IgE, IgE Receptors and Anti-IgE Biologics: Protein Structures and Mechanisms of Action.

The evolution of IgE in mammals added an extra layer of immune protection at body surfaces to provide a rapid and local response against antigens from the environment. The IgE immune response employs potent expulsive and inflammatory forces against local antigen provocation, at the risk of damaging host tissues and causing allergic disease. Two well-known IgE receptors, the high-affinity FcεRI and low-affinity CD23, mediate the activities of IgE. Unlike other known antibody receptors, CD23 also regulates IgE expression, maintaining IgE homeostasis. This mechanism evolved by adapting the function of the complement receptor CD21. Recent insights into the dynamic character of IgE structure, its resultant capacity for allosteric modulation, and the potential for ligand-induced dissociation have revealed previously unappreciated mechanisms for regulation of IgE and IgE complexes. We describe recent research, highlighting structural studies of the IgE network of proteins to analyze the uniquely versatile activities of IgE and anti-IgE biologics.

Antibody feedback regulation.

Antibodies are able to up- or downregulate antibody responses to the antigen they bind. Two major mechanisms can be distinguished. Suppression is most likely caused by epitope masking and can be induced by all isotypes tested (IgG1, IgG2a, IgG2b, IgG3, IgM, and IgE). Enhancement is often caused by the redistribution of antigen in a favorable way, either for presentation to B cells via follicular dendritic cells (IgM and IgG3) or to CD4+ T cells via dendritic cells (IgE, IgG1, IgG2a, and IgG2b). IgM and IgG3 complexes activate complement and are transported from the marginal zone to follicles by marginal zone B cells expressing complement receptors. IgE-antigen complexes are captured by CD23+ B cells in the blood and transported to follicles, delivered to CD8α+ conventional dendritic cells, and presented to CD4+ T cells. Enhancement of antibody responses by IgG1, IgG2a, and IgG2b in complex with proteins requires activating FcγRs. These immune complexes are captured by dendritic cells and presented to CD4+ T cells, subsequently helping cognate B cells. Endogenous feedback regulation influences the response to booster doses of vaccines and passive administration of anti-RhD antibodies is used to prevent alloimmunization of RhD-negative women carrying RhD-positive fetuses.

IgE directly affects eosinophil migration in chronic rhinosinusitis with nasal polyps through CCR3 and predicts the efficacy of omalizumab.

BACKGROUND: Whether IgE affects eosinophil migration in chronic rhinosinusitis with nasal polyps (CRSwNP) remains largely unclear. Moreover, our understanding of local IgE, eosinophils, and omalizumab efficacy in CRSwNP remains limited. OBJECTIVE: We investigated whether IgE acts directly on eosinophils and determined its role in omalizumab therapy. METHODS: Eosinophils and their surface receptors were detected by hematoxylin and eosin staining and flow cytometry. IgE and its receptors, eosinophil peroxidase (EPX), eosinophilic cationic protein, and CCR3 were detected by immunohistochemistry and immunofluorescence. Functional analyses were performed on blood eosinophils and polyp tissues. Logistic regression was performed to screen for risk factors. Receiver operating characteristic curve was generated to evaluate the accuracy. RESULTS: Both FcεRI and CD23 were expressed on eosinophils. The expression of FcεRI and CD23 on eosinophil in nasal polyp tissue was higher than in peripheral blood (both P < .001). IgE and EPX colocalized in CRSwNP. IgE directly promoted eosinophil migration by upregulating CCR3 in CRSwNP but not in healthy controls. Omalizumab and lumiliximab were found to be effective in restraining this migration, indicating CD23 was involved in IgE-induced eosinophil migration. Both IgE+ and EPX+ cells were significantly reduced after omalizumab treatment in those who experienced response (IgE+ cells, P = .001; EPX+ cells, P = .016) but not in those with no response (IgE+ cells, P = .060; EPX+ cells, P = .151). Baseline IgE+ cell levels were higher in those with response compared to those without response (P = .024). The baseline local IgE+ cell count predicted omalizumab efficacy with an accuracy of 0.811. CONCLUSIONS: IgE directly promotes eosinophil migration, and baseline local IgE+ cell counts are predictive of omalizumab efficacy in CRSwNP.

