Doses Of IgG Research Articles

Antibody Response after Homologous and Heterologous Prime-Boost COVID-19 Vaccination in a Bangladeshi Residential University Cohort.

COVID-19 vaccination strategies, including heterologous prime-boost regimens and additional booster doses, aim to optimize immune responses. However, seroepidemiological studies on immune responses to different COVID-19 vaccine types and schedules remain limited. This study investigated antibody levels following homologous and heterologous prime-and-boost COVID-19 vaccination in Bangladesh. In a cohort of 606 participants who received first/second/booster doses of vaccines (AstraZeneca, Moderna, Pfizer-BioNTech, and Sinopharm), anti-spike IgG and anti-nucleocapsid IgG levels were measured. Antibody titer variations with respect to age, gender, intervals between doses, and prior infection status were analyzed. mRNA vaccines elicited the highest antibody levels after homologous and heterologous boosting. The AstraZeneca booster resulted in a sharp titer decline rate of ~0.04 units per day. Second or booster vaccine doses significantly increased antibody levels, especially in males (p < 0.05). Older age correlated with higher titers, likely reflecting previous infection, which was further confirmed by the elevation of anti-nucleocapsid IgG levels. About 95.5% of non-Sinopharm recipients were anti-nucleocapsid IgG positive, suggesting prior exposure exceeding self-reported infections (12.5%). mRNA and heterologous COVID-19 boosting enhances humoral immunity over homologous prime-boost vector/inactivated vaccination. However, waning immunity merits further investigation across vaccine platforms.

No evidence for enhanced disease with human polyclonal SARS-CoV-2 antibody in the ferret model.

Since SARS-CoV-2 emerged in late 2019, it spread from China to the rest of the world. An initial concern was the potential for vaccine- or antibody-dependent enhancement (ADE) of disease as had been reported with other coronaviruses. To evaluate this, we first developed a ferret model by exposing ferrets to SARS-CoV-2 by either mucosal inoculation (intranasal/oral/ocular) or inhalation using a small particle aerosol. Mucosal inoculation caused a mild fever and weight loss that resolved quickly; inoculation via either route resulted in virus shedding detected in the nares, throat, and rectum for 7-10 days post-infection. To evaluate the potential for ADE, we then inoculated groups of ferrets intravenously with 0.1, 0.5, or 1 mg/kg doses of a human polyclonal anti-SARS-CoV-2 IgG from hyper-immunized transchromosomic bovines (SAB-185). Twelve hours later, ferrets were challenged by mucosal inoculation with SARS-CoV-2. We found no significant differences in fever, weight loss, or viral shedding after infection between the three antibody groups or the controls. Signs of pathology in the lungs were noted in infected ferrets but no differences were found between control and antibody groups. The results of this study indicate that healthy, young adult ferrets of both sexes are a suitable model of mild COVID-19 and that low doses of specific IgG in SAB-185 are unlikely to enhance the disease caused by SARS-CoV-2.

Efficacy and safety of hyaluronidase-facilitated subcutaneous immunoglobulin 10% in US pediatric patients with primary immunodeficiency disease

IntroductionThis study assessed the efficacy and safety of facilitated subcutaneous immunoglobulin (fSCIG; immunoglobulin G [IgG] 10% and recombinant human hyaluronidase [rHuPH20]) in US pediatric patients with primary immunodeficiency disease (PIDD). MethodsThis phase 3, open-label, prospective study (NCT03277313) was conducted at 17 centers in the US. Patients were eligible for enrollment if they were aged 2 to <16 years, diagnosed with PIDD requiring immunoglobulin replacement therapy and had received a consistent IgG dose for ≥3 months prior to screening. Patients received fSCIG 10% using a dose ramp-up over ≤6 weeks (Epoch 1) followed by fSCIG 10% treatment every 3 or 4 weeks for ≤3 years (Epoch 2). The primary endpoint, rate of acute serious bacterial infections (ASBIs), was compared with the regulatory-defined threshold (< 1.0 ASBIs per patient-year). ResultsFinal data were provided by 44 patients for Epoch 1 (mean age [range] 9.0 [3–15] years, 59.1% male) and 43 patients for Epoch 2; 34 patients completed the study. Two ASBIs (both bacterial pneumonia) were reported in the same patient. The mean rate of ASBIs (0.04 events/patient-year [99% upper confidence interval: 0.20]) was significantly lower than the regulatory-defined threshold. The mean rate of all infections was 3.12 events/patient-year. Stable mean serum trough IgG levels were maintained during Epoch 2 (10.4, 9.2, and 9.2 g/L at Months 0, 6 and 12, respectively). Excluding infections, 336 fSCIG-related treatment-emergent adverse events (TEAEs) were reported in 34 patients (Epochs 1 and 2 combined); most were mild (247 events in 32 patients) and two TEAEs in two patients were severe (celiac disease flare and headache). One serious TEAE of tonsillar hypertrophy was considered unrelated to fSCIG 10%. One patient developed anti-rHuPH20 binding antibodies (titer ≥160) without neutralizing anti-rHuPH20 antibodies. At end of Epoch 2, the majority of patients stated that they would choose to continue fSCIG 10%. ConclusionsfSCIG 10% effectively prevented ASBIs in US pediatric patients with PIDD with a safety profile consistent with previous clinical studies. Takeda Development Center Americas, Inc. and Baxalta funded this study. Takeda Pharmaceuticals International AG funded writing support.

