Heterogeneity of human effector CD4+ T cells

Role of autoreactive Tc17 cells in the pathogenesis of experimental autoimmune encephalomyelitis

Background

The pathogenesis of multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE—an animal model of MS) is primarily mediated by T cells. However, recent studies have only focused on interleukin (IL)‐17‐secreting CD4+ T‐helper cells, also known as Th17 cells. This study aimed to compare Th17 cells and IL‐17‐secreting CD8+ T‐cytotoxic cells (Tc17) in the context of MS/EAE.

Methods

Female C57BL/6 mice were immunized with myelin oligodendrocyte glycoprotein peptides 35–55 (MOG35–55), pertussis toxin, and complete Freund's adjuvant to establish the EAE animal model. T cells were isolated from the spleen (12–14 days postimmunization). CD4+ and CD8+ T cells were purified using isolation kit and then differentiated into Th17 and Tc17, respectively, using MOG35–55 and IL‐23. The secretion levels of interferon‐γ (IFN‐γ) and IL‐17 were measured via enzyme‐linked immunosorbent assay using cultured CD4+ and CD8+ T cell supernatants. The pathogenicity of Tc17 and Th17 cells was assessed through adoptive transfer (tEAE), with the clinical course assessed using an EAE score (0–5). Hematoxylin and eosin as well as Luxol fast blue staining were used to examine the spinal cord. Purified CD8+ CD3+ and CD4+ CD3+ cells differentiated into Tc17 and Th17 cells, respectively, were stimulated with MOG35–55 peptide for proliferation assays.

Results

The results showed that Tc17 cells (15,951 ± 1985 vs. 55,709 ± 4196 cpm; p < 0.050) exhibited a weaker response to highest dose (20 μg/mL) MOG35–55 than Th17 cells. However, this response was not dependent on Th17 cells. After the 48 h stimulation, at the highest dose (20 μg/mL) of MOG35–55. Tc17 cells secreted lower levels of IFN‐γ (280.00 ± 15.00 vs. 556.67 ± 15.28 pg/mL, p < 0.050) and IL‐17 (102.67 ± 5.86 pg/mL vs. 288.33 ± 12.58 pg/mL; p < 0.050) than Th17 cells. Similar patterns were observed for IFN‐γ secretion at 96 and 144 h. Furthermore, Tc17 cell‐induced tEAE mice exhibited similar EAE scores to Th17 cell‐induced tEAE mice and also showed similar inflammation and demyelination.

Conclusion

The degree of pathogenicity of Tc17 cells in EAE is lower than that of Th17 cells. Future investigation on different immune cells and EAE models is warranted to determine the mechanisms underlying MS.

Neointimal myofibroblasts contribute to maintaining Th1/Tc1 and Th17/Tc17 inflammation in giant cell arteritis

Vascular smooth muscle cells (VSMCs) have been shown to play a role in the pathogenesis of giant cell arteritis (GCA) through their capacity to produce chemokines recruiting T cells and monocytes in the arterial wall and their ability to migrate and proliferate in the neointima where they acquire a myofibroblast (MF) phenotype, leading to vascular stenosis. This study aimed to investigate if MFs could also impact T-cell polarization. Confocal microscopy was used to analyze fresh fragments of temporal artery biopsies (TABs). Healthy TAB sections were cultured to obtain MFs, which were then treated or not with interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) and analyzed by immunofluorescence and RT-PCR. After peripheral blood mononuclear cells and MFs were co-cultured for seven days, T-cell polarization was analyzed by flow cytometry. In the neointima of GCA arteries, we observed a phenotypic heterogeneity among VSMCs that was consistent with a MF phenotype (α-SMA+CD90+desmin+MYH11+) with a high level of STAT1 phosphorylation. Co-culture experiments showed that MFs sustain Th1/Tc1 and Th17/Tc17 polarizations. The increased Th1 and Tc1 polarization was further enhanced following the stimulation of MFs with IFN-γ and TNF-α, which induced STAT1 phosphorylation in MFs. These findings correlated with increases in the production of IL-1β, IL-6, IL-12 and IL-23 by MFs. Our study showed that MFs play an additional role in the pathogenesis of GCA through their ability to maintain Th17/Tc17 and Th1/Tc1 polarizations, the latter being further enhanced in case of stimulation of MF with IFN-γ and TNF-α.

Crosstalk: keratinocytes and immune cells in psoriasis

In the past, psoriasis was considered a skin disease caused only by keratinocyte disorders. However, the efficacy of immunosuppressive drugs and biologics used to treat psoriasis proves that psoriasis is an immune-mediated disease. Indeed, a variety of immune cells are involved in the pathogenesis of psoriasis, including dendritic cells, Th17 cells, and resident memory T cells. Furthermore, keratinocytes play a role in the development of psoriasis as immune cells by secreting antibacterial peptides, chemokines, tumor necrosis factor-α, interleukin (IL)-36, and IL-23. These immune cells and skin cells interact and drive the aberrant differentiation and proliferation of keratinocytes. This crosstalk between keratinocytes and immune cells critical in the pathogenesis of psoriasis forms an inflammatory loop, resulting in the persistence or exacerbation of psoriasis plaques.

CD4-1 and CD4-2 single positive are two major CD4 lymphocyte subpopulations in ginbuna crucian carp Carassius auratus langsdorfii

In this study, we established a murine cell line that expresses ginbuna crucian carp (ginbuna) CD4-2 and used it to develop an anti-CD4-2 monoclonal antibody (mAb). An established mAb, named D5, showed good reactivities to BALB/3T3 cells expressing CD4-2 and a lymphocyte population in the ginbuna leukocytes. Gene expression analysis showed that D5⁺ cells express CD4-2 and TCRβ genes but not CD4-1 and IgM genes, meanwhile May Grunwald-Giemsa staining of sorted D5⁺ cells had the typical morphology of lymphocytes. Two-color immunofluorescence analysis with anti-CD4-1 mAb (6D1) and anti-CD4-2 mAb (D5) by flow cytometry revealed that the percentages of CD4-1 single positive (SP) and CD4-2 SP lymphocytes were comparatively higher than CD4-1/CD4-2 double positive (CD4 DP) lymphocytes in all tissues examined in ginbuna. The highest percentages of CD4-2 SP cells (∼40%) were found in the thymus, while the head-kidney exhibited the highest percentages of CD4-1 SP (∼30%) and CD4 DP (∼5%) cells. These findings indicated that ginbuna CD4⁺ lymphocyte population consists of two major subpopulations (CD4-1 SP and CD4-2 SP) and a minor subset (CD4 DP).

FAM171B as a Novel Biomarker Mediates Tissue Immune Microenvironment in Pulmonary Arterial Hypertension

The purpose of this study was to uncover potential diagnostic indicators of pulmonary arterial hypertension (PAH), evaluate the function of immune cells in the pathogenesis of the disease, and find innovative treatment targets and medicines with the potential to enhance prognosis. Gene Expression Omnibus was utilized to acquire the PAH datasets. We recognized differentially expressed genes (DEGs) and investigated their functions utilizing R software. Weighted gene coexpression network analysis, least absolute shrinkage and selection operators, and support vector machines were used to identify biomarkers. The extent of immune cell infiltration in the normal and PAH tissues was determined using CIBERSORT. Additionally, the association between diagnostic markers and immune cells was analyzed. In this study, 258DEGs were used to analyze the disease ontology. Most DEGs were linked with atherosclerosis, arteriosclerotic cardiovascular disease, and lung disease, including obstructive lung disease. Gene set enrichment analysis revealed that compared to normal samples, results from PAH patients were mostly associated with ECM-receptor interaction, arrhythmogenic right ventricular cardiomyopathy, the Wnt signaling pathway, and focal adhesion. FAM171B was identified as a biomarker for PAH (area under the curve = 0.873). The mechanism underlying PAH may be mediated by nave CD4 T cells, resting memory CD4 T cells, resting NK cells, monocytes, activated dendritic cells, resting mast cells, and neutrophils, according to an investigation of immune cell infiltration. FAM171B expression was also associated with resting mast cells, monocytes, and CD8 T cells. The results suggest that PAH may be closely related to FAM171B with high diagnostic performance and associated with immune cell infiltration, suggesting that FAM171B may promote the progression of PAH by stimulating immune infiltration and immune response. This study provides valuable insights into the pathogenesis and treatment of PAH.

