CCL20-CCR6 axis directs sperm-oocyte interaction and its dysregulation correlates/associates with male infertility‡.

The interaction of sperm with the oocyte is pivotal during the process of mammalian fertilization. The limited numbers of sperm that reach the fallopian tube as well as anatomic restrictions indicate that human sperm-oocyte encounter is not a matter of chance but a directed process. Chemotaxis is the proposed mechanism for re-orientating sperm toward the source of a chemoattractant and hence to the oocyte. Chemokines represent a superfamily of small (8-11 kDa), cytokine-like proteins that have been shown to mediate chemotaxis and tissue-specific homing of leukocytes through binding to specific chemokine receptors such as CCRs. Here we show that CCR6 is abundantly expressed on human sperms and in human testes. Furthermore, radioligand-binding experiments showed that CCL20 bound human sperm in a specific manner. Conversely, granulosa cells of the oocyte-surrounding cumulus complex as well as human oocytes represent an abundant source of the CCR6-specific ligand CCL20. In human ovaries, CCL20 shows a cycle-dependent expression pattern with peak expression in the preovulatory phase and CCL20 protein induces chemotactic responses of human sperm. Neutralization of CCL20 in ovarian follicular fluid significantly impairs sperm migratory responses. Conversely, analyses in infertile men with inflammatory conditions of the reproductive organs demonstrate a significant increase of CCL20/CCR6 expression in testis and ejaculate. Taken together, findings of the present study suggest that CCR6-CCL20 interaction may represent an important factor in directing sperm-oocyte interaction.

Recurrent eczema herpeticum - a retrospective European multicenter study evaluating the clinical characteristics of eczema herpeticum cases in atopic dermatitis patients.

BACKGROUND: Eczema herpeticum (EH) is a disseminated viral infection of eczematous skin disease with the herpes simplex virus. Knowledge on clinical characteristics, risk factors and recurrent disease is limited. Our aim was to better define clinical characteristics and risk factors for EH and especially for recurrent EH. METHODS: A retrospective analysis of EH cases assessed the history, clinical signs, prior treatment and laboratory results using a predefined questionnaire. RESULTS: A total of 224 EH cases from eight European centres were included. Extrinsic AD was identified as risk factor for EH, and only one patient suffered from intrinsic AD. Early onset of AD was identified as risk factor for recurrent EH. Pretreatment with topical steroids, systemic steroids, topical calcineurin inhibitors or plain emollients reflected standard therapy. Many patients showed AD lesions without EH, but skin without AD lesions was never affected by herpetic lesions. CONCLUSION: Patients with clinically active, extrinsic AD are at risk of EH. Recurrent EH is associated with confounders of severe atopic distortion and requires active AD lesions for clinical manifestation. Recurrent eczema herpeticum mainly affects patients with early onset of AD.

Stabilization of Polar Nanoregions in Pb-free Ferroelectrics.

The formation of polar nanoregions through solid-solution additions is known to enhance significantly the functional properties of ferroelectric materials. Despite considerable progress in characterizing the microscopic behavior of polar nanoregions (PNR), understanding their real-space atomic structure and dynamics of their formation remains a considerable challenge. Here, using the method of dynamic pair distribution function, we provide direct insights into the role of solid-solution additions towards the stabilization of polar nanoregions in the Pb-free ferroelectric of Ba(Zr,Ti)O_{3}. It is shown that for an optimum level of substitution of Ti by larger Zr ions, the dynamics of atomic displacements for ferroelectric polarization are slowed sufficiently below THz frequencies, which leads to increased local correlation among dipoles within PNRs. The dynamic pair distribution function technique demonstrates a unique capability to obtain insights into locally correlated atomic dynamics in disordered materials, including new Pb-free ferroelectrics, which is necessary to understand and control their functional properties.

[Immunological mechanisms of allergen-specific immunotherapy]. / Immunologische Mechanismen der allergenspezifischen Immuntherapie.

Allergen-specific immunotherapy is accompanied by multiple changes on the cellular and humoral level. A shift of Th2 immune responses towards immune responses of the Th1 type, which goes along with an increase of regulatory T cells and B cells, IL-10 as well as reduction of effector cells and eosinophils in the tissue, combined with lower IgE production in favor of higher IgG4 production, are regarded as key mechanisms of allergen-specific immunotherapy . A better understanding of immunologic pathways of specific immunotherapy would be essential for the improvement of this therapy as well as for the development of reliable biomarkers capable to monitor therapeutic responses as well as compliance of the patients.