Mechanisms of Obesity-Induced Changes in Pharmacokinetics of IgG in Rats.

To evaluate how obesity affects the pharmacokinetics of human IgG following subcutaneous (SC) and intravenous (IV) administration to rats and the homeostasis of endogenous rat IgG. Differences in body weight and size, body composition, and serum concentration of endogenous rat IgG in male Zucker obese (ZUC-FA/FA) and control (ZUC-LEAN) rats were measured from the age of 5weeks up to 30weeks. At the age of 23-24weeks animals received a single IV or SC dose of human IgG (1g/kg of total body weight), and serum pharmacokinetics was followed for 7weeks. A mechanistic model linking obesity-related changes in pharmacokinetics with animal growth and changes in body compositionwas developed. Significant differences were observed in both endogenous and exogenous IgG pharmacokinetics between obese and control groups. The AUC for human IgG was lower in obese groups (57.6% of control after IV and 48.1% after SC dosing), and clearance was 1.75-fold higher in obese animals. The mechanistic population model successfully captured the data and included several major components: endogenous rat IgG homeostasis with age-dependent synthesis rate; competition of human IgG and endogenous rat IgG for FcRn binding and its effect on endogenous rat IgG concentrations following injection of a high dose of human IgG; and the effect of body size and composition (changing over time and dependent on the obesity status) on pharmacokinetic parameters. We identified important obesity-induced changes in the pharmacokinetics of IgG. Results can potentially facilitate optimization of the dosing of IgG-based therapeutics in the obese population.

Antigen copy number and antibody dose can determine the outcome of erythrocyte alloimmunization inducing either antibody-mediated immune suppression or enhancement in a murine model.

The administration of anti-D for the prevention of hemolytic disease of the fetus and newborn is one of the most successful clinical uses of the phenomenon of antibody-mediated immune suppression (AMIS). However, despite adequate prophylaxis, failures can still occur in the clinic and are poorly understood. Recently, the copy number of red blood cell (RBC) antigens has been shown to influence immunogenicity in the context of RBC alloimmunization; however, its influence on AMIS remains unexplored. RBCs expressing approximately 3,600 and approximately 12,400 copy numbers of surface-bound hen egg lysozyme (HEL), named respectively HELmed -RBCs and HELhi -RBCs, and selected doses of a polyclonal HEL-specific IgG were transfused into mice. Recipient HEL-specific IgM, IgG, and IgG subclass responses were evaluated by ELISA. Antigen copy number affected the antibody dose required for AMIS induction with higher antigen copy numbers requiring larger doses of antibody. For instance, 5μg of antibody caused AMIS for HELmed -RBCs but not HELhi -RBCs, while 20 μg induced significant suppression for both HEL-RBCs. Overall, increasing amounts of the AMIS-inducing antibody were associated with a more complete AMIS effect. In contrast, the lowest tested doses of the AMIS-inducing IgG led to evidence of enhancement at the IgM and IgG levels. The results demonstrate that the relationship between antigen copy number and antibody dose can influence the outcome of AMIS. Further, this work suggests that the same antibody preparation can induce both AMIS and enhancement but that the outcome may depend on the quantitative interrelationship of antigen-antibody binding.

