IgG Substitution Research Articles

Multicentre, randomized, double-blind, prospective study on the effects of ImmunoAdSorptiOn on cardiac function in patients with Dilated CardioMyopathy (IASO-DCM): Rationale and design.

Pilot studies indicate that immunoadsorption with subsequent IgG substitution (IA/IgG) induces beneficial effects in patients with dilated cardiomyopathy (DCM) and heart failure. This placebo-controlled study investigates whether IA/IgG treatment enhances left ventricular (LV) systolic function as compared to a control group receiving pseudo-treatment. This multicentre, randomized, double-blind, parallel-group trial aims to include 200 patients with heart failure due to DCM (LV ejection fraction [LVEF] <40%) on optimized guideline-directed heart failure medication. Participants are randomly assigned in a 1:1 ratio to IA/IgG using protein-A columns, or to pseudo-immunoadsorption followed by an intravenous infusion without IgG. Follow-up visits take place by telephone after 1 and 3 months and at the study centres after 6, 12 and 24 months. The primary efficacy endpoint is the change in LVEF from baseline to 6 months determined by contrast echocardiography, analysed at a core lab. In addition, LV end-diastolic and end-systolic volumes will be analysed as secondary endpoints over the entire study period to assess whether IA/IgG affects LV remodelling. As main secondary outcome, a composite of all-cause death, cardiac resuscitation, hospitalization for heart failure, and need for cardiac surgery to improve myocardial pump function will be evaluated after 24 months. In addition, exploratory outcomes as well as safety endpoints related to the treatment will be assessed throughout the whole study period. IASO-DCM is a randomized study which will provide comprehensive insights into the effects of immunoadsorption with subsequent IgG substitution in patients with DCM.

Management of Patients Undergoing CAR-T Cell Therapy in Germany

Introduction: Chimeric antigen receptor positive T cell (CAR-T cell) treatment became standard therapy for relapsed or refractory hematologic malignancies, such as non-Hodgkin’s lymphoma and multiple myeloma. Owing to the rapidly progressing field of CAR-T cell therapy and the lack of generally accepted treatment guidelines, we hypothesized significant differences between centers in the prevention, diagnosis, and management of short- and long-term complications. Methods: To capture the current CAR-T cell management among German centers to determine the medical need and specific areas for future clinical research, the DAG-HSZT (Deutsche Arbeitsgemeinschaft für Hämatopoetische Stammzelltransplantation und Zelluläre Therapie; German Working Group for Hematopoietic Stem Cell Transplantation and Cellular Therapy) performed a survey among 26 German CAR-T cell centers. Results: We received answers from 17 centers (65%). The survey documents the relevance of evidence in the CAR-T cell field with a homogeneity of practice in areas with existing clinical evidence. In contrast, in areas with no – or low quality – clinical evidence, we identified significant variety in management in between the centers: management of cytokine release syndrome, immune effector cell-related neurotoxicity syndrome, IgG substitution, autologous stem cell backups, anti-infective prophylaxis, and vaccinations. Conclusion: The results indicate the urgent need for better harmonization of supportive care in CAR-T cell therapies including clinical research to improve clinical outcome.

Total escape of SARS-CoV-2 from dual monoclonal antibody therapy in an immunocompromised patient

Monoclonal antibodies (mAbs) directed against the spike of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are effective therapeutic options to combat infections in high-risk patients. Here, we report the adaptation of SARS-CoV-2 to the mAb cocktail REGN-COV in a kidney transplant patient with hypogammaglobulinemia. Following mAb treatment, the patient did not clear the infection. During viral persistence, SARS-CoV-2 acquired three novel spike mutations. Neutralization and mouse protection analyses demonstrate a complete viral escape from REGN-COV at the expense of ACE-2 binding. Final clearance of the virus occurred upon reduction of the immunosuppressive regimen and total IgG substitution. Serology suggests that the development of highly neutralizing IgM rather than IgG substitution aids clearance. Our findings emphasise that selection pressure by mAbs on SARS-CoV-2 can lead to development of escape variants in immunocompromised patients. Thus, modification of immunosuppressive therapy, if possible, might be preferable to control and clearance of the viral infection.

