Atopic dermatitis in West Highland white terriers - Part III: early life peripheral blood regulatory T cells are reduced in atopic dermatitis.

BACKGROUND: Regulatory T (Treg) cells are involved in homeostasis of immune regulation and suppression of inflammation and T-cell polarisation. Current knowledge regarding the role of Treg cells in the initiation of allergic disease is limited for both people and dogs. OBJECTIVES: To explore the role of circulating Treg cells and their possible influencing factors, on the development of atopic dermatitis (AD). METHODS AND MATERIALS: This study followed part of a birth cohort of West Highland white terrier dogs and classified them according to eventual clinical signs of AD (i.e. allergic versus healthy). The Treg phenotypes were assessed longitudinally by flow cytometry at 3, 3-12 and 12-36 months of age, and associated with development of AD. Different early life antigenic factors [endotoxins and allergens in house dust, Toxocara canis-specific immunoglobulin (Ig)E/IgG, allergen-specific and total IgE, skin microbiota] were measured at three months of age, and a possible association with Treg cell levels was assessed. RESULTS: The percentages of CD4+ CD25+ Foxp3+ Treg cells in healthy dogs were significantly higher at in 3-month-old (mean 4.5% healthy versus 3.3% allergic; P = 0.021) and <1-year-old (4.0% healthy versus 2.9% allergic; P = 0.028) dogs when compared to percentages of Treg cells in dogs that developed AD. There was a significantly positive correlation between the relative abundance of Lachnospiraceae on the skin and CD4+ CD25+ Foxp3+ Treg cells in puppies that became allergic (r = 0.568, P = 0.017). CONCLUSION AND CLINICAL IMPORTANCE: Further large-scale studies are needed to identify the practical value of these findings in AD diagnosis, treatment and prevention.

Circulating CD4(+)CD25(+)Foxp3(+) T regulatory cell levels in an experimental model of canine atopic dermatitis.

BACKGROUND: The pathogenesis of canine atopic dermatitis (cAD) is characterized immunologically by an imbalanced T-cell response. Mechanisms of immune regulation in cAD have not yet been completely elucidated. OBJECTIVES: To investigate peripheral blood T regulatory (Treg) cells and their associated cytokines (TGF-ß and IL-10) in an experimental model of cAD. ANIMALS: Eight beagle dogs that were initially naïve and subsequently sensitized to house dust mites (HDM). METHODS AND MATERIALS: T regulatory cell phenotyping was performed by flow-cytometric analysis on peripheral blood; serum cytokine levels were measured by ELISA, before sensitization and after challenge with HDM allergens. Additionally, clinical scores and allergen-specific IgE were determined. RESULTS: After challenge of sensitized dogs to HDM allergen, a significant increase of Treg cells and simultaneous decrease in the serum TGF-ß were observed. However, in most dogs, serum IL-10 values were below the detection limit. Treg cell proportions before sensitization were significantly negatively correlated with the HDM-specific IgE levels and clinical scores after induction of AD signs. CONCLUSION AND CLINICAL IMPORTANCE: The results confirm that Treg responses are involved in the pathogenesis of an experimental model cAD. Further investigations are required to clarify the precise immune modulating function of canine Treg cells and their interplay with other immune cell types.

Association between inflammatory and obesity markers in a Swiss population-based sample (CoLaus Study).

OBJECTIVE: To assess the associations between obesity markers (BMI, waist circumference and %body fat) and inflammatory markers (interleukin-1ß (IL-1ß); interleukin-6 (IL-6); tumor necrosis factor-α (TNF-α) and high-sensitivity C-reactive protein (hs-CRP)). METHODS: Population sample of 2,884 men and 3,201 women aged 35-75 years. Associations were assessed using ridge regression adjusting for age, leisure-time physical activity, and smoking. RESULTS: No differences were found in IL-1ß levels between participants with increased obesity markers and healthy counterparts; multivariate regression showed %body fat to be negatively associated with IL-1ß. Participants with high %body fat or abdominal obesity had higher IL-6 levels, but no independent association between IL-6 levels and obesity markers was found on multivariate regression. Participants with abdominal obesity had higher TNF-α levels, and positive associations were found between TNF-α levels and waist circumference in men and between TNF-α levels and BMI in women. Obese participants had higher hs-CRP levels, and these differences persisted after multivariate adjustment; similarly, positive associations were found between hs-CRP levels and all obesity markers studied. CONCLUSION: Obesity markers are differentially associated with cytokine levels. %Body fat is negatively associated with IL-1ß; BMI (in women) and waist circumference (in men) are associated with TNF-α; all obesity markers are positively associated with hs-CRP.

Associations between alcohol consumption and selected cytokines in a Swiss population-based sample (CoLaus study).

