T-helper 17 cell cytokines and interferon type I: partners in crime in systemic lupus erythematosus?

Introduction

A hallmark of systemic autoimmune diseases like systemic lupus erythematosus (SLE) is the increased expression of interferon (IFN) type I inducible genes, so-called IFN type I signature. Recently, T-helper 17 subset (Th17 cells), which produces IL-17A, IL-17F, IL-21, and IL-22, has been implicated in SLE. As CCR6 enriches for Th17 cells, we used this approach to investigate whether CCR6⁺ memory T-helper cells producing IL-17A, IL-17F, IL-21, and/or IL-22 are increased in SLE patients and whether this increase is related to the presence of IFN type I signature.

Methods

In total, 25 SLE patients and 15 healthy controls (HCs) were included. SLE patients were divided into IFN type I signature-positive (IFN⁺) (n = 16) and negative (IFN^-) (n = 9) patients, as assessed by mRNA expression of IFN-inducible genes (IFIGs) in monocytes. Expression of IL-17A, IL-17F, IL-21, and IL-22 by CD4⁺CD45RO⁺CCR6⁺ T cells (CCR6⁺ cells) was measured with flow cytometry and compared between IFN⁺, IFN^- patients and HCs.

Results

Increased percentages of IL-17A and IL-17A/IL-17F double-producing CCR6⁺ cells were observed in IFN⁺ patients compared with IFN^- patients and HCs. IL-17A and IL-17F expression within CCR6⁺ cells correlated significantly with IFIG expression. In addition, we found significant correlation between B-cell activating factor of the tumor necrosis family (BAFF)–a factor strongly correlating with IFN type I - and IL-21 producing CCR6⁺ cells.

Conclusions

We show for the first time higher percentages of IL-17A and IL-17A/IL-17F double-producing CCR6⁺ memory T-helper cells in IFN⁺ SLE patients, supporting the hypothesis that IFN type I co-acts with Th17 cytokines in SLE pathogenesis.     

What neurons hide behind calretinin immunoreactivity in the human gut?

Calretinin (CALR) is often used as an immunohistochemical marker for the histopathological diagnosis of human intestinal neuropathies. However, little is known about its distribution pattern with respect to specific human enteric neuron types. Prior studies revealed CALR in both myenteric and submucosal neurons, most of which colabel with choline acetyl transferase (ChAT). Here, we specified the chemical code of CALR-positive neurons in small and large intestinal wholemounts in a series of 28 patients. Besides other markers, we evaluated the labeling pattern of CALR in combination with vasoactive intestinal peptide (VIP). In colonic submucosa, CALR and VIP were almost completely colocalized in about three-quarters of all submucosal neurons. In the small intestinal submucosa, both the colocalization rate of CALR and VIP as well as the proportion of these neurons were lower (about one-third). In the myenteric plexus of both small intestine and colon, CALR amounted to 11 and 10 %, respectively, whereas VIP to 5 and 4 % of the whole neuron population, respectively. Colocalization of both markers was found in only 2 and 3 % of myenteric neurons, respectively. In section specimens, nerve fibers coreactive for CALR and VIP were found in the mucosa but not in the muscle coat. Summarizing the present and earlier results, CALR was found in at least one submucosal and two myenteric neuron populations. Submucosal CALR+/VIP+/ChAT± neurons innervate mucosal structures. Furthermore, CALR immunoreactivity in the myenteric plexus was observed in morphological type II (supposed primary afferent) and spiny type I (supposed inter- or motor-) neurons.     