Multiple Modes of Action Mediate the Therapeutic Effect of Intravenous IgG in Experimental Epidermolysis Bullosa Acquisita

Substitution of IgG in antibody deficiency or application of high-dose intravenous IgG in patients with autoimmunity is a well-established treatment. However, data on the mode of action of intravenous IgG are controversial and may differ for distinct diseases. In this study, we investigated the impact and molecular mechanism of high-dose IgG (hd-IgG) treatment in murine autoantibody‒induced skin inflammation, namely, epidermolysis bullosa acquisita. Epidermolysis bullosa acquisita is caused by antibodies directed against type VII collagen and is mediated by complement activation, the release of ROS, and proteases by myeloid cells. In murine experimental epidermolysis bullosa acquisita, the disease can be induced by injection of anti‒type VII collagen IgG. In this study, we substantiate that treatment with hd-IgG improves clinical disease manifestation. Mechanistically, hd-IgG reduced the amount of anti‒type VII collagen in the skin and sera, which is indicative of an FcRn-dependent mode of action. Furthermore, in a nonreceptor-mediated fashion, hd-IgG showed antioxidative properties by scavenging extracellular ROS. Hd-IgG also impaired complement activation and served as a substrate for proteases, both key events during epidermolysis bullosa acquisita pathogenesis. Collectively, the nonreceptor-mediated anti-inflammatory properties of hd-IgG may explain the therapeutic benefit of intravenous IgG treatment in skin autoimmunity.

Tolerability and Efficacy of s.c. IgG Self-Treatment in ME/CFS Patients with IgG/IgG Subclass Deficiency: A Proof-of-Concept Study.

Background: Chronic fatigue syndrome (ME/CFS) is a complex disease frequently triggered by infections. IgG substitution may have therapeutic effect both by ameliorating susceptibility to infections and due to immunomodulatory effects. Methods: We conducted a proof of concept open trial with s.c. IgG in 17 ME/CFS patients suffering from recurrent infections and mild IgG or IgG subclass deficiency to assess tolerability and efficacy. Patients received s.c. IgG therapy of 0.8 g/kg/month for 12 months with an initial 2 months dose escalation phase of 0.2 g and 0.4 g/kg/month. Results: Primary outcome was improvement of fatigue assessed by Chalder Fatigue Scale (CFQ; decrease ≥ 6 points) and of physical functioning assessed by SF-36 (increase ≥ 25 points) at month 12. Of 12 patients receiving treatment per protocol 5 had a clinical response at month 12. Two additional patients had an improvement according to this definition at months 6 and 9. In four patients treatment was ceased due to adverse events and in one patient due to disease worsening. We identified LDH and soluble IL-2 receptor as potential biomarker for response. Conclusion: Our data indicate that self-administered s.c. IgG treatment is feasible and led to clinical improvement in a subset of ME/CFS patients.

Outcome of BCMA Bite (AMG420) Therapy in Relapse and Refractory Multiple Myeloma (RRMM) Patients