Evolution of pathologic B-cell subsets and serum environment-specific sIgEs in patients with atopic dermatitis and controls, from infancy to adulthood.

BACKGROUND: While B-cells have historically been implicated in allergy development, a growing body of evidence supports their role in atopic dermatitis (AD). B-cell differentiation across ages in AD, and its relation to disease severity scores, has not been well defined. OBJECTIVE: To compare the frequency of B-cell subsets in blood of 0-5, 6-11, 12-17, and ≥18 years old patients with AD versus age-matched controls. METHODS: Flow cytometry was used to measure B-cell subset frequencies in the blood of 27 infants, 17 children, 11 adolescents, and 31 adults with moderate-to-severe AD and age-matched controls. IgD/CD27 and CD24/CD38 core gating systems and an 11-color flow cytometry panel were used to determine frequencies of circulating B-cell subsets. Serum total and allergen-specific IgE (sIgEs) levels were measured using ImmunoCAP®. RESULTS: Adolescents with AD had lower frequencies of major B-cells subsets (p < .03). CD23 expression increased with age and was higher in AD compared to controls across all age groups (p < .04). In AD patients, multiple positive correlations were observed between IL-17-producing T-cells and B-cell subsets, most significantly non-switched memory (NSM) B-cells (r = .41, p = .0005). AD severity positively correlated with a list of B-cell subsets (p < .05). IL-9 levels gradually increased during childhood, reaching a peak in adolescence, paralleling allergen sensitization, particularly in severe AD. Principal component analysis of the aggregated environmental sIgE data showed that while controls across all ages tightly clustered together, adolescents with AD demonstrated distinct clustering patterns relative to controls. CONCLUSIONS: Multiple correlations between B-cells and T-cells, as well as disease severity measures, suggest a complex interplay of immune pathways in AD. Unique B-cell signature during adolescence, with concurrent allergen sensitization and IL-9 surge, point to a potentially wider window of opportunity to implement interventions that may prevent the progression of the atopic march.

A targeted antibody-based array reveals a serum protein signature as biomarker for adolescent idiopathic scoliosis patients.

BACKGROUND: Evident adolescent idiopathic scoliosis (AIS) incurs high treatment costs, low quality of life, and many complications. Early screening of AIS is essential to avoid progressing to an evident stage. However, there is no valid serum biomarker for AIS for early screening. METHODS: Antibody-based array is a large-scale study of proteins, which is expected to reveal a serum protein signature as biomarker for AIS. There are two segments of the research, including biomarkers screening and validation. In the biomarkers screening group, a total of 16 volunteers participated in this study, and we carried out differentially expressed proteins screening via protein array assay between No-AIS group and the AIS group, through which GeneSet enrichment analysis was performed. In the validation group with a total of 62 volunteers, the differentially expressed proteins from screening group were verified by Enzyme-Linked immunosorbent assay (ELISA), and then multiple regression analysis. RESULTS: In our study, there were twenty-nine differentially expressed proteins in AIS, through Protein array assay and GeneSet enrichment analysis in the biomarkers screening group. Then the expression of FAP, CD23 and B2M decreased as the degree of AIS increased via ELISA in validation group (FAP, p < 0.0001; CD23, p = 0.0002; B2M, p < 0.0001). Further, the results of multiple regression analysis showed that FAP, CD23 are linked to Cobb angle, whereas B2M were excluded because of multicollinearity. CONCLUSIONS: Altogether, we found that serum protein FAP and CD23 are intimately related to AIS, suggesting FAP and CD23 are expected to serve as the serum biomarkers, which significantly facilitate frequent longitudinal monitoring as to keep track of disease progression and tailor treatment accordingly.

