseases, vasculitides, toxic epidermal necrolysis, and infectious disorders (such as streptococcal toxic shock syndrome). Currently the biggest drawback in the consideration of i.v. IG therapy in dermatologic disorders is the lack of randomized controlled trials. Nevertheless, there is a significant body of evidence demonstrating the efficacy of i.v. IG in patients with dermatologic disorders that are resistant to treatment with standard agents. In summary, i.v. IG constitutes a valuable and potentially life-saving agent in managing patients with a variety of dermatologic disorders under the appropriate circumstances.

Intravenous Immunoglobulin and Cytokines: Focus on Tumor Necrosis Factor Family Members BAFF and APRIL

The presence of natural autoantibodies against cytokines has been reported in healthy individuals. Because circulating cytokines may be implicated in the clinical outcome of numerous diseases, the mode of action of intravenous immunoglobulin (IVIg) (pooled from sera over a thousand normal individuals) may involve immunomodulation of the cytokine network. We review the anti-cytokine effects of IVIg as well as the consequences of IVIg infusions on cytokine production. Furthermore, IVIg exerts therapeutic effects in autoimmune diseases and lymphoid malignancies. These two conditions have in common an overproduction of BAFF (for B-cell-activating factor of the TNF family). The presence of antibodies with BAFF and APRIL (a proliferation-inducing ligand) specificity was investigated. We found that IVIg recognizes BAFF and APRIL and that IVIg binding prevents BAFF from exerting its antiapoptotic effect on B cells. These anti-BAFF IgGs might prevent the deleterious effects of BAFF in B-cell-mediated autoimmune diseases.

Effects of Intravenous Immunoglobulins on Peripheral Blood Mononuclear Cell Activation in Vitro

The therapeutic effects of intravenous immunoglobulins (IVIGs) on different chronic inflammatory and autoimmune diseases is well appreciated, though clinical studies with high-evidence levels are largely missing. Similar to the broad spectrum of diseases and their underlying etiopathogenic background, the mechanisms of action seem heterogenous and multifold. Several studies addressing in vitro and in vivo effects of IVIG on various immunological parameters have been described with partly contradictory results. In this study immunoglobulins and stabilizers present in commercial IVIG preparations were studied in regard to the in vitro proliferation and cytokine production of peripheral blood mononuclear cells when stimulated with phytohemagglutinin (PHA), interleukin 2, and tetanus toxoid. Whereas the immunoglobulins stimulate the proliferation of PBMCs and decrease IFNgamma secretion, stabilizers of IVIG seem to inhibit the proliferation of PBMCs while increasing the secretion of IFN gamma. These effects have to be taken into account when balancing the impact of IVIG dosage and infusion intervals and relating them to clinical side effects and therapeutic efficacy.

Effective treatment of experimental autoimmune neuritis with human immunoglobulin

High-dose intravenous immunoglobulin (IVIg) is an effective treatment for inflammatory demyelinating neuropathies, although the mechanism(s) of action remain incompletely understood. Experimental autoimmune neuritis (EAN) is an animal model of inflammatory demyelinating neuropathies; however, there have been conflicting reports regarding the efficacy of human IVIg in EAN. To obtain a model suitable for the study of the mechanism(s) of action of IVIg in Guillain-Barré syndrome, we investigated the effect of IVIg in EAN in the rat using clinical, electrophysiological and morphological measures. Human IVIg administered at the onset of signs of disease proved effective in preventing further progression of disease and shortening disease duration. This effectiveness was associated with significant differences in electrophysiological parameters including less prolongation of somatosensory evoked potential (S wave) latencies, better maintained S wave amplitudes, less reduction of distal motor nerve conduction velocity, and better maintained amplitudes of compound muscle action potentials of the dorsal foot muscles after stimulation at ankle and hip. Moreover, treatment with IVIg resulted in significantly lower histological grades in rat EAN. The current study provides evidence that human IVIg is effective in the treatment of EAN in the rat, indicating that this model may facilitate further investigation of the mechanism(s) of action of IVIg in inflammatory demyelinating neuropathies.

