A comprehensive overview of FCGR3A gene variability by full-length gene sequencing including the identification of V158F polymorphism

Site-Specific Glycosylation Analysis of Murine and Human Fcγ Receptors Reveals High Heterogeneity at Conserved N-Glycosylation Site

Fc γ-receptors (FcγRs) on leukocytes bind immunoglobulin G (IgG) immune complexes to mediate effector functions. Dysregulation of FcγR-mediated processes contributes to multiple inflammatory diseases, including rheumatoid arthritis, lupus, and immune thrombocytopenia. Critically, immunoregulatory N-glycan modifications on both FcγRs and IgGs alter FcγR-IgG binding affinity. Rapid methods for the characterization of N-glycans across multiple Fcγ receptors are needed to propel investigations into disease-specific contributions of FcγR N-glycans. Here, we utilize nanoliquid chromatography tandem mass spectrometry (nLC-MS/MS) to characterize FcγR glycosylation and report quantitative and site-specific N-glycan characterization of recombinant human FcγRI, FcγRIIIA V158, and FcγRIIIA F158 from CHO cells and murine FcγRI, FcγRIII, and FcγRIV from NS0 cells. Data are available via ProteomeXchange with identifier PXD043966. Broad glycoform distribution (≥30) was observed at mouse FcγRIV site N159 and human FcγRIIIA site N162, an evolutionarily conserved site. Further, mouse FcγRIII N-glycopeptides spanning all four predicted N-glycosylation sequons were detected. Glycoform relative abundances for hFcγRIIIA V/F158 polymorphic variants are reported, demonstrating the clinical potential of this workflow to measure differences in glycosylation between common human FcγRIIIA allelic variants with disease-associated outcomes. The multi-Fcγ receptor glycoproteomic workflow reported here will empower studies focused on the role of FcγR N-glycosylation in autoimmune diseases.

Affibody-based hBCMA x CD16 dual engagers for NK cell-mediated killing of multiple myeloma cells

We describe the development and characterization of the (to date) smallest Natural Killer (NK) cell re-directing human B Cell Maturation Antigen (hBCMA) x CD16 dual engagers for potential treatment of multiple myeloma, based on combinations of small 58 amino acid, non-immunoglobulin, affibody affinity proteins. Affibody molecules to human CD16a were selected from a combinatorial library by phage display resulting in the identification of three unique binders with affinities (KD) for CD16a in the range of 100 nM-3 µM. The affibody exhibiting the highest affinity demonstrated insensitivity towards the CD16a allotype (158F/V) and did not interfere with IgG (Fc) binding to CD16a. For the construction of hBCMA x CD16 dual engagers, different CD16a binding arms, including bi-paratopic affibody combinations, were genetically fused to a high-affinity hBCMA-specific affibody. Such 15-23 kDa dual engager constructs showed simultaneous hBCMA and CD16a binding ability and could efficiently activate resting primary NK cells and trigger specific lysis of a panel of hBCMA-positive multiple myeloma cell lines. Hence, we report a novel class of uniquely small NK cell engagers with specific binding properties and potent functional profiles.

Apoptosis and inflammatory genes variants in primary non-response to anti-TNF therapy in Crohn's disease patients

Anti-TNF therapy has indeed revolutionized the treatment of Crohn's disease, leading to higher rates of response and remission in patients. However, a significant proportion of 20-40% of patients do not respond to the initial therapy, others experience a secondary loss of response with ongoing treatment. Adverse drug reactions also occur in some patients. The effectiveness of anti-TNF treatment may be influenced by genetic variability, including FCGR3A, ADAM17, TNFRSF1A, TNFRSF1B, FAS, FASL, IL1B, CASP9 , and MIF genes. In this article, we provide an overview of the current knowledge and findings in the pharmacogenetics of anti-TNF drugs in CD focusing on the aspect of apoptosis and inflammatory genes variants in primary non-response. Pharmacogenetic investigations have been conducted to identify genetic markers that can predict response to anti-TNF therapy. However, large multi-center validation studies and multi-loci algorithms development are required to effectively prognose the treatment effect. The identification of predictive markers of response to anti-TNF therapy can help clinicians make informed decisions about treatment options and minimize adverse drug reactions in patients.

Ublituximab-xiiy as a treatment option for relapsing multiple sclerosis

INTRODUCTION

B cell depletion has been established as an efficacious anti-inflammatory therapy in people with relapsing forms of multiple sclerosis (MS). Ublituximab (ublituximab-xiiy) is the latest approved chimeric glycoengineered anti-CD20 monoclonal antibody (mAb) for the treatment of relapsing forms of MS.

AREAS COVERED

In this narrative review, the authors explore the safety and effectiveness of data derived from the Phase 2 and Phase 3 ublituximab trials and from their respective post-hoc analyses. Moreover, they consider the similarities and differences between the currently available anti-CD20 antibodies for treatment of relapsing MS. Lastly, the authors discuss the role and place of ublituximab in the current disease modifying therapy landscape.

EXPERT OPINION

Ublituximab is a rapid-acting and effective anti-inflammatory option as a treatment in people with relapsing MS that significantly reduced the annualized relapse rate and MRI-based disease activity. When compared to the Phase III trials of the other two anti-CD20 mAbs (ocrelizumab and ofatumumab), ublituximab did not result with reduction of 3 or 6-month confirmed disability progression. These differences may be attributed to the overall low rate of progression in both the ublituximab and the active comparator teriflunomide arm. Future data from open-label extensions are warranted. There was no significant reduction of ublituximab on whole-brain atrophy compared to teriflunomide.

