Mechanisms of action of Ig preparations: immunomodulatory and anti-inflammatory effects

Immunoglobulin therapies for primary immunodeficiency diseases (part 1): understanding the pharmacokinetics

Immunoglobulin G (IgG) therapies have been used for decades as standard treatment for patients with primary antibody deficiencies. Monitoring the pharmacokinetics (PK) of IgG is a key component in guiding treatment regimens. Despite the wealth of clinical experience, substantial gaps exist in our understanding of the true nature of IgGs and their disposition in humans. Furthermore, intrinsic and extrinsic factors may alter the PK of IgG, necessitating an individualized approach for patients. A comprehensive literature review was performed in order to summarize the PK of IgGs, examine the mechanisms of IgG disposition (including catabolism), outline considerations for special patient populations and discuss knowledge gaps and future perspectives for improving our understanding of IgG PK in relation to the individualized treatment paradigm.

Levels of Natural Antibodies Before and After Immunoglobulin Replacement Treatment Affect the Clinical Phenotype in Common Variable Immunodeficiency

Natural antibodies (NAbs) occurring in individuals without prior exposure to specific antigens, provide direct first barrier protection against pathogens, and exert immunoregulation thus actively contributing to the maintenance of immune homeostasis, controlling inflammatory processes and preventing autoimmunity. Common variable immunodeficiency (CVID) is a heterogeneous group of disorders characterized by a compromised immune function that brings into focus the role of NAbs. Our aim was to explore whether NAb levels could serve as potential key indicators in CVID for monitoring disease progression and predicting outcomes. In this study, we analyzed a Hellenic cohort of 56 patients with CVID (31 newly diagnosed and 25 under immunoglobulin replacement therapy-IgRT) and 33 healthy controls, for total Ig levels and serum IgM and IgG NAb levels against five informative target-antigens of NAbs, namely, actin, DNA, carbonic anhydrase, F(ab΄)2 fragments of human IgG and TriNitroPhenyl. In addition, follow-up pre- and post- IgRT samples were analyzed in ten (10) patients of our cohort. Results showed that Ig-treated patients exhibited significantly lower IgM NAb levels than untreated patients and healthy controls against all panel antigens. In the follow-up samples, pre-treatment IgM NAb levels negatively correlated with total serum IgM. This imbalance was only partially restored after IgRT, with a significant decrease in IgM NAb levels observed in nine out of ten patients. Moreover, post-treatment patients with recurrent infections presented significantly lower IgM NAb levels, a reduction also observed in patients with bronchiectasis independently of treatment status. On the contrary, post-treatment patients with enteropathy had significantly higher IgM NAb levels against all panel antigens, an increase also noted in patients with autoimmune diseases. Regarding IgG NAbs, replacement therapy restored levels to those of healthy controls. In conclusion, impaired NAb levels are found in CVID patients, particularly related to certain phenotypes. Moreover, the significant decrease in IgM NAb levels after IgRT suggests a potential association with disease course and complications. The results suggest that administration of human IgM NAbs may be an effective combinatorial treatment in selected patients. Further research is needed to understand the functional roles of NAbs in CVID and its complex clinical phenotypes.

No-observed adverse effect levels of deoxynivalenol and aflatoxin B1 in combination induced immune inhibition and apoptosis in vivo and in vitro

Mycotoxins are toxic metabolites produced by fungal species, commonly exist in animal feeds, and pose a serious risk to human as well as animal health. But limited studies have focused on combined effects of no-observed adverse effect levels. In vivo study, 6 weeks old twenty-four mice were individually exposed to Deoxynivalenol (DON) at 0.1 mg/kg BW, Aflatoxin B1 (AFB1) at 0.01 mg/kg BW, and mixture of DON and AFB1 (0.1 mg/kg BW and 0.01 mg/kg BW, respectively) for 28 days. Then, DON at 0.5 μg/mL, AFB1 at 0.04 μg/mL, and mixtures of DON and AFB1 (0.5 μg/mL, 0.04 μg/mL, respectively) were applied to porcine alveolar macrophages (PAMs) in vitro study. Our in vivo results revealed that the combined no-observed adverse effect levels of DON and AFB1 administration decreased IgA and IgG levels in the serum, the splenic TNF-α, IFN-γ, IL-2 and IL-6 mRNA expression and T-lymphocyte subset levels (CD4+ and CD8+) in the spleen. Additionally, the combined administration increased caspase-3, caspase-9, Bax, Cyt-c, and decreased Bcl-2 protein expression. Taken together, the combined no-observed adverse effect levels of DON and AFB1 could induce immunosuppression, which may be related to apoptosis. This study provides new insights into the combined immune toxicity (DON and AFB1).