Dokumentation von Biologika-Therapien bei chronischer Rhinosinusitis mit Polyposis nasi (CRSwNP): Dupilumab, Omalizumab und Mepolizumab

Hintergrund: Die chronische Rhinosinusitis mit Nasenpolypen (CRSwNP) ist eine multifaktorielle entzündliche Erkrankung der paranasalen Schleimhäute, der als Endotyp meistens eine Typ-2-Inflammation zugrunde liegt. Mittlerweile sind drei Antikörper (Dupilumab, Omalizumab und Mepolizumab) für die Therapie der schweren CRSwNP zugelassen. Eine Dokumentation der Erkrankungsschwere im Behandlungsverlauf ist unverzichtbar.

Methoden: In einer Literaturrecherche in Medline, Pubmed sowie den nationalen und internationalen Studien- und Leitlinienregistern und der Cochrane Library wurde die Immunologie der CRSwNP analysiert und die Evidenz zur Wirkung von Dupilumab, Omalizumab und Mepolizumab bei dieser Erkrankung ermittelt. Hieraus wurden drei Positionspapiere durch unsere Autorengruppe erstellt, die Grundlage dieser zusammenfassenden Übersichtsarbeit sind.

Ergebnisse: Basierend auf den Angaben aus der internationalen Literatur werden von einem Expertengremium Empfehlungen für die Anwendung von Dupilumab, Omalizumab und Mepolizumab bei CRSwNP im deutschen Gesundheitssystem gegeben.

Schlussfolgerung: Dupilumab, Omalizumab und Mepolizumab sind zugelassen für Patienten ab 18 Jahren mit schwerer CRSwNP als Zusatztherapie zu intranasalen Glukokortikosteroiden (INCS), wenn, bei Dupilumab und Mepolizumab, durch eine Therapie mit systemischen Glukokortikosteroiden und/oder chirurgischem Eingriff keine ausreichende Krankheitskontrolle erzielt werden kann. Eine Therapie mit Omalizumab ist angezeigt, wenn eine Therapie mit INCS keine suffiziente Kontrolle der Erkrankung ergibt. Es werden dezidierte Empfehlungen zur Dokumentation der Anwendung im Deutschen Gesundheitssystem gegeben, die auf den hierzu bereits publizierten Positionspapieren unserer Autorengruppe basieren.

Zitierweise: Klimek L, Förster-Ruhrmann U, Beule AG, Chaker AM, Hagemann J, Klimek F, Casper I, Huppertz T, Hoffmann TK, Dazert S, Deitmer T, Olze H, Strieth S, Wrede H, Schlenter W, Welkoborsky H-J, Wollenberg B, Bergmann C, Cuevas M, Beutner C, Gröger M, Becker S. Indicating biologics for chronic rhinosinusitis with nasal polyps (CRSwNP): Recommendations by German Allergy and ORL-societies AeDA and DGHNO for Dupilumab, Omalizumab and Mepolizumab. Allergo J Int 2022;31:149-60

https://doi.org/10.1007/s40629-022-00220-x

Gearing up for battle: Harnessing adaptive T cell immunity against gram-negative pneumonia

Pneumonia is one of the leading causes of morbidity and mortality worldwide and Gram-negative bacteria are a major cause of severe pneumonia. Despite advances in diagnosis and treatment, the rise of multidrug-resistant organisms and hypervirulent strains demonstrates that there will continue to be challenges with traditional treatment strategies using antibiotics. Hence, an alternative approach is to focus on the disease tolerance components that mediate immune resistance and enhance tissue resilience. Adaptive immunity plays a pivotal role in modulating these processes, thus affecting the incidence and severity of pneumonia. In this review, we focus on the adaptive T cell responses to pneumonia induced by Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. We highlight key factors in these responses that have potential for therapeutic targeting, as well as the gaps in current knowledge to be focused on in future work.

Expansion of CD3+CD8+PD1+ T lymphocytes and TCR repertoire diversity predict clinical responses to adoptive cell therapy in advanced gastric cancer

The adoptive cell therapy (ACT) and delivery of ex vivo activated cellular products, such as dendritic cells (DCs), NK cells, and T cells, have shown promise for the treatment of gastric cancer (GC). However, it is unknown which cells can improve patient survival. This study was focused on the antitumour activity of a subset of these cellular products and their relationships with clinical outcomes. Nineteen patients were enrolled at the Capital Medical University Cancer Center, Beijing Shijitan Hospital, from June 1, 2013, to May 30, 2016. CD8⁺PD1⁺ T-cell sorting was carried out using flow cytometry, and the T-cell receptor (TCR) repertoire during ex vivo expansion for 15 days was analyzed by next-generation sequencing. After 15 days of culture, the number of CD8⁺ T cells had increased significantly, and the number of CD4⁺ T cells had increased correspondingly. After ex vivo expansion, CD8⁺ T cells exhibited significantly enhanced expression of PD-1, LAG-3, and TIM-3 but not 4-1BB. Survival analysis showed that patients with a pro/pre value of CD8⁺PD-1⁺ T cells >2.4 had significantly favorable overall survival (OS) (median OS time, 248 days versus 96 days, P=0.02) and progression-free survival (PFS) (median PFS time, 183 days vs. 77 days, P=0.002). The sorted CD8⁺PD-1⁺ T cells displayed enhanced antitumor activity and increased IFN-γ secretion after coculture with autologous tumor cell lines. TCR repertoire diversity was decreased after ex vivo expansion, which decreased the Shannon index and increased the clonality value. The prognosis of patients was significantly improved and was associated with the extent of CD8⁺PD-1⁺ T-cell expansion. In summary, this study showed that after ex vivo expansion for 15 days, CD8⁺PD-1⁺ T cells could be identified as tumor-reactive cells in patients treated for GC. Changing TCR species can predict the extent of CD3⁺CD8⁺PD1⁺ T-cell growth and the effect of ACT treatment.

A high-dimensional cytometry atlas of peripheral blood over the human life span

Age can profoundly affect susceptibility to a broad range of human diseases. Children are more susceptible to some infectious diseases such as diphtheria and pertussis, while in others, such as coronavirus disease 2019 and hepatitis A, they are more protected compared with adults. One explanation is that the composition of the immune system is a major contributing factor to disease susceptibility and severity. While most studies of the human immune system have focused on adults, how the immune system changes after birth remains poorly understood. Here, using high-dimensional spectral flow cytometry and computational methods for data integration, we analyzed more than 50 populations of immune cells in the peripheral blood, generating an immune cell atlas that defines the healthy human immune system from birth up to 75 years of age. We focused our efforts on children under 18 years old, revealing major changes in immune cell populations after birth and in children of schooling age. Specifically, CD4⁺ T effector memory cells, Vδ2⁺ gamma delta (γδ)T cells, memory B cells, plasmablasts, CD11c⁺ B cells and CD16⁺ CD56^bright natural killer (NK) cells peaked in children aged 5-9 years old, whereas frequencies of T helper 1, T helper 17, dendritic cells and CD16⁺ CD57⁺ CD56^dim NK cells were highest in older children (10-18 years old). The frequency of mucosal-associated invariant T cells was low in the first several years of life and highest in adults between 19 and 30 years old. Late adulthood was associated with fewer mucosal-associated invariant T cells and Vδ2⁺ γδ T cells but with increased frequencies of memory subsets of B cells, CD4⁺ and CD8⁺ T cells and CD57⁺ NK cells. This human immune cell atlas provides a critical resource to understand changes to the immune system during life and provides a reference for investigating the immune system in the context of human disease. This work may also help guide future therapies that target specific populations of immune cells to protect at-risk populations.