Deciphering the Genetic Code of Autoimmune Kidney Diseases

Autoimmune kidney diseases occur due to the loss of tolerance to self-antigens, resulting in inflammation and pathological damage to the kidneys. This review focuses on the known genetic associations of the major autoimmune kidney diseases that result in the development of glomerulonephritis: lupus nephritis (LN), anti-neutrophil cytoplasmic associated vasculitis (AAV), anti-glomerular basement disease (also known as Goodpasture's disease), IgA nephropathy (IgAN), and membranous nephritis (MN). Genetic associations with an increased risk of disease are not only associated with polymorphisms in the human leukocyte antigen (HLA) II region, which governs underlying processes in the development of autoimmunity, but are also associated with genes regulating inflammation, such as NFkB, IRF4, and FC γ receptors (FCGR). Critical genome-wide association studies are discussed both to reveal similarities in gene polymorphisms between autoimmune kidney diseases and to explicate differential risks in different ethnicities. Lastly, we review the role of neutrophil extracellular traps, critical inducers of inflammation in LN, AAV, and anti-GBM disease, where inefficient clearance due to polymorphisms in DNase I and genes that regulate neutrophil extracellular trap production are associated with autoimmune kidney diseases.

Inhibitory receptors for HLA class I as immune checkpoints for natural killer cell-mediated antibody-dependent cellular cytotoxicity in cancer immunotherapy

Natural killer (NK) cells mediate potent anti-tumor responses, which makes them attractive targets for immunotherapy. The anti-tumor response of endogenous- or allogeneic NK cells can be enhanced through clinically available monoclonal antibodies that mediate antibody-dependent cellular cytotoxicity (ADCC). NK cell activation is regulated by interaction of inhibitory receptors with classical- and non-classical human leukocyte antigens (HLA) class I molecules. Inhibitory receptors of the killer immunoglobulin-like receptor (KIR) family interact with HLA-A, -B or -C epitopes, while NKG2A interacts with the non-classical HLA-E molecule. Both types of inhibitory interactions may influence the strength of the ADCC response. In the present review, we provide an overview of the effect of inhibitory KIRs and NKG2A on NK cell-mediated ADCC, which highlights the rationale for combination strategies with ADCC triggering antibodies and interference with the NK cell relevant inhibitory immune checkpoints, such as KIR and NKG2A.

Analysis of FCGR3A-p.176Val variants in women with recurrent pregnancy loss and the association with CD16a expression and anti-HLA antibody status

Natural Killer (NK) cells have been implicated in recurrent pregnancy loss (RPL). The p.Val176Phe (or Val158Phe) Single Nucleotide Polymorphism (SNP) in the FCGR3A gene encoding the FcγRIIIA or CD16a receptor has been associated with an enhanced affinity for IgG and stronger NK-mediated antibody-dependent cellular cytotoxicity. We hypothesized that the presence of at least one p.176Val variant associates with RPL and increased CD16a expression and alloantibodies e.g., against paternal human leukocyte antigen (HLA). In 50 women with RPL, we studied frequencies of the p.Val176Phe FCGR3A polymorphisms. Additionally, CD16a expression and anti-HLA antibody status were analyzed by flowcytometry and Luminex Single Antigens. In woman with RPL, frequencies were: 20% (VV), 42% (VF) and 38% (FF). This was comparable to frequencies from the European population in the NCBI SNP database and in an independent Dutch cohort of healthy women. NK cells from RPL women with a VV (22,575 [18731-24607]) and VF (24,294 [20157-26637]) polymorphism showed a higher expression of the CD16a receptor than NK cells from RPL women with FF (17,367 [13257-19730]). No difference in frequencies of the FCGR3A-p.176 SNP were detected when comparing women with or without class I and class II anti-HLA antibodies. Our study does not provide strong evidence for an association between the p.Val176Phe FCGR3A SNP and RPL.

Human natural killer cells: Form, function, and development

Human natural killer (NK) cells are innate lymphoid cells that mediate important effector functions in the control of viral infection and malignancy. Their ability to distinguish "self" from "nonself" and lyse virally infected and tumorigenic cells through germline-encoded receptors makes them important players in maintaining human health and a powerful tool for immunotherapeutic applications and fighting disease. This review introduces our current understanding of NK cell biology, including key facets of NK cell differentiation and the acquisition and execution of NK cell effector function. Further, it addresses the clinical relevance of NK cells in both primary immunodeficiency and immunotherapy. It is intended to provide an up-to-date and comprehensive overview of this important and interesting innate immune effector cell subset.

A Review of Margetuximab-Based Therapies in Patients with HER2-Positive Metastatic Breast Cancer

Breast cancer (BC) is the most commonly diagnosed cancer globally, with high mortality rates. Targeted drug therapies have revolutionized cancer treatment. For example, treatment with human epidermal receptor 2 (HER2) antagonists has markedly improved the prognosis of patients with HER2-positive BC (HER2 + BC). However, HER2+ metastatic BC (MBC) remains prevalent owing to its resistance to conventional anti-HER2 drugs. Therefore, novel agents are needed to overcome the limitations of existing cancer treatments and to enhance the progression-free and overall survival rates. Progress has been made by optimizing the fragment crystallizable (Fc) domain of trastuzumab, an IgG1 monoclonal, chimeric anti-HER2 antibody, to develop margetuximab. The modified Fc domain of margetuximab enhances its binding affinity to CD16A and decreases its binding affinity to CD32B, thereby promoting its antitumor activity. This review summarizes studies on the efficacy of margetuximab, discusses its utility as an anti-HER2 monoclonal antibody drug for the treatment of HER2 + BC, and presents the latest advances in the treatment of BC. This review provides insights into the clinical implication of margetuximab in HER2 + MBC treatment.

