Infusion Of IgG Research Articles

CASE OF A GRANULOMATOUS-LYMPHOCYTIC INTERSTITIAL LUNG DISEASE IN A PATIENT WITH COMMON VARIABLE IMMUNODEFICIENCY DISORDER

SESSION TITLE: Pulmonary Manifestations of Systemic Disease 1 SESSION TYPE: Med Student/Res Case Report PRESENTED ON: 10/09/2018 03:45 PM - 04:45 PM INTRODUCTION: Common variable Immunodeficiency Disorder (CVID), is the most common primary immunodeficiency disorder. Approximately 30% of patients with CVID develop autoimmune and granulomatous disease. Interstitial lung disease (ILD) manifests in 5-15% of CVID patients and represents a diagnostic challenge. It may present with sarcoid like granulomas, organizing pneumonia, lymphocytic interstitial pneumonia and nonspecific interstitial pneumonia. We present one such case of granulomatous-lymphocytic interstitial lung disease (GL-ILD). CASE PRESENTATION: 60 year old African American non-smoking female with no significant underlying medical history presented with cough in March 2006. Family history consisted of mother with stomach cancer, aunt with bone cancer, and grandmother with liver cancer. On physical exam, she had palpable axillary and inguinal lymph nodes. She had an abnormal CT chest showing bilateral lung nodules along with mediastinal lymphadenopathy. CT abdomen/pelvis showed retroperitoneal and pelvic adenopathy. PET scan showed uptake in multiple regions in neck, chest, abdomen and pelvis. PPD and HIV tests were negative.Workup for connective tissue disease came back negative except for low IgA, low normal IgG, and reduced IgM levels. She had minimally elevated ACE level. Inguinal and left axillary lymph node biopsies were non-diagnostic, showing benign lymph nodes with reactive follicular hyperplasia. Flow cytometry was negative. Video-assisted thoracoscopic left lung biopsies showed nodular airway-centered lymphoid hyperplasia with associated scattered small non-necrotizing granulomas. Follicular bronchiolitis was present. Biopsies did not suggest sarcoidosis. Mycobacterial and fungal cultures were negative. She had serial CT chest, abdomen and pelvis for the next two years showing no progression of her disease. After 2008, she had slow progression of lymphadenopathy and was evaluated at a tertiary care center in 2012. Definitive diagnosis of GL-ILD was given at that point. She was placed on steroids for about a year with stabilization of her disease. Subsequently, she had worsening of her lymphadenopathy off steroids and has been maintained on IgG infusions. DISCUSSION: CVID is present in a considerable number of patients with a small subset presenting with cryptic ILD. Exhaustive diagnostic workup is usually needed including open lung biopsy. Patients with GL-ILD may remain stable over years after optimization of their immunoglobulin levels. Following this, steroids remain first line treatment and response may be variable. In progressive disease, immunosuppressive treatment is recommended. CONCLUSIONS: This case illustrates an example of a form of interstitial lung disease associated with CVID. When lung biopsies demonstrate lymphocytic infiltrate and/or granuloma in the lung, CVID should be considered in the differential. Reference #1: British Lung Foundation/United Kingdom PrimaryImmunodeficiency Network Consensus Statement. J Allergy Clin Immunol Pract. 2017 Jul - Aug;5(4):938-945. https://doi.org/10.1016/j.jaip.2017.01.021. Epub 2017 Mar 25. Reference #2: Granulomatous-lymphocytic interstitial lung disease as the first manifestation of common variable immunodeficiency. Clin Respir J. 2018 Jan;12(1):337-343. https://doi.org/10.1111/crj.12511. Epub 2016 Jun 22. DISCLOSURES: No relevant relationships by Riju Dasgupta, source=Web Response No relevant relationships by Asok Dasgupta, source=Web Response No relevant relationships by Chelsea Leipold, source=Web Response No relevant relationships by David Taylor, source=Web Response No relevant relationships by Paresh Timbadia, source=Web Response

ANP antibody attenuates RIHP amplification during acute Saline Volume Expansion in rats