PU.1-CD23 signaling mediates pulmonary innate immunity against Aspergillus fumigatus infection by driving inflammatory response.

BACKGROUND: Aspergillosis is a common cause of morbidity and mortality in immunocompromised populations. PU.1 is critical for innate immunity against Aspergillus fumigatus (AF) in macrophages. However, the molecular mechanism underlying PU.1 mediating immunity against AF infection in human alveolar macrophages (AMs) is still unclear. METHODS: In this study, we detected the expressions of PU.1, CD23, p-ERK, CCL20 and IL-8 and key inflammatory markers IL-1ß, IL-6, TNF-α and IL-12 in human THP-1-derived macrophages (HTMs) or PU.1/CD23-overexpressed immunodeficient mice with AF infection. Moreover, we examined these expressions in PU.1-overexpressed/interfered HTMs. Additionally, we detected the phagocytosis of macrophages against AF infection with altered PU.1 expression. Dual luciferase, ChIP and EMSAs were performed to detect the interaction of PU.1 and CD23. And we invested the histological changes in mouse lung tissues transfected with PU.1/CD23-expressing adenoviruses in AF infection. RESULTS: The results showed that the expressions of PU.1, CD23, p-ERK, CCL20, IL-8, IL-1ß, IL-6, TNF-α and IL-12 increased significantly with AF infection, and PU.1 regulated the later 8 gene expressions in HTMs. Moreover, CD23 was directly activated by PU.1, and overexpression of CD23 in PU.1-interfered HTMs upregulated IL-1ß, IL-6, TNF-α and IL-12 levels which were downregulated by PU.1 interference. PU.1 overexpression strengthened the phagocytosis of the HTMs against AF. And injection of PU.1/CD23-expressing adenoviruses attenuated pathological defects in immunodeficient mouse lung tissues with AF infection. Adenovirus (Ad)-PU.1 increased the CD23, p-ERK, CCL20, IL-8 levels. CONCLUSIONS: Our study concluded that PU.1-CD23 signaling mediates innate immunity against AF in lungs through regulating inflammatory response. Therefore, PU.1-CD23 may be a new anti-aspergillosis therapeutic for the treatment of invasive aspergillosis with the deepening of gene therapy and its wide application in the clinic.

Expression of CD117 (c-Kit) on Circulating B Cells in Pediatric Schistosomiasis.

Few B cells express CD27, the primary marker for memory B cells, in pediatric schistosomiasis, suggesting B cell malfunction. This study further demonstrates unexpected high expression of CD117 on circulating B cells in children highly exposed to Schistosoma mansoni infectious larvae. CD117 is expressed by immature or lymphoma B cells, but not by mature, circulating cells. We therefore sought to define the significance of CD117 on blood B cells. We found that CD117-positive (CD117+) B cells increased with the intensity of schistosome infection. In addition, CD117 expression was reduced on CD23+ B cells previously shown to correlate with resistance to infection. Stimulation with a panel of cytokines demonstrated that CD117 levels were upregulated in response to a combination of interleukin 4 (IL-4) and stem cell factor (SCF), the ligand for CD117, whereas IL-2 led to a reduction. In addition, stimulation with SCF generally reduced B cell activation levels. Upon further investigation, it was established that multiple circulating cells expressed increased levels of CD117, including monocytes, neutrophils, and eosinophils, and expression levels correlated with that of B cells. Finally, we identified a population of large circulating cells with features of reticulocytes. Overall, our results suggest that hyperexposure to intravascular parasitic worms elicits immature cells from the bone marrow. Levels of SCF were shown to reduce as children began to transition through puberty. The study results pose an explanation for the inability of children to develop significant immunity to infection until after puberty.

Immunoglobulin E response in health and disease beyond allergic disorders.

