Monocyte-macrophage system as targets for immunomodulation by intravenous immunoglobulin

Eculizumab as a Treatment for Hyper-Haemolytic and Aplastic Crisis in Sickle Cell Disease

Background

Patients with sickle cell disease can experience various crises including sequestration crisis, haemolytic crisis and aplastic crisis. Due to alloantibody formation, transfusion alloantibodies can cause a haemolytic crisis. Treatment involves avoiding packed red blood cell transfusions, as well as intravenous immunoglobulin, steroids and eculizumab to decrease the chances of haemolysis.

Case description

We report the case of a 42-year-old man who was found to have worsening anaemia after packed red blood cell transfusion with evidence suggestive of haemolytic crisis. Due to reticulocytopenia, aplastic crisis was also suspected and later confirmed via parvovirus IgG and IgM titres. The patient did not improve with steroid and intravenous immunoglobulin therapy and was treated with eculizumab as a salvage therapy.

Conclusion

Concurrent hyper-haemolytic crisis and aplastic crisis should be suspected in patients with features of haemolysis and reticulocytopenia. Prompt recognition and treatment with eculizumab are paramount in those who fail steroid and intravenous immunoglobulin treatment.

LEARNING POINTS

Treatment of hyper-haemolytic and aplastic crisis in sickle cell disease with eculizumab offers therapeutic benefit.A high index of suspicion for hyper-haemolytic crisis and aplastic crisis should be maintained in those with haemolytic features as well as reticulocytopenia in the setting of sickle cell disease.

A prospective observational study of the incidence, natural history, and risk factors for intravenous immunoglobulin-mediated hemolysis

BACKGROUND

Intravenous Immune Globulin (IVIG) is used to treat numerous immune-mediated and inflammatory conditions. There is growing awareness of hemolysis, occasionally severe, as a side-effect of this therapy. While most cases are associated with anti-A and/or anti-B isoagglutinins, the frequency and mechanism of hemolysis remain poorly characterized.

STUDY DESIGN AND METHODS

A prospective observational study was conducted to determine incidence, natural history and risk factors for IVIG-mediated hemolysis. A total of 99 infusions of high-dose IVIG (2 g/kg or higher) administered to 78 non-group O patients were monitored and graded according to Canadian IVIG Hemolysis Pharmacovigilance Group. Serum ferritin and C3/C4 levels were monitored as indicators of macrophage activation and complement consumption, respectively. Supplementary investigations included assessment for ABO zygosity, Secretor status, FcR polymorphisms, eluate IgG subclass, monocyte monolayer assay, and a panel of cytokines.

RESULTS

Hemolysis was observed in 32 of 99 (32%) of infusions, with 19 of 99 (19%) grade 2 or higher. Hemolysis was only apparent 5-10 days after a completed IVIG infusion in 84% of cases and was associated with increases in serum ferritin without complement-consumption. In univariate analysis, increased risk was observed in group AB patients, first-time IVIG recipients, those not taking immuosuppressive medications, or patients treated with a specific IVIG brand; however, in multivariate analysis, product association was no longer observed. No other patient- or practice-related risk factors were identified.

CONCLUSION

IVIG-mediated hemolysis is common and frequently severe. Monitoring for 5-10 days following an infusion should be considered in non-O patients receiving high-dose IVIG with known risk factors.

Intravenous Immunoglobulin for Overwhelming Postsplenectomy Infection

Overwhelming postsplenectomy infection (OPSI) is a life-threatening condition causing fulminant bacteremia in asplenic patients. Intravenous immunoglobulin (IVIG) therapy is theoretically effective for OPSI. Herein, we present a case of OPSI treated successfully with IVIG, along with results of a literature review. An asplenic 70-year-old male with acute ischemic stroke presented with rapid and fulminant septic shock from pneumococcus pneumonia and bacteremia. Resuscitation and antibiotics including IVIG therapy were instituted. The patient survived with favorable outcomes. We analyzed all case reports or case series of OPSI from 1971 through 2017. Cases with IVIG treatment showed a significantly higher survival rate than those without IVIG, even with multivariable regression analysis, suggesting IVIG as an independent predictive factor for survival. It suggests that IVIG is effective for OPSI and that it can be regarded as an adjunctive treatment option for OPSI.