Positionspapier: Empfehlungen zur Anwendung von Omalizumab bei chronischer Rhinosinusitis mit Polyposis nasi (CRSwNP) im deutschen Gesundheitssystem – Empfehlungen des Ärzteverbandes Deutscher Allergologen (AeDA) und der AGs Klinische Immunologie, Allergologie und Umweltmedizin und Rhinologie und Rhinochirurgie der Deutschen Gesellschaft für HNO-Heilkunde, Kopf- und Halschirurgie (DGHNOKHC)

Hintergrund Die chronische Rhinosinusitis mit Nasenpolypen (CRSwNP) ist eine multifaktorielle entzündliche Erkrankung der paranasalen Schleimhäute, der als Endotyp meistens eine TH2-Inflammation zugrunde liegt. IgE-Antikörper spielen dabei eine wichtige Rolle. Der anti-IgE-Antikörper Omalizumab wurde im August 2020 für die Therapie der schweren CRSwNP zugelassen.

Methoden In einer Literatursuche wurde die Immunologie der CRSwNP analysiert und die Evidenz zur Wirkung von Omalizumab bei dieser Erkrankung ermittelt durch Recherchen in Medline, Pubmed sowie den nationalen und internationalen Studien- und Leitlinien-Registern und der Cochrane Library.

Ergebnisse Basierend auf diesen Angaben aus der internationalen Literatur werden von einem Expertengremium Empfehlungen für die Anwendung von Omalizumab bei CRSwNP im deutschen Gesundheitssystem gegeben.

Schlussfolgerung Omalizumab ist zugelassen für Patienten ab 18 Jahren mit schwerer chronischer Rhinosinusitis mit Nasenpolypen als Zusatztherapie zu intranasalen Kortikosteroiden (INCS), wenn durch eine Therapie mit INCS keine ausreichende Krankheitskontrolle erzielt werden kann.

Role of the Immune System Elements in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a relatively rare disease, but, today, its incidence tends to increase. The severe course of the disease and poor patient survival rate make PAH a major diagnostic and therapeutic challenge. For this reason, a thorough understanding of the pathogenesis of the disease is essential to facilitate the development of more effective therapeutic targets. Research shows that the development of PAH is characterized by a number of abnormalities within the immune system that greatly affect the progression of the disease. In this review, we present key data on the regulated function of immune cells, released cytokines and immunoregulatory molecules in the development of PAH, to help improve diagnosis and targeted immunotherapy.

In Situ Characterization of Human Lymphoid Tissue Immune Cells by Multispectral Confocal Imaging and Quantitative Image Analysis; Implications for HIV Reservoir Characterization

CD4 T cells are key mediators of adaptive immune responses during infection and vaccination. Within secondary lymphoid organs, helper CD4 T cells, particularly those residing in germinal centers known as follicular helper T cells (Tfh), provide critical help to B-cells to promote their survival, isotype switching and selection of high affinity memory B-cells. On the other hand, the important role of Tfh cells for the maintenance of HIV reservoir is well documented. Thus, interrogating and better understanding the tissue specific micro-environment and immune subsets that contribute to optimal Tfh cell differentiation and function is important for designing successful prevention and cure strategies. Here, we describe the development and optimization of eight multispectral confocal microscopy immunofluorescence panels designed for in depth characterization and immune-profiling of relevant immune cells in formalin-fixed paraffin-embedded human lymphoid tissue samples. We provide a comprehensive library of antibodies to use for the characterization of CD4+ T-cells -including Tfh and regulatory T-cells- as well as CD8 T-cells, B-cells, macrophages and dendritic cells and discuss how the resulting multispectral confocal datasets can be quantitatively dissected using the HistoCytometry pipeline to collect information about relative frequencies and immune cell spatial distributions. Cells harboring actively transcribed virus are analyzed using an in-situ hybridization assay for the characterization of HIV mRNA positive cells in combination with additional protein markers (multispectral RNAscope). The application of this methodology to lymphoid tissues offers a means to interrogate multiple relevant immune cell targets simultaneously at increased resolution in a reproducible manner to guide CD4 T-cell studies in infection and vaccination.

Cow's milk allergy in infancy and later development of type 1 diabetes-nationwide case-cohort study

BAKGROUND

It is suggested that early intake of cow's milk could be a risk factor for type 1 diabetes (T1DM). Further, the different immunological background, gives a suggestion of an inverse relationship for the occurrence of these diseases. The aim of this study was to explore the association between cow's milk allergy (CMA) and the risk of T1DM in a register-based case-cohort study.

METHODS

Data were obtained from Finnish nationwide health registers. The study included all children born in Finland between January 01, 1986 and December 31, 2008 and diagnosed with T1DM before the age of 16 years (n = 7754). A 10% random sample from each birth year cohort was selected as a reference cohort (n = 137,798). T1DM, CMA, and asthma were defined based on valid special reimbursements for the costs of drugs/special formulas needed in the treatment of the diseases. Child's sex, birth decade, asthma, maternal diabetes and asthma, smoking during pregnancy, and previous deliveries were considered as confounding factors. Time-dependent, weighted Cox regression was applied for statistical analyses.

RESULTS

Children with CMA had an increased risk of developing T1DM in fully adjusted model (HR = 1.17; 95% CI 1.02-1.34), but the association was no longer observed when including the use of special infant formulas in the definition of CMA in the sensitivity analysis (HR = 1.11; 95% CI 0.92-1.32). CMA was associated with an increased risk of T1DM in children without asthma (HR = 1.27; 95%CI 1.10-1.47), but not in children with asthma (HR = 0.80; 95% CI 0.92-1.27).

CONCLUSION

Children with CMA may have an increased risk of T1DM.

Interleukin 21 impairs tumor immunosurveillance of colitis-associated colorectal cancer

The pathogenesis of colitis-associated colorectal cancer is strongly influenced by immune cells, cytokines and other immune mediators present in the inflamed colon. Current research has emerged that T helper cell associated cytokines play a prominent role in tumor growth. In our recent manuscript we have revealed that the Th17 associated cytokine IL-21 prominently influences tumor development and immunosurveillance of colitis-associated colorectal cancer.

Th22 response induced by Mycobacterium tuberculosis strains is closely related to severity of pulmonary lesions and bacillary load in patients with multi-drug-resistant tuberculosis

The role of interleukin-22 (IL-22) in the pathogenesis or tissue repair in human tuberculosis (TB) remains to be established. Here, we aimed to explore the ex-vivo and in-vitro T helper 22 (Th22) response in TB patients and healthy donors (HD) induced by different local multi-drug-resistant (MDR) Mvcobacterium tuberculosis (Mtb) strains. For this purpose, peripheral blood mononuclear cells from drug-susceptible (S-TB) MDR-TB patients and HD were stimulated with local MDR strains and the laboratory strain H37Rv. IL-22 and IL-17 expression and senescent status were assessed in CD4+ and CD8+ cells by flow cytometry, while IL-22 amount was measured in plasma and culture supernatants by enzyme-linked immunosorbent assay (ELISA). We found lower IL-22 amounts in plasma from TB patients than HD, together with a decrease in the number of circulating T cells expressing IL-22. In a similar manner, all Mtb strains enhanced IL-22 secretion and expanded IL-22+ cells within CD4+ and CD8+ subsets, being the highest levels detected in S-TB patients. In MDR-TB, low systemic and Mtb-induced Th22 responses associated with high sputum bacillary load and bilateralism of lung lesions, suggesting that Th22 response could be influencing the ability of MDR-TB patients to control bacillary growth and tissue damage. In addition, in MDR-TB patients we observed that the higher the percentage of IL-22+ cells, the lower the proportion of programmed cell death 1 (PD-1)+ or CD57+ T cells. Furthermore, the highest proportion of senescent T cells was associated with severe lung lesions and bacillary load. Thus, T cell senescence would markedly influence Th22 response mounted by MDR-TB patients.