Oral pathogens change proliferation properties of oral tumor cells by affecting gene expression of human defensins.

The impact of oral pathogens onto the generation and variability of oral tumors has only recently been investigated. To get further insights, oral cancer cells were treated with pathogens and additionally, as a result of this bacterial cellular infection, with human defensins, which are as anti-microbial peptide members of the innate immune system. After cell stimulation, proliferation behavior, expression analysis of oncogenic relevant defensin genes, and effects on EGFR signaling were investigated. The expression of oncogenic relevant anti-microbial peptides was analyzed with real-time PCR and immunohistochemistry. Cell culture experiments were performed to examine cellular impacts caused by stimulation, i.e., altered gene expression, proliferation rate, and EGF receptor-dependent signaling. Incubation of oral tumor cells with an oral pathogen (Porphyromonas gingivalis) and human α-defensins led to an increase in cell proliferation. In contrast, another oral bacterium used, Aggregatibacter actinomycetemcomitans, enhanced cell death. The bacteria and anti-microbial peptides exhibited diverse effects on the transcript levels of oncogenic relevant defensin genes and epidermal growth factor receptor signaling. These two oral pathogens exhibited opposite primary effects on the proliferation behavior of oral tumor cells. Nevertheless, both microbe species led to similar secondary impacts on the proliferation rate by modifying expression levels of oncogenic relevant α-defensin genes. In this respect, oral pathogens exerted multiplying effects on tumor cell proliferation. Additionally, human defensins were shown to differently influence epidermal growth factor receptor signaling, supporting the hypothesis that these anti-microbial peptides serve as ligands of EGFR, thus modifying the proliferation behavior of oral tumor cells.

Pathogenesis of atopic dermatitis.

Atopic dermatitis (AD) is the most common allergic inflammatory skin disease. Interactions of genetic, environmental and immunological factors result in the initiation and progress of AD. Although the clinical picture, characterized by acute flare-ups of eczematous, pruritic lesions on dry skin at typical predilection such as the flexural folds, is quite homogenous, the trigger factors of the disease are diverse and the pathophysiologic network involved is complex. Therefore, first attempts have been made to classify subtypes of AD based on the most relevant causal factors in the individual patient. To optimize such a stratification of patients, detailed knowledge about cofactors impacting on manifestation of AD as well as impairment of the course of the disease is indispensable. AD shares general features of barrier dysfunction and skin inflammation with other inflammatory diseases of the skin such as psoriasis or allergic contact dermatitis, but a plethora of disease-specific genetic, immunologic and environmental factors have been identified in AD as well. It is the purpose of this review to illustrate key concepts of the pathogenesis of AD. Important findings of recent years will be summarized and cofactors of the pathogenesis will be controversially discussed. We will summarize knowledge on pathogenic factors on the immunologic level contributing to skin barrier dysfunction in AD and the role of the microbiome as first line of defence. Furthermore, we will elucidate the role of innate lymphoid cells in AD and outline the pattern of T helper cell subtypes present in the skin during different stages of AD.

Exaggerated IDO1 expression and activity in Langerhans cells from patients with atopic dermatitis upon viral stimulation: a potential predictive biomarker for high risk of Eczema herpeticum.

BACKGROUND: Atopic dermatitis (AD) is a heterogenous and highly complex disease characterized by an increased microbial colonization. For unknown reasons, a subgroup of patients with AD develops Eczema herpeticum (EH), a severe viral complication due to spreading of herpes simplex virus (HSV). Indoleamine 2,3-dioxygenase (IDO1) is a tryptophan (Trp)-catabolizing enzyme which is assumed to be instrumental in the antibacterial and antiviral defence mechanisms. METHODS: Comparative investigation of the IDO1 expression and activity in freshly isolated monocytes, plasmacytoid DC (pDC) and in vitro-generated Langerhans cells (LC) obtained from AD patients with HSV infections and EH and nonatopic controls. RESULTS: We demonstrate an increase in Trp degradation in the serum of patients during acute EH episodes. Circulating pDC from patients with history of EH display an increased IDO1 expression. An increased Trp degradation is detected in the supernatants of circulating monocytes from AD patients with acute EH. Mature LC from AD patients with history of EH and with acute EH display an increased IDO1 expression and activity, respectively. In LC from patients with history of EH, viral signals induce an exaggerated IDO1 expression and activity. CONCLUSION: IDO1 expression and activity in LC seem to be involved in the pathophysiology of EH in AD and could represent a predictive biomarker for patients with risk to develop EH and other viral complications.