Immunoglobulin E is the latest discovered of immunoglobulin family and has been long associated with anaphylaxis and worm expulsion. Immunoglobulin E, along with mast cells, basophils, and eosinophils, is also a hallmark of type 2 immunity which is dysregulated in numerous diseases such as asthma, rhinitis, atopic dermatitis, and eosinophilic esophagitis in addition to anaphylaxis as aforementioned. However, recent advances have shed light on IgE regulation and memory explaining the low level of free IgE, the scarcity of IgE plasma cells that are mainly short live and the absence of IgE memory B cells in homeostatic conditions. Furthermore, IgE was implicated in inflammatory conditions beyond allergic disorders where IgE-mediated facilitated antigen presentation can enhance cellular and humoral response against autoantigens in systemic lupus or chronic urticaria leading to more severe disease and even against neoantigen facilitating tumor cell lysis. At last, IgE was unexpectedly associated with allograft rejection or atheromatous cardiovascular diseases where precise mechanisms remain to be deciphered. The purpose of this review is to summarize these recent advances in IgE regulation, biology, and physiopathology beyond allergic diseases opening whole new fields of IgE biology to explore.

Follicular dendritic cell sarcoma of the cervical lymph node diagnosed on fine needle aspiration cytology.

Follicular dendritic cell sarcomas (FDCS) are rare tumours of lymph nodes and extranodal tissues which are grouped with the histiocytic and dendritic cell neoplasms. The diagnosis is usually made after thorough clinical and pathological examination with immunohistochemical analysis. Difficulties persist in diagnosing FDCS on cytological preparations. We report herein a case of a 57-year-old female who presented with a right neck mass of 5 months duration. Computed Tomography (CT) imaging of the neck reported a necrotic right level IIb lymph node and asymmetric fullness of the right palatine tonsil. Fine needle aspiration (FNA) biopsy revealed numerous spindle, oval and stellate neoplastic cells, arranged singly and in syncytia with moderate nuclear pleomorphism, vesicular chromatin pattern, and prominent nucleoli, sprinkled with small lymphocytes. The tumour cells were strongly diffusely positive for CD21, CD23, and D2-40 immunostaining on cell bock sections, but were negative for CD1a and CD34, supporting the diagnosis of FDCS. Follow-up surgical pathology on the resection showed histopathological features and an immunohistochemical profile consistent with FDCS.

Stunting as a Risk Factor for Asthma: The Role of Vitamin D, Leptin, IL-4, and CD23.

Stunting, which results from chronic malnutrition, is common in children from low- and middle-income countries. Several studies have reported an association between obesity and asthma. However, only a handful of studies have identified stunting as a significant risk factor for wheezing, a symptom of asthma, although the underlying mechanism remains unclear. This article aimed to review possible mechanisms underlying asthma in stunted children. Overall, changes in diet or nutritional status and deficiencies in certain nutrients, such as vitamin D, can increase the risk of developing asthma. Vitamin D deficiency can cause linear growth disorders such as stunting in children, with lower levels of 25(OH)D found in underweight and stunted children. Stunted children show a decreased lean body mass, which affects lung growth and function. Low leptin levels during undernutrition cause a Th1-Th2 imbalance toward Th2, resulting in increased interleukin (IL)-4 cytokine production and total immunoglobulin E (IgE). Studies in stunted underweight children have also found an increase in the proportion of the total number of B cells with low-affinity IgE receptors (CD23+). CD23+ plays an important role in allergen presentation that is facilitated by IgE to T cells and strongly activates allergen-specific T cells and the secretion of Th2-driving cytokines. Stunted children present with low vitamin D and leptin levels, impaired lung growth, decreased lung function, and increased IL-4 and CD23+ levels. All of these factors may be considered consequential in asthma in stunted children.

Alemtuzumab mediates the CD39+ T-regulatory cell response via CD23+ macrophages.