SARS-CoV-2 S1-RBD IgG and IL-6 serum level reduction after 120 days (4 months) of the second dose of Pfizer–BioNTech vaccine administration to the medical students in the University of Diyala

Background: SARS-CoV-2 mRNA vaccines such as Pfizer–BioNTech have confirmed a high efficiency; however, there is a limitation of data existence about the duration of immune responses and their relation to age and side effects. The aim of this study is to estimate the SARS-CoV-2 S1-RBD IgG level after 30 days (1 month) and 120 days (4 months) of the second dose of Pfizer–BioNTech vaccine administered to the medical students of the University of Diyala. Methods: The study was conducted after the approval of the Medical College of Al-Iraqia University, the Medical College of the University of Diyala, and the Iraqi Ministry of Health. We selected 45 students from the Medical College of the University of Diyala randomly who were fully vaccinated (two doses of Pfizer–BioNTech vaccine, 0.5 ml of the vaccine for each dose), and they agreed to give 5 ml of their blood twice (after 1 month and 4 months), which was carried out in the Higher Education Laboratory inside the Medical College, University of Diyala. The period of sample collection was 5 months (from September 2021 until February 2022). A serological analysis to measure SARS-CoV-2 S1-RBD IgG was done by using Diasino, SARS-CoV-2 S1-RBD IgG ELISA Kit, China, which was carried out in the Higher Education Laboratory, inside the Medical College, University of Diyala. Demographic data were taken from the study participants (age and gender). The same individuals of the study were divided into two groups according to the time frame (1 month and 4 months) after the second dose of the Pfizer–BioNTech vaccine administration. For statistical analysis, we used SPSS version 26 and STATISTICA version 12 to input, check, and analyze data. For qualitative variables, standard approaches of frequencies and percentages were used, whereas for quantitative variables, mean and standard deviation were used. A P-value of less than 0.05 was considered as significant for SARS CoV-2 S1-RBD IgG plasma levels. Results: The study found that the male–female ratio was 17.8: 82.2, and the mean of the age of the vaccinated students was 20.977 years. The serum quantities of SARS-CoV-2 S1-RBD IgG and IL-6 levels post second dose of the Pfizer–BioNTech vaccine after 30 days (1 month) and 120 days (4 months) were shown to be statistically non-parametric. Using the independent two-sample Mann–Whitney test, a significant difference (P &lt; 0.05) was observed for SARS-CoV-2 S1-RBD IgG and IL-6 levels between 120 days (4 months) after the second dose of the Pfizer–BioNTech vaccine and 30 days (1 month). Conclusion: SARS-CoV-2 S1-RBD IgG and IL-6 levels decreased significantly after 120 days (4 months) of the second dose of Pfizer–BioNTech vaccination.

Passive Immunisation against RHDV2 Induces Protection against Disease but Not Infection

Rabbit haemorrhagic disease virus 2 (RHDV2) is a lagovirus in the family Caliciviridae. The closely related Rabbit haemorrhagic disease virus (RHDV, termed RHDV1 throughout this manuscript for clarity) has been used extensively as a biocontrol agent in Australia since the mid-1990s to manage wild rabbit populations, a major economic and environmental pest species. Releasing RHDV1 into populations with a high proportion of rabbits less than 8–10 weeks of age leads to non-lethal infection in many of these young animals, with subsequent seroconversion and long-term immunity against reinfection. In contrast, RHDV2 causes lethal disease even in young rabbits, potentially offering substantial benefits for rabbit management programs over RHDV1. However, it is not clear how acquired resistance from maternal antibodies may influence immunity after RHDV2 infection. In this study, we assessed serological responses after RHDV2 challenge in young rabbits of three different ages (5-, 7-, or 9-weeks-old) that were passively immunised with either high- (titre of 2560 by RHDV IgG ELISA; 2.41 mg/mL total protein) or low- (titre of 160–640 by RHDV IgG ELISA; 1.41 mg/mL total protein) dose RHDV2 IgG to simulate maternal antibodies. All rabbits treated with a high dose and 75% of those treated with a low dose of RHDV2 IgG survived virus challenge. Surviving animals developed robust lagovirus-specific IgA, IgM, and IgG responses within 10 days post infection. These findings demonstrate that the protection against RHDV2 conferred by passive immunisation is not sterilising. Correspondingly, this suggests that the presence of maternal antibodies in wild rabbit populations may impede the effectiveness of RHDV2 as a biocontrol.

Hyper-Enriched Anti-RSV Immunoglobulins Nasally Administered: A Promising Approach for Respiratory Syncytial Virus Prophylaxis.