Heterogeneity in IgG-CD16 signaling in infectious disease outcomes

In this review, we discuss how IgG antibodies can modulate inflammatory signaling during viral infections with a focus on CD16a-mediated functions. We describe the structural heterogeneity of IgG antibody ligands, including subclass and glycosylation that impact binding by and downstream activity of CD16a, as well as the heterogeneity of CD16a itself, including allele and expression density. While inflammation is a mechanism required for immune homeostasis and resolution of acute infections, we focus here on two infectious diseases that are driven by pathogenic inflammatory responses during infection. Specifically, we review and discuss the evolving body of literature showing that afucosylated IgG immune complex signaling through CD16a contributes to the overwhelming inflammatory response that is central to the pathogenesis of severe forms of dengue disease and coronavirus disease 2019 (COVID-19).

The weaker-binding Fc γ receptor IIIa F158 allotype retains sensitivity to N-glycan composition and exhibits a destabilized antibody-binding interface

Antibodies engage Fc γ receptors (FcγRs) to elicit healing cellular immune responses following binding to a target antigen. Fc γ receptor IIIa/CD16a triggers natural killer cells to destroy target tissues with cytotoxic proteins and enhances phagocytosis mediated by macrophages. Multiple variables affect CD16a antibody-binding strength and the resulting immune response, including a genetic polymorphism. The predominant CD16a F158 allotype binds antibodies with less affinity than the less common V158 allotype. This polymorphism likewise affects cellular immune responses and clinical efficacy of antibodies relying on CD16a engagement, though it remains unclear how V/F158 affects CD16a structure. Another relevant variable shown to affect affinity is composition of the CD16a asparagine-linked (N)-glycans. It is currently not known how N-glycan composition affects CD16a F158 affinity. Here, we determined N-glycan composition affects the V158 and F158 allotypes similarly, and N-glycan composition does not explain differences in V158 and F158 binding affinity. Our analysis of binding kinetics indicated the N162 glycan slows the binding event, and shortening the N-glycans or removing the N162 glycan increased the speed of binding. F158 displayed a slower binding rate than V158. Surprisingly, we found N-glycan composition had a smaller effect on the dissociation rate. We also identified conformational heterogeneity of CD16a F158 backbone amide and N162 glycan resonances using NMR spectroscopy. Residues exhibiting chemical shift perturbations between V158 and F158 mapped to the antibody-binding interface. These data support a model for CD16a F158 with increased interface conformational heterogeneity, reducing the population of binding-competent forms available and decreasing affinity.

FCGR3A Is a Prognostic Biomarker and Correlated with Immune Infiltrates in Lower-Grade Glioma

Low-grade gliomas (LGGs) are primary invasive brain tumors that grow slowly but are incurable and eventually develop into high malignant glioma. Fc fragment of IgG receptor IIIa (FCGR3A) gene polymorphism may correlate with some cancers’ treatment responses. However, the expression and prognosis value of FCGR3A and correlation with tumor-immune infiltrate in LGG remain unclear. FCGR3A mRNA expression in gastric cancer (GC) was examined using TIMER and GEPIA databases. Correlations between FCGR3A expression and clinicopathological parameters were analyzed using ULACAN and CGGA databases. GEPIA, OncoLnc, and ULACAN databases were used to examine the clinical prognostic significance of FCGR3A in LGG. TIMER was used to analyze the correlations among FCGR3A and tumor-infiltrating immune cells. Signaling pathways related to FCGR3A expression were identified by LinkedOmics. We found that FCGR3A expression was higher in LGG than in normal tissue and was correlated with various clinical parameters. In addition, high FCGR3A expression predicted poor overall survival in LGG. More importantly, FCGR3A expression positively correlated with immune checkpoint molecules, including PD1, PD-L1, PD-L2, CTLA4, LAG-3 and TIM-3, and tumor-associated macrophage (TAM) gene markers in LGG. GO and KEGG pathway analyses indicated that TUBA1C may potentially regulate the pathogenesis of LGG through immune-related pathways. These findings indicated that FCGR3A plays a vital role in the infiltration of immune cells and could constitute a promising prognostic biomarker in LGG patients.

Genome-wide pharmacogenetics of anti-drug antibody response to bococizumab highlights key residues in HLA DRB1 and DQB1

In this largest to-date genetic analysis of anti-drug antibody (ADA) response to a therapeutic monoclonal antibody (MAb), genome-wide association was performed for five measures of ADA status among 8844 individuals randomized to bococizumab, which targets PCSK9 for LDL-C lowering and cardiovascular protection. Index associations prioritized specific amino acid substitutions at the DRB1 and DQB1 MHC class II genes rather than canonical haplotypes. Two clusters of missense variants at DRB1 were associated with general ADA measures (residues 9, 11, 13; and 96, 112, 120, 180) and a third cluster of missense variants in DQB1 was associated with ADA measures including neutralizing antibody (NAb) titers (residues 66, 67, 71, 74, 75). The structural disposition of the missense substitutions implicates peptide antigen binding and CD4 effector function, mechanisms that are potentially generalizable to other therapeutic mAbs.

Clinicaltrials.gov: NCT01968954, NCT01968967, NCT01968980, NCT01975376, NCT01975389, NCT02100514.

Functional antibody-dependent cell mediated cytotoxicity (ADCC) responses to vaccine and circulating influenza strains following vaccination

Novel cell-based assays were developed to assess antibody-dependence cellular cytotoxicity (ADCC) antibodies against both vaccine and a representative circulation strain HA and NA proteins for the 2014-15 influenza season. The four assays using target cells stably expressing one of the four proteins worked well. In pre- and post-vaccine sera from 70 participants in a pre-season vaccine trial, we found ADCC antibodies and a rise in ADCC antibody titer against target cells expressing the 4 proteins but a much higher titer for the vaccine than the circulating HA in both pre-and post-vaccine sera. These differences in HA ADCC antibodies were not reflected in differences in HA binding antibodies. Our observations suggested that relatively minor changes on the subtype HA can result in large differences in ADCC activity.