OBJECTIVE: To assess the associations between alcohol consumption and cytokine levels (interleukin-1beta - IL-1ß; interleukin-6 - IL-6 and tumor necrosis factor-α - TNF-α) in a Caucasian population. METHODS: Population sample of 2884 men and 3201 women aged 35-75. Alcohol consumption was categorized as nondrinkers, low (1-6 drinks/week), moderate (7-13/week) and high (14+/week). RESULTS: No difference in IL-1ß levels was found between alcohol consumption categories. Low and moderate alcohol consumption led to lower IL-6 levels: median (interquartile range) 1.47 (0.70-3.51), 1.41 (0.70-3.32), 1.42 (0.66-3.19) and 1.70 (0.83-4.39) pg/ml for nondrinkers, low, moderate and high drinkers, respectively, p<0.01, but this association was no longer significant after multivariate adjustment. Compared to nondrinkers, moderate drinkers had the lowest odds (Odds ratio=0.86 (0.71-1.03)) of being in the highest quartile of IL-6, with a significant (p<0.05) quadratic trend. Low and moderate alcohol consumption led to lower TNF-α levels: 2.92 (1.79-4.63), 2.83 (1.84-4.48), 2.82 (1.76-4.34) and 3.15 (1.91-4.73) pg/ml for nondrinkers, low, moderate and high drinkers, respectively, p<0.02, and this difference remained borderline significant (p=0.06) after multivariate adjustment. Moderate drinkers had a lower odds (0.81 [0.68-0.98]) of being in the highest quartile of TNF-α. No specific alcoholic beverage (wine, beer or spirits) effect was found. CONCLUSIONS: Moderate alcohol consumption is associated with lower levels of IL-6 and (to a lesser degree) of TNF-α, irrespective of the type of alcohol consumed. No association was found between IL-1ß levels and alcohol consumption.

Levels and determinants of inflammatory biomarkers in a Swiss population-based sample (CoLaus study).

OBJECTIVE: to assess the levels and determinants of interleukin (IL)-1ß, IL-6, tumour necrosis factor (TNF)-α and C-reactive protein (CRP) in a healthy Caucasian population. METHODS: population sample of 2884 men and 3201 women aged 35 to 75. IL-1ß, IL-6 and TNF-α were assessed by a multiplexed particle-based flow cytometric assay and CRP by an immunometric assay. RESULTS: Spearman rank correlations between duplicate cytokine measurements (N = 80) ranged between 0.89 and 0.96; intra-class correlation coefficients ranged between 0.94 and 0.97, indicating good reproducibility. Among the 6085 participants, 2289 (37.6%), 451 (7.4%) and 43 (0.7%) had IL-1ß, IL-6 and TNF-α levels below detection limits, respectively. Median (interquartile range) for participants with detectable values were 1.17 (0.48-3.90) pg/ml for IL-1ß; 1.47 (0.71-3.53) pg/ml for IL-6; 2.89 (1.82-4.53) pg/ml for TNF-α and 1.3 (0.6-2.7) ng/ml for CRP. On multivariate analysis, greater age was the only factor inversely associated with IL-1ß levels. Male sex, increased BMI and smoking were associated with greater IL-6 levels, while no relationship was found for age and leisure-time PA. Male sex, greater age, increased BMI and current smoking were associated with greater TNF-α levels, while no relationship was found with leisure-time PA. CRP levels were positively related to age, BMI and smoking, and inversely to male sex and physical activity. CONCLUSION: Population-based levels of several cytokines were established. Increased age and BMI, and to a lesser degree sex and smoking, significantly and differentially impact cytokine levels, while leisure-time physical activity has little effect.

Distinct reactivities of interleukin-4-specific antibodies with recombinant and native canine interleukin-4 in various assays.

Interleukin 4 (IL-4) plays a central role in immune responses to parasites and allergens. IL-4 drives the differentiation of naive T cells into Th2 cells and regulates immunoglobulin class switching to IgE.Little is known about the role of IL-4 in canine allergies and parasite infections. Most of the information derives from measurement of IL-4 mRNA expression in dog tissues, but detection of IL-4 protein has been difficult so far, probably due to low sensitivity of available methods. Antibodies (Ab) specific for canine IL-4 are available from various sources, but these Ab have been produced against recombinant Escherichia coli-expressed canine IL-4 and there is only limited information on their reactivities with native canine IL-4. Therefore, in the present study, we tested six available canine IL-4-specific Ab for their reactivities with recombinant canine IL-4 expressed in E. coli (rec.IL-4) or in mammalian cells (mam.IL-4), and with supernatants from stimulated canine peripheral blood mononuclear cells (PBMCs) using several detection methods, including Western blotting, ELISA, cytokine bead assay, and intracellular IL-4 staining. Additionally, we tested a bovine IL-4-specific antibody that has been previously shown to cross-react with canine IL-4. All tested Ab except anti-bovine IL-4 reacted with rec.IL-4, and most of them reacted with mam.IL-4. However, only the cytokine bead assay was sensitive enough to allow the detection of IL-4 in supernatants of canine PBMCs.

The time of prenatal immune challenge determines the specificity of inflammation-mediated brain and behavioral pathology.

Disturbance to early brain development is implicated in several neuropsychiatric disorders including autism, schizophrenia, and mental retardation. Epidemiological studies have indicated that the risk of developing these disorders is enhanced by prenatal maternal infection, presumably as a result of neurodevelopmental defects triggered by cytokine-related inflammatory events. Here, we demonstrate that the effects of maternal immune challenge between middle and late gestation periods in mice are dissociable in terms of fetal brain cytokine responses to maternal inflammation and the pathological consequences in brain and behavior. Specifically, the relative expression of pro- and anti-inflammatory cytokines in the fetal brains in response to maternal immune challenge may be an important determinant among other developmental factors for the precise pathological profile emerging in later life. Thus, the middle and late gestation periods correspond to two windows with differing vulnerability to adult behavioral dysfunction, brain neuropathology in early adolescence, and of the acute cytokine responses in the fetal brain.