Respiratory syncytial virus (RSV) is a public health concern that causes acute lower respiratory tract infection. So far, no vaccine candidate under development has reached the market and the only licensed product to prevent RSV infection in at-risk infants and young children is a monoclonal antibody (Synagis®). Polyclonal human anti-RSV hyper-immune immunoglobulins (Igs) have also been used but were superseded by Synagis® owing to their low titer and large infused volume. Here we report a new drug class of immunoglobulins, derived from human non hyper-immune plasma that was generated by an innovative bioprocess, called Ig cracking, combining expertises in plasma-derived products and affinity chromatography. By using the RSV fusion protein (F protein) as ligand, the Ig cracking process provided a purified and concentrated product, designated hyper-enriched anti-RSV IgG, composed of at least 15-20% target-specific-antibodies from normal plasma. These anti-RSV Ig displayed a strong in vitro neutralization effect on RSV replication. Moreover, we described a novel prophylactic strategy based on local nasal administration of this unique hyper-enriched anti-RSV IgG solution using a mouse model of infection with bioluminescent RSV. Our results demonstrated that very low doses of hyper-enriched anti-RSV IgG can be administered locally to ensure rapid and efficient inhibition of virus infection. Thus, the general hyper-enriched Ig concept appeared a promising approach and might provide solutions to prevent and treat other infectious diseases.ImportanceRespiratory Syncytial Virus (RSV) is the major cause of acute lower respiratory infections in children, and is also recognized as a cause of morbidity in the elderly. There are still no vaccines and no efficient antiviral therapy against this virus. Here, we described an approach of passive immunization with a new class of hyper-enriched anti-RSV immunoglobulins (Ig) manufactured from human normal plasma. This new class of immunoglobulin plasma derived product is generated by an innovative bioprocess, called Ig cracking, which requires a combination of expertise in both plasma derived products and affinity chromatography. The strong efficacy in a small volume of these hyper-enriched anti-RSV IgG to inhibit the viral infection was demonstrated using a mouse model. This new class of immunoglobulin plasma-derived products could be applied to other pathogens to address specific therapeutic needs in the field of infectious diseases or even pandemics, such as COVID-19.

Intrinsic antibody mediated enhancement of ZIKV infection in placental macrophages

Abstract Zika virus (ZIKV) vertical transmission from mother to child in utero is associated with a number of neonatal abnormalities, including congenital microcephaly. Yet, the mechanism by which ZIKV infects the placenta and subsequently the fetus remains poorly understood. ZIKV and Dengue virus (DENV) endemic regions are commonly overlapping, and DENV specific antibodies can cross-react with ZIKV. We and others have previously demonstrated that cross-reactive DENV IgG can mediate ZIKV infection of placental cells though increased viral entry via Fc receptors. Specifically, we found that infection with ZIKV immune complexes (ZIKV-IC) generated from cross-reactive anti-DENV monoclonal IgG was enhanced in human placental macrophages called Hofbauer cells, which are found within the chorionic villus stroma near the fetal vasculature. In this study, we aimed to characterize the intrinsic cellular changes that occur in Hofbauer cells as a result of ZIKV-IC infection. We performed RNA sequencing on Hofbauer cells infected with ZIKV complexed with different concentrations of anti-DENV monoclonal IgG. Principal component analysis revealed that while ZIKV incubated with anti-influenza IgG had a similar gene expression profile to ZIKV alone, ZIKV-IC infection with increasing anti-DENV IgG skewed gene expression towards a unique phenotype. We identified a number of transcriptional profiles related to anti-DENV IgG dose. Notably, we observed a pattern of decreased interferon stimulated genes with increasing anti-DENV IgG dose. Yet, increasing anti-DENV IgG also increased ZIKV viral RNA. These results may indicate that ZIKV-IC infection makes Hofbauer cells more permissive to ZIKV replication by modulating the innate antiviral response.

Abstract 5511: Frontline therapy with anti-PD1 enhances the durability of combination targeted therapy in NRAS-mutant melanoma

