Chronic inflammatory diseases like psoriasis, Crohn's disease (CD), multiple sclerosis (MS), rheumatoid arthritis (RA), and others are increasingly recognized as disease entities, where dysregulated ...cytokines contribute substantially to tissue-specific inflammation. A dysregulation in the IL-23/IL-17 axis can lead to inflammation of barrier tissues, whereas its role in internal organ inflammation remains less clear. Here we discuss the most recent developments in targeting IL-17 for the treatment of chronic inflammation in preclinical models and in patients afflicted with chronic inflammatory diseases.
Brain malignancies can either originate from within the CNS (gliomas) or invade from other locations in the body (metastases). A highly immunosuppressive tumor microenvironment (TME) influences brain ...tumor outgrowth. Whether the TME is predominantly shaped by the CNS micromilieu or by the malignancy itself is unknown, as is the diversity, origin, and function of CNS tumor-associated macrophages (TAMs). Here, we have mapped the leukocyte landscape of brain tumors using high-dimensional single-cell profiling (CyTOF). The heterogeneous composition of tissue-resident and invading immune cells within the TME alone permitted a clear distinction between gliomas and brain metastases (BrM). The glioma TME presented predominantly with tissue-resident, reactive microglia, whereas tissue-invading leukocytes accumulated in BrM. Tissue-invading TAMs showed a distinctive signature trajectory, revealing tumor-driven instruction along with contrasting lymphocyte activation and exhaustion. Defining the specific immunological signature of brain tumors can facilitate the rational design of targeted immunotherapy strategies.
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•Leukocyte invasion is higher in brain metastasis than in CNS-endogenous cancers•The tumor type shapes the differentiation of monocyte-derived macrophages•Brain metastases harbor a high frequency of regulatory T cells•Both activation and exhaustion are prevalent in lymphocytes of the metastatic TME
High-parametric single-cell mapping of the tumor microenvironment of patients with primary brain tumors or brain metastases reveals that the immune response to cancer in the brain is shaped by cancer type, with metastases favoring T cell and monocyte-derived macrophage invasion and gliomas characterized by activated microglia.
High‐dimensional single‐cell (HDcyto) technologies, such as mass cytometry (CyTOF) and flow cytometry, are the key techniques that hold a great promise for deciphering complex biological processes. ...During the last decade, we witnessed an exponential increase of novel HDcyto technologies that are able to deliver an in‐depth profiling in different settings, such as various autoimmune diseases and cancer. The concurrent advance of custom data‐mining algorithms has provided a rich substrate for the development of novel tools in translational medicine research. HDcyto technologies have been successfully used to investigate cellular cues driving pathophysiological conditions, and to identify disease‐specific signatures that may serve as diagnostic biomarkers or therapeutic targets. These technologies now also offer the possibility to describe a complete cellular environment, providing unanticipated insights into human biology. In this review, we present an update on the current cutting‐edge HDcyto technologies and their applications, which are going to be fundamental in providing further insights into human immunology and pathophysiology of various diseases. Importantly, we further provide an overview of the main algorithms currently available for data mining, together with the conceptual workflow for high‐dimensional cytometric data handling and analysis. Overall, this review aims to be a handy overview for immunologists on how to design, develop and read HDcyto data.
The technological advancement in high‐dimensional single cell cytometry (HDcyto) has improved our ability to investigate cellular heterogeneity in humans. With adequate automated data mining algorithms and appropriate computational power, HDcyto provides new tools for the identification of stratification biomarkers, fundamental for precision medicine.
Non-canonical NF-κB-pathway signaling is integral in immunoregulation. Heterozygous mutations in
have recently been established as a molecular cause of common variable immunodeficiency (CVID) and ...DAVID-syndrome, a rare condition combining deficiency of anterior pituitary hormone with CVID. Here, we investigate 15 previously unreported patients with primary immunodeficiency (PID) from eleven unrelated families with heterozygous
-mutations including eight patients with the common p.Arg853
nonsense mutation and five patients harboring unique novel C-terminal truncating mutations. In addition, we describe the clinical phenotype of two patients with proximal truncating mutations. Cohort analysis extended to all 35 previously published
-cases revealed occurrence of early-onset PID in 46/50 patients (mean age of onset 5.9 years, median 4.0 years). ACTH-deficiency occurred in 44%. Three mutation carriers have deceased, four developed malignancies. Only two mutation carriers were clinically asymptomatic. In contrast to typical CVID, most patients suffered from early-onset and severe disease manifestations, including clinical signs of T cell dysfunction e.g., chronic-viral or opportunistic infections. In addition, 80% of patients suffered from (predominately T cell mediated) autoimmune (AI) phenomena (alopecia > various lymphocytic organ-infiltration > diarrhea > arthritis > AI-cytopenia). Unlike in other forms of CVID, auto-antibodies or lymphoproliferation were not common hallmarks of disease. Immunophenotyping showed largely normal or even increased quantities of naïve and memory CD4
or CD8
T-cells and normal T-cell proliferation. NK-cell number and function were also normal. In contrast, impaired B-cell differentiation and hypogammaglobinemia were consistent features of
-associated disease. In addition, an array of lymphocyte subpopulations, such as regulatory T cell, Th17-, cTFH-, NKT-, and MAIT-cell numbers were decreased. We conclude that heterozygous damaging mutations in
represent a distinct PID entity exceeding the usual clinical spectrum of CVID. Impairment of the non-canonical NF-κB pathways affects function and differentiation of numerous lymphocyte-subpopulations and thus causes a heterogeneous, more severe form of PID phenotype with early-onset. Further characteristic features are multifaceted, primarily T cell-mediated autoimmunity, such as alopecia, lymphocytic organ infiltration, and in addition frequently ACTH-deficiency.