Introduction The B-Cell Maturation Antigen (BCMA) serves as a target for T cell directed therapy either by CAR-T or bispecific antibodies (BiAb's) in relapsed or refractory multiple myeloma patients. ITo this end we recently reported on the outcome of the BiAb's short half life BITE® molecule (AMG420//BI 836909) targeting BCMA in RRMM patients (NCT02514239), which resulted in ORR rate of 70% at a recommend dose level of 400 mg/d (Topp et al, Vol.38. JCO 2020). Here we report on the long term outcome of our patients with medium follow up of close to 3 years. Methods In the first in human dose escalation trial with the anti-BCMA BITE® molecule AMG420/42 patients were recruited and treated with 4 weeks on and two weeks off by continuous infusion. The primary end points were DLT and MTD. Secondary end points included response per International Myeloma Working Group 2006 including the objective response rate (ORR; partial response [PR], very good PR [VGPR], complete response [CR], minimal residual disease [MRD]-negative CR) and duration of response. At our center, 23 out of 42 drug exposed study subjects were recruited and this is the reported outcome of this subgroup with respect to overall survial by ad hoc analysis (OS), progression free survival (PFS), the ORR rate, medium cycles given for non resonders versus responders, time of B-cell recovery in patients with long term control of their RRMM as well as additional safety events. Results We enrolled 23 patients out of 42 treated study patients of the Anti-BCMA BITE trial with AMG 420 in RRMM. Patients received treatment from May 2015 until June 2019 with a data cut off 3. August 2020. Among the 23 patients, who had on average 3,5 prior lines of therapy (range 2-9); 10 patients showed a response (7 CR including 5 stringent CR and 3 PR) starting from 6,5 mg/d to 400 mg/d. The OS for the entire 23 patients is 34,9 months (range from 4 to 59), the median OS for the responders was 32 months (range from 26 to 42 months) and for the 13 non responders 39 month (4- 59) with a medium follow up of 35 months. Of note, the vast majority of patients in the early dose escalation proportion of the study did not responded whereas the patients in the last cohort at 400 mg/d showed a response of 70%. The PFS was for the 10 responders 23,5 months, who received on average 7 cycles of AMG 420 with 4 patients completing 10 cycles. 2 patients are still in CR and one patient remains in continuous PR. Relapses were documented either medullary and/or extramedullary of patterns. For 5 responding patients a B cell recovery was observed on an average at 17 months after achieving a response. Post treatment recovery of B cells was seen at 6.3 months. The initial safety event of increased rate of infectious diseases led to adaption of management guidelines by including mandatory herpes virus and PcP prophylaxis. For patients with respiratory infections IgG substitution every four weeks was applied until endogenous IgG recovery was documented. No long-term severe safety events were observed. Discussion Our report of the subgroup of patients treated at our institution demonstrates that these heavily pretreated cohort of RRMM patients had a durable response of 23,5 months after AMG420 BITE® therapy. Despite this small numbers and reporting of single institutional experience these results are encouraging in light of recent long term data of BCMA CAR-T therapy reporting on a PFS of less than 12 months. The data warrante further investigation of -BCMA targeted BiAB's as a treatment modality in RRMM patients. Disclosures Topp: Amgen, Boehringer Ingelheim, KITE, Regeneron, Roche: Research Funding; Amgen, KITE, Novartis, Regeneron, Roche: Consultancy. Duell:Morphosys: Research Funding. Einsele:Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Speakers Bureau; Sanofi: Consultancy, Honoraria, Research Funding, Speakers Bureau; GlaxoSmithKline: Honoraria, Research Funding, Speakers Bureau.

Pooled Human Immunoglobulin Preparations as Immunomodulating Drugs

It is time to celebrate the 125th anniversary of the first successful attempt to develop and use a specific high-titer antitoxic serum for treating diphtheria, a deadly infectious disease. This was followed by major advances in passive immunotherapy 75 years ago (production of pooled human IgG for subcutaneous injection) and 50 years ago (widespread technology for producing immunoglobulin preparations for intravenous administration). More than 200 tons of pooled human IgG are produced per year worldwide. The preparation is used primarily for IgG substitution in patients with primary and secondary immunodeficiencies, as well as for an immunomodulating treatment of a growing number of autoimmune and inflammatory diseases. These preparations contain the pooled IgG antibody repertoire of a large population of healthy plasma donors. This repertoire includes antibodies that neutralize pathogens and their factors of virulence, anti-idiotypic antibodies, and antibodies to other foreign and own proteins, as well as to carbohydrate antigens. Naturally polyspecific antibodies that are present in all healthy individuals play an important role as a first-line defense against bacteria and viruses. After exposure to protein-modifying agents, some IgG molecules can acquire the ability to bind novel structurally unrelated antigens. This phenomenon is referred to as induced polyspecificity. The list of these protein-modifying molecules was shown to include low-pH buffers, free heme, pro-oxidative ferrous ions, reactive oxygen species, etc. Such modified antibody preparations may have a therapeutic potential, since their administration to animals with experimental sepsis or aseptic systemic response syndromes significantly improved survival rates, while the same dose of the native preparation had no effect. We also hypothesize that the aggressive protein-modifying molecules released in sites of inflammation and tissue damage could also modify the antigen-binding behavior of surface immunoglobulin B cell receptors and the structurally related T cell receptors. This “specificity editing” of both types of receptors may play a major role in the body’s defense mechanisms.

Reduced serum immunoglobulin G concentrations in multiple sclerosis: prevalence and association with disease-modifying therapy and disease course.