Alemtuzumab (ALM) effectively prevents relapses of multiple sclerosis (MS). It causes lymphocyte depletion with subsequent enhancement of the T-regulatory cell population. Direct administration of ALM to T cells causes cytolysis. However, the T cells may be indirectly affected by monocyte-derived cells, which are resistant to ALM cytotoxicity. We aimed to examine whether ALM modulates monocytes and whether the crosstalk between monocytes and lymphocytes previously exposed to ALM would result in anti-inflammatory effects. The CD14+ monocytes of 10 healthy controls and 10 MS (treatment naive) patients were isolated from peripheral blood mononuclear cells (PBMCs), exposed to ALM and reintroduced to PBMCs depleted of CD14+ cells. The macrophage profile was assessed and T-cell markers were measured. ALM promoted M2 anti-inflammatory phenotype as noted by an increased percentage in the populations of CD23+ , CD83+ and CD163+ cells. The CD23+ cells were the most upregulated (7-fold, P = 0.0002), and the observed effect was higher in patients with MS than in healthy subjects. ALM-exposed macrophages increased the proportion of T-regulatory cells, without affecting the proportion of T-effector cells. Neutralizing the CD23+ monocytes with antibodies reversed the effect specifically on the CD4+ CD39+ T-regulatory cell subpopulation but not on the CD4+ CD25hi CD127lo FOXP3+ subpopulation. ALM induces the conversion of monocytes into anti-inflammatory macrophages, which in turn promotes T-regulatory cell enhancement, in a CD23-dependent manner. These findings suggest that the mechanism of action of ALM is relevant to aspects of MS pathogenesis.

The role of CD23 in the regulation of allergic responses.

IgE, the key molecule in atopy has been shown to bind two receptors, FcεRI, the high-affinity receptor, and FcεRII (CD23), binding IgE with lower affinity. Whereas cross-linking of IgE on FcεRI expressed by mast cells and basophils triggers the allergic reaction, binding of IgE to CD23 on B cells plays an important role in both IgE regulation and presentation. Furthermore, IgE-immune complexes (IgE-ICs) bound by B cells enhance antibody and T cell responses in mice and humans. However, the mechanisms that regulate the targeting of the two receptors and the respective function of the two pathways in inflammation or homeostasis are still a matter of debate. Here, we focus on CD23 and discuss several mechanisms related to IgE binding, as well as the impact of the IgE/antigen-binding on different immune cells expressing CD23. One recent paper has shown that free IgE preferentially binds to FcεRI whereas IgE-ICs are preferentially captured by CD23. Binding of IgE-ICs to CD23 on B cells can, on one hand, regulate serum IgE and prevent effector cell activation and on the other hand facilitate antigen presentation by delivering the antigen to dendritic cells. These data argue for a multifunctional role of CD23 for modulating IgE serum levels and immune responses.

Formation of IgE-Allergen-CD23 Complex Changes in Children Treated with Subcutaneous Immunotherapy for Japanese Cedar Pollinosis.

BACKGROUND: Subcutaneous immunotherapy (SCIT) is used to treat Japanese cedar (JC) pollinosis. The formation of IgE-allergen-CD23 complex after SCIT for JC pollinosis has not yet been fully elucidated. OBJECTIVE: The objective of this study was to investigate the formation of IgE-allergen-CD23 complex after SCIT for JC pollinosis. METHODS: Eleven patients were treated with 3-year SCIT for JC pollinosis at Sa-gamihara National Hospital from 2013 to 2014. Nasal and ocular symptoms (in terms of symptom scores) during the scattering of JC pollen and immunological changes were investigated. Levels of JC pollen-specific antibodies (IgE and IgG4) were measured by ImmunoCAP assays. To detect the changes in allergen-presenting ability of B cells, the levels of IgE-allergen-CD23 complexes in serum were measured by a cell-free, enzyme-linked immunosorbent-facilitated antigen-binding assay. RESULTS: The median (interquartile range) age of the subjects was 8 (6-10) years. Three patients (27%) had comorbid atopic dermatitis, and 5 patients (45%) had comorbid bronchial asthma. Before starting SCIT, the total IgE level was 373 (75-2,870) kU/L, and the level of JC pollen-specific IgE was 77.2 (15.4-528) kUA/L. Symptom scores improved significantly from the year after treatment. JC pollen-specific IgE levels did not change after 3 years of treatment. JC pollen-specific IgG4 levels increased significantly throughout the treatment period. The levels of IgE-allergen-CD23 complexes decreased significantly after 3 years of treatment. CONCLUSION: The ability of IgE-allergen complexes to bind to CD23 decreased after SCIT, suggesting that increasing levels of IgE-blocking antibodies, including IgG4, may play an important role in the mechanism of SCIT.