Microbial invasion into the intestinal mucosa after allogeneic hematopoietic cell transplantation (allo-HCT) triggers neutrophil activation and requires antibiotic interventions to prevent sepsis. ...However, antibiotics lead to a loss of microbiota diversity, which is connected to a higher incidence of acute graft-versus-host disease (aGVHD). Antimicrobial therapies that eliminate invading bacteria and reduce neutrophil-mediated damage without reducing the diversity of the microbiota are therefore highly desirable. A potential solution would be the use of antimicrobial antibodies that target invading pathogens, ultimately leading to their elimination by innate immune cells. In a mouse model of aGVHD, we investigated the potency of active and passive immunization against the conserved microbial surface polysaccharide poly-N-acetylglucosamine (PNAG) that is expressed on numerous pathogens. Treatment with monoclonal or polyclonal antibodies to PNAG (anti-PNAG) or vaccination against PNAG reduced aGVHD-related mortality. Anti-PNAG treatment did not change the intestinal microbial diversity as determined by 16S ribosomal DNA sequencing. Anti-PNAG treatment reduced myeloperoxidase activation and proliferation of neutrophil granulocytes (neutrophils) in the ileum of mice developing GVHD. In vitro, anti-PNAG treatment showed high antimicrobial activity. The functional role of neutrophils was confirmed by using neutrophil-deficient LysMcre Mcl1fl/fl
mice that had no survival advantage under anti-PNAG treatment. In summary, the control of invading bacteria by anti-PNAG treatment could be a novel approach to reduce the uncontrolled neutrophil activation that promotes early GVHD and opens a new avenue to interfere with aGVHD without affecting commensal intestinal microbial diversity.
Common variable immunodeficiency (CVID) represents a large heterogeneous group of antibody deficiency syndromes associated with a plethora of clinical features and as yet largely undefined molecular ...causes. We are now seeing this heterogeneous group being increasingly defined into single‐gene and polygenic disorders after stratification into homogeneous patient subgroups based on improved clinical and immunological criteria, including molecular, functional, immunohistological, and longitudinal and outcome information. In this perspective, we highlight recent developments in CVID, addressing mainly its genetic and immunological dimensions.
Purpose
The aim of this study was to identify characteristics of hypogammaglobulinemia secondary to glucocorticoid therapy and their value in the differential diagnosis to primary forms of antibody ...deficiency.
Methods
We investigated prevalence and character of hypogammaglobulinemia in a cohort of 36 patients with giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) on glucocorticoid therapy in comparison to a gender- and age-matched cohort of hospital controls. We therefore determined serum immunoglobulin levels as well as B- and T cell-subsets in the peripheral blood of all participants. In addition, prior serum immunoglobulin levels and clinical data of the GCA and PMR patients were extracted from the electronic patient data-base.
Results
21/36 GCA/PMR patients on glucocorticoid treatment developed antibody deficiency. In 19 patients this included IgG and in 13 patients IgG was the only affected isotype. The reduction of IgG was persistent in nearly 50 % of these patients during the observed period. GCA/PMR patients had reduced circulating naive and transitional B cells (
p
= 0.0043 and
p
= 0.0002 respectively) while IgM, IgG and IgA memory B cells were preserved. Amongst T-cell subsets, we found a reduction of CD4 memory T cells (
p
< 0.0001), CD4 regulatory T cells (
p
= 0.0002) and few CD8 memory T-cell subtypes.
Conclusion
Persistent humoral immunodeficiency occurs in about a quarter of GCA/PMR patients under glucocorticoid therapy. Because most patients have isolated IgG deficiency, preserved IgA production and class-switched memory B cells, by these markers this form of secondary hypogammaglobulinemia can be clearly distinguished from common variable immunodeficiency (CVID).
Background
About 20% of patients with common variable immunodeficiency (CVID) suffer from interstitial lung disease (ILD) as part of a systemic immune dysregulation. Current understanding suggests a ...role of B cells in the pathogenesis based on histology and increased levels of BAFF and IgM associated with active disease corroborated by several reports which demonstrate the successful use of rituximab in CVID-ILD. It is debated whether histological confirmation by biopsy or even video-assisted thoracoscopy is required and currently not investigated whether less invasive methods like a bronchoalveolar lavage (BAL) might provide an informative diagnostic tool.