Background:In multiple sclerosis (MS), the frequency of hypogammaglobulinemia is unknown. We aimed to evaluate the frequency of reduced immunoglobulin (Ig) concentrations and its association with immunotherapy and disease course in two independent MS cohorts.Methods:In our retrospective cross-sectional study, MS patients and control patients with head or neck pain from Bern University Hospital (Bern, Switzerland) and Eginition University Hospital (Athens, Greece) were included. The lower limits of normal (LLN) for serum Ig concentration were IgG < 700 mg/dl, IgM < 40 mg/dl, and IgA < 70 mg/dl. Mann–Whitney U test, analysis of variance test, and multiple linear regression analysis were employed.Results:In total, 327 MS patients were retrospectively identified (Bern/Athens: n = 226/101). Serum IgG concentrations were frequently under LLN in both MS cohorts (Bern/Athens: 15.5%/14.9%), even when considering only untreated patients (Bern/Athens: 7.9%/8.6%). MS patients (n = 327) were significantly more likely to have IgG concentrations below LLN and below 600 mg/dl in comparison with controls (n = 58) (p = 0.015 and 0.047, respectively). Between both patient groups, no significant differences were found in frequencies of IgA and IgM concentrations under LLN [n (MS patients/controls): IgA 203/30, IgM 224/24]. Independently of age, secondary progressive MS patients had lower IgG concentrations than relapsing–remitting and primary progressive patients (both: p ⩽ 0.01). After adjusting for sex, age, and disease course, IgG concentrations were lower in patients treated with rituximab (p = 0.001; n = 42/327), intravenous corticosteroids (p < 0.001; n = 16/327), natalizumab (p < 0.001; n = 48/327), and fingolimod (p = 0.003; n = 6/327).Conclusion:Our study demonstrated high prevalence rates of reduced serum IgG concentrations in MS patients with and without disease-modifying treatments. The significance of lower IgG concentrations at the levels noted is unclear considering that infections or interference with antibody production generally occur when IgG levels are much lower, at or below 400 mg/dl. However, the information is useful to monitor IgG levels especially with anti-B-cell therapies and consider IgG substitution when levels drop below 400 mg/dl.

Pooled Human Immunoglobulin Preparations as Immunomodulating Drugs

It is time to celebrate the 125th anniversary of the first successful attempt to develop and use a specific high-titer antitoxic serum for treating diphtheria, a deadly infectious disease. This was followed by major advances in passive immunotherapy 75 years ago (production of pooled human IgG for subcutaneous injection) and 50 years ago (widespread technology for producing immunoglobulin preparations for intravenous administration). More than 200 tons of pooled human IgG are produced per year worldwide. The preparation is used primarily for IgG substitution in patients with primary and secondary immunodeficiencies, as well as for an immunomodulating treatment of a growing number of autoimmune and inflammatory diseases. These preparations contain the pooled IgG antibody repertoire of a large population of healthy plasma donors. This repertoire includes antibodies that neutralize pathogens and their factors of virulence, anti-idiotypic antibodies, and antibodies to other foreign and own proteins, as well as to carbohydrate antigens. Naturally polyspecific antibodies that are present in all healthy individuals play an important role as a first-line defense against bacteria and viruses. After exposure to protein-modifying agents, some IgG molecules can acquire the ability to bind novel structurally unrelated antigens. This phenomenon is referred to as induced polyspecificity. The list of these protein-modifying molecules was shown to include low-pH buffers, free heme, pro-oxidative ferrous ions, reactive oxygen species, etc. Such modified antibody preparations may have a therapeutic potential, since their administration to animals with experimental sepsis or aseptic systemic response syndromes significantly improved survival rates, while the same dose of the native preparation had no effect. We also hypothesize that the aggressive protein-modifying molecules released in sites of inflammation and tissue damage could also modify the antigen-binding behavior of surface immunoglobulin B cell receptors and the structurally related T cell receptors. This "specificity editing" of both types of receptors may play a major role in the body's defense mechanisms.