Abstract Melanoma is one of the deadliest form of skin cancer. Although the activating NRAS mutations are present in 20% of melanoma patients, currently, there are no FDA-approved therapies for treating NRAS-mutant melanoma. In this project, our goal is to prime the immune system by immunotherapy and then improve the targeted therapy responses by suppressing recruitment of inhibitory immune cell populations and by increasing T cell infiltration, which would lead to enhanced responses in NRAS-mutant melanoma. We used a syngeneic C3H/HeNCrl mouse model of NRAS-mutant melanoma. The mice were treated with two doses of either anti-PD1 or IgG every 5 days followed by everyday treatment with either single agent or combination of ceritinib and trametinib for a total period of 40 days. Single cell RNA-seq platform was used to determine the impact of immunotherapy and targeted therapy upon each individual cell type. Flow cytometry experiments were carried out to assess the percentage of T cells and MDSCs recruitment. Altered signaling responses and chemokines/ cytokines responsible for MDSCs recruitment were determined from RPPA and RNA-seq data respectively. The in vivo studies demonstrated that the tumors in the mice treated with anti-PD1 followed by combination shrunk significantly over a period of 40 days without any relapse. Single cell RNA seq analysis and flow cytometry experiments revealed a 15- and 20-fold increase in T cell infiltration in these tumors. Immune cells depletion experiments showed that the cytotoxic effects of combination therapy was dependent upon CD8+ T cells only. Single cell RNA seq analysis also demonstrated that priming with immunotherapy increased IFN γ expression on T cells and subsequent treatment with ceritinib+trametinib increased melanoma antigen presentation by increased MHC class I expression. The RPPA data from tumors treated with anti-PD-1 followed by combination demonstrated inhibition of RTKs implicated in therapy escape such as c-MET, EGFR, IGF1R, HER2/3. Flow cytometric analysis also revealed around 60% decrease in Tregs and 80% decrease in MDSCs recruitment in the tumors treated with anti-PD1 followed by combination. RNA seq analysis revealed that ceritinib decreased mRNA expression of cytokines/ chemokines such as Cxcl5, Cxcl3, Cxcl2, Csf1, Cx3cl1, Cklf, that have been implicated in the recruitment and differentiation of MDSCs. Hence, we demonstrate that frontline immunotherapy primes the immune system, making the tumors more immunogenic with an increased accumulation of activated CD8+ T cells. Successive treatment with combination targeted therapy not only increases antigen presentation to T cells but also decreases recruitment of immunosuppressive MDSCs thus preventing immune escape and tumor progression. In summary, we have developed novel targeted therapy combinations that can be sequentially used with immunotherapy to maximize the durations of response in treatment of NRAS-mutant melanoma. Citation Format: Manali S. Phadke, Zhihua Chen, Eslam Mohamed, Michael Davies, Ann Chen, Uwe Rix, Paulo Rodriguez, Keiran Smalley. Frontline therapy with anti-PD1 enhances the durability of combination targeted therapy in NRAS-mutant melanoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5511.

Dissecting the mechanism of action of intravenous immunoglobulin in human autoimmune disease: Lessons from therapeutic modalities targeting Fcγ receptors

Since the first description of the administration of high doses of pooled serum IgG, also referred to as intravenous IgG (IVIg) therapy, as being able to ameliorate various autoimmune diseases, researchers have been investigating which molecular and cellular pathways underlie IVIg activity. Apart from trying to understand the obvious conundrum that IgG can trigger both autoimmune pathology and resolution of inflammation, the rapidly expanding use of IVIg has led to a lack of availability of this primary blood product, providing a strong rationale for developing recombinant alternatives. During the last decade, a tremendous number of novel insights into IVIg activity brought the goal of replacing IVIg within reach, at least in select indications, and has led to the initiation of several clinical trials. At the forefront of this effort is the modulation of autoantibody half-life and blocking access of autoantibodies to fragment cystallizable γ receptors (Fcγ receptors). In this rostrum article, we will briefly discuss current models of IVIg activity, followed by a more specific focus on novel therapeutic avenues that are entering the clinic and may replace IVIg in the future.

Astrocyte-microglia interaction drives evolving neuromyelitis optica lesion.

Neuromyelitis optica (NMO) is a severe inflammatory autoimmune CNS disorder triggered by binding of an IgG autoantibody to the aquaporin 4 (AQP4) water channel on astrocytes. Activation of cytolytic complement has been implicated as the major effector of tissue destruction that secondarily involves myelin. We investigated early precytolytic events in the evolving pathophysiology of NMO in mice by continuously infusing IgG (NMO patient serum-derived or AQP4-specific mouse monoclonal), without exogenous complement, into the spinal subarachnoid space. Motor impairment and sublytic NMO-compatible immunopathology were IgG dose dependent, AQP4 dependent, and, unexpectedly, microglia dependent. In vivo spinal cord imaging revealed a striking physical interaction between microglia and astrocytes that required signaling from astrocytes by the C3a fragment of their upregulated complement C3 protein. Astrocytes remained viable but lost AQP4. Previously unappreciated crosstalk between astrocytes and microglia involving early-activated CNS-intrinsic complement components and microglial C3a receptor signaling appears to be a critical driver of the precytolytic phase in the evolving NMO lesion, including initial motor impairment. Our results indicate that microglia merit consideration as a potential target for NMO therapeutic intervention.

No evidence for hypogammaglobulinemia in patients with paroxysmal nocturnal hemoglobinuria (PNH) chronically treated with ravulizumab.