Role of Fcγ receptors in HER2-targeted breast cancer therapy

Several therapeutic monoclonal antibodies (mAbs), including those targeting epidermal growth factor receptor, human epidermal growth factor receptor 2 (HER2), and CD20, mediate fragment crystallizable gamma receptor (FcγR)–dependent activities as part of their mechanism of action. These activities include induction of antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP), which are innate immune mechanisms of cancer cell elimination. FcγRs are distinguished by their affinity for the Fc fragment, cell distribution, and type of immune response they induce. Activating FcγRIIIa (CD16A) on natural killer cells plays a crucial role in mediating ADCC, and activating FcγRIIa (CD32A) and FcγRIIIa on macrophages are important for mediating ADCP. Polymorphisms in FcγRIIIa and FcγRIIa generate variants that bind to the Fc portion of antibodies with different affinities. This results in differential FcγR-mediated activities associated with differential therapeutic outcomes across multiple clinical settings, from early stage to metastatic disease, in patients with HER2+ breast cancer treated with the anti-HER2 mAb trastuzumab. Trastuzumab has, nonetheless, revolutionized HER2+ breast cancer treatment, and several HER2-directed mAbs have been developed using Fc glyco-engineering or Fc protein-engineering to enhance FcγR-mediated functions. An example of an approved anti-HER2 Fc-engineered chimeric mAb is margetuximab, which targets the same epitope as trastuzumab, but features five amino acid substitutions in the IgG 1 Fc domain that were deliberately introduced to increase binding to activating FcγRIIIa and decrease binding to inhibitory FcγRIIb (CD32B). Margetuximab enhances Fc-dependent ADCC in vitro more potently than the combination of pertuzumab (another approved mAb directed against an alternate HER2 epitope) and trastuzumab. Margetuximab administration also enhances HER2-specific B cell and T cell–mediated responses ex vivo in samples from patients treated with prior lines of HER2 antibody-based therapies. Stemming from these observations, a worthwhile future goal in the treatment of HER2+ breast cancer is to promote combinatorial approaches that better eradicate HER2+ cancer cells via enhanced immunological mechanisms.

Congenital Hyperinsulinism: Current Laboratory-Based Approaches to the Genetic Diagnosis of a Heterogeneous Disease

Congenital hyperinsulinism is characterised by the inappropriate release of insulin during hypoglycaemia. This potentially life-threatening disorder can occur in isolation, or present as a feature of syndromic disease. Establishing the underlying aetiology of the hyperinsulinism is critical for guiding medical management of this condition especially in children with diazoxide-unresponsive hyperinsulinism where the underlying genetics determines whether focal or diffuse pancreatic disease is present. Disease-causing single nucleotide variants affecting over 30 genes are known to cause persistent hyperinsulinism with mutations in the KATP channel genes (ABCC8 and KCNJ11) most commonly identified in children with severe persistent disease. Defects in methylation, changes in chromosome number, and large deletions and duplications disrupting multiple genes are also well described in congenital hyperinsulinism, further highlighting the genetic heterogeneity of this condition. Next-generation sequencing has revolutionised the approach to genetic testing for congenital hyperinsulinism with targeted gene panels, exome, and genome sequencing being highly sensitive methods for the analysis of multiple disease genes in a single reaction. It should though be recognised that limitations remain with next-generation sequencing with no single application able to detect all reported forms of genetic variation. This is an important consideration for hyperinsulinism genetic testing as comprehensive screening may require multiple investigations.

Targeting ADCC: A different approach to HER2 breast cancer in the immunotherapy era

The clinical outcome of patients with human epidermal growth factor receptor 2 (HER2) amplified breast carcinoma (BC) has improved with the development of anti-HER2 targeted therapies. However, patients can experience disease recurrence after curative intent and disease progression in the metastatic setting. In the current era of evolving immunotherapy agents, the understanding of the immune response against HER2 tumor cells developed by anti-HER2 antibodies (Abs) is rapidly evolving. Trastuzumab therapy promotes Natural Killer (NK) cell activation in patients with BC overexpressing HER2, indicating that the efficacy of short-term trastuzumab monotherapy, albeit direct inhibition of HER, could also be related with antibody-dependent cell-mediated cytotoxicity (ADCC). Currently, dual HER2 blockade using trastuzumab and pertuzumab is the standard of care in early and advanced disease as this combination could confer an additive effect in ADCC. In patients with disease relapse or progression, ADCC may be hampered by several factors such as FcγRIIIa polymorphism and an immunosuppressive environment, among others. Hence, new drug development strategies are being investigated aiming to boost the ADCC response triggered by anti-HER2 therapy. In this review, we summarize these strategies and the rationale, through mAbs engineering and combinatorial strategies, focusing on clinical results and ongoing trials.

Detection of single nucleotide and copy number variants in the Fabry disease-associated GLA gene using nanopore sequencing

More than 900 variants have been described in the GLA gene. Some intronic variants and copy number variants in GLA can cause Fabry disease but will not be detected by classical Sanger sequence. We aimed to design and validate a method for sequencing the GLA gene using long-read Oxford Nanopore sequencing technology. Twelve Fabry patients were blindly analyzed, both by conventional Sanger sequence and by long-read sequencing of a 13 kb PCR amplicon. We used minimap2 to align the long-read data and Nanopolish and Sniffles to call variants. All the variants detected by Sanger (including a deep intronic variant) were also detected by long-read sequencing. One patient had a deletion that was not detected by Sanger sequencing but was detected by the new technology. Our long-read sequencing-based method was able to detect missense variants and an exonic deletion, with the added advantage of intronic analysis. It can be used as an efficient and cost-effective tool for screening and diagnosing Fabry disease.