Therapeutic effect of immunoadsorption and subsequent immunoglobulin substitution in patients with dilated cardiomyopathy: Results from the observational prospective Bad Berka Registry

BackgroundElimination of cardiac autoantibodies, frequently detected in patients with dilated cardiomyopathy (DCM), with immunoadsorption (IA) improves functional capacity and left ventricular (LV) function. This study aimed to prospectively address this issue in a large cohort of unselected patients. MethodsConsecutive patients undergoing IA followed by IgG substitution were included. Clinical and echocardiographic parameters were assessed at baseline (BL) and 12-month follow-up (FU). Patients were classified as IA responders when ≥2 of the following criteria were achieved: improvement in the Minnesota Living with Heart Failure Questionnaire (MLHFQ) ≥5 points, symptoms [≥1 New York Heart Association (NYHA) class], LV ejection fraction (EF) ≥10% or decrease in LV end-diastolic diameter (EDD) ≥10%, or N-terminal pro B-type natriuretic peptide (NT-pro-BNP) ≥50%. Results93 patients (median age 61 years, LVEF 30%, duration of symptoms 14 months, 87% in NYHA class III/IV, >90% treated with β-blocker/angiotensin-converting enzyme inhibitor) were included. When the entire cohort was analyzed, a significant improvement in MLHFQ (50 vs. 26 points), NYHA-class (median 3.0 vs. 2.0), LVEF (30% vs. 38%), LVEDD (62 vs. 59mm), NT-pro-BNP (892 vs. 523pg/ml) was observed at FU (p<0.05 for all). 48% (n=43) were classified as responders. Those were characterized by a shorter disease duration (11 vs. 22 months), larger BL LVEDD (64 vs. 60mm), presence of >1 viral genome, and higher values of mononuclear inflammatory cells at endomyocardial biopsy. Sixteen (17.2%) patients experienced IA related complications. ConclusionsA positive response is observed in 48% of inflammatory DCM patients undergoing IA, and this translates into a significant improvement in clinical and echocardiographic parameters.

Infectious and immunologic phenotype of MECP2 duplication syndrome.

MECP2 (methyl CpG binding protein 2) duplication causes syndromic intellectual disability. Patients often suffer from life-threatening infections, suggesting an additional immunodeficiency. We describe for the first time the detailed infectious and immunological phenotype of MECP2 duplication syndrome. 17/27 analyzed patients suffered from pneumonia, 5/27 from at least one episode of sepsis. Encapsulated bacteria (S.pneumoniae, H.influenzae) were frequently isolated. T-cell immunity showed no gross abnormalities in 14/14 patients and IFNy-secretion upon ConA-stimulation was not decreased in 6/7 patients. In 6/21 patients IgG2-deficiency was detected – in 4/21 patients accompanied by IgA-deficiency, 10/21 patients showed low antibody titers against pneumococci. Supra-normal IgG1-levels were detected in 11/21 patients and supra-normal IgG3-levels were seen in 8/21 patients – in 6 of the patients as combined elevation of IgG1 and IgG3. Three of the four patients with IgA/IgG2-deficiency developed multiple severe infections. Upon infections pronounced acute-phase responses were common: 7/10 patients showed CRP values above 200 mg/l. Our data for the first time show systematically that increased susceptibility to infections in MECP2 duplication syndrome is associated with IgA/IgG2-deficiency, low antibody titers against pneumococci and elevated acute-phase responses. So patients with MECP2 duplication syndrome and low IgA/IgG2 may benefit from prophylactic substitution of sIgA and IgG.Electronic supplementary materialThe online version of this article (doi:10.1007/s10875-015-0129-5) contains supplementary material, which is available to authorized users.

The effect of a repeated immunoadsorption in patients with dilated cardiomyopathy after recurrence of severe heart failure symptoms.

In patients suffering from dilated cardiomyopathy (DCM), immunoadsorption with subsequent IgG substitution (IA/IgG) leads to an acute and prolonged improvement of hemodynamics and heart failure symptoms. However, some patients receiving IA/IgG experience recurrence of heart failure after an initial benefit. The aim of this study was to investigate whether a second IA/IgG treatment episode improves left ventricular systolic function and further mitigates heart failure symptoms in these patients. We retrospectively analyzed 15 DCM patients who experienced a significant improvement of LVEF (≥ 5% absolute or ≥ 20% relative) and heart failure symptoms (≥ 1 NYHA functional class) but a subsequent deterioration (decline in LVEF ≥ 5% absolute or ≥ 20% relative and NYHA worsening ≥1 class) after the first IA/IgG. These patients underwent a second IA/IgG treatment 41.7 ± 27.4 months after the first cycle. Follow up data were acquired 3-6 months after both IA/IgG treatments. The first IA/IgG induced an improvement of LVEF from 33 ± 6.4% to 43.2 ± 7.9% (P < 0.001) and of mean NYHA functional class from 2.9 ± 0.26 to 1.8 ± 0.56 (P < 0.001). The second treatment was associated with a significant improvement in LVEF (from 29.7 ± 4.6% to 34.9 ± 8.3%, P = 0.013) and NYHA functional class (2.87 ± 0.64 to 2.33 ± 0.72; P = 0.02). This improvement was less pronounced compared to the first treatment with respect to both, LVEF (P = 0.09) and NYHA improvement (P = 0.04). In DCM patients, who experience a significant improvement of LVEF and heart failure symptoms after IA/IgG but a subsequent relapse during follow up, repeated IA/IgG may be considered.