The role of Atrial Natriuretic Peptide (ANP) on renal interstitial hydrostatic pressure (RIHP), urinary excretion of sodium (UNaV) and water (V) amplification responses during saline volume expansion (SVE, 5% bw, ~30 min, 0.9%), and immediately after (maintained SVE, 10 min) was studied in male adult wistar rats 24 h after antiseptic intra‐arterial infusion of polyglonal IgG anti‐Atrial Natriuretic Factor (ANF) antibody (AbANP, 18 μg, wich theoretically blocked all ANP secretion, n=8) versus control (CTR, gluc5%, n=10). The day of the acute experiment, variables were continously measured in anesthetized animals with hormonal clamp (without ANP), kidney denervation (chemical and mechanical) and renal perfusion pressure control at 100 mmHg during hydropenia (H), SVE, and maintained SVE(mSVE).The results are shown in table 1. For Ht and plasmatic protein, there were no differences between groups during H period and the hemodilution response was similar between groups. For RIHP, an attenuation in the amplification response was obtained, from 3 times in CTR vs H to 1 time in abANP group (MANOVA test, p<0.05 between groups, SVE and mSVE., t‐student test vs H each group p<0.05). For V and UNaV responses, there were no differences between groups or periods, achieving the amplification response in the same magnitude for both groups. Finally, an increase in UGMPcV and UNOxV during SVE and mSVE were similar in both groups.Conclusionsin rats, the acute increase in plasmatic ANP is necessary for the complete RIHP amplification during acute SVE, probably involving an independent nitric‐oxide mechanism. Also, a dissociation between RIHP and natriuretic response was observed.Support or Funding InformationSupported by IPL's financial resourcesThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Long-Term Tolerability, Safety, and Efficacy of Recombinant Human Hyaluronidase-Facilitated Subcutaneous Infusion of Human Immunoglobulin for Primary Immunodeficiency

PurposeTreatment of primary immunodeficiency diseases (PIDD) with subcutaneous (SC) infusions of IgG preceded by injection of recombinant human hyaluronidase (rHuPH20) (IGHy) to increase SC tissue permeability was evaluated in two consecutive, prospective, non-controlled, multi-center studies.MethodsSubjects >4 years of age received SC IgG replacement at a weekly dose equivalent of 108 % of their previous intravenous (IV) dose, facilitated by prior injection of 75 U/g IgG of rHuPH20. Starting with weekly SC infusions, the interval was increased (ramped-up) to a 3- or 4-week schedule.ResultsEighty-three subjects (24 < 18 years; 59 ≥ 18 years) received 2729 infusions (excluding ramp-up) at a mean dose of 0.155 g/kg/week in the pivotal and 0.156 g/kg/week in the extension study. IGHy exposure exceeded 30 months in 48 subjects.During 187.7 subject-years of IGHy exposure, 2005 adverse events (AEs) (10.68 per subject-year) occurred. The rate of related systemic AEs during consecutive 1-year periods remained low; the rate of related local AEs decreased from 3.68/subject-year in months 1–12 to approximately 1.50/subject-year after 30 months of treatment. Fifteen subjects transiently developed anti-rHuPH20 binding antibody. There was no difference in AE rates in these subjects before and after the first titer increase to ≥1:160.The rate of infections during IGHy exposure was 2.99 per subject-year and did not increase during the studies. Annual infection rates were 3.02 in subjects <18 years and 2.98 in subjects ≥18 years.ConclusionsLong-term replacement therapy with IGHy was safe and effective in 83 pediatric and adult subjects with PIDD.Electronic supplementary materialThe online version of this article (doi:10.1007/s10875-016-0298-x) contains supplementary material, which is available to authorized users.

Systemic administration of an HIV-1 broadly neutralizing dimeric IgA yields mucosal secretory IgA and virus neutralization.

We investigated the mucosal distribution and neutralization potency of rhesus recombinant versions of the HIV-specific, broadly neutralizing antibody b12 (RhB12) following intravenous administration to lactating rhesus monkeys. IgG and dimeric IgA (dIgA) administration resulted in high plasma concentrations of bnAb, but the monomeric IgA (mIgA) was rapidly cleared from the systemic compartment. Interestingly differences in the distribution of the RhB12 isoform were observed between the mucosal compartments. The peak concentration of RhB12 IgG was higher than dIgA in saliva, rectal and vaginal secretions, but the bnAb concentration in milk was one to two logs higher after dIgA administration than with IgG or mIgA infusion. Neutralization was observed in plasma of all animals, but only those infused with RhB12 dIgA showed moderate levels of virus neutralization in milk. Remarkably, virus-specific secretory IgA was detected in mucosal compartments following dIgA administration. The high milk RhB12 dIgA concentration suggests that passive immunization with dIgA could be more effective than IgG to inhibit virus in breast milk.