Immunoglobulin replacement therapies in inborn errors of immunity: a review

Immunoglobulins (Ig) were used as a therapeutic modality for the first time in a patient with X-linked agammaglobulinemia in 1952 by Colonel Ogden Bruton, decades before the molecular mechanisms causing the disease were unraveled. In many autoimmune and inflammatory illnesses, human immunoglobulin has been employed as a significant immunomodulatory and immunosuppressive drug. In patients with inborn errors of immunity (IEI), immunoglobulin remains a cornerstone of management. IEIs are notable causes of recurrent infections and autoimmunity due to inheritable single-gene defects in genes encoding for different components of the immune system. As there is decreased immunoglobulin production in IEIs with antibody defects, immunoglobulin replacement is the mainstay of therapy in these disorders. Although serum immunoglobulin levels may not be low in combined immune defects, immunoglobulin replacement is still necessary in these disorders due to a deficiency of functional antibodies and qualitative defects of immunoglobulins. Commercial immunoglobulin preparations are generated from plasma donated by thousands of donors. Immunoglobulin preparations are usually available in two forms: intravenous and subcutaneous immunoglobulins. In the developed world, both intravenous immunoglobulin (IVIg) and subcutaneous immunoglobulin (SCIg) are available, and SCIg is preferred over IVIg for replacement therapy in patients with IEIs. In developing countries, IVIg remains the mainstay of replacement therapy. The rate of adverse events has significantly reduced over the last few years due to advancements in the production process. In this review article, we discuss different aspects of the use of Ig (indications, dosing, mechanism of action, route, adverse effects) in patients with IEIs.

Replacement and Immunomodulatory Activities of 20% Subcutaneous Immunoglobulin Treatment: A Single-Center Retrospective Study in Autoimmune Myositis and CVID Patients

Background

Immunoglobulin (Ig) replacement therapy represents a life-saving treatment in primary antibody deficiencies. The introduction of subcutaneous Ig (SCIg) administration brings a major improvement in quality of life for patients, compared to the traditional intravenous administration. In recent years, an additional role has been proposed for Ig therapy for various inflammatory and immune-mediated diseases. Consequently, the use of SCIg has expanded from immunodeficiencies to immune-mediated diseases, such as polymyositis (PM) and dermatomyositis (DM). Given the rarity of these conditions, it is still difficult to evaluate the real impact of SCIg treatment on PM and DM, and additional data are constantly required on this topic, particularly for long-term treatments in real-life settings.

Aim

This study aimed to increase the knowledge about the anti-inflammatory and immunomodulatory effects of SCIg treatment for myositis. To this aim, a long-term evaluation of the effectiveness of 20% human SCIg treatment (20% SCIg, Hizentra^®, CSL Behring) was carried out in patients with PM/DM in care at our Center. In addition, an evaluation of the 20% SCIg therapy in CVID patients was provided. This analysis, beside adding knowledge about the use of SCIg therapy in this real-life setting, was intended as a term of comparison, regarding the safety profile.

Results

Results support the beneficial effect and tolerability of long-term 20% SCIg therapy in PM/DM patients, reporting a significant improvement in creatine kinase levels, muscle strength, skin conditions, dysphagia, disease activity (MITAX score) and disability (HAQ-DI score). None of the patients reported systemic reactions. The duration of the reported local reactions was a few hours in 80% of the patients, and all resolved spontaneously. CVID patients reported an improvement in all the considered effectiveness parameters at the end of 20% SCIg therapy. The frequency of the adverse events reported by PM/DM patients was not different from what reported in CVID patients, where the use of SCIg therapy is more consolidated

Conclusions

This study suggests that 20% SCIg treatment represents a viable and safe treatment for PM/DM patients and a valid therapeutic alternative to IVIg, with important advantages for patients’ quality of life.