Occurrence of B-cell lymphomas in patients with activated phosphoinositide 3-kinase δ syndrome

Occurrence of B-cell lymphomas in patients with activated phosphoinositide 3-kinase δ syndrome

Increased BAFF concentrations in patients with dilated cardiomyopathy and impact on response to immunotherapy (P4548)

Abstract DCM is a heart disease characterized by ventricular chamber enlargement and systolic dysfunction. Autoantibodies against cardiac proteins have been described in DCM. Removing these IgG antibodies from the blood by immunoadsorption with subsequent IgG substitution (IA/IgG therapy) can improve the clinical outcome and heart function. To determine whether the increased number and survival of autoreactive B cells in DCM patients could be related to the overexpression of BAFF, we measured BAFF in the plasma of groups of 59 DCM patients and 37 age-matched controls by ELISA. Thereafter, DCM patients were treated with IA/IgG therapy, and left ventricular ejection fraction (LVEF) was measured directly after therapy and after 6 months to quantify heart function. BAFF was significantly elevated in DCM patients compared to controls [2333±124 pg/ml vs. 927±58 pg/ml (mean±SEM), p&amp;lt;0.0001]. Similar results were obtained for BAFF mRNA expression in PBMC. After IA/IgG therapy, DCM patients were divided into 2 groups according to their change in LVEF: increase of ≥20% (responder), and decrease or increase of &amp;lt;20% (non-responder). BAFF in the non-responder group was slightly, but significantly higher than in the responder group (3107±357 pg/ml vs. 2078±151 pg/ml, p&amp;lt;0.01). These results suggest that BAFF might play an important role in the pathophysiology of DCM. Moreover, patients with the highest levels of BAFF might represent a subgroup, which does not respond well to IA/IgG therapy.

Efficacy of Gene Therapy for Wiskott-Aldrich-Syndrome

Abstract 165▪FN2▪This icon denotes a clinically relevant abstractCB and KB contributed equally and should be considered aequo loco.Wiskott-Aldrich-Syndrome (WAS) is a rare and life-threatening immune-disorder characterized by autoimmunity, microthrombocytopenia, immunodeficiency and susceptibility to lymphoma. WAS is caused by mutations in the WAS gene which encodes WASP, a key regulator of actin polymerization exclusively expressed in hematopoietic cells. WASP deficiency causes defects in lymphocytes, myeloid cells, and platelets.We here report a comprehensive analysis of ten patients treated by hematopoietic stem cell gene therapy between 2006 and 2009 (median follow up time 29.6 months, range 15 to 58 months).Patients were mobilized with G-CSF alone (3/10) or G-CSF combined with anti-CXCR4/AMD3100 (7/10), conditioned with busulfan (8mg/kg body weight) and received between 2.8×106 and 24.9×106 cells/kg bw, with a median transduction efficacy of 52%. Upon transplantation of retrovirus-transduced WASP-expressing progenitor cells, the proportion of corrected platelets and lymphocytes increased steadily over time reaching 85–90% and 80–85%, respectively. Interestingly, also myeloid cells showed a continuously increasing percentage of WASP-expressing fractions (20 to 70%).Due to transplantation of insufficient numbers of WASP-transduced HSC, one patient failed to engraft. He had no evidence of corrected myeloid/hematopoietic progenitor cells and continued to suffer from life-threatening infections and autoimmunity. He was successfully treated by haploidentical HSCT. All other patients had marked improvement of their clinical status. Bleeding diatheses, susceptibility to infections, and autoimmunity resolved. Patients had evidence of significant and sustained increase in platelet counts (p=0.01) together with a reconstituted WASP expression and normalization of thrombocyte size (p<0.001).After gene therapy, we observed a normalization of the T cell compartment (T cell proliferative responses and TCR Vb spectratyping), NK cell function (assessed by in vitro cytotoxicity and formation of NK cell immunological synapse). The B cell compartment showed consistent expression of WASP. In 4 of 7 patients, IgG substitution could be discontinued. These patients and also those without initial IgG substitution mounted a specific immune response to vaccines, as evidenced by determination of specific antibody titers.One patient developed a T-cell acute lymphoid leukemia 488 days after gene therapy associated with vector integration close to the LMO2 locus. Chemotherapeutic treatment induced remission that is documented since d33 after initiation of induction therapy.Long-term follow up observation indicated that gene therapy for WAS, although not without toxicity, is feasible and provides an effective alternative treatment strategy to allogeneic HSC transplantation. Disclosures:Baum:Patent office: Patents & Royalties.