Allergic Reactions to Pine Nut: A Review.

Pine nut is a nutrient-rich food with a beneficial impact on human health. The many bioactive constituents of pine nut interact synergistically to affect human physiology in a favorable way. However, pine nut can trigger dangerous allergic reactions. Severe anaphylactic reactions to pine nut accounted for most of the 45 cases reported in the scientific literature. Pine nut allergy seems to be characterized by low IgE cross-reactivity with other commonly consumed nuts and a high monosensitization rate. The present review provides updated information on allergic reactions to pine nut, molecular characterization of its allergens, and potential homologies with other nut allergens.

[Semen allergy]. / Spermaallergie.

A semen allergy is a type I reaction. Reliable figures about incidence/prevalence are not available. Symptoms can be characterized as local and systemic. After exposure to ejaculate, the patient may experience itching and swelling at points of contact, while systemically it may also lead to generalized urticaria with angioedema or higher grade anaphylaxis. As triggering allergens, substances in seminal plasma (SP) have been identified, which can be SP typical or SP atypical. Reactions against spermatozoa have not yet been clearly proven. With regard to SP-typical allergens, prostate-specific antigen (PSA) has been identified, while for SP-atypical allergens, medications or food allergens have been reported, which apparently accumulate in the SP and can then trigger symptoms in women with existing sensitization. The main criteria for the diagnosis of sperm allergy is freedom from symptoms when condoms are used during intercourse. In addition, skin prick tests and determination of allergen-specific IgE are used. In patients with a desire for children, washed, SP-free spermatozoa can be used for insemination. In addition, desensitization may be considered.

Immunoglobulin E epitope mapping by microarray immunoassay reveals differences in immune response to genetic variants of caseins from different ruminant species.

The allergenicity of the caseins (CN), one of the major allergens in cow milk, is well characterized and their immunoglobulin E (IgE)-binding epitopes have been identified. However, investigations about the allergenic potential of the genetic variants occurring in the caseins are lacking. Therefore, this study determined the influence of the genetic polymorphism on IgE binding to epitopes of bovine casein variants. Furthermore, differences in IgE binding between epitopes of goats and water buffaloes were analyzed. A set of 187 peptides, covering the previously identified sequential IgE-binding epitopes of αS1-, αS2-, ß-, and κ-CN variants from cows and the corresponding homologous peptides of water buffaloes and goats, were synthesized and tested by means of peptide microarray for IgE binding, using sera from 16 cow milk-sensitized individuals. Seven of the 16 sera samples showed positive signals on microarrays and were included in this study. In 5 αS1-CN variants (A, B, C, E, and I), the AA substitution or deletion affected the immunoreactivity of epitopes AA 4 to 23, AA 17 to 36, AA 83 to 102, AA 173 to 192, and AA 175 to 194, as well as of the variant-specific peptides AA 184 to 196, AA 187 to 199, AA 174 to 193, and AA 179 to 198, which were found to resist gastrointestinal digestion. Variation in IgE binding was further detected for peptides AA 103 to 123 and AA 108 to 129 of 3 ß-CN variants (A(1), A(2), and B). The majority of sera showed IgE binding to αS1-CN peptides of cows and the homologous counterpart of goats and water buffaloes. However, αS1- and ß-CN epitopes from goats and water buffaloes had lower immunoreactivity than those of cows, but, in some cases, higher or exclusive IgE binding was observed. The results of this study indicate that genetic variants of the caseins differ in their allergenicity. This might be useful in the search for a suitable protein source for cow milk-allergic patients. In addition, milk from water buffaloes and goats harbor an allergenic potential due to cross-reactivity of IgE antibodies with cow milk caseins and are, therefore, not an acceptable alternative in the nutrition of cow milk-allergic patients.

Differential leucocyte detection by flow cytometry improves the diagnosis of genital tract inflammation and identifies macrophages as proinflammatory cytokine-producing cells in human semen.