Immunotoxicology of cadmium: Cells of the immune system as targets and effectors of cadmium toxicity

Cadmium (Cd) has been listed as one of the most toxic substances affecting numerous tissues/organs, including the immune system. Due to variations in studies examining Cd effects on the immune system (exposure regime, experimental systems, immune endpoint measured), data on Cd immunotoxicity in humans and experimental animals are inconsistent. However, it is clear that Cd can affect cells of the immune system and can modulate some immune responses. Due to the complex nature of the immune system and its activities which are determined by multiple interactions, the underlying mechanisms involved in the immunotoxicity of this metal are still vague. Here, the current knowledge regarding the interaction of Cd with cells of the immune system, which may affect immune responses as well as potential mechanisms of consequent biological effects of such activities, is reviewed. Tissue injury caused by Cd-induced effects on innate cell activities depicts components of the immune system as mediators/effectors of Cd tissue toxicity. Cd-induced immune alterations, which may compromise host defense against pathogenic microorganisms and homeostatic reparative activities, stress this metal as an important health hazard.

Low-dose influenza vaccine Grippol Quadrivalent with adjuvant Polyoxidonium induces a T helper-2 mediated humoral immune response and increases NK cell activity

The influenza vaccine Grippol® Quadrivalent (GQ) is a new vaccine, containing the adjuvant Polyoxidonium® and recombinant hemagglutinins from 4 strains of the influenza virus in amount of 5-6 μg of each hemagglutinin per human dose. These doses of antigens are about 3 times less than the standard dose recommended by WHO. We sought to characterize the immune response to the GQ vaccine and to determine the contribution of the adjuvant in this response. BALB/c mice were vaccinated with GQ or with adjuvant-free antigen mixtures (AGs). Then, the antibody response, the number of memory T cells in the spleen, and the functional properties of splenocytes were determined. The vaccine GQ has been shown to induce antibodies to all 4 influenza hemagglutinins. The vaccination with GQ caused a strong increase in the AG-induced proliferation and production of Th2 cytokines ex vivo. These effects were equal to effect achieved by standard dose of antigens. Vaccination also caused the accumulation of CD4⁺ large lymphocytes with the phenotype of central and effector memory T cells in the spleen. The GQ vaccine enhanced the cytolytic activity of natural killer (NK) cells, whereas the adjuvant-free mixture of AGs in lowered and standard doses did not affect NK activity. We did not find a noticeable response of Th1 and CD8⁺ T cells to vaccination. In vitro, the GQ vaccine stimulated the maturation of human monocyte-derived dendritic cells (DCs) enhancing the expression of HLA-DR, CD80, CD83, CD86 and ICOSL molecules. Polyoxidonium without AGs also induced expression of ICOSL, which plays an important role in T-dependent humoral immune response. In summary, the low-dose influenza vaccine GQ with Polyoxidonium adjuvant is immunogenic, induces a Th2-polarized T-cell response and CD4⁺ memory T cells maturation, activates the production of antibodies to influenza hemagglutinins, and increases the activity of NK cells.

[Immunodeficiency in chronic rhinosinusitis : An important and often underestimated cause]

BACKGROUND

Chronic rhinosinusitis (CRS) is one of the most frequent chronic diseases. Among these patients the prevalence of immune defects is higher than in the healthy general population.

METHODS

A selective review of the literature was carried out in PubMed and Medline covering the period between 2008 and 2019. Additionally, recent German publications in journals not listed in the abovementioned databases were analyzed.

RESULTS

The diagnostic workflow with respect to the immunodeficiency consists of a detailed anamnesis and physical examination, laboratory tests and the antibody reaction to polysaccharide vaccines and antigens. Beside antibiotic treatment, vaccinations and immunoglobulin replacement are available. Notwithstanding the above, functional endoscopic surgery of the paranasal sinuses should be performed according to guideline recommendations.

CONCLUSION

Patients with CRS who do not sufficiently respond to conservative and surgical treatment should be checked for underlying immunodeficiencies.

[Treatment of giant cell arteritis]

Glucocorticoids (GC) remain the gold standard of the treatment of giant cell arteritis provided objectives of GC-tapering are accurately followed: 15 to 20mg/day at 3 months, 10mg/day at 6 months, 5mg/day at 9-12 months and withdrawal between 12 and 18 months. In case of corticodependance at ≥7.5 mg/day of prednisone or intolerance to GC, a GCsparing therapy has to be introduced, mainly methotrexate or tocilizumab. Individual characteristics of each patient, data about the efficacy of the treatment, its cost and how easy the follow-up under this treatment is are important factors to consider for choosing the right GC-sparing therapy. For all these reasons, except particular situations, we prefer using methotrexate before tocilizumab. Prevention of cardiovascular events is an important aspect of the treatment of GCA. We recommend using aspirin (75-100mg/day) during the first month of treatment or longer in case of occurrence of an ischemic complication. Each patient treated for GCA should receive a prevention of osteoporosis with respect of usual recommendations.

[Immunology of chronic rhinosinusitis with nasal polyps as a basis for treatment with biologicals]

BACKGROUND

Chronic rhinosinusitis (CRS) is a heterogeneous and multifactorial inflammation of the nasal and paranasal mucosa. Until now, no internationally standardized classification could be developed. In most cases, CRS is phenotypically classified according to chronic rhinosinusitis with (CRScNP) and without nasal polyps (CRSsNP). However, recent studies could show that there are numerous endotypes within these phenotypes based on different inflammatory mechanisms. This review describes the important immunological mechanisms of CRScNP and highlights modern treatment options with biologicals directly addressing particular immunological processes.

METHODS

Current knowledge on immunological and molecular processes of CRS, particularly CRScNP, was extracted from Medline, PubMed, national and international study- and guideline-registers, and the Cochrane library by a systematic review of the literature.

RESULTS

Based on current literature, various immunological mechanisms for CRS and CRScNP could be identified. Relevant studies for the treatment of eosinophilic conditions such as asthma or CRScNP are presented and, if available, results of these studies are discussed.

CONCLUSION

The growing insight into the underlying immunological mechanisms of CRScNP could pave the way for new personalized treatment options such as biologicals in the future.

Anisakis pegreffii impacts differentiation and function of human dendritic cells

Human dendritic cells (DCs) show remarkable phenotypic changes when matured in the presence of helminth-derived products. These modifications frequently elicited a polarization towards Th2 cells and regulatory T cells thus contributing to immunological tolerance against these pathogens. In this study, the interaction between DCs and larvae of the zoonotic anisakid nematode Anisakis pegreffii was investigated. A. pegreffii larvae were collected from fish hosts, and monocyte-derived DCs were cocultured in the presence of the live larvae (L) or its crude extracts (CE). In both experimental conditions, A. pegreffii impacted DC viability, hampered DC maturation by reducing the expression of molecules involved in antigen presentation and migration (ie HLA-DR, CD86, CD83 and CCR7), increased the phagosomal radical oxygen species (ROS) levels and modulated the phosphorylation of ERK1,2 pathway. These biological changes were accompanied by the impairment of DCs to activate a T-cell-mediated IFNγ. Interestingly, live larvae appeared to differently modulate DC secretion of cytokines and chemokines as compared to CE. These results demonstrate, for the first time, the immunomodulatory role of A. pegreffii on DCs biology and functions. In addition, they suggest a dynamic contribution of DCs to the induction and maintenance of the inflammatory response against A. pegreffii.