Vaccination against tick-borne encephalitis virus tests specific IgG production ability in patients under immunoglobulin substitution therapy

To assess B-cell function in patients under immunoglobulin (IgG)-replacement therapy, the non-licensed artificial bacteriophage (ΦX174)-neo-antigen may be used despite limited availability and experience. Active immunization against tick-borne encephalitis (TBE) is performed in few European countries. To test the feasibility of using licensed TBE vaccination as (neo-)antigen to determine residual or restored B-cell function in patients under regular IgG substitution, TBE-IgG levels were analyzed in 18 patients with ≥1–2 years of regular intravenous or subcutaneous IgG substitution and in pharmaceutical IgG-preparations ( n = 21 batches, 10 products). Six individuals were boosted against TBE. Although TBE-specific IgG was detectable in concentrates (281–57,100 VieU/0.5 μL), levels were only borderline in patient sera ( n = 31, 18 individuals; median 132 VieU; positive >155). Thus, TBE vaccination may be used to test B-cell function under IgG replacement therapy because IgG substitution appears insufficient to yield protective TBE-specific antibody levels in children.

Immunoadsorption in dilated cardiomyopathy: long‐term reduction of cardiodepressant antibodies

Disturbances of humoral immunity have been described in dilated cardiomyopathy (DCM), and a number of antibodies against cardiac cell proteins have been identified. Previous studies showed that immunoadsorption therapy with subsequent IgG substitution (IA/IgG) enhances cardiac function, and that removal of cardiodepressant antibodies may represent one essential mechanism of this therapy. The long-term effect of IA/IgG on the level of cardiodepressant antibodies remains to be elucidated. A total of 17 patients with DCM were observed up to 12 months after IA/IgG. Echocardiographic measurements were performed at baseline, 3, 6 and 12 months after therapy. Cardiodepressant antibodies were detected by incubation of rat cardiomyocytes with purified patients' IgG and recording of contractility and Ca(2+) ratio. In contrast to patients without cardiodepressant antibodies before IA/IgG, patients with negative inotropic antibodies showed an improvement of left ventricular ejection fraction (LVEF) from 33.8 +/- 1.7% to 44.7 +/- 2.7%; 44.5 +/- 2.3% and 51.8 +/- 1.7% after 3, 6 and 12 months (P < 0.001 vs. baseline, P < 0.05 vs. LVEF of non-cardiodepressant group). Immediately after IA/IgG therapy, no cardiodepressant effects of patients' IgG on isolated cardiomyocytes were detectable, and this effect remained diminished until 6 months after IA/IgG (P < 0.001 for contractility and Ca(2+) ratio). Compared with the levels after 3 and 6 months, cardiodepressant antibodies reoccured after 12 months (P = 0.067 for contractility, P < 0.05 for Ca(2+) ratio vs. 6 months after IA/IgG). However, the negative inotropic reaction is still diminished compared with the reaction before IA/IgG. IA/IgG therapy induces long-term reduction of negative inotropic antibodies. After 12 months, however, re-increase of negative inotropic antibodies cannot be excluded.