Genital tract inflammation is considered as a major cause of male infertility with leucocytospermia as widely used diagnostic marker. However, threshold of 10(6) leucocytes ml(-1) recommended by the WHO is a matter of debate. Moreover, leucocyte subpopulations and their impact cannot be identified by the routine peroxidase method (POM). Ejaculates of subfertile men (n = 47) were analysed by flow cytometry (FACS) using a bead-based method. Leucocytes were identified by CD18 and further divided into macrophages (HLA-Dr+/CD66abce-) and neutrophils (HLA-Dr-/CD66abce+). IL-1ß, TNF-α and IL-6 production was investigated in these subpopulations. It was found that CD18-positive cells correlated significantly with POM. However, only in samples with POM below 10(6) per millilitre, FACS detected significantly higher leucocyte numbers. Moreover, in 31% of these samples, FACS leucocyte detection reached threshold values greater than 1 × 10(6)  ml(-1) , fulfilling the criteria for diagnosis of leucocytospermia. Neutrophils were the predominating leucocyte population. Nevertheless, in 24% of samples, macrophages encountered more than 50% of leucocytes. Most interestingly, only macrophages produced significant amounts of IL-1ß, TNF-α and IL-6. It is concluded that FACS improves detection and functional differentiation of seminal leucocytes as one of the diagnostic hallmarks of male genital tract inflammation.

Immunology of atopic eczema: overcoming the Th1/Th2 paradigm.

Atopic eczema (AE) is a challenge for modern medicine, because it is prevalent, severely affects quality of life of patients and their families, and causes high socioeconomic costs. The pathogenesis of AE is complex. While initial studies suggested a Th2 deviation as primary reason for the disease, numerous studies addressed a genetically predetermined impaired epidermal barrier as leading cause in a subgroup of patients. Recently, immune changes beyond the initial Th2 concept were defined in AE, with a role for specialized dendritic cells as well as newly identified T helper cell subsets such as Th17 and Th22 cells. Furthermore, trigger factors are expanded beyond classical Th2 allergens such as pollen or house dust mites to microbial products as well as self-antigens. This review pieces together our current understanding of immune as well as barrier abnormalities into the pathogenesis mosaic of AE.

FcεRI stimulation promotes the differentiation of histamine receptor 1-expressing inflammatory macrophages.

BACKGROUND: Monocyte differentiation into dendritic cells or macrophages and recruitment to peripheral organs in chronic inflammatory diseases are directed by allergen challenge via FcεRI as well as the nature of soluble factors in the microenvironment. High-affinity receptor for IgE stimulation of effector cells results in the release of histamine, which acts on various histamine receptors (HR) 1-4, expressed by immune cells. METHODS: We examined the effect of FcεRI stimulation of human monocytes on H1R expression and function of differentiating cells. The mRNA levels of H1R, H2R and histidine decarboxylase of differentiating cells were detected by quantitative real-time PCR. Expression of CD1c, CD11c, CD68 and CD163 was detected by flow cytometry. Amount of histamine, IL-6 and IL-12p70 in the cell culture was measured with the help of cytometric bead arrays or ELISA assays. Numbers of H1R-expressing macrophages were evaluated by immunofluorescence double staining of CD68 and H1R on human skin sections. RESULTS: We demonstrated that FcεRI stimulation promotes the generation of H1R-expressing macrophage-like cells with enhanced histamine biosynthesis and H1R-mediated proinflammatory properties. Supporting our in vitro findings, high numbers of H1R-expressing CD68(pos) macrophages were detected in the dermis of atopic dermatitis (AD) skin lesions. CONCLUSION: Our observations point to a close histamine-/HR-mediated activation of dermal macrophages, leading to modified cell differentiation and responsiveness via H1R, which might contribute to the aggravation of allergic skin inflammation in AD.

Characterization of different courses of atopic dermatitis in adolescent and adult patients.