Modulatory role of intravenous gammaglobulin (IgIV) on the in vitro antibody response to a pneumococcal polysaccharide antigen.

Clinical observations in patients with specific antibody deficiency treated for periods of time with IgG infusion have suggested that IgG may have a positive immunoregulatory effect on the production of specific antibodies against pneumococcal polysaccharides. We developed an in vitro model to test the effect of an IgIV preparation on the antibody production in response to a pneumococcal polysaccharide serotype and on the antibody and cytokine production in response to both a protein antigen and a pneumococcal polysaccharide antigen. We studied 37 consecutive patients referred to our clinics for evaluation of their recurrent respiratory infections. Subjects were divided into two groups: 22 patients without SAD and 15 patients with SAD. PBMCs were left unstimulated or were stimulated with tetanus toxoid or pneumococcal polysaccharide serotype 19, in the presence of human albumin or IgIV. IgG anti-Pn-19 antibody, IL-4 and IFN-γ concentrations in culture supernatants were determined by ELISA. An increase in IgG anti-Pn-19 antibodies, associated with an increase in IFN-γ and a decrease in IL-4 production was observed in cultures stimulated with pneumococcal polysaccharide in the presence of IgIV when patients were analyzed together. The enhancing effect of IgIV was more significant for both IgG anti-Pn19 antibodies and IFN-γ in patients without SAD. In contrast, IgIV caused a significant decrease in IL-4 secretion in patients with SAD, which was associated with an increase in IgG anti-Pn19 antibodies in 3 of 7 of these patients. These results suggest that IgIV has some immunomodulatory effect on the in vitro production of IgG anti-Pn19 antibodies and cytokine production in cell cultures stimulated with Pn-19 antigen and that this modulation may be associated with a Th1/Th2 regulatory mechanism. Further studies at a cellular and molecular level are in progress to examine if the differences in the in vitro modulatory response to IgIV in these two groups of patients may point to a functional defect in patients with SAD.

VWF Modulates the in Vivo FVIII Recovery of Different FVIII Concentrates in a Mice Model of Severe Hemophilia with Inhibitors