Immunohistochemical analyses point to epidermal origin of human Merkel cells

Merkel cells, the neurosecretory cells of skin, are essential for light-touch responses and may probably fulfill additional functions. Whether these cells derive from an epidermal or a neural lineage has been a matter of dispute for a long time. In mice, recent studies have clearly demonstrated an epidermal origin of Merkel cells. Given the differences in Merkel cell distribution between human and murine skin, it is, however, unclear whether the same holds true for human Merkel cells. We therefore attempted to gain insight into the human Merkel cell lineage by co-immunodetection of the Merkel cell marker protein cytokeratin 20 (CK20) with various proteins known to be expressed either in epidermal or in neural stem cells of the skin. Neither Sox10 nor Pax3, both established markers of the neural crest lineage, exhibited any cell co-labeling with CK20. By contrast, β1 integrin, known to be enriched in epidermal stem cells, was found in nearly 70 % of interfollicular epidermal and 25 % of follicular Merkel cells. Moreover, LRIG1, also enriched in epidermal stem cells, displayed significant co-immunolabeling with CK20 as well (approximately 20 % in the interfollicular epidermis and 7 % in the hair follicle, respectively). Further epidermal markers were detected in sporadic Merkel cells. Cells co-expressing CK20 with epidermal markers may represent a transitory state between stem cells and differentiated cells. β1 integrin is probably also synthesized by a large subset of mature Merkel cells. Summarizing, our data suggest that human Merkel cells may originate from epidermal rather than neural progenitors.     

DHA Serum Levels Were Significantly Higher in Celiac Disease Patients Compared to Healthy Controls and Were Unrelated to Depression

Objectives

Celiac disease (CD), a genetically predisposed intolerance for gluten, is associated with an increased risk of major depressive disorder (MDD). We investigated whether dietary intake and serum levels of the essential n-3 polyunsaturated fatty acids (PUFA) eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA) found in fatty fish play a role in this association.

Methods

Cross-sectional study in 71 adult CD patients and 31 healthy volunteers, matched on age, gender and level of education, who were not using n-3 PUFA supplements. Dietary intake, as assessed using a 203-item food frequency questionnaire, and serum levels of EPA and DHA were compared in analyses of covariance, adjusting for potential confounders. Serum PUFA were determined using gas chromatography.

Results

Mean serum DHA was significantly higher in CD patients (1.72 mass%) than controls (1.28 mass%) after multivariable adjustment (mean diff. 0.45 mass%; 95% CI: 0.22–0.68; p = 0.001). The mean intake of EPA plus DHA did not differ between CD patients and controls after multivariable adjustment (0.15 and 0.22 g/d, respectively; p = 0.10). There were no significant differences in intake or serum levels of EPA and DHA between any of the CD patient groups (never depressed, current MDD, minor/partially remitted MDD, remitted MDD) and controls.

Conclusions

Patients on a long term gluten-free diet had similar intakes of EPA plus DHA compared to controls. Contrary to expectations, DHA serum levels were significantly higher in CD patients compared to healthy controls and were unrelated to MDD status.     

Evaluation of a New Recombinant Oncolytic Vaccinia Virus Strain GLV-5b451 for Feline Mammary Carcinoma Therapy

Virotherapy on the basis of oncolytic vaccinia virus (VACV) infection is a promising approach for cancer therapy. In this study we describe the establishment of a new preclinical model of feline mammary carcinoma (FMC) using a recently established cancer cell line, DT09/06. In addition, we evaluated a recombinant vaccinia virus strain, GLV-5b451, expressing the anti-vascular endothelial growth factor (VEGF) single-chain antibody (scAb) GLAF-2 as an oncolytic agent against FMC. Cell culture data demonstrate that GLV-5b451 virus efficiently infected, replicated in and destroyed DT09/06 cancer cells. In the selected xenografts of FMC, a single systemic administration of GLV-5b451 led to significant inhibition of tumor growth in comparison to untreated tumor-bearing mice. Furthermore, tumor-specific virus infection led to overproduction of functional scAb GLAF-2, which caused drastic reduction of intratumoral VEGF levels and inhibition of angiogenesis.In summary, here we have shown, for the first time, that the vaccinia virus strains and especially GLV-5b451 have great potential for effective treatment of FMC in animal model.     