Transfusion-related inhibition of cytokines (TRICK). Experimental transfer of neutralizing autoantibodies to interleukin-6 by plasma transfusions

BACKGROUND

For some unknown reason humans may 'spontaneously' produce high amounts of neutralizing autoantibodies to a number of growth factors and cytokines. Reaching a certain high level the antibodies render the person cytokine deficient, mostly without overt clinical manifestations. The autoantibodies in question are detectable in normal immunoglobulin preparations and correspondingly in normal human plasma for transfusion. High affinity neutralizing autoantibodies to interleukin-6 (aAb-IL-6) are present in high titres in 0.1% of plasma from blood donors. Using aAb-IL-6 as a model we here report the first study addressing transfer of cytokine autoantibodies with blood components.

MATERIALS AND METHODS

We transferred high amounts of aAb-IL-6 to two patients suffering from end-stage disease of multiple myeloma. This was done by serial transfusions with normal human plasma highly positive for aAb-IL-6. We assessed recovery and kinetics of the transferred aAb-IL-6 and exposed how the recipients' plasma IL-6 bound to aAb-IL-6.

RESULTS

Free IL-6 was detectable in plasma of the recipients before transfusion. After the first transfusion IL-6 became immune complexed to aAb-IL-6 the molar plasma concentrations of which exceeded total IL-6 at least 500 times.

CONCLUSION

The observations signify that high amounts of neutralizing autoantibodies to cytokines (in this context aAb-IL-6) are occasionally transferred by transfusion. Although neither beneficial nor obvious detrimental effects of the plasmas were observed in this study our measurements evidently uncover a hitherto unknown form of transfusion-related immune modulation: transfusion-related inhibition of cytokines (TRICK). Depending on the cytokine autoantibody in question, the phenomenon might affect immune responses to infection and recovery after stem cell transplantation.

Off-label uses of biologics in dermatology: Interferon and intravenous immunoglobulin (Part 1 of 2)

The introduction of a number of biologic therapies into the market has revolutionized the practice of dermatology. These therapies include interferons, intravenous immunoglobulin, infliximab, adalimumab, etanercept, efalizumab, alefacept, and rituximab. Most dermatologists are familiar with the Food and Drug Administration-approved indications of these medications. However, numerous off-label uses have evolved. As part 1 of a 2-part series, this article will review the literature regarding the off-label uses of the interferons and intravenous immunoglobulin in dermatology.

Immunologic and functional evidence for anti–Siglec-9 autoantibodies in intravenous immunoglobulin preparations

Human intravenous immunoglobulin (IVIg) preparations are increasingly used for the treatment of autoimmune diseases. Earlier work demonstrated the presence of autoantibodies against Fas in IVIg, suggesting that IVIg might be able to induce caspase-dependent cell death in Fas-sensitive cells. In this study, we demonstrate that sialic acid–binding Ig-like lectin 9 (Siglec) represents a surface molecule on neutrophils that is activated by IVIg, resulting in caspase-dependent and caspase-independent forms of cell death. Neutrophil death was mediated by naturally occurring anti–Siglec-9 autoantibodies present in IVIg. Moreover, the efficacy of IVIg-mediated neutrophil killing was enhanced by the proinflammatory cytokines granulocyte/macrophage colony-stimulating factor (GM-CSF) and interferon-γ (IFN–γ), and this additional cell death required reactive oxygen species (ROSs) but not caspases. Anti– Siglec-9 autoantibody–depleted IVIg failed to induce this caspase-independent neutrophil death. These findings contribute to our understanding of how IVIg preparations exert their immunoregulatory effects under pathologic conditions and may provide a possible explanation for the neutropenia that is sometimes seen in association with IVIg therapy.