Anti-IL-6 cytokine treatment has no impact on elevated hematocrit and splenomegaly in a polycythemia vera mouse model

Somatic mutations in JAK2, MPL and Calreticulin and inflammation play a key role in pathophysiology of chronic myeloproliferative neoplasia (CMN). One of the most prominent cytokines elevated in serum of Polycythemia vera patients is interleukin-6 (IL-6). Currently, it is being discussed whether suppression of inflammation by anti-cytokine approaches as anti-IL-6 treatment may be therapeutically useful in CMN. We here sought to investigate the efficacy of anti-IL-6 treatment on inflammatory cytokines, hematocrit and splenomegaly in CMN like disease. JAK2-V617F knock-in mice (JAK2+/V617F) were treated for three weeks with anti-IL-6 antibody (Ab) or IgG-control. Upon anti-IL-6 Ab treatment, serum levels of CXCL2 and CXCL10 were significantly reduced. In addition, CXCL1, CCL11, M-CSF, G-CSF, IL-17, IL-12p40 and CCL2 were reduced by a factor of 0.3 - 0.8. Partly, this was also achieved by applying high-dose IgG. Hematocrit, erythrocyte and leukocyte counts were elevated in JAK2+/V617F mice but were not reduced by anti-IL6 Ab treatment. In addition, there was no apparent amelioration of splenomegaly and spleen histopathology. In conclusion, anti-IL-6 Ab treatment did not result in improvement of hematological disease parameters but was shown to modulate the serum cytokine signature.

Role of Immunoglobulins in Muscular Dystrophies and Inflammatory Myopathies

Muscular dystrophies and inflammatory myopathies are heterogeneous muscular disorders characterized by progressive muscle weakness and mass loss. Despite the high variability of etiology, inflammation and involvement of both innate and adaptive immune response are shared features. The best understood immune mechanisms involved in these pathologies include complement cascade activation, auto-antibodies directed against muscular proteins or de-novo expressed antigens in myofibers, MHC-I overexpression in myofibers, and lymphocytes-mediated cytotoxicity. Intravenous immunoglobulins (IVIGs) administration could represent a suitable immunomodulator with this respect. Here we focus on mechanisms of action of immunoglobulins in muscular dystrophies and inflammatory myopathies highlighting results of IVIGs from pre-clinical and case reports evidences.

Intravenous immunoglobulin as adjuvant therapy for COVID-19: A case report and literature review

Severe acute respiratory syndrome coronavirus 2 has infected and caused the death of an alarming number of individuals worldwide. No specific treatment has been internationally standardized for coronavirus disease 2019 (COVID-19); however, in some cases, intravenous immunoglobulin (IVIG) has been used as adjuvant treatment in critically ill patients with COVID-19 pneumonia. We report a case of a 50-year-old man with severe COVID-19 pneumonia who received 5 days course of IVIG as adjuvant therapy. Invasive respiratory support was avoided. The patient had a successful recovery and was discharged without supplemental oxygen. A high dose of IVIG may improve survival in patients with severe COVID-19 pneumonia. In the current report, we reviewed literature on how IVIG use may improve the early stages of the disease.

Administration of intravenous immunoglobulin in the treatment of COVID-19: A review of available evidence

Since December 31, 2019, unknown causes of pneumonia have been reported in Wuhan, China. This special pneumonia associated with a novel coronavirus was named 2019-nCoV by the World Health Organization (WHO) in January 2020. From the beginning of this infectious disease, clinicians and researchers have been endeavoring to discover an effective and suitable treatment for affected patients. To date, there is no definitive and specific treatments for coronavirus disease-19 (COVID-19) infection while drugs introduced are still in the clinical trial phase. Intravenous immune globulin (IVIG) is a biological product prepared from the serum and an optional treatment for patients with antibody deficiencies. In many countries, much attention has been paid to the use of IVIG in the treatment of patients with COVID-19. Due to the therapeutic importance of IVIG in virus infections, in the current study, we reviewed the possible effect of IVIG in viral infections and potential evidence of IVIG therapy in patients with COVID-19 virus.