CD23 provides a noninflammatory pathway for IgE-allergen complexes.

BACKGROUND: Type I hypersensitivity is mediated by allergen-specific IgE, which sensitizes the high-affinity IgE receptor FcεRI on mast cells and basophils and drives allergic inflammation upon secondary allergen contact. CD23/FcεRII, the low-affinity receptor for IgE, is constitutively expressed on B cells and has been shown to regulate immune responses. Simultaneous binding of IgE to FcεRI and CD23 is blocked by reciprocal allosteric inhibition, suggesting that the 2 receptors exert distinct roles in IgE handling. OBJECTIVE: We aimed to study how free IgE versus precomplexed IgE-allergen immune complexes (IgE-ICs) target the 2 IgE receptors FcεRI and CD23, and we investigated the functional implications of the 2 pathways. METHODS: We performed binding and activation assays with human cells in vitro and IgE pharmacokinetics and anaphylaxis experiments in vivo. RESULTS: We demonstrate that FcεRI preferentially binds free IgE and CD23 preferentially binds IgE-ICs. We further show that those different binding properties directly translate to distinct biological functions: free IgE initiated allergic inflammation through FcεRI on allergic effector cells, while IgE-ICs were noninflammatory because of reduced FcεRI binding and enhanced CD23-dependent serum clearance. CONCLUSION: We propose that IgE-ICs are noninflammatory through reduced engagement by FcεRI but increased targeting of the CD23 pathway.

Allergen-specific IgE levels and the ability of IgE-allergen complexes to cross-link determine the extent of CD23-mediated T-cell activation.

BACKGROUND: CD23 mediates IgE-facilitated allergen presentation and subsequent allergen-specific T-cell activation in allergic patients. OBJECTIVE: We sought to investigate key factors regulating IgE-facilitated allergen presentation through CD23 and subsequent T-cell activation. METHODS: To study T-cell activation by free allergens and different types of IgE-Bet v 1 complexes, we used a molecular model based on monoclonal human Bet v 1-specific IgE, monomeric and oligomeric Bet v 1 allergen, an MHC-matched CD23-expressing B-cell line, and a T-cell line expressing a human Bet v 1-specific T-cell receptor. The ability to cross-link Fcε receptors of complexes consisting of either IgE and monomeric Bet v 1 or IgE and oligomeric Bet v 1 was studied in human FcεRI-expressing basophils. T-cell proliferation by monomeric or oligomeric Bet v 1, which cross-links Fcε receptors to a different extent, was studied in allergic patients' PBMCs with and without CD23-expressing B cells. RESULTS: In our model non-cross-linking IgE-Bet v 1 monomer complexes, as well as cross-linking IgE-Bet v 1 oligomer complexes, induced T-cell activation, which was dependent on the concentration of specific IgE. However, T-cell activation by cross-linking IgE-Bet v 1 oligomer complexes was approximately 125-fold more efficient. Relevant T-cell proliferation occurred in allergic patients' PBMCs only in the presence of B cells, and its magnitude depended on the ability of IgE-Bet v 1 complexes to cross-link CD23. CONCLUSION: The extent of CD23-mediated T-cell activation depends on the concentration of allergen-specific IgE and the cross-linking ability of IgE-allergen complexes.

Increasing the breadth and potency of response to the seasonal influenza virus vaccine by immune complex immunization.