Fc Receptor Variants and Disease: A Crucial Factor to Consider in the Antibody Therapeutics in Clinic

The fragment crystallizable (Fc) domain of antibodies is responsible for their protective function and long-lasting serum half-life via Fc-mediated effector function, transcytosis, and recycling through its interaction with Fc receptors (FcRs) expressed on various immune leukocytes, epithelial, and endothelial cells. Therefore, the Fc-FcRs interaction is a control point of both endogenous and therapeutic antibody function. There are a number of reported genetic variants of FcRs, which include polymorphisms in (i) extracellular domain of FcRs, which change their affinities to Fc domain of antibodies; (ii) both cytoplasmic and intracellular domain, which alters the extent of signal transduction; and (iii) the promoter region of the FcRs gene, which affects the expression level of FcRs, thus being associated with the pathogenesis of disease indications. In this review, we firstly describe the correlation between the genetic variants of FcRs and immunological disorders by individual differences in the extent of FcRs-mediated regulations. Secondly, we discuss the influence of the genetic variants of FcRs on the susceptibility to infectious diseases or cancer in the perspective of FcRs-induced effector functions. Overall, we concluded that the genetic variants of FcRs are one of the key elements in the design of antibody therapeutics due to their variety of clinical outcomes among individuals.

Allotype-specific processing of the CD16a N45-glycan from primary human natural killer cells and monocytes

Fc γ receptor IIIa/CD16a is an activating cell surface receptor with a well-defined role in natural killer (NK) cell and monocyte effector function. The extracellular domain is decorated with five asparagine (N)-linked glycans; N-glycans at N162 and N45 directly contribute to high-affinity antibody binding and protein stability. N-glycan structures at N162 showed significant donor-dependent variation in a recent study of CD16a isolated from primary human NK cells, but structures at N45 were relatively homogeneous. In this study, we identified variations in N45 glycan structures associated with a polymorphism coding for histidine instead of leucine at position 48 of CD16a from two heterozygous donors. It is known that H48 homozygous individuals suffer from immunodeficiency and recurrent viral infections. A mass spectrometry analysis of protein isolated from the primary natural killer cells of individuals expressing both CD16a L48 and H48 variants demonstrated clear processing differences at N45. CD16a H48 displayed a greater proportion of complex-type N45 glycans compared to the more common L48 allotype with predominantly hybrid N45-glycoforms. Structures at the four other N-glycosylation sites showed minimal differences from data collected on donors expressing only the predominant L48 variant. CD16a H48 purified from a pool of monocytes similarly displayed increased processing at N45. Here, we provide evidence that CD16a processing is affected by the H48 residue in primary NK cells and monocytes from healthy human donors.

Pharmacogenetic variants of infliximab response in young patients with inflammatory bowel disease

Infliximab is commonly used in inflammatory bowel disease (IBD), however, differences in clinical response among patients are common. Several studies have considered the possibility that these differences are caused by genetic variability even if no unique marker has been yet identified in pediatric patients. We evaluated the impact of two candidate single-nucleotide polymorphisms (SNPs) rs396991 in FCGR3A and rs1800629 in TNFα genes on infliximab response in an Italian cohort of 76 pediatric patients with IBD. Results showed that patients with the variant FCGR3A allele had a reduced clinical response at the end of induction (p value = 0.004), at 22 weeks (p value = 0.001), and at 52 weeks of treatment (p value = 0.01). A significant association between the FCGR3A variant and median infliximab levels measured during maintenance therapy was also observed: patients with wild type genotype had higher infliximab levels compared to patient with variant allele. Furthermore, patients with the variant allele had a higher probability to produce antidrug antibodies (ADAs). No association was found among the TNFα SNP, clinical response, and infliximab levels. This study addressed for the first time in pediatric patients with IBD, the association of FCGR3A SNP, infliximab response, and ADA production.

Exploring pharmacogenetic variants for predicting response to anti-TNF therapy in autoimmune diseases: a meta-analysis

Aim: The aim of this study is to explore how SNPs may affect the response to anti-TNF-α therapy in the major autoimmune diseases, such as psoriasis, rheumatoid arthritis, inflammatory bowel diseases and Spondyloarthritis. Methodology: We conducted a systematic overview on the field, by assessing all studies that examined the association between polymorphisms and response to anti-TNF-α therapy in participants of European descent. Results: In total, six independent SNPs located in FCGR2A, FCGR3A, TNF-α and TNFRSF1B genes were significantly associated with response to TNF-α blockers, found mainly in disease-subgroup analyses. Conclusion: No common pharmacogenetic variant was identified for all autoimmune diseases under study, suggesting the requirement of more studies in the field in order to capture such predictive variants that will aid treatment selection.

Targeting NK Cells to Enhance Melanoma Response to Immunotherapies

Natural killer (NK) cells are a key component of an innate immune system. They are important not only in initiating, but also in augmenting adaptive immune responses. NK cell activation is mediated by a carefully orchestrated balance between the signals from inhibitory and activating NK cell receptors. NK cells are potent producers of proinflammatory cytokines and are also able to elicit strong antitumor responses through secretion of perforin and granzyme B. Tumors can develop many mechanisms to evade NK cell antitumor responses, such as upregulating ligands for inhibitory receptors, secreting anti-inflammatory cytokines and recruiting immunosuppressive cells. Enhancing NK cell responses will likely augment the effectiveness of immunotherapies, and strategies to accomplish this are currently being evaluated in clinical trials. A comprehensive understanding of NK cell biology will likely provide additional opportunities to further leverage the antitumor effects of NK cells. In this review, we therefore sought to highlight NK cell biology, tumor evasion of NK cells and clinical trials that target NK cells.