Immunogenic properties of immunoglobulin superfamily members within complex biological networks

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Antibody-based therapies induce CDR-specific T and B cell responses.

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Idiotype-anti-idiotype network alters immune system memory compartment.

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Antigenized antibodies are efficient vaccine immunogen.

Antibodies, T cell receptors and major histocompatibility complex molecules are members of the immunoglobulin superfamily and have pivotal roles in the immune system. The fine interrelation between them regulates several immune functions. Here, we describe lesser-known functions ascribed to these molecules in generating and maintaining immune response. Particularly, we outline the contribution of antibody- and T cell receptor-derived complementarity-determining region neoantigens, antigenized antibodies, as well as major histocompatibility complex class I molecules-derived epitopes to the induction of protective/therapeutic immune responses against pathogens and cancer. We discuss findings of our own and other studies describing protective mechanisms, based on immunogenic properties of immunoglobulin superfamily members, and evaluate the perspectives of application of this class of immunogens in molecular vaccines design.

Phenotypic analysis of T follicular helper and T follicular regulatory cells in primary selective IgM deficiency

Selective IgM deficiency (SIgMD) is a rare immunodeficiency characterized by serum IgM below two standard of mean, and normal IgG and IgA levels. Both in human and mice with selective IgM deficiency, germinal centers cells are decreased. The development of germinal center and humoral immunity are regulated in part by follicular helper T (T_FH) and follicular regulatory T (T_FR) cells. However, the analysis of circulating T_FH (cT_FH) and T_FR (cT_FR) cells in the pathogenesis of SIgMD has not been explored. We observed lower percentage of cT_FR cells in SIgMD patients than in control group. However, we did not observe any significant difference in the percentage of cT_FH cells and their subsets between both experimental groups. When data were analyzed according to specific antibody response to pneumococcal polysaccharide, we observed a higher percentage of cT_FH cells in SIgMD patients with specific antibody deficiency than in SIgMD patients with normal specific antibody response. Our results suggest that cT_FH cells and their subsets are preserved in SIgMD patients. However, the role of lower percentage of cT_FR cells in the pathogenesis of this immunodeficiency is not clear.

A New Intravenous Immune Globulin: Novel or Not?

OBJECTIVE

To assess the clinical use and determine the place in therapy for immune globulin intravenous (IV), human-slra, a recently approved IV immune globulin for the treatment of primary immune deficiency diseases (PIDD).

DATA SOURCES

A PubMed and MEDLINE search (2010 to April 2020) was conducted for relevant articles. Data were also obtained from the package insert.

STUDY SELECTION AND DATA EXTRACTION

English language publications regarding the clinical efficacy and safety of immune globulin-slra were analyzed. Publications focused on use of immune globulin products were also included.

DATA SYNTHESIS

Immune globulin-slra is indicated for patients with PIDD and was specifically developed to include donor plasma with high respiratory syncytial virus (RSV) antibody titers. Efficacy was demonstrated through favorable incidence of infections and infection-related complications. Patients treated with immune globulin-slra had increases in anti-RSV neutralizing antibody titers compared with baseline. Adverse events occurred at rates similar to or less than other available immune globulin products.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

This review describes a new immune globulin product available for use in patients with PIDD. A novel approach to managing patients at risk of serious infections may be to utilize products with formulations proven to not only boost IgG levels, but also antibodies to specific pathogens.

CONCLUSIONS

The choice of which immune globulin product to select for a patient or formulary is complex. Each product is unique, and differences between products should be taken into consideration, along with cost and availability.