Comprehensive Phenotyping of T Cells Using Flow Cytometry

The T cell compartment can form a powerful defense against extrinsic (e.g., pathogens) and intrinsic danger (e.g., malignant cells). At the same time, specific subsets of T cells control this process to keep the immune system in check and prevent autoimmunity. A wide variety in T cell functionalities exists, which is dependent on the differentiation and maturation state of the T cells. In this review, we report an overview for the identification of CD4⁺ T-αβ cells (T-helper (Th)1, Th2, Th9, Th17, Th22, and CD4⁺ regulatory T cells), CD8⁺ T-αβ cells (cytotoxic T lymphocyte (Tc)1, Tc2, Tc9, Tc17, and CD8⁺ regulatory T cells), and their additional effector memory status (naïve, stem cell memory, central memory, effector memory, and effector) using flow cytometry. These different subsets can be discriminated based on selective extracellular markers, in combination with intracellular transcription factor and/or cytokine stainings. Additionally, identification of very small subsets, including antigen-specific T cells, and important technical considerations of flow cytometry are discussed. Together, this overview can be used for comprehensive phenotyping of a T cell subset of interest. © 2019 International Society for Advancement of Cytometry.

CD4: a vital player in the teleost fish immune system

CD4 is a nonpolymorphic transmembrane glycoprotein molecule that is expressed on the surface of T-helper cells and plays an essential role in the immune response. It functions as a coreceptor with the T-cell receptor by binding to major histocompatibility complex class II on the surface of dendritic cells that present antigens. CD4⁺ T cells hold a key position in coordinating the immune system through production of several cytokines after activation and differentiation. The CD4⁺ T helper subtypes (T-helper 1, T-helper 2, T-helper 17, T-helper 9, and regulatory-T cells) perform different immune functions subsequent to their differentiation from the naive T cells. Different types of CD4⁺ T cells require different cytokines such as drivers and effectors, as well as master transcription factors for their activation. Fish cells that express CD4-related genes are activated in the presence of a pathogen and release cytokines against the pathogen. This review highlights the types of CD4⁺ T cells in fish and describes their direct role in cell-mediated and humoral immunity for protection against the intracellular bacterial as well as viral infections in fish.

The Unsolved Jigsaw Puzzle of the Immune Response in Chagas Disease

Trypanosoma cruzi interacts with the different arms of the innate and adaptive host's immune response in a very complex and flowery manner. The history of host-parasite co-evolution has provided this protozoan with means of resisting, escaping or subverting the mechanisms of immunity and establishing a chronic infection. Despite many decades of research on the subject, the infection remains incurable, and the factors that steer chronic Chagas disease from an asymptomatic state to clinical onset are still unclear. As the relationship between T. cruzi and the host immune system is intricate, so is the amount and diversity of scientific knowledge on the matter. Many of the mechanisms of immunity are fairly well understood, but unveiling the factors that lead each of these to success or failure, within the coordinated response as a whole, requires further research. The intention behind this Review is to compile the available information on the different aspects of the immune response, with an emphasis on those phenomena that have been studied and confirmed in the human host. For ease of comprehension, it has been subdivided in sections that cover the main humoral and cell-mediated components involved therein. However, we also intend to underline that these elements are not independent, but function intimately and concertedly. Here, we summarize years of investigation carried out to unravel the puzzling interplay between the host and the parasite.

Single-cell Analysis of Immunophenotype and Cytokine Production in Peripheral Whole Blood via Mass Cytometry

Cytokines play a pivotal role in the pathogenesis of autoimmune diseases. Hence, the measurement of cytokine levels has been the focus of multiple studies in an attempt to understand the precise mechanisms that lead to the breakdown of self-tolerance and subsequent autoimmunity. Approaches thus far have been based on the study of one specific aspect of the immune system (a single or few cell types or cytokines), and do not offer a global assessment of complex autoimmune disease. While patient sera-based studies have afforded important insights into autoimmunity, they do not provide the specific cellular source of the dysregulated cytokines detected. A comprehensive single-cell approach to evaluate cytokine production in multiple immune cell subsets, within the context of "intrinsic" patient-specific plasma circulating factors, is described here. This approach enables monitoring of the patient-specific immune phenotype (surface markers) and function (cytokines), either in its native "intrinsic pathogenic" disease state, or in the presence of therapeutic agents (in vivo or ex vivo).

Regulation of T helper cell responses during antigen presentation by norepinephrine-exposed endothelial cells

Dermal blood vessels and regional lymph nodes are innervated by sympathetic nerves and, under stress, sympathetic nerves release norepinephrine (NE). Exposure of primary murine dermal microvascular endothelial cells (pDMECs) to NE followed by co-culture with Langerhans cells (LCs), responsive CD4+ T-cells and antigen resulted in modulation of CD4+ T-cell responses. NE-treatment of pDMECs induced increased production of interleukin (IL)-6 and IL-17A while down-regulating interferon (IFN)-γ and IL-22 release. This effect did not require contact between pDMECs and LCs or T-cells and depended upon pDMEC production of IL-6. The presence of NE-treated pDMECs increased the proportion of CD4+ T-cells expressing intracellular IL-17A and increased IL-17A mRNA while decreasing the proportion of IFN-γ- or IL-22-expressing CD4+ T-cells and mRNA levels for those cytokines. Retinoic acid receptor-related orphan receptor gamma (ROR-γt) mRNA was significantly increased in CD4+ T-cells while T-box transcription factor (T-bet) mRNA was decreased. Intradermal administration of NE prior to hapten immunization at the injection site produced a similar bias in draining lymph node CD4+ T-cells towards IL-17A and away from IFN-γ and IL-22 production. Under stress, release of NE may have significant regulatory effects on the outcome of antigen presentation through actions on ECs with enhancement of inflammatory skin disorders involving IL-17/T helper type 17 (Th17) cells.

Biological treatments in giant cell arteritis & Takayasu arteritis

Giant cell arteritis (GCA) and Takayasu arteritis (TAK) are the two main large vessel vasculitides. They share some similarities regarding their clinical, radiological and histological presentations but some pathogenic processes in GCA and TAK are activated differently, thus explaining their different sensitivity to biological therapies. The treatment of GCA and TAK essentially relies on glucocorticoids. However, thanks to major progress in our understanding of their pathogenesis, the role of biological therapies in the treatment of these two vasculitides is expanding, especially in relapsing or refractory diseases. In this review, the efficacy, the safety and the limits of the main biological therapies ever tested in GCA and TAK are discussed. Briefly, anti TNF-α agents appear to be effective in treating TAK but not GCA. Recent randomized placebo-controlled trials have reported on the efficacy and safety of abatacept and mostly tocilizumab in inducing and maintaining remission of GCA. Abatacept was not effective in TAK and robust data are still lacking to draw any conclusions concerning the use of tocilizumab in TAK. Furthermore, ustekinumab appears promising in relapsing/refractory GCA whereas rituximab has been reported to be effective in only a few cases of refractory TAK patients. If a biological therapy is indicated, and in light of the data discussed in this review, the first choice would be tocilizumab in GCA and anti-TNF-α agents (mainly infliximab) in TAK.

Subtyping of polyposis nasi: phenotypes, endotypes and comorbidities

BACKGROUND

Chronic rhinosinusitis (CRS) is a heterogeneous, multifactorial inflammatory disease of the nasal and paranasal mucosa. It has not been possible to date to develop an internationally standardized, uniform classification for this disorder. A phenotype classification according to CRS with (CRSwNP) and without polyposis (CRSsNP) is usually made. However, a large number of studies have shown that there are also different endotypes of CRS within these phenotypes, with different pathophysiologies of chronic inflammation of the nasal mucosa. This review describes the central immunological processes in nasal polyps, as well as the impact of related diseases on the inflammatory profile of nasal polyps.