Paroxysmal Nocturnal Hemoglobinuria Clones in Children with Acquired Aplastic Anemia: A Multicentre Study

A multicentre study evaluating the presence of glycosil phosphatidyl-inositol (GPI)-negative populations was performed in 85 children with acquired aplastic anemia (AA). A GPI-negative population was observed in 41% of patients at diagnosis, 48% during immune-suppressive therapy (IST), and 45% in patients off-therapy. No association was found between the presence of a GPI-negative population at diagnosis and the response to IST. In addition, the response rate to IST did not differ between the patients who were GPI-positive at diagnosis and later developed GPI-negative populations and the 11 patients who remained GPI-positive. Two patients with a GPI-negative population >10%, and laboratory signs of hemolysis without hemoglobinuria were considered affected by paroxysmal nocturnal hemoglobinuria (PNH) secondary to AA; no thrombotic event was reported. Excluding the 2 patients with a GPI-negative population greater than 10%, we did not observe a significant correlation between LDH levels and GPI-negative population size. In this study monitoring for laboratory signs of hemolysis was sufficient to diagnose PNH in AA patients. The presence of minor GPI-negative populations at diagnosis in our series did not influence the therapeutic response. As occasionally the appearance of a GPI-negative population was observed at cyclosporine (CSA) tapering or AA relapse, a possible role of GPI-negative population monitoring during IST modulation may need further investigation.     

Replication Rates of Mycobacterium tuberculosis in Human Macrophages Do Not Correlate with Mycobacterial Antibiotic Susceptibility

The standard treatment of tuberculosis (TB) takes six to nine months to complete and this lengthy therapy contributes to the emergence of drug-resistant TB. TB is caused by Mycobacterium tuberculosis (Mtb) and the ability of this bacterium to switch to a dormant phenotype has been suggested to be responsible for the slow clearance during treatment. A recent study showed that the replication rate of a non-virulent mycobacterium, Mycobacterium smegmatis, did not correlate with antibiotic susceptibility. However, the question whether this observation also holds true for Mtb remains unanswered. Here, in order to mimic physiological conditions of TB infection, we established a protocol based on long-term infection of primary human macrophages, featuring Mtb replicating at different rates inside the cells. During conditions that restricted Mtb replication, the bacterial phenotype was associated with reduced acid-fastness. However, these phenotypically altered bacteria were as sensitive to isoniazid, pyrazinamide and ethambutol as intracellularly replicating Mtb. In support of the recent findings with M. smegmatis, we conclude that replication rates of Mtb do not correlate with antibiotic tolerance.     

The Importance of Biologically Relevant Microclimates in Habitat Suitability Assessments

Predicting habitat suitability under climate change is vital to conserving biodiversity. However, current species distribution models rely on coarse scale climate data, whereas fine scale microclimate data may be necessary to assess habitat suitability and generate predictive models. Here, we evaluate disparities between temperature data at the coarse scale from weather stations versus fine-scale data measured in microhabitats required for a climate-sensitive mammal, the American pika (Ochotona princeps). We collected two years of temperature data in occupied talus habitats predicted to be suitable (high elevation) and unsuitable (low elevation) by the bioclimatic envelope approach. At low elevations, talus surface and interstitial microclimates drastically differed from ambient temperatures measured on-site and at a nearby weather station. Interstitial talus temperatures were frequently decoupled from high ambient temperatures, resulting in instantaneous disparities of over 30°C between these two measurements. Microhabitat temperatures were also highly heterogeneous, such that temperature measurements within the same patch of talus were not more correlated than measurements at distant patches. An experimental manipulation revealed that vegetation cover may cool the talus surface by up to 10°C during the summer, which may contribute to this spatial heterogeneity. Finally, low elevation microclimates were milder and less variable than typical alpine habitat, suggesting that, counter to species distribution model predictions, these seemingly unsuitable habitats may actually be better refugia for this species under climate change. These results highlight the importance of fine-scale microhabitat data in habitat assessments and underscore the notion that some critical refugia may be counterintuitive.