Intravenous immunoglobulin therapy: a snapshot for the internist

Intravenous immunoglobulins are the cornerstone for the treatment of primary humoral immunodeficiencies and may be used for a great number of other autoimmune, neurological and hematological conditions as well. Given their wide application, the possibility of running across a patient who needs this kind of therapy is becoming increasingly common. Generally, intravenous immunoglobulins are well tolerated. However, numerous adverse reactions ranging from mild to severe have been reported and linked to patient- and product-related factors. For all these reasons, we present herein a comprehensive review of the on- and off-label applications of intravenous immunoglobulins and provide a guide for the internist how to minimize the risk of adverse reactions and manage them.

Generation and characterization of a high affinity anti-human FcRn antibody, rozanolixizumab, and the effects of different molecular formats on the reduction of plasma IgG concentration

Rozanolixizumab (UCB7665), a humanized high-affinity anti-human neonatal Fc receptor (FcRn) monoclonal antibody (IgG4P), has been developed to reduce pathogenic IgG in autoimmune and alloimmune diseases. We document the antibody isolation and compare rozanolixizumab with the same variable region expressed in various mono-, bi- and trivalent formats. We report activity data for rozanolixizumab and the different molecular formats in human cells, FcRn-transgenic mice, and cynomolgus monkeys. Rozanolixizumab, considered the most effective molecular format, dose-dependently and selectively reduced plasma IgG concentrations in an FcRn-transgenic mouse model (no effect on albumin). Intravenous (IV) rozanolixizumab dosing in cynomolgus monkeys demonstrated non-linear pharmacokinetics indicative of target-mediated drug disposition; single IV rozanolixizumab doses (30 mg/kg) in cynomolgus monkeys reduced plasma IgG concentration by 69% by Day 7 post-administration. Daily IV administration of rozanolixizumab (initial 30 mg/kg loading dose; 5 mg/kg daily thereafter) reduced plasma IgG concentrations in all cynomolgus monkeys, with low concentrations maintained throughout the treatment period (42 days). In a 13-week toxicology study in cynomolgus monkeys, supra-pharmacological subcutaneous and IV doses of rozanolixizumab (≤ 150 mg/kg every 3 days) were well tolerated, inducing sustained (but reversible) reductions in IgG concentrations by up to 85%, with no adverse events observed. We have demonstrated accelerated natural catabolism of IgG through inhibition of IgG:FcRn interactions in mice and cynomolgus monkeys. Inhibition of FcRn with rozanolixizumab may provide a novel therapeutic approach to reduce pathogenic IgG in human autoimmune disease. Rozanolixizumab is being investigated in patients with immune thrombocytopenia (NCT02718716) and myasthenia gravis (NCT03052751).

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.

Pharmacokinetics of a novel human intravenous immunoglobulin 10% in patients with primary immunodeficiency diseases: Analysis of a phase III, multicentre, prospective, open-label study

Intravenous immunoglobulin (IVIG) therapy is commonly used to treat patients with primary antibody deficiency. This prospective, open-label, non-randomised, multicentre, phase III trial investigated the pharmacokinetics of a new 10% liquid IVIG product (panzyga®; Octapharma) in 51 patients aged 2-75 years with common variable immunodeficiency (n = 43) or X-linked agammaglobulinaemia (n = 8). Patients were treated with IVIG 10% every 3 (n = 21) or 4 weeks (n = 30) at a dose of 200-800 mg/kg for 12 months. Total immunoglobulin G (IgG) and subclass concentrations approximately doubled from pre- to 15 min post-infusion. The maximum concentration of total IgG (mean ± SD) was 21.82 ± 5.83 g/L in patients treated 3-weekly and 17.42 ± 3.34 g/L in patients treated 4-weekly. Median trough IgG concentrations were nearly constant over the course of the study, remaining between 11.0 and 12.2 g/L for patients on the 3-week schedule and between 8.10 and 8.65 g/L for patients on the 4-week schedule. The median terminal half-life of total IgG was 36.1 (range 18.5-65.9) days, with generally similar values for the IgG subclasses (26.7-38.0 days). Median half-lives for specific antibodies ranged between 21.3 and 51.2 days for anti-cytomegalovirus, anti-Haemophilus influenzae, anti-measles, anti-tetanus toxoid, anti-varicella zoster virus antibodies, and anti-Streptococcus pneumoniae subtype antibodies. Overall, IVIG 10% demonstrated pharmacokinetic properties similar to those of other commercial IVIG 10% preparations and 3- or 4-weekly administration achieved sufficient concentrations of IgG, IgG subclasses, and specific antibodies, exceeding the recommended level needed to effectively prevent serious bacterial infections.