IntroductionRavulizumab (ALXN1210) is a long-lasting recycling IgG monoclonal antibody with an increased affinity for the neonatal Fc receptor (FcRn). The FcRn is essential for regulating IgG homeostasis. Saturation of the FcRn pathway is seen under high IgG doses as they compete with endogenous IgG to bind the FcRn by their Fc regions, resulting in enhanced IgG clearance.Patients/MethodsBetween Jan 2016 and Jun 2019 (median observation time 21.6 months (6–37.7 months)) serum IgG concentrations and IgG1-4 subclasses were evaluated over a longitudinal course (post-hoc analysis) in 12 ravulizumab-treated adult patients with paroxysmal nocturnal hemoglobinuria (PNH) (58% (7/12) males, median age 50 years (yrs) (18–70 yrs)). All patients were enrolled in one of the three ravulizumab-PNH-related trials (201-, 301-, or 302-study) at the University Hospital Essen.ResultsBaseline IgG concentrations were documented in 11 out of the 12 patients prior to ravulizumab treatment (median IgG 9.9 g/L (5–13.5 g/L)). In two female patients a clinically not relevant hypogammaglobulinemia with an associated IgG1 or a combined IgG1/IgG2 deficiency prior to treatment was documented. The data were further stratified with regard to various treatment intervals as multiple analyses were obtained. Throughout observation time IgG concentrations remained within physiologic ranges with no evidence of a treatment-related IgG depletion (median IgG at study endpoint 10.1 g/L (6–13.4 g/L)).ConclusionIn ravulizumab-treated PNH patients, IgG and IgG subclass levels which are regulated by the FcRn remained unaffected. Therefore, no treatment associated hypogammaglobulinemia is to be feared under chronic ravulizumab therapy.

Use of FEF25-75% to Guide IgG Dosing to Protect Pulmonary Function in CVID.

Immunoglobulin replacement therapy (IGRT) can protect against lung function decline in CVID. We tested whether increasing IgG dosage was beneficial in patients who exhibited a decline in forced expiratory flow at 25-75% (FEF25-75%) even though they were receiving IgG doses within the therapeutic range. Of 189 CVID patients seen over 12years, 38 patients met inclusion criteria, were seen on ≥ 3 visits, and demonstrated a ≥ 10% decrease in FEF25-75% from visits 1 to 2. FEF25-75%, forced expiratory flow at 1s (FEV1), and FEV1/FVC at visit 3 were compared among those with non-dose adjustment (non-DA) versus additional IgG dose adjustment (DA). Three FEF25-75% tiers were identified: top (> 80% predicted), middle (50-80%), and bottom (< 50%). DA and non-DA groups did not differ in clinical infections or bronchodilator use, although the non-DA group tended to use more antibiotics. In the top, normal tier, FEF25-75% increased in DA, but the change did not achieve statistical significance. In the middle moderate obstruction tier, visit 3 FEF25-75% increased among DA but not non-DA sets (11.8 ± 12.4%, p = 0.003 vs. 0.3 ± 9.9%, p = 0.94). Improvement in FEV1/FVC at visit 3 was also significant among DA vs. non-DA (7.2 ± 12.4%, p = 0.04 vs. - 0.2 ± 2.7%, p = 0.85). In the bottom, severe tier, FEF25-75% was unchanged in DA (- 0.5 ± 5.2%, p = 0.79), but increased in non-DA (5.1 ± 5.2%, p = 0.02). Among IGRT CVID patients with moderate but not severe obstruction as assessed by spirometry, increasing IgG dosage led to an increase in FEF25-75% and FEV1/FVC.

Epidermolysis Bullosa Acquisita: The 2019 Update.

Epidermolysis bullosa acquisita (EBA) is an orphan autoimmune disease. Patients with EBA suffer from chronic inflammation as well as blistering and scarring of the skin and mucous membranes. Current treatment options rely on non-specific immunosuppression, which in many cases, does not lead to a remission of treatment. Hence, novel treatment options are urgently needed for the care of EBA patients. During the past decade, decisive clinical observations, and frequent use of pre-clinical model systems have tremendously increased our understanding of EBA pathogenesis. Herein, we review all of the aspects of EBA, starting with a detailed description of epidemiology, clinical presentation, diagnosis, and current treatment options. Of note, pattern analysis via direct immunofluorescence microscopy of a perilesional skin lesion and novel serological test systems have significantly facilitated diagnosis of the disease. Next, a state-of the art review of the current understanding of EBA pathogenesis, emerging treatments and future perspectives is provided. Based on pre-clinical model systems, cytokines and kinases are among the most promising therapeutic targets, whereas high doses of IgG (IVIG) and the anti-CD20 antibody rituximab are among the most promising “established” EBA therapeutics. We also aim to raise awareness of EBA, as well as initiate basic and clinical research in this field, to further improve the already improved but still unsatisfactory conditions for those diagnosed with this condition.