MATERIALS AND METHODS

The current knowledge on the immunological and molecular processes of CRS, in particular CRSwNP and its classification into specific endotypes, was put together by means of a structured literature search in Medline, PubMed, the national and international guideline registers, and the Cochrane Library.

RESULTS

Based on the current literature, the different immunological processes in CRS and nasal polyps were elaborated and a graphical representation in the form of an immunological network developed. In addition, different inflammatory profiles can be found in CRSwNP depending on related diseases, such as bronchial asthma, cystic fibrosis (CF), or NASID-Exacerbated Respiratory Disease (N‑ERD).

CONCLUSION

The identification of different endotypes of CRSwNP may help to improve diagnostics and develop novel individual treatment approaches in CRSwNP.

Immune cells and autoantibodies in pulmonary arterial hypertension

Analyses of immunity in pulmonary arterial hypertension (PAH) support the notion that maladaptation of the immune response exists. Altered immunity is an increasingly recognized feature of PAH. Indeed, a delicate balance between immunity and tolerance exists and any disturbance may result in chronic inflammation or autoimmunity. This is suggested by infiltration of various immune cells (e.g. macrophages, T and B lymphocytes) in remodeled pulmonary vessels. In addition, several types of autoantibodies directed against antinuclear antigens, endothelial cells (ECs) and fibroblasts have been found in idiopathic and systemic sclerosis-associated PAH. These autoantibodies may play an important role in EC apoptosis and in the expression of cell adhesion molecules. This review article provides an overview of immunity pathways highlighting their potential roles in pulmonary vascular remodeling in PAH and the possibility of future targeted therapy.

Characterization of T-cell subpopulations in patients with chronic rhinosinusitis with nasal polyposis

Background:

There is an ongoing discussion concerning the potential origins of chronic rhinosinusitis with nasal polyposis (CRSwNP).

Objective:

The aim of this study was to quantify subpopulations of T cells in peripheral blood and nasal polyps in CRSwNP to examine their influence on the etiology of this disease.

Methods:

Tissue and blood samples were collected from 11 patients who underwent nasal sinus surgery, and these samples were analyzed by multicolor flow cytometry.

Results:

There was a significantly lower frequency of CD4⁺ T-helper (Th) cells and a significantly higher frequency of CD8⁺ T cells among lymphocytes isolated from nasal polyps compared with peripheral blood mononuclear cells (PBMC). In both T-cell subpopulations, a shift mainly from naive T cells among peripheral blood lymphocytes toward an effector memory and terminally differentiated subtype predominance in nasal polyps was observed. Among CD4⁺ T cells, the frequencies of cluster of differentiation (CD) 45RA- Forkhead-Box-Protein P3high (FoxP3^high) cytotoxic T-lymphocyte-associated Protein 4high (CTLA-4^high) activated regulatory T (T_reg) cells, and CD45RA- Forkhead-Box-Protein P3low (FoxP3^low) memory T cells were significantly increased in nasal polyps compared with PBMC.

Conclusion:

In this study, we presented a detailed characterization of CD4⁺ and CD8⁺ T-cell subpopulations in patients with CRSwNP. CD8⁺ T cells were more prominent in nasal polyps than in CD4⁺ T cells. Both nasal CD8⁺ T cells and CD4⁺ T cells predominantly had an effector memory phenotype. Among CD4⁺ T cells, activated T_reg cells were increased in nasal polyps compared with PBMC. The data point toward a local regulation of T-cell composition within the microenvironment of nasal polyps, which might be further exploited in the future to develop novel immunotherapeutic strategies.

Angiostatic and Angiogenic Chemokines in Systemic Sclerosis: An Overview

In systemic sclerosis (SSc), the dysregulation of several molecular pathways seem to have a role in the disease pathogenesis. Either angiogenesis and vasculogenesis are disturbed and impaired, and an imbalance between angiogenic and angiostatic factors may be involved in the genesis and maintenance of vasculopathy. Aberrant immune system activation and function involves both B and T cells, as well as many different chemokines and cytokines. Particularly, chemokines are central to the initiation and maintenance of inflammatory responses as well as angiogenesis and fibrosis. Increased expression of several chemokines as CXCL4 (platelet factor 4), CXCL8 (IL8), CXCL5 (ENA-78), CCL5 (RANTS), CXCL9 (MIG), CCL24, CXCL10 IP-10), CXCL12, CXCL16 (SRPSDX), CCL2 (MCP-1), CCL19 (MIP-3β/ELC), CCL24 (Eotaxin 2), suggests a complex mechanism by which many immune cell types, including T cells, macrophages and neutrophils are recruited to the skin in SSc patients. Many of these chemokines have redundant roles, possibly to ensure recruitment of specific cell types. Several studies have shown a synergistic effect of combinations of these chemokines in cell recruitment, emphasizing the importance of understanding global chemokine expressions. urthermore, chemokines can be detected in peripheral blood compared with cytokines or growth factors. The utility of cytokines as biomarkers has been investigated but longitudinal studies are necessary to clarify their clinical utility for the evaluation of disease activity, therapeutic effects on skin sclerosis or interstitial lung disease and risk stratification of SSc patients. An effective therapeutic agent, able to interfere with complex chemokine networks, is warranted to attenuate perivascular inflammation, dysregulated angiogenesis and the evolution of skin and internal organ fibrosis, is the most ambitious goal for the scientific research of the future.

Faecalibacterium prausnitzii supernatant ameliorates dextran sulfate sodium induced colitis by regulating Th17 cell differentiation

AIM: To explore the preventive and therapeutic effects of Faecalibacterium prausnitzii (F. prausnitzii) supernatant on dextran sulfate sodium (DSS) induced colitis in mice.

METHODS: Forty C57BL/6J male mice were randomly divided into four groups: control group, model group, treatment group, and prevention group. Mice were weighed daily. On day 10, the colon length was measured, the colorectal histopathologic damage score (HDS) was assessed, and plasma interleukin (IL)-17A, IL-6, and IL-4 levels were detected by enzyme-linked immunosorbent assay. The expression of transcription factor retinoic acid-related orphan receptor-γt (RORγt) and IL-17A in colon inflammatory mucosa tissue were determined by immunohistochemical assay, and the expression levels of RORγt mRNA, IL-17A mRNA, and IL-6 mRNA were detected by real-time quantitative polymerase chain reaction (PCR). The proportion of Th17 in mononuclear cells in spleen was assayed by fluorescence activated cell sorter.

RESULTS: When compared with the model group, the colon length (P < 0.05) and body weight (P < 0.01) in the treatment and prevention groups were significantly increased, and the colon HDS was decreased (P < 0.05 and P < 0.01). There was no statistical difference between the treatment group and prevention group. After treatment with F. prausnitzii supernatant, the plasma levels of IL-17A and IL-6 (P < 0.05), the protein and mRNA expression of IL-17A and RORγt, and the Th17 cell ratio of spleen cells (P < 0.01) were significantly decreased compared to the model group. Plasma IL-4 level in the prevention group was significantly higher than that in the model group (P < 0.05), but there was no significant difference between these two groups in the expression of IL-6 in both the plasma and colon mucosa tissues.

CONCLUSION: F. prausnitzii supernatant exerts protective and therapeutic effects on DSS-induced colitis in mice, probably via inhibition of Th17 differentiation and IL-17A secretion in the plasma and colon mucosa tissues. It can also improve colitis in mice by downregulating IL-6 and prevent colitis by upregulating IL-4.