About 25% of severe hemophilia A patients undergoing factor VIII (FVIII) replacement therapy develop antibodies against FVIII (FVIII inhibitors). The formation of inhibitor is generally accepted as the most common and challenging complication of hemophilia treatment. In the circulation, FVIII is tightly bound to von Willebrand factor (VWF), forming a complex that plays a significant role in FVIII protection from premature degradation (Delignat S et al, Haemophilia 2012;18:248-54). Several laboratory and clinical studies suggest that the presence of VWF in FVIII concentrates might have some benefits due to the protective effect against antibodies (Shi Q et al, J Thromb Haemost 2012;10:2328-37; Mannucci PM, Haemophilia 2012;18 Suppl 2:2-7). Plasma-derived (pd) FVIII/VWF concentrates show higher residual FVIII activity and more thrombin generation after incubation with inhibitors compared to isolated FVIII concentrates (pdFVIII or recombinant, rFVIII). The protective effect of VWF observed in native pdFVIII/VWF complex is not completely restored for isolated FVIII even after mixing with VWF before analyzing the reaction with inhibitors (Bravo MI et al, Haemophilia 2014; in press).This study analyzes the impact of VWF on FVIII protection against inhibitors in an in vivo model, by evaluating the differences of FVIII in vivo recovery between FVIII concentrates with or without VWF in FVIIInull E16Knockout (KO) mice infused with inhibitors purified from hemophilic patients’ plasma.Inhibitor IgG was purified from a pool of human plasmas from hemophilic patients (Technoclone GmbH, Vienna, Austria) by using Protein G Sepharose chromatography as described elsewhere. IgGs were tail vein infused to achieve 3.2 BU/ml (or buffer as a control) prior to FVIII treatment. Five minutes after IgG infusion, animals (n=5-6 for each treatment group) were infused with FVIII therapeutic concentrates (100 IU/kg) from different sources, including native pdFVIII/VWF complex; isolated pdFVIII and full-length recombinant FVIII (rFVIII). In addition, some animal groups were treated with in vitro preformed complexes with pdVWF (therapeutic concentrate for von Willebrand disease) and FVIII (rFVIII+pdVWF and pdFVIII+pdVWF mixed at 1IU:1IU ratio; 15 min at 25ºC). After 5 min post-FVIII infusion, plasma samples were obtained by abdominal cave vein sampling and residual FVIII:C was measured using chromogenic assay. FVIII recovery was estimated according on the empirical finding that 1IUFVIII/kg body weight raises the plasma FVIII activity by 2.1±0.4% of normal activity.In the absence of inhibitor, in vivo FVIII recovery in FVIIInull E16 KO mice was similar for all FVIII concentrates as expected, with values ranging from 107% to 124% (see table). In contrast, in the presence of inhibitors the FVIII recovery showed marked differences among treatment groups. Recovery was higher for the native VWF-containing FVIII concentrate (pdFVIII/VWF: 71.1±17.4%) when compared to concentrates composed of isolated FVIII (rFVIII: 31.4±9.9%; pdFVIII: 25.0±2.7%). When the products containing isolated FVIII were premixed with VWF prior to infusion, FVIII recovery was only partially restored (rFVIII+VWF: 67.1±15.1%; pdFVIII+VWF: 45.2±8.8%). FVIIIC recovery and ratio FVIII:C, 5 min post-infusion of FVIII products (100 IU/kg), without inhibitor and with inhibitor (3.2±0.4 BU/ml) in severe hemophilic mice. Abstract 2826. TableFVIII productsFVIII:C Recovery (%) [mean±SD (n)]FVIII:C ratio (IU) in absence vs. presence of inhibitorWithout inhibitorWith inhibitorpdFVIII /VWF107.9 ± 6.1 (6)71.1 ± 17.4 (5)1.52rFVIII106.9 ± 8.3 (6)31.4 ± 9.9 (5)3.41pdFVIII120.5 ± 5.1 (6)25.0 ± 2.7 (5)4.77rFVIII+pdVWF124.3 ± 11.2 (6)67.1 ± 15.1 (6)1.84pdFVIII+pdVWF111.8 ± 5.9 (6)45.2 ± 8.8 (6)2.47Our data indicate that VWF-containing FVIII concentrates are more efficient in the restoration of FVIII circulating levels in the FVIIInull E16 KO mice model with inhibitors. Moreover, results also suggest that this protection would be higher in native pdFVIII/VWF complex that in the complex of FVIII+VWF formed from the isolated proteins. DisclosuresBravo:Instituto Grifols: Employment. Da Rocha-Souto:Instituto Grifols: Employment. Grancha:Instituto Grifols: Employment. Jorquera:Grifols Bioscience: Employment.

Adverse effects of immunoglobulin G therapy: thromboembolism and haemolysis.

Adverse effects of immunoglobulin G therapy: thromboembolism and haemolysis.

Efficiency of immunoglobulin G replacement therapy in common variable immunodeficiency: correlations with clinical phenotype and polymorphism of the neonatal Fc receptor.

Efficiency of immunoglobulin G replacement therapy in common variable immunodeficiency: correlations with clinical phenotype and polymorphism of the neonatal Fc receptor.

Three major uncertainties in the antibody therapy of cancer.

Antibodies against surface molecules of human tumors are now frequently administered in combination with strong chemotherapy, increasing therapeutic efficacy but making the task of elucidating immunological events more difficult. Experiments on genetically manipulated mice indicate that antibody efficacy is greatest when IgG antibody coating tumor cells is engaged by the Fcγ-receptors of effector cells, chiefly the monocyte/macrophage lineage. Evidence suggests lesser roles for NK cells, neutrophils, receptor-mediated cytotoxicity and complement-mediated cytotoxicity. The classical mode of killing employed by macrophages is phagocytosis, but much has to be learned about optimally activating macrophages for this task, and about any other modes of cytotoxicity used. There is renewed interest in antigenic modulation, which implies removal of therapeutic antibody linked with antigen from target-cell surfaces. It is now apparent that this removal of immune complexes can be achieved either by internalization by the target cell, or by transfer of the complexes to another cell by trogocytosis. In trials, anti-idiotype antibodies surprisingly proved therapeutically more effective than anti-CD20, despite anti-idiotype being more effectively removed from target-cell surfaces by antigenic modulation. This anomalous result might reflect the fact that persistence of anti-CD20 immune complexes in large amounts induces serious effector modulation, which paralyzes macrophage attacks on antibody-coated cells. The case for effector modulation is argued by analogy with the therapeutic suppression of autoimmune inflammation by effector modulation, achieved by infusion either of normal IgG in large amounts, or of anti-red cell IgG in relatively small amounts.