Novel TLR 7/8 agonists for improving NK cell mediated antibody-dependent cellular cytotoxicity (ADCC)

There is a significant interest in designing therapeutic agents that can enhance ADCC and thereby improve clinical responses with approved antibodies. We recently reported the combination of an imidazoquinoline-based TLR7/8 agonist (522) with a monoclonal antibody improved ADCC in vitro and in vivo. In the present study, we tested several new small molecule TLR7/8 agonists that induce significantly higher cytokines compared to both the FDA-approved TLR7 agonist, imiquimod, and 522. We evaluated these agonists in combination with monoclonal antibody therapy, with the main goal of enhancing ADCC. Our studies show these TLR7/8 agonists induce robust pro-inflammatory cytokine secretion and activate NK cells. Specifically, we found the agonists 574 and 558 significantly enhanced NK cell-mediated ADCC in vitro as well as enhanced the anti-cancer efficacy of monoclonal antibodies in two different in vivo mouse models. Additionally, we found the agonists were able to stimulate CD8 T cells, likely indicative of an early adaptive immune response.

A novel endogenous CD16-Expressing Natural Killer Cell for cancer immunotherapy

Natural killer (NK) cells, as a potential source for off-the-shelf cell therapy, attack tumor cells with low risk of severe cytokine release syndrome (CRS) or graft-versus-host disease (GvHD). Fcγ receptor IIIA, also known as CD16, further confers NK cells with antibody-dependent cell-mediated cytotoxicity (ADCC), one mechanism of action of antibody-based immunotherapy. Here, we establish a novel human NK cell line, oNK-1, endogenously expressing CD16 along with high levels of NK activation markers and low levels of NK inhibitory markers. The long-term expansion and CD16 expression of oNK-1 cells were demonstrated. Furthermore, oNK-1 cells elicit superior cytotoxicity against cancer cells than primary NK cells. In conclusion, this study suggests that endogenous CD16-expressing oNK-1 has the potential to develop an effective NK-based therapy.

Network preservation reveals shared and unique biological processes associated with chronic alcohol abuse in NAc and PFC

Chronic alcohol abuse has been linked to the disruption of executive function and allostatic conditioning of reward response dysregulation in the mesocorticolimbic pathway (MCL). Here, we analyzed genome-wide mRNA and miRNA expression from matched cases with alcohol dependence (AD) and controls (n = 35) via gene network analysis to identify unique and shared biological processes dysregulated in the prefrontal cortex (PFC) and nucleus accumbens (NAc). We further investigated potential mRNA/miRNA interactions at the network and individual gene expression levels to identify the neurobiological mechanisms underlying AD in the brain. By using genotyped and imputed SNP data, we identified expression quantitative trait loci (eQTL) uncovering potential genetic regulatory elements for gene networks associated with AD. At a Bonferroni corrected p≤0.05, we identified significant mRNA (NAc = 6; PFC = 3) and miRNA (NAc = 3; PFC = 2) AD modules. The gene-set enrichment analyses revealed modules preserved between PFC and NAc to be enriched for immune response processes, whereas genes involved in cellular morphogenesis/localization and cilia-based cell projection were enriched in NAc modules only. At a Bonferroni corrected p≤0.05, we identified significant mRNA/miRNA network module correlations (NAc = 6; PFC = 4), which at an individual transcript level implicated miR-449a/b as potential regulators for cellular morphogenesis/localization in NAc. Finally, we identified eQTLs (NAc: mRNA = 37, miRNA = 9; PFC: mRNA = 17, miRNA = 16) which potentially mediate alcohol's effect in a brain region-specific manner. Our study highlights the neurotoxic effects of chronic alcohol abuse as well as brain region specific molecular changes that may impact the development of alcohol addiction.

Polymorphisms in Fc Gamma Receptors and Susceptibility to Malaria in an Endemic Population

Repeated infections by Plasmodium falciparum result in a humoral response that could reduce disease symptoms and prevent the development of clinical malaria. The principal mechanism underlying this humoral response is that immunoglobulin G (IgG) binds directly to the parasites, thus causing their neutralization. However, the action of antibodies alone is not always sufficient to eliminate pathogens from an organism. One key element involved in the recognition of IgG that plays a crucial role in the destruction of the parasites responsible for spreading malaria is the family of Fc gamma receptors. These receptors are expressed on the surface of immune cells. Several polymorphisms have been detected in the genes encoding these receptors, associated with susceptibility or resistance to malaria in different populations. In this review, we describe identified polymorphisms within the family of Fc gamma receptors and the impact of these variations on the response of a host to infection as well as provide new perspectives for the design of an effective vaccine for malaria.

FCGR1A Serves as a Novel Biomarker and Correlates With Immune Infiltration in Four Cancer Types

BACKGROUND

FCGR1A encodes a protein that plays an important role in the immune response. The prognostic impact and immune infiltration of FCGR1A in heterogeneous cancers remain unclear.

METHODS

Differential expression of FCGR1A between tumor and normal tissues and the discrepancies in overall survival (OS) among diverse cancer types were performed by Gene Expression Profiling Interactive Analysis. The correlation between FCGR1A and immune cells or gene marker sets of immune infiltrates was analyzed via Tumor Immune Estimation Resource (TIMER). Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and protein-to-protein interaction (PPI) network were used to explore the function and related genes of FCGR1A. The relationships among these genes were further analyzed by TIMER.