High-Dose Intravenous Immunoglobulins in the Treatment of Severe Acute Viral Pneumonia: The Known Mechanisms and Clinical Effects

The current outbreak of viral pneumonia, caused by novel coronavirus SARS-CoV-2, is the focus of worldwide attention. The WHO declared the COVID-19 outbreak a pandemic event on Mar 12, 2020, and the number of confirmed cases is still on the rise worldwide. While most infected individuals only experience mild symptoms or may even be asymptomatic, some patients rapidly progress to severe acute respiratory failure with substantial mortality, making it imperative to develop an efficient treatment for severe SARS-CoV-2 pneumonia alongside supportive care. So far, the optimal treatment strategy for severe COVID-19 remains unknown. Intravenous immunoglobulin (IVIg) is a blood product pooled from healthy donors with high concentrations of immunoglobulin G (IgG) and has been used in patients with autoimmune and inflammatory diseases for more than 30 years. In this review, we aim to highlight the known mechanisms of immunomodulatory effects of high-dose IVIg therapy, the immunopathological hypothesis of viral pneumonia, and the clinical evidence of IVIg therapy in viral pneumonia. We then make cautious therapeutic inferences about high-dose IVIg therapy in treating severe COVID-19. These inferences may provide relevant and useful insights in order to aid treatment for COVID-19.

Tick-borne encephalitis in Europe and Russia: Review of pathogenesis, clinical features, therapy, and vaccines

Tick-borne encephalitis (TBE) is an illness caused by tick-borne encephalitis virus (TBEV) infection which is often limited to a febrile illness, but may lead to very aggressive downstream neurological manifestations. The disease is prevalent in forested areas of Europe and northeastern Asia, and is typically caused by infection involving one of three TBEV subtypes, namely the European (TBEV-Eu), the Siberian (TBEV-Sib), or the Far Eastern (TBEV-FE) subtypes. In addition to the three main TBEV subtypes, two other subtypes; i.e., the Baikalian (TBEV-Bkl) and the Himalayan subtype (TBEV-Him), have been described recently. In Europe, TBEV-Eu infection usually results in only mild TBE associated with a mortality rate of <2%. TBEV-Sib infection also results in a generally mild TBE associated with a non-paralytic febrile form of encephalitis, although there is a tendency towards persistent TBE caused by chronic viral infection. TBE-FE infection is considered to induce the most severe forms of TBE. Importantly though, viral subtype is not the sole determinant of TBE severity; both mild and severe cases of TBE are in fact associated with infection by any of the subtypes. In keeping with this observation, the overall TBE mortality rate in Russia is ∼2%, in spite of the fact that TBEV-Sib and TBEV-FE subtypes appear to be inducers of more severe TBE than TBEV-Eu. On the other hand, TBEV-Sib and TBEV-FE subtype infections in Russia are associated with essentially unique forms of TBE rarely seen elsewhere if at all, such as the hemorrhagic and chronic (progressive) forms of the disease. For post-exposure prophylaxis and TBE treatment in Russia and Kazakhstan, a specific anti-TBEV immunoglobulin is currently used with well-documented efficacy, but the use of specific TBEV immunoglobulins has been discontinued in Europe due to concerns regarding antibody-enhanced disease in naïve individuals. Therefore, new treatments are essential. This review summarizes available data on the pathogenesis and clinical features of TBE, plus different vaccine preparations available in Europe and Russia. In addition, new treatment possibilities, including small molecule drugs and experimental immunotherapies are reviewed. The authors caution that their descriptions of approved or experimental therapies should not be considered to be recommendations for patient care.

The role of inflammation in intravenous immune globulin-mediated hemolysis

Intravenous immune globulin (IVIG) therapy has shown great success in a number of autoimmune and inflammatory conditions and its use continues to increase worldwide. There is growing awareness of significant side effects of high-dose IVIG: however, particularly severe hemolysis in patients that are non-group O. It has been proposed that IVIG-associated hemolysis may be heralded by an existing inflammatory condition. In the work presented herein, we have provided a review of the pathophysiology of inflammation, particularly as it applies in immune-mediated red blood cell hemolysis, and a summary of previous publications that suggest an association between IVIG-mediated hemolysis and a state of existing inflammation. In addition, preliminary results from a prospective study to address the mechanism of IVIG-associated hemolysis are provided. These preliminary data support the idea of an existing inflammatory condition preceding overt hemolysis after high-dose IVIG therapy that: 1) is restricted to non-group O patients, 2) is seen when using IVIG doses of more than 2 g/kg, 3) involves an activated mononuclear phagocyte system, 4) may be presaged by a significant increase in the anti-inflammatory cytokine interleukin-1 receptor agonist, and 5) is independent of secretor status.

Polyclonal and monoclonal antibodies in clinic

Immunoglobulins (Ig) or antibodies are heavy plasma proteins, with sugar chains added to amino-acid residues by N-linked glycosylation and occasionally by O-linked glycosylation. The versatility of antibodies is demonstrated by the various functions that they mediate such as neutralization, agglutination, fixation with activation of complement and activation of effector cells. Naturally occurring antibodies protect the organism against harmful pathogens, viruses and infections. In addition, almost any organic chemical induces antibody production of antibodies that would bind specifically to the chemical. These antibodies are often produced from multiple B cell clones and referred to as polyclonal antibodies. In recent years, scientists have exploited the highly evolved machinery of the immune system to produce structurally and functionally complex molecules such as antibodies from a single B clone, heralding the era of monoclonal antibodies. Most of the antibodies currently in the clinic, target components of the immune system, are not curative and seek to alleviate symptoms rather than cure disease. Our group used a novel strategy to identify reparative human monoclonal antibodies distinct from conventional antibodies. In this chapter, we discuss the therapeutic relevance of both polyclonal and monoclonal antibodies in clinic.