Interference of confounding factors on the use of (1,3)-beta-D-glucan in the diagnosis of invasive candidiasis in the intensive care unit.

Invasive fungal infections (IFIs) are an increasing problem in intensive care units (ICUs), and conventional diagnostic methods are not always reliable or timely enough to deliver appropriate antimicrobial therapy. The dosage of fungal antigens in serum is a promising diagnostic technique, but several confounding factors, such as treatment with immunoglobulins (Ig), albumin, or antifungals, could interfere with the correct interpretation of the (1,3)-beta-D-glucan (BG) assay. This study assessed the reliability of the BG assay and the influence of timing and dosage of major confounding factors on circulating levels of IFI biomarkers. 267 ICU patients who underwent a BG assay were retrospectively studied. The timing and dosage of albumin, use of azole treatment, and infusions of intravenous IgG, red blood cells, concentrated platelets, and frozen plasma were analyzed to find possible correlations with the BG results. The sensitivity and specificity of the BG assay were calculated. The BG test in serum showed high sensitivity (82.9 %) but low specificity (56.7 %). The optimal cut-off for the test was 95.9 pg/mL. The mean BG level in proven invasive candidiasis was around 400 pg/mL. The only factor that was found to significantly confound (p < 0.05) the diagnostic performance of the BG assay was the administration of more than 30 g of albumin within 2 days prior to BG testing. The BG assay remains a useful diagnostic test in ICU patients and the levels of BG are useful in evaluating the positive predictive value of this biomarker. The only confounding factor in our study was the use of albumin.

Overview of recombinant human hyaluronidase-facilitated subcutaneous infusion of IgG in primary immunodeficiencies.

Subcutaneous administration of immunoglobulin (IGSC) in a home setting, compared with intravenous administration, can improve patient quality of life. During IGSC, however, the subcutaneous extracellular matrix inhibits flow and fluid entry into the vascular compartment, which limits the amount of drug delivered. Recombinant human hyaluronidase (rHuPH20) increases the absorption and dispersion of infused fluids and drugs. Results from a Phase III, prospective, open-label, noncontrolled study of patients with primary immunodeficiencies indicated that IGSC infusion, facilitated by rHuPH20, is well tolerated and delivers infusion volumes at treatment intervals and rates equivalent to intravenous administration. This drug evaluation provides an overview of rHuPH20 and results of clinical studies of IGSC infusion facilitated by rHuPH20 in patients with primary immunodeficiencies.

Long-Term Treatment and Transfusion of Normal Blood Components Following Tolerance Induction in Patients with Anti-IgA Anaphylactic Reactions

Background: In general, patients with significant anti-Ig-A do not tolerate intravenous (i.v.) administration of normal blood products. Here, we present our experiences in the induction of immune tolerance (IIT) and long-term treatment in a series of such patients affected in such a way. The question whether blood components from IgA-deficient donors are required will be discussed. Methods: Ten adult patients (4 females and 6 males; age ranging from 36 to 75 years) with anti-IgA were included in this study. All patients required long-term treatment with blood components. One patient had IgA deficiency and paroxysmal nocturnal hemoglobinuria (PNH), and all other patients had common variable immunodeficiency (CVID). The particle gel immunoassay was used for the detection of anti-IgA. Immune tolerance to IgA was induced by controlled subcutaneous (s.c.) and/or i.v. infusions of IgG preparations. Results: Prior to IIT, anti-IgA was detectable in plasma samples of all patients and significantly diminished or abolished by controlled s.c. and/or i.v. infusions of IgG. Multiple transfusions with normal blood components could be repeatedly performed with the patient suffering from PNH without any complications. As long as i.v. IgG (IVIgG) infusions were consequently administered as individually required (intervals 2-8 weeks), none of the patients developed reactions during observation (up to 10 years). However, interruption of treatment and re-exposure to IVIgG resulted in adverse reactions. Conclusion: Patients with significant anti-IgA can be safely desensitized and tolerate long-term IgG substitutions independent of the IgA concentration of the used blood component.