II Brazilian Consensus on the use of human immunoglobulin in patients with primary immunodeficiencies

In the last few years, new primary immunodeficiencies and genetic defects have been described. Recently, immunoglobulin products with improved compositions and for subcutaneous use have become available in Brazil. In order to guide physicians on the use of human immunoglobulin to treat primary immunodeficiencies, based on a narrative literature review and their professional experience, the members of the Primary Immunodeficiency Group of the Brazilian Society of Allergy and Immunology prepared an updated document of the 1^st Brazilian Consensus, published in 2010. The document presents new knowledge about the indications and efficacy of immunoglobulin therapy in primary immunodeficiencies, relevant production-related aspects, mode of use (routes of administration, pharmacokinetics, doses and intervals), adverse events (major, prevention, treatment and reporting), patient monitoring, presentations available and how to have access to this therapeutic resource in Brazil.

Immunoglobulin therapy

Immunoglobulin is an expensive blood product of potentially limited supply used in a wide variety of medical conditions, across a number of specialties. Historically, immunoglobulin has been associated with transmission of blood borne infection (eg hepatitis C). Immunoglobulin use needs to be carefully considered, appropriately prescribed and recorded. The Department of Health, in conjunction with relevant stakeholders, has established a demand management programme to secure immunoglobulin supplies for patients most in need of treatment and to limit use for indications where evidence is lacking.

From immune substitution to immunomodulation

Intravenous immunoglobulins (IVIGs) are currently used in many fields of medicine for replacement and immunomodulation. This review focuses on the milestones in the history of human immunoglobulins since the initial observation by Ogden C. Bruton who described replacement therapy in a boy with agammaglobulinemia. Since then, the preparations used for treatment have been markedly improved with respect to tolerability, clinical efficacy, and pathogen safety. Preparations and appropriate pumps for subcutaneous administration of IgG have been developed and offer an alternative mode of treatment for immunodeficient patients. Appropriate replacement today allows patients with humoral immunodeficiencies to reach adulthood and normal or near-normal quality of life. In 1981 a second fundamental discovery was made. Paul Imbach and coauthors in children with idiopathic thrombocytopenic purpura (ITP) showed that IVIG has immunomodulatory potential, offering a chance for affected children to receive effective treatment with little or no side effects compared to systemic corticosteroids. This new principle of treatment encouraged many researchers worldwide to exploit the potential of IVIG in many other immunopathological situations. As an example, Rhesus hemolytic disease in newborn babies is discussed.

Intravenous immunoglobulin replacement treatment does not alter polymorphonuclear leukocytes function and surface receptors expression in patients with common variable immunodeficiency

The study of the expression of CD16, CD11b and Siglec 9 receptors and the oxidative burst provides insights on polymorphonuclear leukocytes (PMN) functionality in common variable immunodeficiency (CVID) and on the possible effects of intravenous immunoglobulin (IVIg) infusion. We evaluated in vivo before and soon after IVIg administration the CD16, CD11b and Siglec 9 expression on unstimulated and Escherichia coli-stimulated PMN and the oxidative burst induced by Escherichia coli and PMA. The E. coli stimulation up-regulated CD16 and Siglec 9 expression and it induced a strong CD11b up-regulation at baseline and soon after IVIg. The oxidative burst overlapped that observed in healthy donors when induced by Escherichia coli while it increased when induced by PMA. Soon after IVIg infusion, the oxidative burst decreased only when induced by PMA. Our results showed that the IVIg infusion in vivo had a minimal effect on CVID's PMN.