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

CONTEXT

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

DISCUSSION AND CONCLUSION

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

Specific antibody in IV immunoglobulin for postsplenectomy sepsis

OBJECTIVE

Overwhelming postsplenectomy infection progresses rapidly and shows unacceptably high mortality even when treated with optimal antibiotics. Recent reports have described beneficial effects of intravenous immunoglobulin in sepsis. However, the underlying mechanisms, especially the roles of the pathogen-specific antibody fraction in intravenous immunoglobulin, remain unclear. We investigated the effects of intravenous immunoglobulin on overwhelming postsplenectomy infection and the role of pathogen-specific antibody.

DESIGN

Prospective, controlled, and randomized animal study.

SETTING

University laboratory.

SUBJECTS

Male C57BL/6JJcl mice.

INTERVENTIONS

Mice underwent splenectomy or a sham operation at 8 weeks old. At 4 weeks after the operation, mice were injected intravenously with 106 colony-forming units pneumococcus. Intraperitoneal injection of 300 mg/kg IV immunoglobulins was conducted simultaneously with infection. Specific antibody-depleted IV immunoglobulin prepared using immunoprecipitation was also injected into the animals.

MEASUREMENTS AND MAIN RESULTS

IV immunoglobulin markedly improved splenectomized mice survival. Removal of pneumococcus-specific antibody canceled it completely. Fluorescence microscopy results indicated significantly increased phagocytosis of antibody-bound bacteria in the livers of splenectomized mice treated with intact IV immunoglobulins. Immunomodulation, including suppression of marginal zone B-cell activation, was induced by IV immunoglobulin.

CONCLUSIONS

IV immunoglobulin showed a significantly protective effect on overwhelming postsplenectomy infection via enhancement of specific antibody-mediated phagocytosis in the liver. Specific antibody, more than immunological modulation, is crucial for effects of IV immunoglobulin on overwhelming postsplenectomy infection.

Intravenous immunoglobulin given to lymphoma patients with recurrent haemolytic transfusion reactions after transfusion of compatible blood

Accelerated destruction of red cells after transfusion of compatible blood has been reported in both sickle cell disease (SCD) and non-SCD patients. We report three patients with lymphoma, all of whom had recurrent haemolytic transfusion reactions after receiving compatible red cell units. The direct antiglobulin test (DAT) was negative and there were no detectable red cell alloantibodies in either pre-transfusion or post-transfusion samples. As there was no evidence of red cell antibody-mediated haemolysis and response to oral steroids, a trial of intravenous immunoglobulin (IVIg) was given. Immediate cessation of haemolysis with sustained haemoglobin level was achieved in all cases. The response to IVIg in these cases suggests that IVIg should be tried when recurrent non-antibody mediated haemolytic transfusion reactions occur in patients with a lymphoid malignancy.

Use of Intravenous Immunoglobulin and Intravenous Methylprednisolone in Hyperhaemolysis Syndrome in Sickle Cell Disease

Hyperhaemolysis syndrome (HS), a syndrome in which there is destruction of both donor and recipient red cells after transfusion, is well recognised in patients with sickle cell disease and beta-thalassaemia. It has also been reported in a patient with myelofibrosis. In acute forms of HS, evidence of red cell antibody-mediated haemolysis is lacking, and it has been proposed that the transfused and the patient's own red blood cells were destroyed by hyperactive macrophages. Continuation of transfusion may be lethal as this can further exacerbate haemolysis. We report two cases of HS successfully treated with IVIg and IV methylprednisolone. The cessation of haemolysis following administration of IVIg and IV methylprednisolone supports the view that hyperactive macrophages contribute to the RBC destruction. IVIg and methylprednisolone appear to have a synergistic effect on suppressing the activity of macrophages.

In VitroCytotoxic Effects of Stabilizing Sugars within Human Intravenous Immunoglobulin Preparations against the Human Macrophage THP-1 Cell-line