RESULTS

FCGR1A is highly expressed in various cancer types. FCGR1A was significantly correlated with the OS of cervical and endocervical cancer (CESC), cholangiocarcinoma (CHOL), kidney renal clear cell carcinoma (KIRC), and skin cutaneous melanoma (SKCM) (P < 0.05). High expression of FCGR1A meant a better prognosis besides KIRC. FCGR1A showed significant differences at different stages of KIRC and SKCM (P < 0.05). Furthermore, FCGR1A was notably associated with infiltrating levels of CD4+ T cells, CD8+ T cells, B cells, macrophages, neutrophils, and dendritic cells in the four cancers (P < 0.05). FCGR1A also showed close relevance with different immune gene markers. The copy number variation of FCGR1A significantly influenced the abundance of immune infiltration in KIRC and SKCM. GO, KEGG analysis, and PPI network analysis revealed that FCGR1A is involved in many pathophysiological processes and was most related to FCGR3A. And this gene indicated highly significant positive correlations with FCGR1A in four cancers.

CONCLUSION

FCGR1A may be a potential prognostic biomarker and related to immune infiltration levels in diverse cancers, especially in CESC, CHOL, KIRC, and SKCM. Besides, FCGR1A may be involved in the activation, regulation, or induction of immune cells and diverse physiological and pathological processes.

Gene expression analysis in formalin fixed paraffin embedded melanomas is associated with density of corresponding immune cells in those tissues

Immune cell infiltrates in melanoma have important prognostic value. Gene expression analysis may simultaneously quantify numbers and function of multiple immune cell subtypes in formalin-fixed paraffin-embedded (FFPE) tissues. Prior studies report single gene expression can represent individual immune cell subtypes, but this has not been shown in FFPE melanomas. We hypothesized that gene expression profiling of human melanomas using a new RNA expression technology in FFPE tissue would correlate with the same immune cells identified by immunohistochemistry (IHC). This retrospective study included melanoma specimens analyzed by IHC on tumor tissue microarray (TMA) cores and by gene expression profiling with EdgeSeq Immuno-Oncology Assay using qNPA technology on the corresponding tumors. Standardized gene expression levels were analyzed relative to enumerated cells by IHC using Spearman rank test to calculate r-values. Multivariate analysis was performed by Kruskal–Wallis test. 119 melanoma specimens had both IHC and gene expression information available. There were significant associations between the level of gene expression and its quantified IHC cell marker for CD45⁺, CD3⁺, CD8⁺, CD4⁺, and CD20⁺ cells (all p < 0.001). There were also significant associations with exhaustion markers FoxP3⁺, PD-1⁺, and PD-L1⁺ (all p ≤ 0.0001). This new qNPA technology is useful to quantify intratumoral immune cells on FFPE specimens through RNA gene expression in metastatic melanoma. As previous studies have shown on other solid human tumors, we also confirm that the expression level of a single gene may be used to represent a single IHC immune cell marker in melanoma.

Natural Killer (NK) Cell Expression of CD2 as a Predictor of Serial Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC)

NK cell ADCC supports monoclonal antibody anti-tumor therapies. We investigated serial ADCC and whether it could be predicted by NK phenotypes, including expression of CD16A, CD2 and perforin. CD16A, the NK receptor for antibodies, has AA158 valine or phenylalanine variants with different affinities for IgG. CD2, a costimulatory protein, associates with CD16A and can augment CD16A-signaling. Pore-forming perforin is essential for rapid NK-mediated killing. NK cells were monitored for their ADCC serial killing frequency (KF). KF is the average number of target cells killed per cell by a cytotoxic cell population. KF comparisons were made at 1:4 CD16pos NK effector:target ratios. ADCC was toward Daudi cells labeled with ⁵¹Cr and obinutuzumab anti-CD20 antibody. CD16A genotypes were determined by DNA sequencing. CD2, CD16A, and perforin expression was monitored by flow cytometry. Serial killing KFs varied two-fold among 24 donors and were independent of CD16A genotypes and perforin levels. However, high percentages of CD2pos of the CD16Apos NK cells and high levels of CD16A were associated with high KFs. ROC analysis indicated that the %CD2pos of CD16Apos NK cells can predict KFs. In conclusion, the extent of serial ADCC varies significantly among donors and appears predictable by the CD2posCD16Apos NK phenotype.

Is Polymorphism in the Apoptosis and Inflammatory Pathway Genes Associated With a Primary Response to Anti-TNF Therapy in Crohn's Disease Patients?

Anti-tumor necrosis factor (TNF) therapy is used for the induction and maintenance of remission in Crohn’s disease (CD) patients. However, primary nonresponders to initial treatment constitute 20%–40% of cases. The causes of this phenomenon are still unknown. In this study, we aimed to determine the genetic predictors of the variable reactions of CD patients to anti-TNF therapy. Using long-range PCR libraries and the next-generation sequencing (NGS) method, we performed broad pharmacogenetic studies including a panel of 23 genes (TNFRSF1A, TNFRSF1B, CASP9, FCGR3A, LTA, TNF, FAS, ADAM17, IL17A, IL6, MMP1, MMP3, S100A8, S100A9, S100A12, TLR2, TLR4, TLR9, CD14, IL23R, IL23, IL1R, and IL1B) in a group of 107 diagnosed and clinically characterized CD patients following anti-TNF therapy. In the studied group, we indicated, in total, 598 single nucleotide variants for all analyzed genomic targets. Twelve patients (11.2%) did not respond to the induction therapy, which was associated with alleles in 11 loci located in FCGR3A (rs7539036, rs6672453, rs373184583, and rs12128686), IL1R (rs2041747), TNFRSF1B (rs5746053), IL1B (rs1071676, rs1143639, rs1143637, and rs1143634), and FAS (rs7896789) genes. After multiple comparison corrections, the results were not statistically significant, however for nonresponders the alleles distribution for those loci presented large differences and specified scheme compared to responders and populations. These findings require further investigation in an independent larger cohort before introducing them for a clinical setting, however, we identified an interesting direction. Polymorphism of the FCGR3A, IL1R, TNFRSF1B, IL1B, and FAS genes could be a predictor of the primary response to anti-TNF therapy in CD patients.