New strategy for testing efficacy of immunotherapeutic compounds for diabetes in vitro

Background

The valuable role of immunotherapy in treating autoimmune diseases is increasingly recognized by those involved in the research and clinical application of new biopharmaceuticals products. However, many aspects related to the mechanisms of immune-modulated therapies remain to be elucidated in order to explore fully the emerging opportunities. The non-obese diabetic NOD mouse develops insulin-dependent diabetes mellitus spontaneously as a consequence of an autoimmune process in the presence of pathogenic CD4⁺ T cells that typically exhibit Th17 cell phenotypes. The change of a Th17 phenotype into a pattern of regulatory T cells (Treg) is extremely important in controlling autoimmune diseases. Heat shock proteins (HSPs) are stress-induced proteins with immunoregulatory properties. In the current study, the capacity of Hsp65 and Hsp70 mycobacterial HSPs and a constructed DNA encoded Hsp65 (DNAhsp65) to transform the pattern of the immune response from Th17 into Treg cells has been studied in vitro using co-cultures of antigen presenting cells (APCs) and T cells in NOD mice.

Results

Cells harvested from NOD mice and cultured for 48 h (without immunoregulatory compounds) presented with Th1/Th17 patterns and secretions of IL-6, IFN-γ, IL-10 and IL-17 cytokines. The cultured cells from the non-diabetic BALB/C mice exhibited a Th1 pattern and the production of IL 6 and IFN-γ secretions. An up-regulation was observed in the supernatants from the co-cultures of NOD cells that were stimulated with DNAhsp65, Hsp65 or Hsp70 through increased levels of IL-10 secretion and the suppression of IL-6, IFN-γ and IL-17 production. In addition, immunoregulation was demonstrated through IL-17 suppression in the co-culture stimulated by the specific insulin antigen. Moreover, an increase of immunoregulatory compounds were observed in the co-culture through the expression of CD11b⁺CD86⁺ activation markers on APCs, as well as the frequency of Treg cells expressing CD4⁺CD3⁺ and CD4⁺CD25^hi.

Conclusions

The in vitro observation of Th17 cells differentiating into Tregs in NOD mice could raise the hypothesis that the immune regulatory activity of HSPs could be an efficient strategy for diabetes prevention and treatment.

Quantitative and Qualitative Analysis of Tumor-Associated CD4⁺ T Cells

CD4(+) T cells comprise a significant portion of tumor-infiltrating lymphocytes. Different subsets of CD4(+) T cells exist and they exert different effector functions in tumor immunity depending on the cytokines produced going from antitumor to pro-tumor. Methods that use small aliquots of cells to identify ex vivo the frequency and functional orientation of tumor-specific CD4(+) T cells in the blood and visualization of the presence of different CD4(+) T cell subsets and their localization at the tumor site are valuable tools to determine their clinical impact in neoplastic diseases.

Calcitonin Gene-Related Peptide-Exposed Endothelial Cells Bias Antigen Presentation to CD4+ T Cells toward a Th17 Response

Calcitonin gene-related peptide (CGRP) is a neuropeptide with well-established immunomodulatory functions. CGRP-containing nerves innervate dermal blood vessels and lymph nodes. We examined whether CGRP regulates the outcome of Ag presentation by Langerhans cells (LCs) to T cells through actions on microvascular endothelial cells (ECs). Exposure of primary murine dermal microvascular ECs (pDMECs) to CGRP followed by coculture with LCs, responsive CD4(+) T cells and Ag resulted in increased production of IL-6 and IL-17A accompanied by inhibition of IFN-γ, IL-4, and IL-22 compared with wells containing pDMECs treated with medium alone. Physical contact between ECs and LCs or T cells was not required for this effect and, except for IL-4, we demonstrated that IL-6 production by CGRP-treated pDMECs was involved in these effects. CD4(+) cells expressing cytoplasmic IL-17A were increased, whereas cells expressing cytoplasmic IFN-γ or IL-4 were decreased by the presence of CGRP-treated pDMECs. In addition, the level of retinoic acid receptor-related orphan receptor γt mRNA was significantly increased, whereas T-bet and GATA3 expression was inhibited. Immunization at the site of intradermally administered CGRP led to a similar bias in CD4(+) T cells from draining lymph node cells toward IL-17A and away from IFN-γ. Actions of nerve-derived CGRP on ECs may have important regulatory effects on the outcome of Ag presentation with consequences for the expression of inflammatory skin disorders involving Th17 cells.

Prediction of disease severity in neuromyelitis optica by the levels of interleukin (IL)-6 produced during remission phase

T helper type 17 (Th17) cytokines have been implicated in the pathogenesis of neuromyelitis optica (NMO). As humanized anti-interleukin (IL)-6R (tocilizumab) immunoglobulin (Ig)G has been used as disease-modifying therapy for NMO, the objective of our study was to investigate the role of endogenous IL-6 on NMO-derived CD4(+) T cell behaviour. High production of IL-6, IL-17 and IL-21 by CD4(+) T-cells was detected in NMO patients. Further, IL-21 and IL-6 levels were related directly to the level of neurological disabilities. The addition of anti-IL-6R IgG not only reduced directly the production of these cytokines, but also almost abolished the ability of activated autologous monocytes in enhancing IL-6, IL-17 and IL-21 release by CD4(+) T cells. In contrast, the production of IL-10 was amplified in those cell cultures. Further, anti-IL-6R monoclonal antibodies (mAb) also potentiated the ability of glucocorticoid in reducing Th17 cytokines. Finally, the in-vivo and in-vitro IL-6 levels were significantly higher among those patients who experienced clinical relapse during 2-year follow-up. In summary, our results suggest a deleterious role of IL-6 in NMO by favouring, at least in part, the expansion of corticoid-resistant Th17 cells.

[Pathogenesis of large vessel vasculitis]

Giant cell arteritis (GCA) and Takayasu's arteritis (TA) are two granulomatous vasculitis affecting large arteries that present specific epidemiological and clinical features. Their pathogenesis is not fully understood but major advances have been obtained during the last years, thus allowing the emergence of new therapeutic strategies. GCA and TA develop on a specific genetic background but share some similarities regarding the immunological pathways involved in their pathogenesis. The trigger of these diseases is not clearly identified but it is thought that an infectious agent could activate and lead to the maturation of dendritic cells that are localized in the adventitia of arteries. Then, the cells of the adaptative immune response are recruited and activated: CD4 T cells that polarize into Th1 and Th17 cells, cytotoxic CD8 T cells and Natural Killer cells. Furthermore, the T regulatory cells (Treg) are decreased both in GCA and TA. Humoral immune response seems also to be involved, especially in TA. Then, the cytokines produced by T lymphocytes (especially IL-17 and IFN-γ) trigger the recruitment and activation of monocytes and their differentiation into macrophages and multinuclear giant cells that produce IL-1β and IL-6 that are responsible for general symptoms of GCA and TA, and cytotoxic mediators and growth factors that trigger the remodeling of the arterial wall leading to aneurysms and ischemic manifestations of GCA an TA.

Asthma-Related Immune Responses in Youth With Asthma: Associations With Maternal Responsiveness and Expressions of Positive and Negative Affect in Daily Life

OBJECTIVES

Stressful family environments early in life have negative effects on physical health. However, less is known about the health effects of positive aspects of families. We examined the associations between maternal responsiveness and immune markers among youth with asthma and identified youth expressions of positive affect as a potential mechanism of these associations.

METHODS

Forty-three youths with asthma (26 boys; aged 10-17 years) wore the Electronically Activated Recorder for 4 days to assess maternal responsiveness and youth expressions of affect from audio-recordings of daily life. Trained coders rated Electronically Activated Recorder sound files for expressions of maternal responsiveness and affect displayed by the youth. Peripheral blood mononuclear cells were isolated, cultured, and assayed to determine stimulated levels of interleukin (IL)-5, IL-13, and interferon-γ.