Intravenous immunoglobulin (IVIg) is a safe and effective therapy for the treatment of primary and secondary humoral immune deficiencies and autoimmune disorders. Both minor and more serious side effects may occur following IVIg administration in approximately 1-15% of infusions and stabilizing sugars found in IVIg preparations may contribute some of these. In this report, we aimed to determine the cytotoxic effects of IVIg as compared with four stabilizing sugars (glucose, sucrose, maltose and D-sorbitol) found in IVIg preparations on human monocyte-macrophages. The human THP-1 macrophage cell-line was used as a model to determine the effects of stabilizing sugars and IVIg preparations on cell viability and growth. The sugars differentially affected the viability of THP-1 cells. In experiments using doses of the sugars commonly found in IVIg preparations, cell viability and proliferation was unaffected when compared with doses of IVIg typically administered to patients (5 mg/ml). However, in an LDH-release cell lysis assay that measures changes in cell permeability, glucose (50 mg/ml) induced significant release of LDH as compared with complete IVIg (5 mg/ml, p<0.0001). Intranucleosomal DNA fragmentation was not detected at therapeutically relevant doses of IVIg. This suggested that THP-1 cell death was not due to apoptosis. We conclude that osmotic stress mediated by the sugars at high doses promoted THP-1 cell death. We propose that IVIg per se is not cytotoxic to the autonomously growing human THP-1 cell-line but rather, the stabilizing sugars used in the preparations are the cytotoxic factors. This observation was evident when preparations of IVIg were used at high concentrations but not at levels one would associate with clinically relevant doses of IVIg.

Intravenous immunoglobulin-mediated immunosuppression and the development of an IVIG substitute

Immunoglobulins are glycoproteins produced by the cells of the immune system. Their primary function is to protect the body from pathogenic infection. Moreover, a concentrated polyclonal mixture of immunoglobulin G (IgG), the so-called intravenous IgG (IVIG), has been used to treat various chronic and systemic disorders of the immune system. Studies on the effects of IVIG in autoimmune disease models have revealed that IgG Fc fragments confer protection against various autoimmune diseases. The identification of this IgG Fc immunomodulatory component is important for the development of IVIG substitutes. The focus of this review is to introduce one of the Fc regulatory entities and to provide a summary of the current knowledge of the putative general mechanisms underlying IVIG activity in vivo on the basis of these Fc fragments. We also address the recent insights into several approaches for the development of IVIG substitutes.

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.

Rebound of residual plasma viremia after initial decrease following addition of intravenous immunoglobulin to effective antiretroviral treatment of HIV

Background

High dosage of intravenous immunoglobulin (IVIG) has been observed as a possible activator of HIV gene expression in latently infected resting CD4⁺ T-cells, leading to a substantial decrease in both the reservoir and the residual plasma viremia when added to effective ART. IVIG treatment has also been reported to expand T regulatory cells (Tregs). The aim of this study was to evaluate possible long-term effect of IVIG treatment on residual viremia and T-lymphocyte activation.

Methods

Nine HIV-infected subjects on effective ART included in a previously reported study on IVIG treatment were evaluated 48-104 weeks after therapy. In addition, 14 HIV-infected controls on suppressive ART were included. HIV-1 RNA was analyzed in cell-free plasma by using an ultrasensitive PCR-method with a detection limit of 2 copies/mL. T-lymphocyte activation markers and serum interleukins were measured.

Results

Plasma residual viremia rebounded to pre-treatment levels, 48-104 weeks after the initial decrease that was observed following treatment with high-dosage IVIG. No long-term effect was observed regarding T-lymphocyte activation markers, T-regulatory cells or serum interleukins. In a post-hoc analysis, a correlation between plasma HIV-1-RNA and CD4⁺ T-cell count was found in both IVIG-treated patients and controls.

Conclusions

These results indicate that the decrease in the latent HIV-1 pool observed during IVIG treatment is transient. Although not our primary objective, we found a correlation between HIV-1 RNA and CD4⁺ T-cell count suggesting the possibility that patients with a higher CD4⁺ T-cell count might harbor a larger residual pool of latently infected CD4⁺ T-cells.

Heterogeneous pathways of maternal-fetal transmission of human viruses (review)

Several viruses can pass the maternal-fetal barrier, and cause diseases of the fetus or the newborn. Recently, however, it became obvious, that viruses may invade fetal cells and organs through different routes without acute consequences. Spermatozoa, seminal fluid and lymphocytes in the sperm may transfer viruses into the human zygotes. Viruses were shown to be integrated into human chromosomes and transferred into fetal tissues. The regular maternal-fetal transport of maternal cells has also been discovered. This transport might implicate that lymphotropic viruses can be released into the fetal organs following cellular invasion. It has been shown that many viruses may replicate in human trophoblasts and syncytiotrophoblast cells thus passing the barrier of the maternal-fetal interface. The transport of viral immunocomplexes had also been suggested, and the possibility has been put forward that even anti-idiotypes mimicking viral epitopes might be transferred by natural mechanisms into the fetal plasma, in spite of the selective mechanisms of apical to basolateral transcytosis in syncytiotrophoblast and basolateral to apical transcytosis in fetal capillary endothelium. The mechanisms of maternal-fetal transcytosis seem to be different of those observed in differentiated cells and tissue cultures. Membrane fusion and lipid rafts of high cholesterol content are probably the main requirements of fetal transcytosis. The long term presence of viruses in fetal tissues and their interactions with the fetal immune system might result in post partum consequences as far as increased risk of the development of malignancies and chronic pathologic conditions are discussed.