Immunoadsorption in patients with dilated cardiomyopathy

Abstract Dilated cardiomyopathy (DCM) is characterized by ventricular enlargement and progressive systolic and diastolic dysfunction. Disturbances of the cellular and humoral immune system are frequently observed in DCM. Circulating antibodies of the IgG class against diverse myocardial antigens have been identified and are thought to play a causative role in the pathogenesis of DCM. Possible mechanisms include the promotion of chronic inflammation, activation of the β1-adrenoreceptor and activation of Fc γ-receptors. Various clinical studies suggest a positive effect of immunoadsorption (IA) using protein A columns, with or without subsequent IgG substitution (IA/IgG) on symptoms, myocardial function and the hemodynamic situation of these patients. Decreased myocardial inflammation was also observed in DCM patients treated with IA/IgG. In addition to conservative medical treatment, IA/IgG may therefore represent a new therapeutic option for patients with heart failure due to DCM.

Abstract 4375: Potential Effects of Immunoadsorption and Subsequent IgG Substitution on Cardiopulmonary Exercise in DCM Patients

Recent data indicate that cardiac antibodies play an active role in the pathogenesis of dilated cardiomyopathy (DCM), and may contribute to cardiac dysfunction of DCM patients. Previous studies have suggested that immunoadsorption with subsequent IgG substitution (IA/IgG) improves left ventricular function in DCM. The potential influence of this immunomodulatory therapy on cardiopulmonary exercise remains to be elucidated. 60 patients with DCM ( n = 60, NYHA II-IV, left ventricular ejection fraction ≤ 45%) underwent either IA/IgG ( n = 30), or were followed up without IA ( n = 30). IA/IgG was performed in one course of five consecutive days. After three months we compared echocardiographic assessment of left ventricular function and spiroergometric exercise parameters in both groups. Left ventricular ejection fraction (LVEF) improved significantly in the IA/IgG group from 33.0 ± 1.2% to 40.1 ± 1.5% (p &lt; 0.001 vs. control, p &lt; 0.001 vs. baseline). In the control group, spiroergometric exercise parameters did not change during follow-up. In contrast, patients receiving IA/IgG improved significantly in the following parameters: peak oxygen uptake (peak VO 2 ; 17.3 ± 0.9 ml/min/kg to 21.8 ± 1.0 ml/min/kg; p &lt; 0.01 vs. control, p &lt; 0.01 vs. baseline), oxygen pulse (10.7 ± 0.7 ml/bpm to 13.6 ± 0.7 ml/bpm; p &lt; 0.05 vs. control, p &lt; 0.01 vs. baseline), and anaerobic threshold (VO 2 AT; 10.3 ± 0.5 ml/min/kg to 13.2 ± 0.5 ml/min/kg; p &lt; 0.001 vs. control, p &lt; 0.001 vs. baseline). The ventilatory response to exercise (V E /VCO 2 slope) decreased after IA/IgG therapy from 32.3 ± 1.5 to 28.7 ± 0.9 (p = 0.18 vs. controls, p = 0.02 vs. baseline), whereas there was no significant change in the control group after 3 months. IA/IgG therapy in DCM patients may induce improvement in echocardiographic and cardiopulmonary exercise parameters.

Immunoadsorption and subsequent immunoglobulin substitution decreases myocardial gene expression of desmin in dilated cardiomyopathy

Cardiac autoantibodies play a pathogenic role in dilated cardiomyopathy (DCM). Removal of antibodies by immunoadsorption (IA) induces hemodynamic improvement in DCM patients. The present study investigated the effects of IA on myocardial gene expression of the intermediate cytoskeletal filament desmin, which is upregulated in heart failure. RNA was isolated from five explanted non-failing hearts and five explanted failing hearts of DCM patients, and myocardial gene expression of desmin was estimated by real-time polymerase chain reaction (PCR). In a case-control study in six DCM patients (LVEF < 40%, NYHA II-III), IA and subsequent IgG substitution were performed at monthly intervals until month 3. Endomyocardial biopsies (EMBs) were obtained before and after IA (after 3-6 months). From six DCM patients without IA therapy (controls), EMBs were also obtained over a comparable time interval. Expression of the desmin gene was analyzed in these EMBs by real-time PCR. In failing explanted hearts, expression of desmin was significantly increased (0.88 +/- 0.12 vs 0.45 +/- 0.15 in non-failing hearts, P < 0.05). After IA, myocardial gene expression of desmin was significantly decreased (from 0.26 +/- 0.05 [baseline] to 0.14 +/- 0.04 [P < 0.05] vs baseline and controls). Removal of antibodies by IA modulates myocardial gene expression of desmin in DCM patients.