Adverse Effects of IgG Therapy

IgG is widely used for patients with immune deficiencies and in a broad range of autoimmune and inflammatory disorders. Up to 40% of intravenous infusions of IgG may be associated with adverse effects (AEs), which are mostly uncomfortable or unpleasant but often are not serious. The most common infusion-related AE is headache. More serious reactions, including true anaphylaxis and anaphylactoid reactions, occur less frequently. Most reactions are related to the rate of infusion and can be prevented or treated just by slowing the infusion rate. Medications such as nonsteroidal anti-inflammatory drugs, antihistamines, or corticosteroids also may be helpful in preventing or treating these common AEs. IgA deficiency with the potential of IgG or IgE antibodies against IgA increases the risk of some AEs but should not be viewed as a contraindication if IgG therapy is needed. Potentially serious AEs include renal dysfunction and/or failure, thromboembolic events, and acute hemolysis. These events usually are multifactorial, related to combinations of constituents in the IgG product as well as risk factors for the recipient. Awareness of these factors should allow minimization of the risks and consequences of these AEs. Subcutaneous IgG is absorbed more slowly into the circulation and has a lower incidence of AEs, but awareness and diligence are necessary whenever IgG is administered.

Porcine model to evaluate local tissue tolerability associated with subcutaneous delivery of protein

IntroductionThe conversion from intravenous (IV) to subcutaneous (SC) delivery of biotherapeutics has increased in recent years. Some of the reasons for this shift in route of delivery are due to patient convenience, reduced adverse systemic effects, lack of a need for vascular access, and reduced cost of patient care, which ultimately lead to improved patient quality of life. One caveat to SC delivery is the limited volumes that can be administered at a single site and the associated local tolerability. To characterize factors that affect subcutaneous delivery of large volumes of therapeutic proteins, a porcine model was developed. Model endpoints included measurement of interstitial pressure, assessment of local skin visco-elasticity, and the qualitative assessment of local infusion sites. MethodsImmunoglobulin G (IgG) was subcutaneously infused into the abdominal region of Yucatan miniature swine. Changes in interstitial pressure were measured, using an in-line pressure transducer, during and after infusions. Additionally, pre- and post-infusion changes in local skin visco-elasticity were measured using a Cutometer®. Lastly, infusion sites were assessed for post-infusion local skin reactions such as erythema and swelling. Similar assessments were made following SC IgG delivery with the permeation enhancer recombinant human hyaluronidase PH20 (rHuPH20). ResultsSubcutaneous infusions of IgG, in the presence of rHuPH20, significantly reduced average interstitial pressures by 55% during the infusion period and by 67% during the post-infusion period, compared to the control. Infusions in the presence of rHuPH20 also maintained better local skin elasticity as seen by a 42% increase in local skin pliability compared to the control. Finally, infusions with rHuPH20 resulted in an 80% reduction in swelling area compared to the control. DiscussionA large animal model was developed that incorporates both quantitative and qualitative assessment methods to aid in understanding SC delivery of proteins.

High-Dose IgG Completely Inhibited TNF-α-Induced, but Not IL-1β- or Poly (I:C)-Induced, G-CSF Expression by Human Coronary Artery Endothelial Cells

Kawasaki Disease (KD) is an acute systemic vasculitis of unknown etiology in infants and young children, and it is frequently associated with coronary artery aneurysms. High-dose infusion of IgG (IVIG) effectively reduces systemic inflammation and the incidence of coronary artery lesions in 80-90% of KD. However, for reasons that remain unclear, some patients do not respond to IVIG. In order to obtain clues to the cause of IVIG resistance, we compared the in vitro effects of high-dose IgG on cultured human coronary artery endothelial cells (HCAECs) exposed to various inflammatory stimuli.