The main barrier to reduction of morbidity caused by influenza is the absence of a vaccine that elicits broad protection against different virus strains. Studies in preclinical models of influenza virus infections have shown that antibodies alone are sufficient to provide broad protection against divergent virus strains in vivo. Here, we address the challenge of identifying an immunogen that can elicit potent, broadly protective, antiinfluenza antibodies by demonstrating that immune complexes composed of sialylated antihemagglutinin antibodies and seasonal inactivated flu vaccine (TIV) can elicit broadly protective antihemagglutinin antibodies. Further, we found that an Fc-modified, bispecific monoclonal antibody against conserved epitopes of the hemagglutinin can be combined with TIV to elicit broad protection, thus setting the stage for a universal influenza virus vaccine.

Intra-abdominal Follicular Dendritic Cell Sarcoma (FDCS): Series of 18 cases of a rare entity from Pakistan.

OBJECTIVES: Follicular Dendritic Cell Sarcoma (FDCS) is a rare neoplastic proliferation of dendritic cells which are immune accessory cells found in both lymphoid and non-lymphoid organs. FDCS can thus occur in lymph nodes as well as non-lymphoid organs. Intraabdominal FDCS is even rarer. Our aim was to describe the clinical and morphological features of intra-abdominal FDCSs diagnosed in our practice and to review published literature on FDCSs including intra-abdominal FDCSs. METHODS: All cases of FDCSs diagnosed between January 1, 2008 and December 31, 2019 were included in the study. Slides of the cases were reviewed and clinical follow up was obtained. RESULTS: A total of 18 cases of intraabdominal FDCS were diagnosed during the study period. Age range was 17 to 55 years. Mean and median ages were 28 and 29 years respectively. Of the 18 patients, 11 were male and 7 were females. Colon was involved in 9 cases and appendix in 2 cases. 9 cases were received as resection specimens while 9 cases were received as slides and blocks for second opinion. Tumor size ranged from 2.7 to 26 cm. Average tumor size in these 9 cases was 8.2 cm and in 6 of these 9 cases, tumor size was greater than 6 cm in largest dimension. Grossly, tumors were nodular or polypoid and had a fleshy, grey white, homogeneous cut surface. Histologically, all 18 cases showed proliferation of plump to spindle shaped cells arranged in a fascicular or storiform pattern. Tumor cells had mild to moderately pleomorphic spindle to ovoid vesicular nuclei with fine chromatin and inconspicuous to variably conspicuous nucleoli, and moderate amount of pale eosinophilic cytoplasm. Mitotic activity was usually brisk. CD21 and CD23 were positive in all 18 cases. Resection margins were negative in all 9 resection specimens. Lymph nodes positive for metastases were seen in 4 cases. Follow up was available in 13 cases. Recurrence was seen in 6 patients, out of which 3 patients died of disease 15, 17- and 24-months following resection. 1 patient with appendiceal FDCS was free of disease almost 12 years after surgery but recently developed recurrence and is currently undergoing chemotherapy. 6 patients were alive and well at the time of follow-up 5 to 68 months after resection. None of them had developed recurrence or metastases at the time of follow up. 8 of the 13 patients received chemotherapy and/or radiotherapy post-surgical resection. CONCLUSION: Colon was involved in 9 of our 18 cases. Lymph nodes were positive for metastases in 4 out of 9 resection specimens. All cases were diagnosed based on morphology supported by positivity for immunohistochemical stains CD21 and CD23. Histological factors associated with aggressive behavior were seen in 14 cases. Majority of patients had an aggressive clinical course.

Filling the Antibody Pipeline in Allergy: PIPE Cloning of IgE, IgG1 and IgG4 against the Major Birch Pollen Allergen Bet v 1.