A long-lived IL-2 mutein that selectively activates and expands regulatory T cells as a therapy for autoimmune disease

Susceptibility to multiple autoimmune diseases is associated with common gene polymorphisms influencing IL-2 signaling and Treg function, making Treg-specific expansion by IL-2 a compelling therapeutic approach to treatment. As an in vivo IL-2 half-life enhancer we used a non-targeted, effector-function-silent human IgG1 as a fusion protein. An IL-2 mutein (N88D) with reduced binding to the intermediate affinity IL-2Rβγ receptor was engineered with a stoichiometry of two IL-2N88D molecules per IgG, i.e. IgG-(IL-2N88D)2. The reduced affinity of IgG-(IL-2N88D)2 for the IL-2Rβγ receptor resulted in a Treg-selective molecule in human whole blood pSTAT5 assays. Treatment of cynomolgus monkeys with single low doses of IgG-(IL-2N88D)2 induced sustained preferential activation of Tregs accompanied by a corresponding 10–14-fold increase in CD4+ and CD8+ CD25+FOXP3+ Tregs; conditions that had no effect on CD4+ or CD8+ memory effector T cells. The expanded cynomolgus Tregs had demethylated FOXP3 and CTLA4 epigenetic signatures characteristic of functionally suppressive cells. Humanized mice had similar selective in vivo responses; IgG-(IL-2N88D)2 increased Tregs while wild-type IgG-IL-2 increased NK cells in addition to Tregs. The expanded human Tregs had demethylated FOXP3 and CTLA4 signatures and were immunosuppressive. These results describe a next-generation immunotherapy using a long-lived and Treg-selective IL-2 that activates and expands functional Tregsin vivo. Patients should benefit from restored immune homeostasis in a personalized fashion to the extent that their autoimmune disease condition dictates opening up the possibility for remissions and cures.

Chronic norovirus infection in primary immune deficiency disorders: an international case series

ObjectivePredictive factors associated with clinical outcomes of chronic norovirus infection (CNI) in primary immunodeficiency diseases (PIDD) are lacking. MethodWe sought to characterize CNI using a multi-institutional cohort of patients with PIDD and CNI using the Clinical Immunology Society's CIS-PIDD Listserv e-mail group. ResultsThirty-four subjects (21 males and 13 females) were reported from centers across North America, Europe, and Asia. All subjects were receiving high doses (median IgG dose: 1200 mg/kg/month) of supplemental immunoglobulin therapy. Fifty-three percent had a complete absence of B cells (median B-cell count 0; range 0–139 cells/μL). Common Variable Immune Deficiency (CVID) subjects manifested a unique phenotype with B-cell lymphopenia, non O+ blood type, and villous atrophy (logistic regression model, P = 0.01). Five subjects died, all of whom had no evidence of villous atrophy. ConclusionWhile Norovirus (NoV) is thought to replicate in B cells, in this PIDD cohort of CNI, B-cell lymphopenia was common, indicating that the presence of B lymphocytes is not essential for CNI.

Abstract 1719: Superior efficacy of neoadjuvant compared to adjuvant immune checkpoint blockade in non-small cell lung cancer