Intravenous immunoglobulins--understanding properties and mechanisms

High-dose intravenous immunoglobulin (IVIg) preparations are used currently for the treatment of autoimmune or inflammatory diseases. Despite numerous studies demonstrating efficacy, the precise mode of action of IVIg remains unclear. Paradoxically, IgG can exert both pro- and anti-inflammatory activities, depending on its concentration. The proinflammatory activity of low-dose IVIg requires complement activation or binding of the Fc fragment of IgG to IgG-specific receptors (FcgammaR) on innate immune effector cells. In contrast, when administered in high concentrations, IVIg has anti-inflammatory properties. How this anti-inflammatory effect is mediated has not yet been elucidated fully, and several mutually non-exclusive mechanisms have been proposed. This paper represents the proceedings of a session entitled 'IVIg--Understanding properties and mechanisms' at the 6th International Immunoglobulin Symposium that was held in Interlaken on 26-28 March 2009. The presentations addressed how IgG may affect the cellular compartment, evidence for IVIg-mediated scavenging of complement fragments, the role of the dimeric fraction of IVIg, the anti-inflammatory properties of the minor fraction of sialylated IgG molecules, and the genetic organization and variation in FcgammaRs. These findings demonstrate the considerable progress that has been made in understanding the mechanisms of action of IVIgs, and may influence future perspectives in the field of Ig therapy.

Reduction of the HIV-1 reservoir in resting CD4+ T-lymphocytes by high dosage intravenous immunoglobulin treatment: a proof-of-concept study

Background

The latency of HIV-1 in resting CD4⁺ T-lymphocytes constitutes a major obstacle for the eradication of virus in patients on antiretroviral therapy (ART). As yet, no approach to reduce this viral reservoir has proven effective.

Methods

Nine subjects on effective ART were included in the study and treated with high dosage intravenous immunoglobulin (IVIG) for five consecutive days. Seven of those had detectable levels of replication-competent virus in the latent reservoir and were thus possible to evaluate. Highly purified resting memory CD4⁺ T-cells were activated and cells containing replication-competent HIV-1 were quantified. HIV-1 from plasma and activated memory CD4⁺ T-cells were compared with single genome sequencing (SGS) of the gag region. T-lymphocyte activation markers and serum interleukins were measured.

Results

The latent HIV-1 pool decreased with in median 68% after IVIG was added to effective ART. The reservoir decreased in five, whereas no decrease was found in two subjects with detectable virus. Plasma HIV-1 RNA ≥ 2 copies/mL was detected in five of seven subjects at baseline, but in only one at follow-up after 8–12 weeks. The decrease of the latent HIV-1 pool and the residual plasma viremia was preceded by a transitory low-level increase in plasma HIV-1 RNA and serum interleukin 7 (IL-7) levels, and followed by an expansion of T regulatory cells. The magnitude of the viral increase in plasma correlated to the size of the latent HIV-1 pool and SGS of the gag region showed that viral clones from plasma clustered together with virus from activated memory T-cells, pointing to the latent reservoir as the source of HIV-1 RNA in plasma.

Conclusion

The findings from this uncontrolled proof-of-concept study suggest that the reservoir became accessible by IVIG treatment through activation of HIV-1 gene expression in latently-infected resting CD4⁺ T-cells. We propose that IVIG should be further evaluated as an adjuvant to effective ART.

Modulation of the cellular immune system by intravenous immunoglobulin

Intravenous immunoglobulin (IVIg) is therapeutically used in a variety of immune-mediated diseases. The beneficial effects of IVIg in auto-antibody-mediated diseases can be explained by neutralization, accelerated clearance and prevention of Fcgamma-receptor binding of auto-antibodies. However, the means by which IVIg exerts therapeutic effects in disorders mediated by cellular immunity have remained enigmatic. Clinical improvements, followed by IVIg treatment, often extend beyond the half-life of infused IgG, thereby indicating that IVIg modifies the cellular immune compartment for a prolonged period. Here, we discuss recent advances in the understanding of different, mutually non-exclusive mechanisms of action of IVIg on cells of the innate and adaptive immune system. These mechanisms might explain the beneficial effects of IVIg in certain autoimmune and inflammatory diseases.

Effects of transfusion on human erythrovirus B19-susceptible or -infected pediatric recipients in a genotype 3-endemic area

BACKGROUND

Human erythrovirus (parvovirus) B19 is transmitted by transfusion of blood, blood components, and plasma derivatives and is resistant to most viral inactivation methods. B19 genotype 3 is prevalent in Ghana, and no related clinical information is available.

STUDY DESIGN AND METHODS

This study assessed the transmission of B19 genotype 3 by transfusion and the potential effect of transfused B19 antibodies in viremic recipients. Immunological aspects of B19 genotype 3 infection in children mainly transfused for acute malarial anemia were examined. Molecular and serologic methods adapted to genotype 3 were developed and used.