Birch pollen allergy is among the most prevalent pollen allergies in Northern and Central Europe. This IgE-mediated disease can be treated with allergen immunotherapy (AIT), which typically gives rise to IgG antibodies inducing tolerance. Although the main mechanisms of allergen immunotherapy (AIT) are known, questions regarding possible Fc-mediated effects of IgG antibodies remain unanswered. This can mainly be attributed to the unavailability of appropriate tools, i.e., well-characterised recombinant antibodies (rAbs). We hereby aimed at providing human rAbs of several classes for mechanistic studies and as possible candidates for passive immunotherapy. We engineered IgE, IgG1, and IgG4 sharing the same variable region against the major birch pollen allergen Bet v 1 using Polymerase Incomplete Primer Extension (PIPE) cloning. We tested IgE functionality and IgG blocking capabilities using appropriate model cell lines. In vitro studies showed IgE engagement with FcεRI and CD23 and Bet v 1-dependent degranulation. Overall, we hereby present fully functional, human IgE, IgG1, and IgG4 sharing the same variable region against Bet v 1 and showcase possible applications in first mechanistic studies. Furthermore, our IgG antibodies might be useful candidates for passive immunotherapy of birch pollen allergy.

Endometriosis-associated pain scores and biomarkers in users of the etonogestrel-releasing subdermal implant or the 52-mg levonorgestrel-releasing intrauterine system for up to 24 months.

Objectives: The aims of the study were to correlate endometriosis-associated pain, evaluated by visual analogue scale (VAS) scores, with serum levels of etonogestrel (ENG), levonorgestrel (LNG), CA-125 and soluble CD23 in users of the ENG implant or the 52-mg LNG-releasing intrauterine system (52 mg LNG-IUS) for up to 2 years after device placement.Methods: A randomised trial was conducted at the University of Campinas Medical School, Brazil. All participants (n = 103) had had endometriosis-associated chronic pelvic pain or dysmenorrhoea, or both, for more than 6 months. Participants were randomly assigned to use an ENG implant (experimental treatment) or a 52-mg LNG-IUS (active comparator). Follow-up was conducted 6 monthly for up to 24 months after device placement. Dysmenorrhoea and chronic pelvic pain were evaluated using a VAS and the scores were correlated with serum levels of ENG, LNG, CA-125 and soluble CD23.Results: Both progestin-only contraceptives significantly reduced VAS scores for dysmenorrhoea and chronic pelvic pain and reduced serum levels of soluble CD23 (p < 0.001). Serum levels of CA-125 decreased only in the ENG implant group after 24 months' use of the device (p < 0.001). No correlation was found between pain scores and ENG or LNG serum levels over time (p > 0.005).Conclusion: Both contraceptives improved dysmenorrhoea and chronic pelvic pain scores in women with endometriosis-associated pain and they reduced serum levels of soluble CD23; however, serum levels of CA-125 were reduced only in ENG implant users over the 24-month study period.

Metalloprotease inhibitor profiles of human ADAM8 in vitro and in cell-based assays.

ADAM8 as a membrane-anchored metalloproteinase-disintegrin is upregulated under pathological conditions such as inflammation and cancer. As active sheddase, ADAM8 can cleave several membrane proteins, among them the low-affinity receptor FcεRII CD23. Hydroxamate-based inhibitors are routinely used to define relevant proteinases involved in ectodomain shedding of membrane proteins. However, for ADAM proteinases, common hydroxamates have variable profiles in their inhibition properties, commonly known for ADAM proteinases 9, 10 and 17. Here, we determined the inhibitor profile of human ADAM8 for eight ADAM/MMP inhibitors by in vitro assays using recombinant ADAM8 as well as the in vivo inhibition in cell-based assays using HEK293 cells to monitor the release of soluble CD23 by ADAM8. ADAM8 activity is inhibited by BB94 (Batimastat), GW280264, FC387 and FC143 (two ADAM17 inhibitors), made weaker by GM6001, TAPI2 and BB2516 (Marimastat), while no inhibition was observed for GI254023, an ADAM10 specific inhibitor. Modeling of inhibitor FC143 bound to the catalytic sites of ADAM8 and ADAM17 reveals similar geometries in the pharmacophoric regions of both proteinases, which is different in ADAM10 due to replacement in the S1 position of T300 (ADAM8) and T347 (ADAM17) by V327 (ADAM10). We conclude that ADAM8 inhibitors require maximum selectivity over ADAM17 to achieve specific ADAM8 inhibition.