Efficiency of immunoglobulin G replacement therapy in common variable immunodeficiency: correlations with clinical phenotype and polymorphism of the neonatal Fc receptor

Treatment of common variable immunodeficiency disorders (CVID) is based on replacement therapy using intravenous (i.v.) or subcutaneous (s.c.) immunoglobulin (Ig)G. Interindividual variation of IgG dose is common. A total of 380 CVID patients on stable IgG replacement from two prospective cohorts were analysed. An 'efficiency' index was defined as the ratio of serum IgG trough level minus IgG residual to the average weekly dose of IgG infusion. A reduced efficiency of IgG was associated independently with the i.v. route (P < 0·001) and with the presence of at least one CVID disease-related phenotype (lymphoproliferation, autoimmune cytopenia or enteropathy) (P < 0·001). High IgG efficiency was noted in patients homozygotes for the variable number tandem repeat (VNTR) 3/3 polymorphism of the neonatal Fc receptor gene [IgG Fc fragment receptor transporter alpha chain (FCGRT)] promoter, and this was particularly significant in patients treated with IVIG (P < 0.01). In a multivariate analysis, FCGRT VNTR 3/3 genotype (P = 0·008) and high serum albumin (P < 0·001) were associated independently with increased efficiency of i.v. Ig.

Treatment with Low Doses of Polyclonal Immunoglobulin Improves B Cell Function During Immune Reconstitution in a Murine Model

[corrected] After autologous stem cell transplantation (ASCT) the immunological B cell compartment recovers slowly. Delays on the recovery of B cell function after autologous stem cell transplantation are due to the low lymphocytes count and to their intrinsic dysfunction. We studied the in vivo B cell reconstitution after ASCT examining the independent effect of polyclonal IgG (PolyIg), Fab or Fc fragments infusions in a murine animal model during a period of 12 weeks. These molecules were used in low doses, mimicking the recommended use of IVIg in the case of hypogammaglobulinemia in humans. Flow cytometry analysis and ELISA tests were conducted to monitor the reconstitution of B cells and serum immunoglobulin production. Panama blot and PCA factor 1 analysis were used to study the kinetics of immunoglobulin repertoires reconstitution. Mechanistic studies were also performed using in vitro cell culture. During follow-up after ASCT, peripheral B cells expand independently of treatment, correcting the immediate increase in sBAFF (soluble B cell activating factor) induced by previous intense myeloablation. Treatments with Fab and Fc fragments infusions promote significant IgM and IgG production comparing to control. Although the complete recovery of antibody repertoire is only achieved at the end of follow-up after ASCT, there is an earlier and significantly stronger recovery in the treated mice, which is evident at 9 weeks after ASCT. At 30 weeks after ASCT, normal values of antibody repertoire were detected in all individuals. Mechanistic studies show that Fab and Fc fragments promote IgG1 production by indirect pathways. The results presented here demonstrate that polyclonal immunoglobulin indirectly improves the function of the reconstituted B cells and their IgG production by means of Fc-mediated effects on bystander cells. These results further stimulate the discussion about the advantages of IVIg therapy during immune reconstitution after human ASCT.

Abstract 215: An Agonistic Human Monoclonal Autoantibody to the β2-adrenergic Receptor: Implications in Postural Hypotension

Functional autoantibodies directed to the autonomic receptors have been increasingly recognized to contribute to the pathophysiology of various cardiovascular diseases. However, to date, no human monoclonal autoantibodies to these receptors with agonist activity have been available. We have recently reported a subgroup of patients with idiopathic postural hypotension who have no known etiology are associated with vasodilatory autoantibodies to the β2-adrenergic receptor (β2AR). Using standard hybridoma techniques, we produced a β2AR-activating monoclonal autoantibody C5F2 from the peripheral blood lymphocytes of a patient with idiopathic postural hypotension and high ELISA antibody titers to a peptide corresponding to the second extracellular loop (ECL2) of β2AR. C5F2 was of the IgG3 isotype and recognized an epitope located at the N-terminus of β2AR ECL2 as determined by epitope mapping using multipin peptide synthesis. Confocal immunofluorescence revealed C5F2 binding to the β2AR in Chinese hamster ovary (CHO) cells transfected with human β2AR and rat cremaster arterioles, both of which were inhibited by presabsorption with the β2AR ECL2 peptide. Functionally, the C5F2 IgG stimulated cyclic AMP production in β2AR-expressing CHO cells in a dose-dependent manner (0.005-5 mg/ml). C5F2-induced cyclic AMP activation was specifically blocked by both the β2AR ECL2 peptide and β2AR selective antagonist ICI-118551. In an isolated rat cremaster arteriole assay, infusion of the C5F2 IgG produced a potent vasodilation which was inhibited by the β2AR ECL2 peptide and β2AR blocker ICI-118551 (from 67.8±5.8% to 9.3±5.1% and 4.4±2.1% of maximal dilatory response, respectively), indicating that antibody activation of vascular β2AR may contribute to systemic vasodilation. These data support the concept that circulating agonistic autoantibodies serve as vasodilators and may cause or exacerbate orthostasis by altering the compensatory postural vascular response. The availability of this first human monoclonal autoantibody to the β2AR provides opportunities to identify previously unrecognized causes and new pharmacological management of postural hypotension.