Objective
To gain insight into potential immune mechanisms underlying granulomatous and lymphocytic interstitial lung disease (GLILD) and to define biomarkers for progressive ILD by characterizing the phenotype of B- and T-cell populations and cytokine profiles in BAL fluid (BALF) of CVID-ILD compared to sarcoidosis patients and healthy donors (HD).
Methods
Sixty-four CVID, six sarcoidosis, and 25 HD BALF samples were analyzed by flow cytometric profiling of B- and T-cells and for cytokines by ELISA and Multiplexing LASER Bead technology.
Results
Both sarcoidosis and CVID-ILD are characterized by a predominantly T-cell mediated lymphocytosis in the BALF. There is an increase in T follicular helper (T
FH
)-like memory and decrease of regulatory T cells in CVID-ILD BALF. This T
FH
-like cell subset is clearly skewed toward T
H
1 cells in CVID-ILD. In contrast to sarcoidosis, CVID-ILD BALF contains a higher percentage of B cells comprising mostly CD21
low
B cells, but less class-switched memory B cells. BALF analysis showed increased levels of APRIL, CXCL10, and IL-17.
Conclusion
Unlike in sarcoidosis, B cells are expanded in BALF of CVID-ILD patients. This is associated with an expansion of T
FH
- and T
PH
-like cells and an increase in APRIL potentially supporting B-cell survival and differentiation and proinflammatory cytokines reflecting not only the previously described T
H
1 profile seen in CVID patients with secondary immune dysregulation. Thus, the analysis of BALF might be of diagnostic value not only in the diagnosis of CVID-ILD, but also in the evaluation of the activity of the disease and in determining potential treatment targets confirming the prominent role of B-cell targeted strategies.
Abstract Background In a substantial number of patients with non-cystic fibrosis (CF) bronchiectasis an etiology cannot be found. Various complex immunodeficiency syndromes account for a significant ...portion of these patients but the mechanism elucidating the predisposition for suppurative lung disease often remains unknown. Objective To investigate the cause and mechanism predisposing a patient to severe bronchiectasis. Methods A patient presenting with severe non-CF bronchiectasis was investigated. Whole exome analysis (WES) was performed and complemented by extensive immunophenotyping. Results The genetic analysis revealed an autosomal dominant gain-of-function mutation (AD- GOF) in the signal transducer and activator of transcription 1 (STAT1) in the patient. STAT1 phosphorylation studies showed increased phosphorylation of STAT1 after stimulation with interferon γ (IFN-γ). Immunophenotyping showed normal counts of CD4 and CD8 T cells, B and NK cells, but a reduction of all memory B cells especially class switched memory B cells. Minor changes in the CD8 T cell subpopulations were seen. Conclusions Early use of WES in the investigation of non-CF bronchiectasis was highly advantageous. The degree of impairment in class-switched memory B cells may predispose patients with AD- GOF mutations in STAT1 to suppurative sinopulmonary disease.
The maintenance of B cell homeostasis requires a tight control of B cell generation, survival, activation, and maturation. In lymphocytes upon activation, increased sensitivity to apoptotic signals ...helps controlling differentiation and proliferation. The death receptor Fas is important in this context because genetic
mutations in humans lead to an autoimmune lymphoproliferative syndrome that is similar to lymphoproliferation observed in Fas-deficient mice. In contrast, the physiological role of TNF-related apoptosis-inducing ligand receptors (TRAIL-Rs) in humans has been poorly studied so far. Indeed, most studies have focused on tumor cell lines and on mouse models whose results are difficult to transpose to primary human B cells. In the present work, the expression of apoptosis-inducing TRAIL-R1 and TRAIL-R2 and of the decoy receptors TRAIL-R3 and TRAIL-R4 was systematically studied in all developmental stages of peripheral B cells isolated from the blood and secondary lymphoid organs. Expression of TRAIL-Rs is modulated along development, with highest levels observed in germinal center B cells. In addition, T-dependent and T-independent signals elicited induction of TRAIL-Rs with distinct kinetics, which differed among B cell subpopulations: switched memory cells rapidly upregulated TRAIL-R1 and -2 upon activation while naïve B cells only reached similar expression levels at later time points in culture. Increased expression of TRAIL-R1 and -2 coincided with a caspase-3-dependent sensitivity to TRAIL-induced apoptosis in activated B cells but not in freshly isolated resting B cells. Finally, both TRAIL-R1 and TRAIL-R2 could signal actively and both contributed to TRAIL-induced apoptosis. In conclusion, this study provides a systematic analysis of the expression of TRAIL-Rs in human primary B cells and of their capacity to signal and induce apoptosis. This dataset forms a basis to further study and understand the dysregulation of TRAIL-Rs and TRAIL expression observed in autoimmune diseases. Additionally, it will be important to foresee potential bystander immunomodulation when TRAIL-R agonists are used in cancer treatment.
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