Anti-CD20 rituximab IgG1, IgG3, and IgG4 but not IgG2 subclass trigger Ca2+ mobilization and cytotoxicity in human NK cells

NK cell-mediated Ab-dependent cellular cytotoxicity (ADCC) is increasingly recognized to play an important role in cancer immunotherapy, transplant rejection, and autoimmunity. However, several aspects of the molecular interactions of IgG subclasses with the Fc-gamma receptor IIIA (FcγRIIIA)/CD16a expressed on NK cells remain unknown. The aim of the current study was to further analyze the role of IgG subclasses and FCGR3A V158F single nucleotide polymorphism (SNP) on Ca²⁺ signaling and NK cell-mediated ADCC against Daudi target cells in vitro. NK cells were isolated from donors with different FCGR3A SNP. The affinity of rituximab IgG subclasses to CD20 expressed on Daudi cells showed similar dissociation constant as tested by flow cytometry. Induction of Ca²⁺ signaling, degranulation, intracellular cytokine production, and ADCC was demonstrated for IgG1 and IgG3, to a lesser degree also for IgG4, but not for IgG2. Compared to NK cells carrying the low-affinity (FF) variant for the FCGR3A V158F SNP, binding of IgG1 and IgG3 to NK cells carrying the high-affinity (VV) and VF SNP variants was two- to threefold higher. Variations of FCGR3A SNP among the eight tested donors (1 VV, 3FF, and 4VF) revealed no significant differences of Ca²⁺ signaling and degranulation; however, ADCC was somewhat weaker in donors with the low-affinity FF variation. In conclusion, this is the first study correlating Ca²⁺ signaling and NK cell-mediated ADCC triggered by the four IgG subclasses with the FCGR3A V158F SNP. Our findings indicate important differences in the interactions of IgG subclasses with FcγRIIIA/CD16a but no major impact of FCGR3A SNP and may therefore help to better correlate the functional properties of particular engineered therapeutic antibodies in vitro with individual differences of their clinical efficacy.

Exploiting antibody biology for the treatment of cancer

Over the last decade, antibodies have become an important component in the arsenal of cancer therapeutics. High-specificity, low off-target effects, desirable pharmacokinetics and high success rate are a few of the many attributes that make antibodies amenable for development as drugs. To design antibodies for successful clinical applications, however, it is critical to have an understanding of their structure, functions, mechanisms of action and pharmacokinetic/pharmacodynamic properties. This review highlights some of these key aspects, as well as certain limitations encountered, with monoclonal antibody therapy. Further, we discuss rational combination therapies for clinical applications, some of which could help overcome the limitations.

Genetic Variation in Low-To-Medium-Affinity Fcγ Receptors: Functional Consequences, Disease Associations, and Opportunities for Personalized Medicine

Fc-gamma receptors (FcγR) are the cellular receptors for Immunoglobulin G (IgG). Upon binding of complexed IgG, FcγRs can trigger various cellular immune effector functions, thereby linking the adaptive and innate immune systems. In humans, six classic FcγRs are known: one high-affinity receptor (FcγRI) and five low-to-medium-affinity FcγRs (FcγRIIA, -B and -C, FcγRIIIA and -B). In this review we describe the five genes encoding the low-to-medium -affinity FcγRs (FCGR2A, FCGR2B, FCGR2C, FCGR3A, and FCGR3B), including well-characterized functionally relevant single nucleotide polymorphisms (SNPs), haplotypes as well as copy number variants (CNVs), which occur in distinct copy number regions across the locus. The evolution of the locus is also discussed. Importantly, we recommend a consistent nomenclature of genetic variants in the FCGR2/3 locus. Next, we focus on the relevance of genetic variation in the FCGR2/3 locus in auto-immune and auto-inflammatory diseases, highlighting pathophysiological insights that are informed by genetic association studies. Finally, we illustrate how specific FcγR variants relate to variation in treatment responses and prognosis amongst autoimmune diseases, cancer and transplant immunology, suggesting novel opportunities for personalized medicine.

Redirected optimized cell killing (ROCK®): A highly versatile multispecific fit-for-purpose antibody platform for engaging innate immunity

Redirection of immune cells to efficiently eliminate tumor cells holds great promise. Natural killer cells (NK), macrophages, or T cells are specifically engaged with target cells expressing markers after infection or neoplastic transformation, resulting in their activation and subsequent killing of those targets. Multiple strategies to redirect immunity have been developed in the past two decades, but they have technical hurdles or cause undesirable side-effects, as exemplified by the T cell-based chimeric antigen receptor approaches (CAR-T therapies) or bispecific T cell engager platforms. Our first-in-class bispecific antibody redirecting innate immune cells to tumors (AFM13, a CD30/CD16A-specific innate immune cell engager) has shown signs of clinical efficacy in CD30-positive lymphomas and the potential to be safely administered, indicating a wider therapeutic window compared to T cell engaging therapies. AFM13 is the most advanced candidate from our fit-for-purpose redirected optimized cell killing (ROCK®) antibody platform, which comprises a plethora of CD16A-binding innate immune cell engagers with unique properties. Here, we discuss aspects of this modular platform, including the advantages of innate immune cell engagement over classical monoclonal antibodies and other engager concepts. We also present details on its potential to engineer a fit-for-purpose innate immune cell engager format that can be equipped with unique CD16A domains, modules that influence pharmacokinetic properties and molecular architectures that influence the activation of immune effectors, as well as tumor targeting. The ROCK® platform is aimed at the activation of innate immunity for the effective lysis of tumor cells and holds the promise of overcoming limitations of other approaches that redirect immune cells by widening the therapeutic window.