RESULTS

Among 114 donor-recipient pairs from Ghana, two donations contained B19 DNA and specific antibodies, and no evidence of transmission was found. B19 immunoglobulin G (IgG)-containing whole blood was transfused to 14 B19 DNA-positive recipients. Three recipients with detectable levels of IgG to B19 failed to clear viremia 1 to 2.3 months after transfusion. Ten recipients without IgG to VP2 before transfusion cleared the virus but failed to develop an immune response to B19 within 1 to 2 months after transfusion. Only 1 patient who received little specific IgG by transfusion produced detectable antibodies.

CONCLUSION

Low levels of B19 genotype 3 DNA associated with specific IgG are not infectious by transfusion. Viral clearance and apparent down regulation of immune response to B19 may be related to removal of the viral antigens by transfused antibodies and/or immunomodulatory effect of transfusion.

Temporarily controlled HIV-1 replication after intravenous immunoglobulin treatment of Guillain-Barré syndrome

HIV establishes a latent infection in resting CD4(+) T-lymphocytes. A possible strategy to eliminate cellular reservoirs in long-lived, HIV-1-infected quiescent CD4(+) T-lymphocytes might be to add T-cell-activating agents to potent antiretroviral therapy. In this report we describe a patient with Guillain-Barré syndrome treated with high dose intravenous immunoglobulin (IVIG) in addition to antiretroviral therapy. A transiently increased viral load and immunoactivation during the IVIG treatment suggest activation of latently infected cells and increased turnover rate of the latent viral reservoir. HIV replication was controlled with plasma viral load <20 copies/ml, for at least 3 months after antiretroviral treatment interruption. CSF neural markers reflecting degenerative processes in the brain during the symptomatic period and follow-up were also analysed. Very high CSF sulfatide concentrations were found indicating that the pathology involves severe demyelination.We hypothesize that IVIG in this case contributed to an activation of latently infected cells, which led to a transient increase in plasma HIV-1 RNA during the IVIG treatment and a long period of undetectable viral load after antiretroviral treatment interruption. Further, this is the first time, to our knowledge, that detailed CSF findings are described in HIV-1 associated GBS.

Intravenous immunoglobulin attenuates mesenteric ischemia-reperfusion injury

Intravenous immunoglobulin (IVIG) has been found useful in the treatment of various clinical entities and its effect has been associated with inhibition of complement-mediated tissue damage. The aim of this study was to determine the ability of IVIG to protect against mesenteric ischemia-reperfusion (IR)-induced local and remote injury. Rats received vehicle or IVIG (150-600 mg/kg) 5 min prior to sham operation or 30 min of superior mesenteric artery occlusion, followed by 5, 120, or 240 min of reperfusion. IVIG reduced IR-induced mucosal injury without altering IR-induced increases in PMN infiltration or LTB(4) generation. At 5 min post IR, the deposition of IgG and C3 in the lamina propria and surface epithelial cells was attenuated by IVIG. The increased capillary leak, evident at 240 min, was inhibited by IVIG and coincided with a reduction in C3 deposition in lung tissue. The beneficial effects of IVIG may be related to the ability to scavenge deleterious products.

Biological effects of induction immunosuppression

The concept of induction immunosuppression is evolving. Once used to buttress the inadequacies of past maintenance immunosuppressive regimens, it is now being used to permit effective maintenance immunosuppression using ever decreasing amounts of modern agents. In addition to lymphocyte depletion, with which it was once synonymous, it is now recognized that induction immunosuppression is associated with a host of non-depletional effects such as receptor modulation and blockade, which profoundly alter the lymphocyte's capacity to mount an effective response. Additionally, the recent focus on the effect of induction agents on antigen presenting cells and on regulatory factors controlling homeostatic repopulation may ultimately permit a safer, more refined and more effective approach to induction immunosuppression.

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.

Immunologic manipulation for the threatened fetus

Management of the pregnant woman with the antiphospholipid syndrome (APLS) has improved over the last 10 years. The recurrent pregnancy loss that is associated with this disease is managed with prophylactic low dose aspirin and heparin therapy. This therapy leads to a 40% absolute risk reduction in pregnancy loss. However, many women still fail to deliver a live infant despite this therapy so immunologic manipulation of the mother's disease in this group needs to be considered. Intravenous immunoglobulin and plasma exchange may have a role. New immunosuppressive drugs such as tacrolimus have yet to be tried. Monoclonal antibodies to B cells, B-cell growth factors, complement proteins and integrin molecules, all of which appear to play a role in the disease process, may also offer patients some hope. Similarly, biologics such as C1 esterase inhibitor protein, cell surface complement regulator proteins or interleukin-3 need to be tried given their efficacy in models of antibody-induced cell injury.