BACKGROUND: Atopic dermatitis (AD) starts most often during the first years of life and goes into remission in a high proportion of cases during childhood. However, in severe cases, AD persists until adulthood or starts and relapses later in life. So far, studies investigating the natural course of AD during adolescence and adulthood are rare. The aim of our study was to classify different courses of AD and to correlate these with specific risk factors for severe variants of AD. METHODS: A detailed clinical examination and retrospective evaluation of the history of the disease were performed in a collective of 725 adolescent and adult patients with AD. Laboratory data including total and specific IgE were evaluated. RESULTS: Six hundred and seven patients of 725 patients could be classified into course types. Of these 607 patients 85.7% could be classified into five main different course types of all 31 course types recorded. The highest differences in the number of sensitizations, total immunoglobulin E serum levels and predilection of the skin lesions were observed between patients with an early type of onset of AD and a chronic persisting course until adulthood and patients with a late type of onset of AD, that is, after the 20th year of life. CONCLUSION: Our data show that the natural course of AD can be divided into subgroups that display different clinical features. The data support the assumption of a broad heterogeneity of AD in adolescence and adulthood and emphasize the future need for careful stratification of patients with AD.

Human ß-defensins differently affect proliferation, differentiation, and mineralization of osteoblast-like MG63 cells.

Purpose of this study was to investigate whether human ß-defensins (hBDs) affect maturation and proliferation of osteoblast-like MG63 cells in vitro. Osteoblast-like MG63 cells were stimulated with hBD-1, -2, and -3 under control conditions and with hBD-2 during experimental inflammation (induced by interleukin-1ß, tumor necrosis factor-α, toll-like receptor-2 and -4 agonists). Expression of different osteogenic markers and hBDs were analyzed by real-time PCR, immunohistochemistry, and enzyme-linked immunosorbent assay. In addition, alkaline phosphatase (ALP) enzyme activity and biomineralization as markers for differentiation were monitored. All tested hBDs were expressed on mRNA and protein level in MG63 cells. Only stimulation with hBD-2 elevated the proliferation rate. hBD-2 and hBD-3 positively affected the differentiation of osteoblast-like cells provided by increased transcript levels of osteogenic markers, up-regulated ALP enzyme activity and enhanced mineralized nodule formation. All pro-inflammatory stimuli enhanced interleukin-6 and hBD-2 expression and down-regulated markers of osteoblastic differentiation. In accordance, inflammation increased transcript level of Notch-1 (an inhibitor of osteoblastic differentiation). hBD-2 was not able to revert effects of inflammation on differentiation. In bone cells human ß-defensins exhibit further functions than antimicrobial peptide activity. These include stimulation of proliferation and differentiation. Differentiation arrest due to inflammation could not be overcome by hBD-2 alone.

Cutaneous dendritic cells in allergic inflammation.

The skin represents a physical barrier, which is capable of protecting the body from damaging invaders. Moreover, the skin operates as an active immunological organ, harbouring a complex network of dendritic cells (DCs), which serve as a bridge between innate and adaptive immunity. Equipped with specific pattern recognition receptors (PRRs), DCs are able to capture, process and present antigens to naïve T cells in the skin draining lymph nodes, thereby inducing adaptive antigen-specific immunity. However, the outcome of the immune response is shaped by numerous factors including the DC subtype, maturation state of DCs, composition of PRRs expressed by DCs, type of pathogen as well as factors in the microenvironment. Thus, cutaneous DC subtypes are known to contribute to both, peripheral tolerance and the generation of allergic skin inflammation. Identifying the underlying mechanisms is a challenging task in understanding DC biology. Based on their functional diversity, cutaneous DCs might represent promising therapeutic targets, with the potential of down-modulating pro-inflammatory immune responses and inducing tolerogenic pathways, thereby ensuring the maintenance of tissue homeostasis and restoring the balance of dysregulated immune reactions in the context of allergic skin diseases. In this review, we summarize the versatile character of DC subtypes in human skin and highlight their phenotypic characteristics and role in allergic skin inflammation. In addition, we discuss current therapeutic approaches for the management of inflammatory skin diseases such as atopic dermatitis with the main focus on strategies targeting DCs. We point towards potential challenges, benefits, risks and limitations for the treatment of patients.

Human periodontal ligament cells facilitate leukocyte recruitment and are influenced in their immunomodulatory function by Th17 cytokine release.