Anti‐inflammatory effects of high‐dose IgG on TNF‐α‐activated human coronary artery endothelial cells

High-dose infusion of IgG (IVIG) is used to treat autoimmune and inflammatory diseases, including Kawasaki disease (KD). Although the immunomodulatory effects of IVIG on blood cells such as macrophages have been well studied, its effects on tissue cells remain unclear. Here, we show that high-dose IgG specifically and completely inhibited TNF-α-induced, but not IL-1β-induced, secretion of proinflammatory cytokines such as G-CSF and IL-6 by cultured human coronary artery endothelial cells (HCAECs). High-dose IgG did not inhibit TNF-α-mediated early signaling events of the NF-κB and MAPK pathways but it potently inhibited gene expression of G-CSF and IL-6 12 h after TNF-α-stimulation. Interestingly, suppression of the G-CSF and IL-6 gene expression correlated closely with functional inhibition of a transcription factor, C/EBPδ, whose binding sites in the promoters of G-CSF and IL-6 have been shown to be critical for their transcriptional activation. Furthermore, the inhibitory effect of intact IgG on HCAECs was exerted mainly via its F(ab')(2) fragment, and not its Fc fragment. These findings suggest that the clinical effects of IVIG on KD patients are at least in part due to its direct anti-inflammatory effects on the coronary endothelium, which is a major lesion site in the pathogenesis of KD.

Autosomal Dominant STAT3 Deficiency and Hyper-IgE Syndrome

Autosomal dominant deficiency of signal transducer and activator of transcription 3 (STAT3) is the main genetic etiology of hyper-immunoglobulin (Ig) E syndrome. We documented the molecular, cellular, and clinical features of 60 patients with heterozygous STAT3 mutations from 47 kindreds followed in France. We identified 11 known and 13 new mutations of STAT3. Low levels of interleukin (IL)-6-dependent phosphorylation and nuclear translocation (or accumulation) of STAT3 were observed in Epstein-Barr virus-transformed B lymphocytes (EBV-B cells) from all STAT3-deficient patients tested. The immunologic phenotype was characterized by high serum IgE levels (96% of the patients), memory B-cell lymphopenia (94.5%), and hypereosinophilia (80%). A low proportion of IL-17A-producing circulating T cells was found in 14 of the 15 patients tested. Mucocutaneous infections were the most frequent, typically caused by Staphylococcus aureus (all patients) and Candida albicans (85%). Up to 90% of the patients had pneumonia, mostly caused by Staph. aureus (31%) or Streptococcus pneumoniae (30%). Recurrent pneumonia was associated with secondary bronchiectasis and pneumatocele (67%), as well as secondary aspergillosis (22%). Up to 92% of the patients had dermatitis and connective tissue abnormalities, with facial dysmorphism (95%), retention of decidual teeth (65%), osteopenia (50%), and hyperextensibility (50%). Four patients developed non-Hodgkin lymphoma. The clinical outcome was favorable, with 56 patients, including 43 adults, still alive at the end of study (mean age, 21 yr; range, 1 mo to 46 yr). Only 4 patients died, 3 from severe bacterial infection (aged 1, 15, and 29 yr, respectively). Antibiotic prophylaxis (90% of patients), antifungal prophylaxis (50%), and IgG infusions (53%) improved patient health, as demonstrated by the large decrease in pneumonia recurrence. Overall, the prognosis of STAT3 deficiency may be considered good, provided that multiple prophylactic measures, including IgG infusions, are implemented.