Intravenously applied IgG stimulates complement attenuation in a complement-dependent autoimmune disease at the amplifying C3 convertase level

Intravenously applied normal human immunoglobulin G (IgG) has anti-inflammatory effects in the treatment of autoimmune diseases. Systemic inflammation can originate from an overreacting amplification loop of the complement system. In blood, C3b2-containing complexes maintain complement amplification much better than the extremely short-lived C3b. Therefore, in patients with the complement-dependent autoimmune disease, dermatomyositis, we studied whether intravenously applied normal human IgG (IVIG) stimulated in vivo inactivation of these complexes. In the course of IVIG treatment, clinically effective in 6 of 8 patients, the concentration of C3b2-containing complexes dropped to 37% ± 14% (n = 6) of the pretreatment level when having infused 0.5 g IgG/kg body weight, increased marginally and in parallel to factor Bb thereafter until full-dose IgG was infused. By day 14 following infusion of 2 g IgG/kg body weight the concentration of C3b2-containing complexes was 66% ± 19%. The plasma concentration of C3 remained constant in myopathic or increased by 15% to 20% in amyopathic patients. In contrast to this, IVIG infusion was associated with consumption of up to 40% of plasma C4 at day 1 to 2 after completion of IVIG infusion. Thus, IVIG had an immediate and long-lasting attenuating effect on complement amplification in vivo, despite the fact that it induced classical complement pathway activation.

Polyreactive autoantibodies purified from human intravenous immunoglobulins prevent the development of experimental autoimmune diseases

Intravenous immunoglobulins (IVIg) are therapeutic preparations of normal human polyclonal Ig G (IgG) that exert immunomodulatory effects in patients with autoimmune or systemic inflammatory diseases. Two different IgG subfractions were evaluated for their respective immunomodulatory effects in the treatment of experimental autoimmune diseases: a fraction enriched in antibodies that recognize the F(ab')(2) portion of IVIg and a fraction of natural polyreactive autoantibodies purified on a dinitrophenyl (DNP)-Affiprep immunoadsorbent. A very small fraction of IgG interacting with DNP but not with F(ab')(2) fragments expressed an increased ability to bind to self-antigens. The anti-DNP fraction, but not the anti-idiotype fraction, protected against inflammation observed in collagen-induced arthritis and experimental autoimmune encephalomyelitis in rats. Furthermore, it was able to reduce the occurrence of spontaneous diabetes mellitus in nonobese diabetic mice at lower concentrations than unfractionated IVIg. The therapeutic benefit of the anti-DNP fraction was associated with the inhibition of secretion of proinflammatory cytokines and stimulation of secretion of IL-1 receptor antagonist. Our results provide evidence that polyreactive autoantibodies play a role in the protective effect of IVIg in experimental models of autoimmune diseases in which inflammatory reactions are part of the disease process.

Mechanism of action of IVIG in ITP

IVIG is prepared from large pools of plasma from healthy donors and the IgG is present predominantly in monomeric form. It was first reported in 1981 by Dr. Paul Imbach that high doses of IVIG promote fast recovery of ITP in children. Despite extensive clinical use in a variety of autoimmune and inflammatory states, the mechanism of action of IVIG remains as yet incompletely understood. Several theories have been proposed to explain how administration of IVIG to individuals with ITP increases the platelet count. Following is an overview of some of the major theories.

Respiratory outcomes in high-risk children 7 to 10 years after prophylaxis with respiratory syncytial virus immune globulin

PURPOSE

Respiratory syncytial virus infections have been implicated in the development of asthma. We evaluated the long-term effects of respiratory syncytial virus immune globulin, an effective prophylactic agent for the prevention of these infections in children, on respiratory and allergic outcomes in children at high risk of chronic airway disease.

SUBJECTS AND METHODS

Thirteen children at high risk of respiratory disease (mean [+/-SD] age, 8.6 +/- 1.1 years) were evaluated using pulmonary function and allergy skin testing 7 to 10 years after they had received prophylaxis with respiratory syncytial virus immune globulin. For comparison, 26 high-risk control children (mean age, 8.5 +/- 0.9 years) were also evaluated. Health outcomes data were collected from all subjects. The children were matched for age and gestational age. There were more boys, and a lesser frequency of a lower respiratory tract infection with respiratory syncytial virus (P <0.001) in the group that had been treated prophylactically than in the controls. The ratio of the forced expiratory volume in 1 second to forced vital capacity was significantly better in children who had received immune globulin (median, 0.88; interquartile range, 0.81 to 0.91) than in the controls (median, 0.76; interquartile range, 0.67 to 0.86; P = 0.02). Children were also less atopic (2 of 13) in the respiratory syncytial virus immune globulin group than in the control group (13 of 26, P <0.04) and were less likely to have missed school (P = 0.006) or have had an asthma attack (P = 0.03).