The objective of this in vitro study was to examine the immunomodulatory impact of human periodontal ligament (PDL) cells on the nature and magnitude of the leukocyte infiltrate in periodontal inflammation, particularly with regard to Th17 cells. PDL cells were challenged with pro-inflammatory cytokines (IL-1ß, IL-17A, and IFN-γ) and analyzed for the expression of cytokines involved in periodontal immunoinflammatory processes (IL-6, MIP-3 alpha, IL-23A, TGFß1, IDO, and CD274). In order to further investigate a direct involvement of PDL cells in leukocyte function, co-culture experiments were conducted. The expression of the immunomodulatory cytokines studied was significantly increased under pro-inflammatory conditions in PDL cells. Although PDL cells did not stimulate leukocyte proliferation or Th17 differentiation, these cells induced the recruitment of leukocytes. The results of our study suggest that PDL cells might be involved in chronic inflammatory mechanisms in periodontal tissues and thus in the transition to an adaptive immune response in periodontitis.

IGF-1 deficiency in combination with a low basic hBD-2 and hBD-3 gene expression might counteract malignant transformation in pleomorphic adenomas in vitro.

This study investigated the IGF-1-influence on oncological relevant genes in pleomorphic adenomas. Therefore A64-tumor cells were stimulated by recombinant IGF-1. After RNA-extraction, transcript levels of hBD-1, hBD-2, hBD-3, DEFA1/3, DEFA4, S100A4, Psoriasin, DOC-1, EGF, EGFR, and IGFR were analyzed by qRT-PCR at t = 0, 4, 8, 24, 48, and 72 hr. The gene-products were visualized by immunostaining. A64-tumor-cells were deficient for hBD-1 and IGF-1. IGF-1 downregulates hBD-2 and hBD-3 without influencing hBD-1-expression. IGF-1 only slightly affects DEFA1/3-, DEFA4-, S100A4-, Psoriasin-, DOC-1-, EGF-, EGFR-, and IGFR-gene-expression. IGF-1-deficiency combined with low basic hBD-2-gene-expression and hBD-3-gene-expression might counteract, whereas hBD-1-deficiency promotes malignant transformation in pleomorphic adenomas.

Antigen-presenting cell marker expression and phagocytotic activity in periodontal ligament cells.

BACKGROUND: Periodontal ligament (PDL) cells are the main cellular constituents of the periodontium, maintain the integrity of the connective tissue, and impact pathology in periodontitis. The aim of this study was to analyze whether PDL cells recognize foreign particles and participate in the immune response to periodontal pathogens. METHODS: Expression of surface proteins characteristic of antigen-presenting cells (APCs) (major histocompatibility complex [MHC] class II, CD40, CD80, CD86) was analyzed in PDL cells after challenge with the cytokines interleukin (IL)-1ß, IL-17A, and interferon-gamma (IFN-γ) or with heat-killed Aggregatibacter actinomycetemcomitans using real-time PCR and flow cytometry. Confocal laser scanning microscopy, transmitted light microscopy, flow cytometry, and time-lapse microscopy were applied to analyze their phagocytotic capacity of collagen (carboxylate-modified microspheres), non-periodontal (Escherichia coli) and periodontal (Aggregatibacter actinomycetemcomitans) pathogens. Furthermore, it was examined whether cytokine activation of PDL cells affects the phagocytosis of collagen or bacteria. RESULTS: PDL cells upregulated MHC class II after cytokine stimulation on transcriptional level, whereas co-stimulatory molecules characteristic of professional APCs were not induced. Analyses on protein level revealed that MHC class II was not constitutively expressed in all PDL cell lines used. PDL cells phagocytosed both collagen and bacteria via acidic vesicles, suggesting the formation of phagosomes. Phagocytosis could be partially inhibited by inhibitors of phagocytosis, i.e., dynasore and wortmannin. Pre-incubation with cytokines did not further enhance the phagocytosis rate of collagen or bacteria. CONCLUSIONS: These results suggest that PDL cells do not only represent bystanders in periodontal infections, but display non-professional APC characteristics, suggesting possible participation in immune reactions of the oral cavity.

[New advances in atopic dermatitis]. / Fortschritte bei der atopischen Dermatitis.

Atopic Dermatitis (AD) is one of the most frequent chronic skin diseases. AD is characterized by a complex, heterogeneous pathogenesis. In this review, we highlight some selected aspects of the pathophysiology of AD, which have gained much attention during recent years. These aspects profoundly changed our view of the pathogenesis of AD and will have impact on its management.