Abstract Introduction: Blockade of immune checkpoints has improved clinical outcomes for patients with metastatic non-small cell lung cancer (NSCLC), but its role in the perioperative setting for early-stage disease is unclear. We generated preclinical models of resectable NSCLC expressing an antigen that permits quantitative assessment of the immune response and compared survival, tumor recurrence, and immune response after neoadjuvant or adjuvant immunotherapy. Experimental Procedures: We transfected murine 344SQ NSCLC cells with an ovalbumin-expression plasmid to generate OVA+ cells that can be identified with an antibody against the peptide SIINFEKL bound to H-2Kb of MHC-I. We implanted 344SQ-OVA+ cells in the flank of syngeneic mice and then randomized mice with established tumors to either 3 doses of neoadjuvant IgG, anti-PD-1, anti-CTLA-4, anti-PD-1+anti-CTLA-4, or to observation. Primary tumors were resected in all mice 2 days after mice in the neoadjuvant group had received their last dose of therapy. Two days post-surgery, mice in the observation group were treated with 3 doses of adjuvant IgG, anti-PD-1, anti-CTLA-4, anti-PD-1+anti-CTLA-4. Mice were euthanized 4 weeks after injection or when moribund and their survival recorded and lung metastases counted. We determined the composition of CD3+CD8+ tumor-infiltrating lymphocytes (TILs) with flow cytometry using tetramers against SIINFEKL-specific T cell receptors and immunohistochemical staining of tumors. Results: Single agent and combined immunotherapy significantly prolonged survival compared to controls in both neoadjuvant and adjuvant groups (p&amp;lt;0.05). Combined therapy was superior to either monotherapy in the neoadjuvant setting (combo vs. anti-PD-1 and vs. anti-CTLA-4 p&amp;lt;0.05), whereas there were no significant differences between combined treatment and monotherapies in the adjuvant setting. Moreover, combined therapy in the neoadjuvant setting significantly prolonged survival compared to adjuvant combined treatment (p&amp;lt;0.05). Neoadjuvant combined therapy produced the most profound reduction in lung metastases when compared to monotherapy (combo vs. IgG, vs. anti-PD-1 and vs. anti-CTLA-4 p&amp;lt;0.01), or to adjuvant combined treatment. Neoadjuvant combined therapy was associated with the greatest amounts of SIINFEKL-tetramer+ TILs in resected primary tumors and also with increased CD8+ TIL density in both resected primary tumors (combo vs. IgG and vs. anti-PD-1 p&amp;lt;0.05) and secondary lung metastases (combo vs. IgG, vs. anti-PD1 and vs. anti-CTLA-4 p&amp;lt;0.05). Functional studies investigating the immune response of tumors treated with perioperative immunotherapies are ongoing. Conclusions: Neoadjuvant combined immune checkpoint blockade is superior to adjuvant immunotherapy at prolonging survival, reducing distal recurrence and inducing anti-tumor immunity in preclinical models of resectable NSCLC. Citation Format: Tina Cascone, Haifa Hamdi, Fahao Zhang, Alissa Poteete, Lerong Li, Courtney W. Hudgens, Leila J. Williams, Qiuyu Wu, Jayanthi Gudikote, Weiyi Peng, Patrick Hwu, Jing Wang, Michael Tetzlaff, William N. William, John V. Heymach. Superior efficacy of neoadjuvant compared to adjuvant immune checkpoint blockade in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1719.

Treating cat allergy with monoclonal IgG antibodies that bind allergen and prevent IgE engagement

Acute allergic symptoms are caused by allergen-induced crosslinking of allergen-specific immunoglobulin E (IgE) bound to Fc-epsilon receptors on effector cells. Desensitization with allergen-specific immunotherapy (SIT) has been used for over a century, but the dominant protective mechanism remains unclear. One consistent observation is increased allergen-specific IgG, thought to competitively block allergen binding to IgE. Here we show that the blocking potency of the IgG response to Cat-SIT is heterogeneous. Next, using two potent, pre-selected allergen-blocking monoclonal IgG antibodies against the immunodominant cat allergen Fel d 1, we demonstrate that increasing the IgG/IgE ratio reduces the allergic response in mice and in cat-allergic patients: a single dose of blocking IgG reduces clinical symptoms in response to nasal provocation (ANCOVA, p = 0.0003), with a magnitude observed at day 8 similar to that reported with years of conventional SIT. This study suggests that simply augmenting the blocking IgG/IgE ratio may reverse allergy.

Tissue Destruction in Bullous Pemphigoid Can Be Complement Independent and May Be Mitigated by C5aR2.

Bullous pemphigoid (BP), the most frequent autoimmune bullous disorder, is a paradigmatic autoantibody-mediated disease associated with autoantibodies against BP180 (type XVII collagen, Col17). Several animal models have been developed that reflect important clinical and immunological features of human BP. Complement activation has been described as a prerequisite for blister formation, however, the recent finding that skin lesions can be induced by anti-Col17 F(ab′)2 fragments indicates complement-independent mechanisms to contribute to blister formation in BP. Here, C5−/− mice injected with anti-Col17 IgG showed a reduction of skin lesions by about 50% associated with significantly less skin-infiltrating neutrophils compared to wild-type mice. Reduction of skin lesions and neutrophil infiltration was seen independently of the employed anti-Col17 IgG dose. Further, C5ar1−/− mice were protected from disease development, whereas the extent of skin lesions was increased in C5ar2−/− animals. Pharmacological inhibition of C5a receptor 1 (C5aR1) by PMX53 led to reduced disease activity when applied in a prophylactic setting. In contrast, PMX-53 treatment had no effect when first skin lesions had already developed. While C5aR1 was critically involved in neutrophil migration in vitro, its role for Col17-anti-Col17 IgG immune complex-mediated release of reactive oxygen species from neutrophils was less pronounced. Our data demonstrate that complement-dependent and -independent mechanisms coexist in anti-Col17-autoantibody-mediated tissue destruction. C5aR1 and C5aR2 seem to play opposing roles in this process with C5aR1 exerting its primary effect in recruiting inflammatory cells to the skin during the early phase of the disease. Further studies are required to fully understand the role of C5aR2 in autoantibody-mediated skin inflammation.