CONCLUSION

The results suggest that prophylaxis of respiratory syncytial virus infections in infancy may have long-term effects on respiratory and immunologic parameters relevant to the development of asthma. Larger-scale studies are needed.

Effects of cryopreservation and phenylacetate on biological characters of adherent LAK cells from patients with hepatocellular carcinoma

AIM: To improve the preparation of adherent lymphokine-activated killer (A-LAK) cells and to study the effects of cryopreservation and phenylacetate (PA) on biological characters of A-LAK cells.

METHODS: A-LAK cells were obtained from peripheral blood mononuclear cells (PBMCs) of the patients with hepatocellular carcinoma (HCC) by using L-phenylalanine methyl ester (PME) to deplete immunosuppressive monocytes. Proliferative activity of SMMC7721 cell line after treatment with phenylacetate (PA) was observed. A-LAK cells were treated with the supernatant of SMMC7721 cells that had been pretreated with PA. The changes of proliferation, cytotoxicity and phenotype of A-LAK cells were investigated after cryopreservation.

RESULTS: The expansion of A-LAK cells (96.79 ± 69.10 folds on Day 14) was significantly higher than that of non-adherent LAK (NA-LAK) cells (22.77 ± 13.20) as well as conventional LAK cells (4.64 ± 0.91). PA significantly suppressed the growth of SMMC7721 cells, and the inhibitor ratio was 46%. The supernatant of cultured tumor cells intensively suppressed the proliferation and cytotoxicity of A-LAK cells, but the suppressive effect of the supernatant was previously decreased after treatment with PA. Impairments in proliferation and cytotoxicity of A-LAK cells immediately after thawing of cryopreservation and recovery after reincubation with IL-2 were observed. The cytotoxicity of thawed A-LAK cells on Day 5 was significantly higher than that of fresh A-LAK before freezing (54.8% ± 10.2% vs 40.5% ± 6.4%). No significant change in the percentage of lymphocyte subsets was identified in frozen A-LAK cells as compared with that in the fresh control cells.

CONCLUSION: A-LAK cells can be simply prepared by using PME, and showed a synergistic anti-tumor effect with the combination of PA. Cryopreservation can increase the immunoactivities of A-LAK cells from the patients with hepatocellular carcinoma.

Intravenous immunoglobulin: regulatory perspectives on use and supply

Technological advancements in the fractionation of plasma in the early 1970s led to the production of immunoglobulin preparations which could be administered intravenously. The ability to deliver larger doses than was possible with intramuscular products was accompanied by clinical studies demonstrating the efficacy of immunoglobulin treatment in a number of autoimmune and inflammatory conditions. This has led to a continuing increase in the usage of this product such that, currently, it is considered to be the driving force for plasma procurement. In recent years, difficulties have been experienced in the supply of this product in various markets. While intravenous immunoglobulins (IVIG) have undoubted clinical superiority over intramuscular products for the majority of indications, their use should be tempered with caution. Early clinical studies revealed that the risk of viral transmission from these products was higher than that of the traditional intramuscular presentation. This has had a profound impact on blood transfusion science as it has provided a major impetus for nucleic acid testing (NAT) for viral agents in blood donations. Perhaps less widely appreciated are the pressures which may be felt in blood services as the traditional drivers for plasma procurement - factor VIII and albumin - become secondary to IVIG. This review discusses the factors affecting the supply and safety of IVIG and the implications of recent global regulatory decisions on the delivery of this product and other therapeutic products derived from human plasma.

Hyperhemolytic transfusion reaction in sickle cell disease

BACKGROUND

An atypical form of life-threatening hemolytic transfusion reaction (HTR) in patients with sickle cell disease (SCD) has been well described in the literature. Continuation of blood transfusion may be lethal, as it can further exacerbate hemolysis. The pathophysiologic mechanism of HTR is not well understood.

CASE REPORTS

Two cases of severe HTR in SCD after the transfusion of compatible RBC units are reported. Hemolysis of both autologous and transfused cells was documented in Case 1 by urine Hb high-performance liquid chromotography. Multispecific HLA antibodies were identified in Case 1. Reticulocytopenia was noted in both cases during the acute hemolytic process. This was followed by a rise in reticulocyte count during receipt of IVIG and steroid therapy. Bone marrow examination during reticulocytopenia in Case 2 showed erythroid hyperplasia.

CONCLUSION

In SCD, both mature sickle cells and sickle reticulocytes adhere more readily to macrophages. In view of the bone marrow aspiration results, it appears that the recipients' HbS cells are destroyed by hyperactive macrophages and that the reticulocytopenia observed during HTR is likely to be due to peripheral consumption (i.e., destruction by macrophages), rather than suppression of erythropoiesis. Cessation of hemolysis during IVIG and steroid treatment may be due to IVIG's blocking of the adhesion of sickle cells and reticulocytes to macrophages, together with steroid suppression of macrophage activity.