RESULTS

Greater maternal responsiveness was associated with decreased stimulated production of IL-5 (r = -0.38, p = .012) and IL-13 (r = -0.33, p = .031). Greater total positive affect in youth was linked to decreased stimulated production of IL-5 (r = -0.46, p = .002) and IL-13 (r = -0.37, p = .014). Total negative affect among youth was unrelated to immune responses. There was a significant indirect effect of maternal responsiveness via positive affect in youth on lower levels of IL-5 (95% confidence interval = -3.41 to -0.03) and IL-13 (95% confidence interval = -2.34 to -0.01) when adjusting for caregiver-youth conflict and negative affect among youth.

CONCLUSIONS

These results indicate the importance of positive family interactions for youth and provide preliminary evidence for a mechanism through which parenting can influence immune responses in youth with asthma.

Plasma phospholipid transfer protein (PLTP) modulates adaptive immune functions through alternation of T helper cell polarization

OBJECTIVE

Plasma phospholipid transfer protein (PLTP) is a key determinant of lipoprotein metabolism, and both animal and human studies converge to indicate that PLTP promotes atherogenesis and its thromboembolic complications. Moreover, it has recently been reported that PLTP modulates inflammation and immune responses. Although earlier studies from our group demonstrated that PLTP can modify macrophage activation, the implication of PLTP in the modulation of T-cell-mediated immune responses has never been investigated and was therefore addressed in the present study. Approach and results: In the present study, we demonstrated that PLTP deficiency in mice has a profound effect on CD4⁺ Th0 cell polarization, with a shift towards the anti-inflammatory Th2 phenotype under both normal and pathological conditions. In a model of contact hypersensitivity, a significantly impaired response to skin sensitization with the hapten-2,4-dinitrofluorobenzene (DNFB) was observed in PLTP-deficient mice compared to wild-type (WT) mice. Interestingly, PLTP deficiency in mice exerted no effect on the counts of total white blood cells, lymphocytes, granulocytes, or monocytes in the peripheral blood. Moreover, PLTP deficiency did not modify the amounts of CD4⁺ and CD8⁺ T lymphocyte subsets. However, PLTP-deficiency, associated with upregulation of the Th2 phenotype, was accompanied by a significant decrease in the production of the pro-Th1 cytokine interleukin 18 by accessory cells.

CONCLUSIONS

For the first time, this work reports a physiological role for PLTP in the polarization of CD4⁺ T cells toward the pro-inflammatory Th1 phenotype.

The role of the acquired immune response in systemic sclerosis

Profound alterations characterize the adaptive immune response in systemic sclerosis, and several layers of evidence support a prominent role exerted by immune cellular effectors and humoral mediators in the pathogenesis of this disease. These include (i) the presence of oligoclonal T cells in tissues undergoing fibrosis consistent with (auto)antigen-specific recruitment, (ii) the preferential expansion of polarized CD4+ and CD8+ T cells producing pro-fibrotic cytokines such as IL-4 and IL-13, (iii) the presence of increased number of cells producing mediators belonging to the IL-17 family, including IL-22, which may drive and participate in inflammatory pathways involving epithelial cells as well as fibroblasts, (iv) the deficient or redirected function of T regulatory cells favoring fibrosis, and (v) the enhanced expression of CD19 and CD21 on naïve B cells, and the upregulation of co-stimulatory molecules in mature B cells, which together with the increased levels of B cell activating factor (BAFF) underlie the propensity to an exaggerated humoral response possibly favoring fibrogenesis. Despite all the progress made in understanding the features of the aberrant immune response in scleroderma, it remains unclear whether the activation of immune effector pathways ultimately drives the disease pathogenesis or rather represents a defective attempt to limit or even reverse excessive extracellular matrix deposition and progressive vasculopathy, the main hallmarks of this disease.

The Profile of T Helper Subsets in Bone Marrow Microenvironment Is Distinct for Different Stages of Acute Myeloid Leukemia Patients and Chemotherapy Partly Ameliorates These Variations

BACKGROUND

T helper (Th) cells immune regulation is important for the pathogenesis of acute myeloid leukemia (AML). Recurrent Th abnormalities in AML peripheral blood were reported, while the comprehensive status of various Th subsets is rarely investigated in bone marrow (BM) microenvironment which is the origin of AML leukemic blast cells.

METHODS

BM was extracted from 48 newly-diagnosed (ND), 34 complete-remission (CR), 19 relapsed-refractory AML patients and 15 controls. Slight iron deficiency anemia patients were used as controls. Th subsets frequencies were examined by flow cytometry. BM plasma Th-associated cytokines levels were determined by ELISA. The expression of key transcription factor was examined by RT-PCR.

RESULTS

Th22, Th17, Th1, Th2 cells, IL-22 and RORC expression were significantly decreased, while Treg cells, related cytokine IL-10 and transcription factor Foxp3 were markedly elevated in ND compared to CR patients or controls. Meanwhile, the imbalanced Th1/Th2 and Th17/Treg ratio were observed in ND and relapsed-refractory patients. Negative correlation between Th1 or Th2 and peripheral WBC, between Th17/Treg or Th1/Th2 and leukemic blast existed in ND patients. Moreover, chemotherapy ameliorated these variations.

CONCLUSION

Th subsets in BM are distinct for different stages of AML and chemotherapy partly ameliorates the abnormality. Our findings suggest that these cells and cytokines may be implicated in AML pathogenesis and provided therapeutic insights.

Interplay among cytokines and T cell subsets in the progression and control of immune-mediated diseases

Cytokines serve as key mediators of inflammation and tissue damage in a variety of immune-mediated disorders. The induction, progression, and resolution of inflammation in such disorders are characterized by a dynamic balance between both the pro-inflammatory and anti-inflammatory cytokines as well as the pathogenic and protective T cell subsets. Over the past two decades, the roles of the interleukin-17 (IL-17) /IL-23 axis and the T helper 17 (Th17)/ T regulatory (Treg) cell balance in the pathogenesis of autoimmunity and other inflammatory diseases have extensively been analyzed, and their significance validated. However, these studies, coupled with others devoted to well-established Th1/Th2 cytokines, have unraveled some challenging issues including the dual action of cytokines and the plasticity of T cell subsets. Nevertheless, major positive advances have also been made regarding cytokines and T cell subsets as therapeutic targets/agents. In this special issue, "Cytokines in Immune Pathology and Therapy," leading experts have shared their research work and perspectives on the roles of cytokines in the development and control of immune-mediated diseases. An outline of 14 articles in the first volume is presented here. The second volume will follow soon.

Unraveling the Hygiene Hypothesis of helminthes and autoimmunity: origins, pathophysiology, and clinical applications

BACKGROUND

The Hygiene Hypothesis (HH) attributes the dramatic increase in autoimmune and allergic diseases observed in recent decades in Western countries to the reduced exposure to diverse immunoregulatory infectious agents. This theory has since largely been supported by strong epidemiological and experimental evidence.

DISCUSSION

The analysis of these data along with the evolution of the Western world's microbiome enable us to obtain greater insight into microorganisms involved in the HH, as well as their regulatory mechanisms on the immune system. Helminthes and their derivatives were shown to have a protective role. Helminthes' broad immunomodulatory properties have already begun to be exploited in clinical trials of autoimmune diseases, including inflammatory bowel disease, multiple sclerosis, rheumatoid arthritis, and type-1 diabetes.

SUMMARY

In this review, we will dissect the microbial actors thought to be involved in the HH as well as their immunomodulatory mechanisms as emphasized by experimental studies, with a particular attention on parasites. Thereafter, we will review the early clinical trials using helminthes' derivatives focusing on autoimmune diseases.